Subject: Re: Digital / Analogue Inverse Filters
From: ChrisAtUpw@.......
Date: Sat, 31 Dec 2005 21:54:13 EST
In a message dated 31/12/2005, Bobhelenmcclure@....... writes:
> If you should still want to try to extend the low frequency response of
> a 4.5Hz geophone, I have implemented a digital inverse filter which can
> operate on PSN Type 4 files. The application is "WQFilter.exe". To download it,
> go to
> http://www.jclahr.com/science/psn/mcclure/wdq_utilities/index.html
> and download the file "seismic_dataq.zip". Extract "WQFilter.exe" and
> "WQFilterHlp.txt" from the zip file.
>
> My personal opinion is that trying to use a 4.5Hz geophone is a pretty
> futile exercise for most amateur seismologists, unless you have an interest in
> local cultural noise or are sitting on top of an active volcano. I use
> moderate period homebuilt sensors for my station. They range in natural period
> from ~5 seconds to ~15 seconds, and for them, the use of "WQFilter" yields event
> waveforms closely resembling those recorded by professional long period
> instruments. I use oversampling and DC amplifiers as well for data acquisition.
Hi Bob,
Thanks for the comments. The negative side of trying to do x10 digital
frequency extension for 4.5 Hz geophones is two fold. The low frequency
signals are inherently small and grainy and most 16 bit ADCs have 2 to 3 bits of
noise on them. This noise can be averaged out by oversampling, as you mention,
but you do need to do it with a processor on the ADC board. You need four times
the number of samples for each bit of ADC noise that you want to average out
-> 64 samples per reading for 3 bits of noise. Normal communication software
does not let you take enough samples quickly enough, using just the main data
logging computer. 24 bit ADCs have built in averaging, but you could still see
1/f noise.
Roberts' original circuit used a two stage low pass filter. This
allowed the very low frequency 1/f circuit noise to be amplified along with the
signal. Changes to the circuit design have removed most of the VLF noise
sensitivity. The noise on the compensated signal is certainly higher than I would get
with a new $1000 1 Hz geophone, but it is still significantly below the
ambient + cultural noise that I experience. This analogue technique is viable and it
can be made to work reasonably well.
I agree with your rather more pessimistic opinion of the digital
technique for 4.5 Hz geophones. If you want a period extension of less than x4, the
digital method should work OK.
I wish everyone a less traumatic year for 2006!
Chris Chapman
<HTML><FONT FACE=3Darial,helvetica><HTML><FONT SIZE=3D2 PTSIZE=3D10 FAMILY=
=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">In a message dated 31/12/2005, Bobh=
elenmcclure@....... writes:<BR>
<BR>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px"> If you shoul=
d still want to try to extend the low frequency response of a 4.5Hz geophone=
, I have implemented a digital inverse filter which can operate on PSN Type=20=
4 files. The application is "WQFilter.exe". To download it, go to <BR>
<A HREF=3D"http://www.jclahr.com/science/psn/mcclure/wdq_utilit=
ies/index.html">http://www.jclahr.com/science/psn/mcclure/wdq_utilities/inde=
x.html</A><BR>
and download the file "seismic_dataq.zip". Extract "WQFilter.exe" and "WQFil=
terHlp.txt" from the zip file.<BR>
<BR>
My personal opinion is that trying to use a 4.5Hz geophon=
e is a pretty futile exercise for most amateur seismologists, unless you hav=
e an interest in local cultural noise or are sitting on top of an active vol=
cano. I use moderate period homebuilt sensors for my station. They range in=20=
natural period from ~5 seconds to ~15 seconds, and for them, the use of "WQF=
ilter" yields event waveforms closely resembling those recorded by professio=
nal long period instruments. I use oversampling and DC amplifiers as well fo=
r data acquisition.</BLOCKQUOTE></FONT><FONT COLOR=3D"#000000" BACK=3D"#fff=
fff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SANS=
SERIF" FACE=3D"Arial" LANG=3D"0"><BR>
</FONT><FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR:=20=
#ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"=
><BR>
Hi Bob,<BR>
<BR>
Thanks for the comments. The negative s=
ide of trying to do x10 digital frequency extension for 4.5 Hz geophones is=20=
two fold. The low frequency signals are inherently small and grainy and most=
16 bit ADCs have 2 to 3 bits of noise on them. This noise can be averaged o=
ut by oversampling, as you mention, but <U>you do need to do it with a proce=
ssor on the ADC board.</U> You need four times the number of samples for eac=
h bit of ADC noise that you want to average out -> 64 samples per reading=
for 3 bits of noise. Normal communication software does not let you take en=
ough samples quickly enough, using just the main data logging computer. 24 b=
it ADCs have built in averaging, but you could still see 1/f noise.<BR>
<BR>
Roberts' original circuit used a two st=
age low pass filter. This allowed the very low frequency 1/f circuit noise t=
o be amplified along with the signal. Changes to the circuit design have rem=
oved most of the VLF noise sensitivity. The noise on the compensated signal=20=
is certainly higher than I would get with a new $1000 1 Hz geophone, but it=20=
is still <U>significantly below</U> the ambient + cultural noise that I expe=
rience. This analogue technique is viable and it can be made to work reasona=
bly well. <BR>
<BR>
I agree with your rather more pessimist=
ic opinion of the digital technique for 4.5 Hz geophones. If you want a peri=
od extension of less than x4, the digital method should work OK.<BR>
<BR>
I wish everyone a less traumatic year f=
or 2006!<BR>
<BR>
Chris Chapman</FONT></HTML>
Subject: from Angel with soem traces.
From: Angel sismos@..............
Date: Mon, 2 Jan 2006 23:28:00 +0000
Happy New year to all!
Quite a bit of shaking in the last few days and I have some jpg's I
would like share and get comment on.
Both the traces are from the experimenta FMES (Dave Nelson)
seismographs. My basic setup is
This instrument has a long period cutoff of 275 seconds. The response
is velocity with the integration below 25 seconds from the hydraulic
damping and from 25 seconds to 275 seconds from electronic integration
One is from the Sandwich Island quake and the other is from the one
just of the coast of Panama a few days ago.
http://volcanbaru.com/nelson/sandwich.jpg
http://volcanbaru.com/nelson/61panama.jpg
In the 6.1 from Panama the inset if has a low pass of 0.3 and I think
that the big dip is real.
The middle of the sandwich trace the period is about 60 seconds. Each
line is 120 minutes.
Larry is there any way to post any ole GIF to the recent event on the
PSN list??
regards to all.
Angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: from Angel with soem traces.
From: Mike Speed mike8s2@.........
Date: Mon, 2 Jan 2006 18:50:32 -0800 (PST)
http://volcanbaru.com/nelson/sandwich.jpg
http://volcanbaru.com/nelson/61panama.jpg
------------------
Hi Angel,
Would you please tell me what software these traces were produced on?
Thanks,
Greg
---------------------------------
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<div id="RTEContent"><blockquote class="replbq" style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;">http://volcanbaru.com/nelson/sandwich.jpg<br>http://volcanbaru.com/nelson/61panama.jpg<br><br><br>------------------<br><br>Hi Angel,<br><br>Would you please tell me what software these traces were produced on?<br><br>Thanks,<br><br>Greg<br></blockquote><br></div><p>
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">Yahoo! Shopping</a>
Subject: Re: from Angel with soem traces.
From: Larry Cochrane lcochrane@..............
Date: Mon, 02 Jan 2006 23:34:32 -0800
Happy New Years Everyone,
Angel Wrote:
> Larry is there any way to post any ole GIF to the recent event on the
> PSN list??
No, sorry all attachments are blocked by my mail server. You will need to place them
on a web server and send out the URL.
Regards,
Larry Cochrane
Redwood City, PSN
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re[2]: from Angel with some traces.
From: Angel sismos@..............
Date: Tue, 3 Jan 2006 09:36:52 +0000
Hello Larry,
What meant to say was "is there any way to post any ole GIF to the recent
event list on the PSN page?
I understand the list does not accept attachments?
Angel
Tuesday, January 3, 2006, 7:34:32 AM, you wrote:
>> Larry is there any way to post any ole GIF to the recent event on the
>> PSN list??
> No, sorry all attachments are blocked by my mail server. You will need to place them
> on a web server and send out the URL.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Swarm software
From: Angel sismos@..............
Date: Tue, 3 Jan 2006 09:47:07 +0000
Hello Greg,
These traces were produced on Swarm a program written by Dan Cervalli
and used USGS Volcano Observatories. The software is freely available
and reads data from Earthworm waveservers or from SEED files. It gets its
data over TCP/IP.
So Dave in LA can see in real time the traces from my seismograph here
in Panama.
Larry's WinSDR boards now communicate with Earthworm so in theory a
person could run WinSDR and turn the data sever, I could capture here
and see it with a small delay and display it in Swarm.
Angel
Tuesday, January 3, 2006, 2:50:32 AM, you wrote:
> http://volcanbaru.com/nelson/sandwich.jpg
> http://volcanbaru.com/nelson/61panama.jpg
> ------------------
> Hi Angel,
> Would you please tell me what software these traces were produced on?
> Thanks,
> Greg
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: from Angel with some traces.
From: Larry Cochrane lcochrane@..............
Date: Tue, 03 Jan 2006 19:36:47 -0800
Hi Angel,
To archive event files on my system you need to send the file in PSN format to the
following email address event@............... GIF files will not be excepted since
the event file must be in the PSN binary format.
Regards,
Larry Cochrane
Redwood City, PSN
Angel wrote:
> Hello Larry,
>
> What meant to say was "is there any way to post any ole GIF to the recent
> event list on the PSN page?
>
> I understand the list does not accept attachments?
>
> Angel
>
>
> Tuesday, January 3, 2006, 7:34:32 AM, you wrote:
>
>>> Larry is there any way to post any ole GIF to the recent event on the
>>> PSN list??
>
>> No, sorry all attachments are blocked by my mail server. You will need to place them
>> on a web server and send out the URL.
>
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with
> the body of the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Swarm software
From: Larry Cochrane lcochrane@..............
Date: Tue, 03 Jan 2006 23:26:14 -0800
Hi Everyone,
Angel wrote:
> Larry's WinSDR boards now communicate with Earthworm so in theory a
> person could run WinSDR and turn the data sever, I could capture here
> and see it with a small delay and display it in Swarm.
More information on my Earthworm modules can be found here
http://www.seismicnet.com/software.html#Earthworm.
Regards,
Larry Cochrane
Redwood City, PSN
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Gulf Of California on a seismic Detector
From: "Geoff" gmvoeth@...........
Date: Wed, 4 Jan 2006 02:30:43 -0700
Hello Folks;
http://users.isp.com/gmvoethb293690/B.MOV
This is a MOV file about 3.11MB 15 seconds
of video showing my seismic detector in action
during the recent quake in the Gulf of California.
http://earthquake.usgs.gov/recenteqsww/Quakes/ushmal.htm
I do not know if you will be able to download
directly from my website but I encourage you
to try and tell me if you were successful or not.
If you can not download I will seek
another site that allows such things.
I am not selling anything here just want to share
what it looks like. The buzzer is about 4000Hz
but no audio in this MOV file.
Comments are welcome.
Sincerely;
Geoff
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Gulf Of California on a seismic Detector
From: Angel sismos@..............
Date: Wed, 4 Jan 2006 10:00:51 +0000
Hello Geoff,
What a great seismoscope. My very first seismic detector was a
modified car alarm with a weight on string and all it did was make a
noise when someting happened.
Nice movie, I saw it with Quicktime.
When I clicked on the link I assumed I was going to see a Lehman
jumping around or falling over.
Here is how it us showing up on my FMES, the event is still going.
The traces are one hour long.
http://volcanbaru.com/nelson/mexico_1_4.jpg
Angel
Wednesday, January 4, 2006, 9:30:43 AM, you wrote:
> Hello Folks;
> http://users.isp.com/gmvoethb293690/B.MOV
> This is a MOV file about 3.11MB 15 seconds
> of video showing my seismic detector in action
> during the recent quake in the Gulf of California.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Gulf Of California on a seismic Detector
From: Kevin McCue asc@...............
Date: Wed, 4 Jan 2006 21:08:03 +1100
Geoff
The movie worked for me. My a2d had trouble with the format but the
flickering red neon was a nice extra touch (bit like my sleeping Mac).
Good to see you guys get excited about regional earthquakes instead of
teles. I run an accelerograph network in and around Canberra, Australia
just for the local and regional earthquakes tho it occasionally picks
up large deep Fiji events which are good to check the station polarity.
Thanks for the movie
Cheers
Kevin
On 04/01/2006, at 8:30 PM, Geoff wrote:
>
> I do not know if you will be able to download
> directly from my website but I encourage you
> to try and tell me if you were successful or not.
Kevin McCue
Director
Australian Seismological Centre
PO Box 324 Jamison Centre
ACT 2614
Australia
ph: 61 (0)2 6251 1291
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Gulf Of California on a seismic Detector
From: ian ian@...........
Date: Wed, 04 Jan 2006 10:19:34 +0000
I saw the mov okay with quicktime. Food for thought, installing a camera.
Unfortunately I've just realised that my Lehman oscillates when it is
cold. The temperature here declined yesterday afternoon and the thing
started oscillating. It's -1C at the moment and the graph looks like I
spilled red ink all over it ( http://www.iasmith.com/realtime.htm ) .
You can, though, see the California quake sticking out above it all,
like the Golden Gate bridge above the fog. When the quake stops I'll
turn it into a psn file, which should clean the red ink off of it.
I don't rate my chances very highly of finding out what is causing it to
oscillate...
Ian Smith
Kevin McCue wrote:
> Geoff
> The movie worked for me. My a2d had trouble with the format but the
> flickering red neon was a nice extra touch (bit like my sleeping Mac).
> Good to see you guys get excited about regional earthquakes instead of
> teles. I run an accelerograph network in and around Canberra,
> Australia just for the local and regional earthquakes tho it
> occasionally picks up large deep Fiji events which are good to check
> the station polarity.
> Thanks for the movie
> Cheers
> Kevin
>
>
> On 04/01/2006, at 8:30 PM, Geoff wrote:
>
>>
>> I do not know if you will be able to download
>> directly from my website but I encourage you
>> to try and tell me if you were successful or not.
>
>
> Kevin McCue
> Director
> Australian Seismological Centre
> PO Box 324 Jamison Centre
> ACT 2614
> Australia
> ph: 61 (0)2 6251 1291
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with the body of
> the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Gulf Of California on a seismic Detector
From: ChrisAtUpw@.......
Date: Wed, 4 Jan 2006 08:59:08 EST
In a message dated 04/01/2006, ian@........... writes:
Unfortunately I've just realised that my Lehman oscillates when it is
cold. The temperature here declined yesterday afternoon and the thing
started oscillating. It's -1C at the moment and the graph looks like I
spilled red ink all over it ( http://www.iasmith.com/realtime.htm ) .
I don't rate my chances very highly of finding out what is causing it to
oscillate.
Ian Smith
Hi Ian,
The energy has to be coming from somewhere! If you only see oscillations
when the outside air is cold, this is likely to be the driving source.
Do you have any photos of the Lehman? Is it housed in it's own sealed
box? Does the box have an internal top heater? What suspension system are you
using? What damping system do you use?
One of the ways you can get 'oscillations' from a Lehman, is if the box
and internal instrument is warmer than the outside air, but there is no top
heater inside the box to maintain a stable vertical temperature gradient.
Rolls of cooler air break off the inside top / sides of the box when the thermal
gradient gets big enough and then interact with the boom.
You only need a few watts of power into Al housed power resistors bolted
to a 1/16" Al top plate inside the top of case.
Is the top of the box completely sealed? How is it 'sealed' to the
floor? Can drafts / air currents get in? One way to 'semi seal' the housing is to
surround the box with a 2" high wood rectangle on the floor and fill the gap
with dry sand.
Worth trying?
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>In a message dated 04/01/2006, ian@........... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20
size=3D2>Unfortunately I've just realised that my Lehman oscillates when i=
t is=20
<BR>cold. The temperature here declined yesterday afternoon and the t=
hing=20
<BR>started oscillating. </FONT><FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>It's -1C=20
at the moment and the graph looks like I <BR>spilled red ink all over it (=
=20
http://www.iasmith.com/realtime.htm ) . <BR><BR>I don't rate my chan=
ces=20
very highly of finding out what is causing it to <BR>oscillate.<BR><BR>Ian=
=20
Smith<BR></FONT></BLOCKQUOTE>
<DIV></DIV>
<DIV>Hi Ian,</DIV>
<DIV> </DIV>
<DIV> The energy has to be coming from somewhere! If=20=
you=20
only see oscillations when the outside air is cold, this is likely to be the=
=20
driving source.</DIV>
<DIV> </DIV>
<DIV> Do you have any photos of the Lehman? Is it hou=
sed=20
in it's own sealed box? Does the box have an internal top heater? What=20
suspension system are you using? What damping system do you use?</DIV>
<DIV> </DIV>
<DIV> One of the ways you can get 'oscillations' from=
a=20
Lehman, is if the box and internal instrument is warmer than the=20
outside air, but there is no top heater inside the box to maintain a stable=20
vertical temperature gradient. Rolls of cooler air break off the inside=
top=20
/ sides of the box when the thermal gradient gets big enough and then intera=
ct=20
with the boom. </DIV>
<DIV> </DIV>
<DIV> You only need a few watts of power into Al hous=
ed=20
power resistors bolted to a 1/16" Al top plate inside the top of case.</DIV>
<DIV> </DIV>
<DIV> Is the top of the box completely sealed? How is=
it=20
'sealed' to the floor? Can drafts / air currents get in? One way to 'semi se=
al'=20
the housing is to surround the box with a 2" high wood rectangle on the=
=20
floor and fill the gap with dry sand.</DIV>
<DIV> </DIV>
<DIV> Worth trying?</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: ebay auction
From: Bob Barns royb1@...........
Date: Wed, 04 Jan 2006 09:38:02 -0500
seismometer, short-period AKA shot-pot for oil survey
Item number: 7578330430
ends Jan 10
Bob
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Gulf Of California on a seismic Detector
From: ian ian@...........
Date: Wed, 04 Jan 2006 14:53:43 +0000
Hi,
thanks for the reply, I'm still working through it! In the meantime, I
don't have any good pictures but here is a drawing of the housing that I
just quickly sketched: http://www.iasmith.com/housing.jpg . Let me know
if the link doesn't work.
I have no heater. I had hoped to avoid one but sounds like I need to
consider it.
It's just the usual wire diagonal from the top of the boom. The pivot
consists of 2 ball bearings. The boom has a flat metal plate on the end
which pivots on them. I have magnetic damping but it is not properly
set up at present. The system is currently under damped. The weight on
the end of the boom is copper and this doubles as the magnetic damping.
The internal may well be warmer than the outside (a thermometer would be
nice addition too!). In theory the box is sealed but nothing is perfect...
Perhaps a car battery to power the resistors would solve it. I'll need
to wait till I go back to work next week to get some of those heatsunk
resistors.
Thanks
Ian
ChrisAtUpw@....... wrote:
> In a message dated 04/01/2006, ian@........... writes:
>
> Unfortunately I've just realised that my Lehman oscillates when it is
> cold. The temperature here declined yesterday afternoon and the thing
> started oscillating. It's -1C at the moment and the graph looks
> like I
> spilled red ink all over it ( http://www.iasmith.com/realtime.htm
> ) .
>
> I don't rate my chances very highly of finding out what is causing
> it to
> oscillate.
>
> Ian Smith
>
> Hi Ian,
>
> The energy has to be coming from somewhere! If you only see
> oscillations when the outside air is cold, this is likely to be the
> driving source.
>
> Do you have any photos of the Lehman? Is it housed in it's own
> sealed box? Does the box have an internal top heater? What suspension
> system are you using? What damping system do you use?
>
> One of the ways you can get 'oscillations' from a Lehman, is if
> the box and internal instrument is warmer than the outside air, but
> there is no top heater inside the box to maintain a stable vertical
> temperature gradient. Rolls of cooler air break off the inside top /
> sides of the box when the thermal gradient gets big enough and then
> interact with the boom.
>
> You only need a few watts of power into Al housed power resistors
> bolted to a 1/16" Al top plate inside the top of case.
>
> Is the top of the box completely sealed? How is it 'sealed' to the
> floor? Can drafts / air currents get in? One way to 'semi seal' the
> housing is to surround the box with a 2" high wood rectangle on the
> floor and fill the gap with dry sand.
>
> Worth trying?
>
> Regards,
>
> Chris Chapman
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
Hi,<br>
<br>
thanks for the reply, I'm still working through it! In the meantime, I
don't have any good pictures but here is a drawing of the housing that
I just quickly sketched: <a class="moz-txt-link-freetext" href="http://www.iasmith.com/housing.jpg">http://www.iasmith.com/housing.jpg</a> . Let me
know if the link doesn't work.<br>
<br>
I have no heater. I had hoped to avoid one but sounds like I need to
consider it.<br>
<br>
It's just the usual wire diagonal from the top of the boom. The pivot
consists of 2 ball bearings. The boom has a flat metal plate on the
end which pivots on them. I have magnetic damping but it is not
properly set up at present. The system is currently under damped. The
weight on the end of the boom is copper and this doubles as the
magnetic damping.<br>
<br>
The internal may well be warmer than the outside (a thermometer would
be nice addition too!). In theory the box is sealed but nothing is
perfect...<br>
<br>
Perhaps a car battery to power the resistors would solve it. I'll need
to wait till I go back to work next week to get some of those heatsunk
resistors.<br>
<br>
Thanks<br>
<br>
Ian<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:ChrisAtUpw@.......">ChrisAtUpw@.......</a> wrote:<br>
<blockquote cite="mid24a.4afa8d7.30ed2eac@......." type="cite">
<meta http-equiv="Content-Type" content="text/html; ">
<meta content="MSHTML 6.00.2900.2802" name="GENERATOR">
<font id="role_document" color="#000000" face="Arial" size="2">
<div>In a message dated 04/01/2006, <a class="moz-txt-link-abbreviated" href="mailto:ian@...........">ian@...........</a> writes:</div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">Unfortunately I've just realised that my Lehman oscillates
when it is <br>
cold. The temperature here declined yesterday afternoon and the thing <br>
started oscillating. </font><font style="background-color: transparent;"
color="#000000" face="Arial" size="2">It's -1C at the moment and the
graph looks like I <br>
spilled red ink all over it ( <a class="moz-txt-link-freetext" href="http://www.iasmith.com/realtime.htm">http://www.iasmith.com/realtime.htm</a> ) . <br>
<br>
I don't rate my chances very highly of finding out what is causing it
to <br>
oscillate.<br>
<br>
Ian Smith<br>
</font></blockquote>
<div>Hi Ian,</div>
<div> </div>
<div> The energy has to be coming from somewhere! If you only see
oscillations when the outside air is cold, this is likely to be the
driving source.</div>
<div> </div>
<div> Do you have any photos of the Lehman? Is it housed in it's
own sealed box? Does the box have an internal top heater? What
suspension system are you using? What damping system do you use?</div>
<div> </div>
<div> One of the ways you can get 'oscillations' from a Lehman, is
if the box and internal instrument is warmer than the outside air, but
there is no top heater inside the box to maintain a stable vertical
temperature gradient. Rolls of cooler air break off the inside top /
sides of the box when the thermal gradient gets big enough and then
interact with the boom. </div>
<div> </div>
<div> You only need a few watts of power into Al housed power
resistors bolted to a 1/16" Al top plate inside the top of case.</div>
<div> </div>
<div> Is the top of the box completely sealed? How is it 'sealed'
to the floor? Can drafts / air currents get in? One way to 'semi seal'
the housing is to surround the box with a 2" high wood rectangle on the
floor and fill the gap with dry sand.</div>
<div> </div>
<div> Worth trying?</div>
<div> </div>
<div> Regards,</div>
<div> </div>
<div> Chris Chapman</div>
</font></blockquote>
</body>
</html>
Subject: Re: Gulf Of California on a seismic Detector
From: ian ian@...........
Date: Wed, 04 Jan 2006 15:47:42 +0000
I've just introduced an angle-pois light with an energy saving 11 Watt
bulb into the box as an experiment and temporary measure. It may take
an hour or two to have an effect...
Ian Smith
ChrisAtUpw@....... wrote:
> In a message dated 04/01/2006, ian@........... writes:
>
> Unfortunately I've just realised that my Lehman oscillates when it is
> cold. The temperature here declined yesterday afternoon and the thing
> started oscillating. It's -1C at the moment and the graph looks
> like I
> spilled red ink all over it ( http://www.iasmith.com/realtime.htm
> ) .
>
> I don't rate my chances very highly of finding out what is causing
> it to
> oscillate.
>
> Ian Smith
>
> Hi Ian,
>
> The energy has to be coming from somewhere! If you only see
> oscillations when the outside air is cold, this is likely to be the
> driving source.
>
> Do you have any photos of the Lehman? Is it housed in it's own
> sealed box? Does the box have an internal top heater? What suspension
> system are you using? What damping system do you use?
>
> One of the ways you can get 'oscillations' from a Lehman, is if
> the box and internal instrument is warmer than the outside air, but
> there is no top heater inside the box to maintain a stable vertical
> temperature gradient. Rolls of cooler air break off the inside top /
> sides of the box when the thermal gradient gets big enough and then
> interact with the boom.
>
> You only need a few watts of power into Al housed power resistors
> bolted to a 1/16" Al top plate inside the top of case.
>
> Is the top of the box completely sealed? How is it 'sealed' to the
> floor? Can drafts / air currents get in? One way to 'semi seal' the
> housing is to surround the box with a 2" high wood rectangle on the
> floor and fill the gap with dry sand.
>
> Worth trying?
>
> Regards,
>
> Chris Chapman
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
I've just introduced an angle-pois light with an energy saving 11 Watt
bulb into the box as an experiment and temporary measure. It may take
an hour or two to have an effect...<br>
<br>
Ian Smith<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:ChrisAtUpw@.......">ChrisAtUpw@.......</a> wrote:<br>
<blockquote cite="mid24a.4afa8d7.30ed2eac@......." type="cite">
<meta http-equiv="Content-Type" content="text/html; ">
<meta content="MSHTML 6.00.2900.2802" name="GENERATOR">
<font id="role_document" color="#000000" face="Arial" size="2">
<div>In a message dated 04/01/2006, <a class="moz-txt-link-abbreviated" href="mailto:ian@...........">ian@...........</a> writes:</div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">Unfortunately I've just realised that my Lehman oscillates
when it is <br>
cold. The temperature here declined yesterday afternoon and the thing <br>
started oscillating. </font><font style="background-color: transparent;"
color="#000000" face="Arial" size="2">It's -1C at the moment and the
graph looks like I <br>
spilled red ink all over it ( <a class="moz-txt-link-freetext" href="http://www.iasmith.com/realtime.htm">http://www.iasmith.com/realtime.htm</a> ) . <br>
<br>
I don't rate my chances very highly of finding out what is causing it
to <br>
oscillate.<br>
<br>
Ian Smith<br>
</font></blockquote>
<div>Hi Ian,</div>
<div> </div>
<div> The energy has to be coming from somewhere! If you only see
oscillations when the outside air is cold, this is likely to be the
driving source.</div>
<div> </div>
<div> Do you have any photos of the Lehman? Is it housed in it's
own sealed box? Does the box have an internal top heater? What
suspension system are you using? What damping system do you use?</div>
<div> </div>
<div> One of the ways you can get 'oscillations' from a Lehman, is
if the box and internal instrument is warmer than the outside air, but
there is no top heater inside the box to maintain a stable vertical
temperature gradient. Rolls of cooler air break off the inside top /
sides of the box when the thermal gradient gets big enough and then
interact with the boom. </div>
<div> </div>
<div> You only need a few watts of power into Al housed power
resistors bolted to a 1/16" Al top plate inside the top of case.</div>
<div> </div>
<div> Is the top of the box completely sealed? How is it 'sealed'
to the floor? Can drafts / air currents get in? One way to 'semi seal'
the housing is to surround the box with a 2" high wood rectangle on the
floor and fill the gap with dry sand.</div>
<div> </div>
<div> Worth trying?</div>
<div> </div>
<div> Regards,</div>
<div> </div>
<div> Chris Chapman</div>
</font></blockquote>
</body>
</html>
Subject: Re: Gulf Of California on a seismic Detector
From: ChrisAtUpw@.......
Date: Wed, 4 Jan 2006 11:25:14 EST
In a message dated 04/01/2006, ian@........... writes:
Hi,
thanks for the reply, I'm still working through it! In the meantime, I
don't have any good pictures but here is a drawing of the housing that I just
quickly sketched: _http://www.iasmith.com/housing.jpg_
(http://www.iasmith.com/housing.jpg) .
I have no heater. I had hoped to avoid one but sounds like I need to
consider it.
Hi Ian,
It is not very easy to seal the open top of a box like this. You might
be able to do it with foam strip around the edge or the bottom of the
thermawall cavity board plug.
I would be inclined to get a big sheet of polythene (~9ft square damp
proof membrane?) from a builder's merchant, drape it over the top and to the
ground all around the box, fold in the corners and secure them with tape or
string. This is in place of the multi layer paper sheet. Alternatively, you
could use gaffer tape either to seal the paper to the sides of the box, or tape
the existing top sheet to a surrounding paper wrap. Then put the sarking board
lid on the box.
I suspect that you will need some form of heating inside the case. You
will probably need at least 10 watts. Power resistors are preferable to
filament bulbs, which tend to attract insects. Can you 'acquire' a large cardboard
box to put over the top of the existing case?
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>In a message dated 04/01/2006, ian@........... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20
size=3D2>Hi,<BR>thanks for the reply, I'm still working through it! =20=
In the=20
meantime, I don't have any good pictures but here is a drawing of the hous=
ing=20
that I just quickly sketched: <A class=3Dmoz-txt-link-freetext=20
title=3Dhttp://www.iasmith.com/housing.jpg=20
href=3D"http://www.iasmith.com/housing.jpg">http://www.iasmith.com/housing=
..jpg</A>=20
. <BR><BR>I have no heater. I had hoped to avoid one but sounds=
=20
like I need to consider it.</FONT></BLOCKQUOTE>
<DIV>Hi Ian,</DIV>
<DIV> </DIV>
<DIV> It is not very easy to seal the open top of a b=
ox=20
like this. You might be able to do it with foam strip around the edge or the=
=20
bottom of the thermawall cavity board plug.</DIV>
<DIV> </DIV>
<DIV></DIV>
<DIV> I would be inclined to get a big sheet of polyt=
hene=20
(~9ft square damp proof membrane?) from a builder's merchant, drape it over=20=
the=20
top and to the ground all around the box, fold in the corners and secure the=
m=20
with tape or string. This is in place of the multi layer paper sheet.=20
Alternatively, you could use gaffer tape either to seal the paper to th=
e=20
sides of the box, or tape the existing top sheet to a surrounding paper wrap=
..=20
Then put the sarking board lid on the box.</DIV>
<DIV> </DIV>
<DIV> I suspect that you will need some form of heati=
ng=20
inside the case. You will probably need at least 10 watts. Power resistors a=
re=20
preferable to filament bulbs, which tend to attract insects. Can you 'acquir=
e' a=20
large cardboard box to put over the top of the existing case?</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Gulf Of California on a seismic Detector
From: ian ian@...........
Date: Wed, 04 Jan 2006 16:51:01 +0000
Hi,
thanks for the suggestions. I won't be able to get to the shops until
next week. I do have an old car lying around the back and I could take
out some of the bulb fittings from that and run 12 volts to the box. I
think the box is light tight (I'll check tonight) so probably okay for
insects.
The temperature is about to drop in the next hour or two so I'll see how
effective a heat source is from the temporary light I put in.
I still access the box every few days as I try to find the optimum
settings and I've still to tackle the damping issue, so it has to be
reasonably easy to get in and out of. So the plastic sheet sounds like
the best solution.
The good news is that this morning's Calafornia 6.7 quake saturated my
A/D. Good as in a quake 5000 miles away did that. If I can get the
oscillations down then I should be able to resolve 4.x teleseismic
quakes. One can dream!
Thanks again
Ian
ChrisAtUpw@....... wrote:
> In a message dated 04/01/2006, ian@........... writes:
>
> Hi,
> thanks for the reply, I'm still working through it! In the
> meantime, I don't have any good pictures but here is a drawing of
> the housing that I just quickly sketched:
> http://www.iasmith.com/housing.jpg .
>
> I have no heater. I had hoped to avoid one but sounds like I need
> to consider it.
>
> Hi Ian,
>
> It is not very easy to seal the open top of a box like this. You
> might be able to do it with foam strip around the edge or the bottom
> of the thermawall cavity board plug.
>
> I would be inclined to get a big sheet of polythene (~9ft square
> damp proof membrane?) from a builder's merchant, drape it over the top
> and to the ground all around the box, fold in the corners and secure
> them with tape or string. This is in place of the multi layer paper
> sheet. Alternatively, you could use gaffer tape either to seal the
> paper to the sides of the box, or tape the existing top sheet to a
> surrounding paper wrap. Then put the sarking board lid on the box.
>
> I suspect that you will need some form of heating inside the case.
> You will probably need at least 10 watts. Power resistors are
> preferable to filament bulbs, which tend to attract insects. Can you
> 'acquire' a large cardboard box to put over the top of the existing case?
>
> Regards,
>
> Chris Chapman
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
Hi,<br>
<br>
thanks for the suggestions. I won't be able to get to the shops until
next week. I do have an old car lying around the back and I could take
out some of the bulb fittings from that and run 12 volts to the box. I
think the box is light tight (I'll check tonight) so probably okay for
insects. <br>
<br>
The temperature is about to drop in the next hour or two so I'll see
how effective a heat source is from the temporary light I put in.<br>
<br>
I still access the box every few days as I try to find the optimum
settings and I've still to tackle the damping issue, so it has to be
reasonably easy to get in and out of. So the plastic sheet sounds like
the best solution.<br>
<br>
The good news is that this morning's Calafornia 6.7 quake saturated my
A/D. Good as in a quake 5000 miles away did that. If I can get the
oscillations down then I should be able to resolve 4.x teleseismic
quakes. One can dream!<br>
<br>
Thanks again<br>
<br>
Ian<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:ChrisAtUpw@.......">ChrisAtUpw@.......</a> wrote:<br>
<blockquote cite="mid15.52fd1193.30ed50ea@......." type="cite">
<meta http-equiv="Content-Type" content="text/html; ">
<meta content="MSHTML 6.00.2900.2802" name="GENERATOR">
<font id="role_document" color="#000000" face="Arial" size="2">
<div>In a message dated 04/01/2006, <a class="moz-txt-link-abbreviated" href="mailto:ian@...........">ian@...........</a> writes:</div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">Hi,<br>
thanks for the reply, I'm still working through it! In the meantime, I
don't have any good pictures but here is a drawing of the housing that
I just quickly sketched: <a class="moz-txt-link-freetext"
title="http://www.iasmith.com/housing.jpg"
href="http://www.iasmith.com/housing.jpg">http://www.iasmith.com/housing.jpg</a>
.. <br>
<br>
I have no heater. I had hoped to avoid one but sounds like I need to
consider it.</font></blockquote>
<div>Hi Ian,</div>
<div> </div>
<div> It is not very easy to seal the open top of a box like this.
You might be able to do it with foam strip around the edge or the
bottom of the thermawall cavity board plug.</div>
<div> </div>
<div> I would be inclined to get a big sheet of polythene (~9ft
square damp proof membrane?) from a builder's merchant, drape it over
the top and to the ground all around the box, fold in the corners and
secure them with tape or string. This is in place of the multi layer
paper sheet. Alternatively, you could use gaffer tape either to seal
the paper to the sides of the box, or tape the existing top sheet to a
surrounding paper wrap. Then put the sarking board lid on the box.</div>
<div> </div>
<div> I suspect that you will need some form of heating inside the
case. You will probably need at least 10 watts. Power resistors are
preferable to filament bulbs, which tend to attract insects. Can you
'acquire' a large cardboard box to put over the top of the existing
case?</div>
<div> </div>
<div> Regards,</div>
<div> </div>
<div> Chris Chapman</div>
</font></blockquote>
</body>
</html>
Subject: Re: Gulf Of California on a seismic Detector
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Wed, 04 Jan 2006 17:07:50 +0000
Hi Geoff and others on Psn postlist.
Thanks for the mov file. I will check it out soon. According to
emsc-csem the earthquake in gulf of Mexico was 6,8Ms in size. For those
who don't know what emsc-csem is, you can check there page here
http://www.emsc-csem.org/
I have been looking for news about this earthquake, but i haven't found
anything at the moment. But i excpect that aftershocks have been
detected yet, at least one that is 4,7 M, but there are problay alot
more happening then i see on the emsc-csem page.
The pre-quakes prior to the 6,8Ms one was a earthquake that was 4,9mb
and a earthquake that was 4,6 M, there is also a time gap of few hours
from the first earthquake happens until the big one hits. I assume that
there is going to be more earthquakes in that area for next few days or
weeks.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Gulf Of California on a seismic Detector
From: John or Jan Lahr JohnJan@........
Date: Wed, 04 Jan 2006 09:14:12 -0800
Hi All,
Quite a few of the educational seismic stations provided by IRIS
recorded the Gulf event. Take a look
here during then next 16 hours or so while the Gulf trace is still visible:
http://jclahr.com/science/psn/as1/heli/allas1.php
The AS1 instruments are simple, not too expensive ($550), and good
for education because they
look like a diagram of a seismic system. For more details see:
http://jclahr.com/science/psn/as1/
The
IRIS Seismographs In Schools Program
is described here:
http://www.iris.washington.edu/edu/AS1.htm
If anyone lives near one of the schools with a system, I'm sure the teachers
involved would love to talk to you about seismic recording, and it's possible
that you could give them a hand with any recording problems.
There is a listing of these and other educational stations here:
http://www.scieds.com/spinet/spinet_stations.php
Cheers,
John
##################################/ John C. Lahr
#################################/ Emeritus Seismologist
################################/ U.S. Geological Survey
===========================/ Geologic Hazards Team
##############################/ Golden, Colorado
#############################//##############################
############################//###############################
PO Box 548 /################################
Corvallis, Oregon 97339 /##################################
Phone: (541) 758-2699 /=============================
Cell: (541) 740-4844 /###################################
Fax: (928) 569-0113 /##################################
jjpub@........ /####################################
http://jclahr.com/science/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: GULF OF CALIFORNIA INFRASOUND DETECTION
From: AHrubetz@.......
Date: Wed, 4 Jan 2006 12:27:55 EST
Hello All,
I have been recording with an infrasound detector on loan from the
Geophysical Dept. of Southern Methodist University for several months now. The 6.7
Gulf of California quake is the first event I've been able to correlate with a
quake. (see my PSN postings).
The local infrasound signal recorded here in Dallas was not caused by a
teleatmospheric pressure wave from the quake, but was generated by the seismic
surface wave coupling to the atmosphere at my location, causing corresponding
vertical movements of the infrasound detector diaphram which in turn disturbed
the local atmosphere. The infrasound disturbance was initiated at the same
time as the surface waves arrived, and lasted about 15 minutes, the same
duration as the surface waves. There was no indication of a teleatmospheric
acoustical pressure wave, which would have arrived at my station about 1.3 hours
after initiation of the quake.
I found this event very interesing and am passing the info along for your
possible interest.
Regards,
Al Hrubetz
Dallas, Texas
<HTML><HEAD>
<META charset=3DUS-ASCII http-equiv=3DContent-Type content=3D"text/html; cha=
rset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY style=3D"FONT-SIZE: 12pt; FONT-FAMILY: Arial; BACKGROUND-COLOR: #fffff=
f">
<DIV><STRONG>Hello All,</STRONG></DIV>
<DIV><STRONG> I have been recording with an infrasound det=
ector on loan from the Geophysical Dept. of Southern Methodist University fo=
r several months now. The 6.7 Gulf of California quake is the first ev=
ent I've been able to correlate with a quake. (see my PSN postings).</=
STRONG></DIV>
<DIV><STRONG> The local infrasound signal recorded here in=
Dallas was not caused by a teleatmospheric pressure wave from the quake, bu=
t was generated by the seismic surface wave coupling to the atmosphere at my=
location, causing corresponding vertical movements of the infrasound detect=
or diaphram which in turn disturbed the local atmosphere. The inf=
rasound disturbance was initiated at the same time as the surface waves arri=
ved, and lasted about 15 minutes, the same duration as the surface waves.&nb=
sp; There was no indication of a teleatmospheric acoustical pressure wave, w=
hich would have arrived at my station about 1.3 hours after initiation of th=
e quake.</STRONG></DIV>
<DIV><STRONG> I found this event very interesing and am pa=
ssing the info along for your possible interest.</STRONG></DIV>
<DIV><STRONG> Regards,</STRONG></DIV>
<DIV><STRONG> Al Hrubetz</STRONG></DIV>
<DIV><STRONG> Dallas, Texas</STRONG></DIV></BODY></HTML>
Subject: Re: GULF OF CALIFORNIA INFRASOUND DETECTION
From: ChrisAtUpw@.......
Date: Wed, 4 Jan 2006 12:50:55 EST
In a message dated 04/01/2006, AHrubetz@....... writes:
Hello All,
I have been recording with an infrasound detector on loan from the
Geophysical Dept. of Southern Methodist University for several months now. The
6.7 Gulf of California quake is the first event I've been able to correlate
with a quake. (see my PSN postings).
The local infrasound signal recorded here in Dallas was not caused by a
teleatmospheric pressure wave from the quake, but was generated by the
seismic surface wave coupling to the atmosphere at my location
Hi Al,
Do you have any specification / characteristics for your Infrasound
detector setup, please? What sort of array do you use to connect to the
atmosphere, please?
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 04/01/2006, AHrubetz@....... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D3>
<DIV><FONT size=3D2>Hello All,</FONT></DIV>
<DIV><FONT size=3D2> I have been recording with an infra=
sound=20
detector on loan from the Geophysical Dept. of Southern Methodist Universi=
ty=20
for several months now. The 6.7 Gulf of California quake is the firs=
t=20
event I've been able to correlate with a quake. (see my PSN=20
postings).</FONT></DIV>
<DIV><FONT size=3D2> The local infrasound signal recorde=
d here=20
in Dallas was not caused by a teleatmospheric pressure wave from the quake=
,=20
but was generated by the seismic surface wave coupling to the atmosphere a=
t my=20
location</FONT></DIV></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Al,</DIV>
<DIV> </DIV>
<DIV> Do you have any specification / characteristics=
for=20
your Infrasound detector setup, please? What sort of array do you use t=
o=20
connect to the atmosphere, please?</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: [Fwd: Your New PSN Event File]
From: ian ian@...........
Date: Wed, 04 Jan 2006 20:16:39 +0000
I posted my event file for the California quake earlier today. Does the
acknowledgment email mean that it has been filed 64 years in the
future? If so, what went wrong?
Thanks
Ian Smith
-------- Original Message --------
Subject: Your New PSN Event File
Date: Wed, 04 Jan 06 09:47:51 -0800
From: event_processor@..............
To: ian <ian@...........>
Your event file has been processed.
Event File Upload Status:
Input Name Archive Path & Name Status
060104.082516.hd0 \quakes\7001\700101.001537.hd0.psn Upload OK
Thanks for the upload!
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
I posted my event file for the California quake earlier today. Does
the acknowledgment email mean that it has been filed 64 years in the
future? If so, what went wrong?<br>
<br>
Thanks<br>
<br>
Ian Smith<br>
<br>
-------- Original Message --------
<table border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<th align="right" nowrap="nowrap" valign="baseline">Subject: </th>
<td>Your New PSN Event File</td>
</tr>
<tr>
<th align="right" nowrap="nowrap" valign="baseline">Date: </th>
<td>Wed, 04 Jan 06 09:47:51 -0800</td>
</tr>
<tr>
<th align="right" nowrap="nowrap" valign="baseline">From: </th>
<td><a class="moz-txt-link-abbreviated" href="mailto:event_processor@..............">event_processor@..............</a></td>
</tr>
<tr>
<th align="right" nowrap="nowrap" valign="baseline">To: </th>
<td>ian <a class="moz-txt-link-rfc2396E" href="mailto:ian@..........."><ian@...........></a></td>
</tr>
</tbody>
</table>
<br>
<br>
<pre>Your event file has been processed.
Event File Upload Status:
Input Name Archive Path & Name Status
060104.082516.hd0 \quakes\7001\700101.001537.hd0.psn Upload OK
Thanks for the upload!
</pre>
</body>
</html>
Subject: Re: GULF OF CALIFORNIA INFRASOUND DETECTION
From: AHrubetz@.......
Date: Wed, 4 Jan 2006 19:39:36 EST
Hi Chris,
The detector is a Validyne pressure transducer modified by Dr. Chris
Haywood at SMU. I don't know what modifications were made, and have borrowed the
detector to see if I could record anything of interest with it. There are 8
inlets into a small volume inlet box. A metal diaphram measures pressure
variations differentially with respect to a reference pressure in a larger
volume. The bridge circuit electronics is contained within the detector and is
powered by 12 volts furnished by an external power supply located about 50' from
the detector. It has an internal 1 Hz low gain cutoff. I have no specs on
the unit. I am only using two of the inlets, connected to two 50' porous hoses
extended inline from opposite sides of the detector. Because of space
restrictions, the hoses are doubled back on each other at a length of 25'.
What type instrument are you using, and have you recorded any
quake-related events?
Best regards,
Al
<HTML><HEAD>
<META charset=3DUS-ASCII http-equiv=3DContent-Type content=3D"text/html; cha=
rset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY style=3D"FONT-SIZE: 12pt; FONT-FAMILY: Arial; BACKGROUND-COLOR: #fffff=
f">
<DIV><STRONG>Hi Chris,</STRONG></DIV>
<DIV><STRONG> The detector is a Validyne pressure transduc=
er modified by Dr. Chris Haywood at SMU. I don't know what modif=
ications were made, and have borrowed the detector to see if I could record=20=
anything of interest with it. There are 8 inlets into a sma=
ll volume inlet box. A metal diaphram measures pressure variation=
s differentially with respect to a reference pressure in a larger volume.&nb=
sp; The bridge circuit electronics is contained within the detect=
or and is powered by 12 volts furnished by an external power supply located=20=
about 50' from the detector. It has an internal 1 Hz low gain cutoff.&=
nbsp; I have no specs on the unit. I am only using two of the inl=
ets, connected to two 50' porous hoses extended inline from oppos=
ite sides of the detector. Because of space restrictions, the hoses ar=
e doubled back on each other at a length of 25'. </STRONG></DIV>
<DIV><STRONG> What type instrument are you using, and have=
you recorded any quake-related events?</STRONG></DIV>
<DIV><STRONG> Best regards,</STRONG></DIV>
<DIV><STRONG> Al</STRONG></DIV></BODY></HTML>
Subject: Re: GULF OF CALIFORNIA INFRASOUND DETECTION
From: ChrisAtUpw@.......
Date: Wed, 4 Jan 2006 22:10:18 EST
In a message dated 05/01/2006 00:40:06 GMT Standard Time, AHrubetz@.......
writes:
Hi Chris,
The detector is a Validyne pressure transducer modified by Dr. Chris
Haywood at SMU. I don't know what modifications were made, and have borrowed the
detector to see if I could record anything of interest with it. There are 8
inlets into a small volume inlet box. A metal diaphram measures pressure
variations differentially with respect to a reference pressure in a larger
volume. The bridge circuit electronics is contained within the detector and is
powered by 12 volts furnished by an external power supply located about 50' from
the detector. It has an internal 1 Hz low gain cutoff. I have no specs on
the unit. I am only using two of the inlets, connected to two 50' porous hoses
extended inline from opposite sides of the detector. Because of space
restrictions, the hoses are doubled back on each other at a length of 25'.
What type instrument are you using, and have you recorded any
quake-related events?
Hi Al,
Lately, I have been mostly occupied with a seismometers for schools
project. One of the sensor types that I have tried uses piezo electric disks.
They have a high voltage sensitivity.
The disks also seem to be quite good at detecting low frequency sound /
air pressure changes; low flying helicopters in particular! I have a twin
flask arrangement which I have been doing some initial experiments with. One
flask acts as a stable air pressure reservoir and the other as a low pass
acoustic filter. I prefer to remove ambient noise as far as possible, rather than
detecting it and then filtering the signal. This also stabilises the
temperature of the detector disk reasonably well. Reducing ambient wind and other
noises is reported to be a major consideration.
One of the older types of infrasound array used a large circular pipe
connected to a sensor at the centre by several hard radial pipes, typically six
to eight. You should be able to use porous hose for the circle and maybe PVC
hose / water pipe for the radial arms? This might give better noise
cancellation and a higher sensitivity than two folded pipes? A circle of 25 ft radius
has a perimeter of about 157 ft. This could give you a collection area of
nearly 2,000 sq ft. Air pressure eddies less than this size will tend to cancel
out. You might get a hf noise cut-off at about 20 Hz. I note that some of
the current CTBT arrays are using solid pipe at the centre of the spokes and
porous pipe for remainder. Porous hose is reported to change it's acoustic
characteristics with time and it is also sensitive to rain.
Is your 1 Hz figure a high frequency cut-off? I have got some
characteristics of Validyne sensors somewhere. The low range sensors are from 0.1"
water FS upwards, but I don't remember any frequency or noise specifications. I
don't know how much they cost, but a Ball Glider Variometer might well offer
both price and sensitivity advantages. They use the same principle of pressure
sensor, but with a mylar membrane. You can also get low pressure range
silicon sensors.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 05/01/2006 00:40:06 GMT Standard Time, AHrubetz@.....
com=20
writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000>
<DIV>Hi Chris,</DIV>
<DIV> The detector is a Validyne pressure transducer=20
modified by Dr. Chris Haywood at SMU. I don't know what modifications=
=20
were made, and have borrowed the detector to see if I could record anythin=
g of=20
interest with it. There are 8 inlets into a small volume inlet=20
box. A metal diaphram measures pressure variations differentially wit=
h=20
respect to a reference pressure in a larger volume. The bridge=20
circuit electronics is contained within the detector and is powered b=
y 12=20
volts furnished by an external power supply located about 50' from the=20
detector. It has an internal 1 Hz low gain cutoff. I have no spe=
cs=20
on the unit. I am only using two of the inlets, connected to two 50'=20
porous hoses extended inline from opposite sides of the detecto=
r.=20
Because of space restrictions, the hoses are doubled back on each oth=
er=20
at a length of 25'. </DIV>
<DIV> What type instrument are you using, and have you=20
recorded any quake-related events?</DIV></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Al,</DIV>
<DIV> </DIV>
<DIV> Lately, I have been mostly occupied with a=20
seismometers for schools project. One of the sensor types that I have tried=20
uses piezo electric disks. They have a high voltage sensitivity.</=
DIV>
<DIV> </DIV>
<DIV> The disks also seem to be quite good at detecti=
ng=20
low frequency sound / air pressure changes; low flying helicopters in=20
particular! I have a twin flask arrangement which I have been doing som=
e=20
initial experiments with. One flask acts as a stable air pressure reservoir=20=
and=20
the other as a low pass acoustic filter. I prefer to remove ambient noise as=
far=20
as possible, rather than detecting it and then filtering the signal. This al=
so=20
stabilises the temperature of the detector disk reasonably well. Reducing=20
ambient wind and other noises is reported to be a major=20
consideration.</DIV>
<DIV> </DIV>
<DIV> One of the older types of infrasound array used=
a=20
large circular pipe connected to a sensor at the centre by several hard radi=
al=20
pipes, typically six to eight. You should be able to use porous hose fo=
r=20
the circle and maybe PVC hose / water pipe for the radial arms? This might g=
ive=20
better noise cancellation and a higher sensitivity than two folded pipes? A=20
circle of 25 ft radius has a perimeter of about 157 ft. This could give=
you=20
a collection area of nearly 2,000 sq ft. Air pressure eddies less than this=20=
size=20
will tend to cancel out. You might get a hf noise cut-off at about 20 H=
z. I=20
note that some of the current CTBT arrays are using solid pipe at the centre=
of=20
the spokes and porous pipe for remainder. Porous hose is reported to change=20=
it's=20
acoustic characteristics with time and it is also sensitive to rain.</D=
IV>
<DIV> </DIV>
<DIV> Is your 1 Hz figure a high frequency cut-off? I=
=20
have got some characteristics of Validyne sensors somewhere. The low range=20
sensors are from 0.1" water FS upwards, but I don't remember=20=
any=20
frequency or noise specifications. I don't know how much they cost, but a Ba=
ll=20
Glider Variometer might well offer both price and sensitivity advantages. Th=
ey=20
use the same principle of pressure sensor, but with a mylar membrane. You ca=
n=20
also get low pressure range silicon sensors. </DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: INFRASOUND
From: AHrubetz@.......
Date: Wed, 4 Jan 2006 23:24:59 EST
Hi Chris,
Thanks very much for the interesting information pertaining to the
various detectors and Infrasound detector arrays. Unfortunately, I am restricted to
a rather narrow outside rectangular area ( about 2' x 25') for my detector
and porous hose layout, hence the linearity of the configuration. Yes, it would
be ideal to use radial arms and/or a circular configuration to supress
ambient noise but I have to work with this restriction, at least for now. I was
advised to use a 1 Hz HP filter, and recorded in this mode for about a month
before removing the filter. I believe it eliminated too much of the lower
frequencies that enriched the Infrasound signal.
I have had some good correlation with weather fronts and barograph
changes. I also recorded what appeared to be Infrasound correlation with solar
radiation storms several months ago, but have not had the time to make further
attempts at this or other correlative studies. I will keep you advised if I
come up with anything interesting, solar or terrestial!
Best regards,
Al
<HTML><HEAD>
<META charset=3DUS-ASCII http-equiv=3DContent-Type content=3D"text/html; cha=
rset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY style=3D"FONT-SIZE: 12pt; FONT-FAMILY: Arial; BACKGROUND-COLOR: #fffff=
f">
<DIV><STRONG>Hi Chris,</STRONG></DIV>
<DIV><STRONG> Thanks very much for the interesting informa=
tion pertaining to the various detectors and Infrasound detector arrays.&nbs=
p; Unfortunately, I am restricted to a rather narrow outside rectangular&nbs=
p;area ( about 2' x 25') for my detector and porous hose layout, hence=20=
the linearity of the configuration. Yes, it would be ideal to use radi=
al arms and/or a circular configuration to supress ambient noise but I have=20=
to work with this restriction, at least for now. I was advised to use=20=
a 1 Hz HP filter, and recorded in this mode for about a month before removin=
g the filter. I believe it eliminated too much of the lower frequencie=
s that enriched the Infrasound signal. </STRONG></DIV>
<DIV><STRONG> I have had some good correla=
tion with weather fronts and barograph changes. I also recorded w=
hat appeared to be Infrasound correlation with solar radiation storms s=
everal months ago, but have not had the time to make further attem=
pts at this or other correlative studies. I will keep you advised if I=
come up with anything interesting, solar or terrestial!</STRONG></DIV>
<DIV><STRONG> Best regards,</STRONG></DIV>
<DIV><STRONG> Al</STRONG> </DIV></BODY></HTML>
Subject: Range of 4,5Hz geophone
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 07 Jan 2006 12:37:59 +0000
Hi all
What is the estimated range of 4,5Hz Geophone to detect earthquakes,
three axis ? Then i am counting in kilometers.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Range of 4,5Hz geophone
From: ian ian@...........
Date: Sat, 07 Jan 2006 13:54:23 +0000
if it's any help, I picked up the 3.0 mag quake at Fort William,
Scotland on the 10th of December. I'm probably about 150 Km away, see
http://www.earthquakes.bgs.ac.uk/recent_events/20051210232129.9.html
(I'm just to the right of Edinburgh, having fallen off the map!).
I have a single, vertical 4.5 Hz geophone and got a very respectable
trace from it. I would agree, though, that life is more "exciting" with
a long period device, like a Lehman, unless you live "on top of a
volcano", as I used to do.
Cheers
Ian
http://www.iasmith.com/realtime.htm
Jón Frímann wrote:
>Hi all
>
>What is the estimated range of 4,5Hz Geophone to detect earthquakes,
>three axis ? Then i am counting in kilometers.
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Range of 4,5Hz geophone
From: ian ian@...........
Date: Sat, 07 Jan 2006 13:54:23 +0000
if it's any help, I picked up the 3.0 mag quake at Fort William,
Scotland on the 10th of December. I'm probably about 150 Km away, see
http://www.earthquakes.bgs.ac.uk/recent_events/20051210232129.9.html
(I'm just to the right of Edinburgh, having fallen off the map!).
I have a single, vertical 4.5 Hz geophone and got a very respectable
trace from it. I would agree, though, that life is more "exciting" with
a long period device, like a Lehman, unless you live "on top of a
volcano", as I used to do.
Cheers
Ian
http://www.iasmith.com/realtime.htm
Jón Frímann wrote:
>Hi all
>
>What is the estimated range of 4,5Hz Geophone to detect earthquakes,
>three axis ? Then i am counting in kilometers.
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Range of 4,5Hz geophone
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 07 Jan 2006 14:11:29 +0000
Hi Ian and others.
I did ask becose i didn't pickup a 3,5 mag earthquake that did happen
yesterday about 100 - 180 Km nne of where i life. You can get more info
on that earthquake here >
http://hraun.vedur.is/ja/englishweb/eqlist.html the automatic system
that i.m.o has marks it as a 3,8Ml in size, the quality was rather poor
on the i.m.o system. But for some reasion i didn't pick it up, i might
have setup the warning system in winsdr too hig or something in the
ground did prevent me from picking it up, but i did change the setting
after i did notice this. To prevent me from recording noise, i did set
the sla/tla ratio to 8.0, but far as i understand it. That controls the
warning levels pickups.
The earthquake that where happening yesterday where on the 2 - 4Hz
(problay higher) bands, as can be seen here >
http://hraun.vedur.is/ja/oroi/hrn.gif there are more stations
http://hraun.vedur.is/ja/englishweb/tremor.html here.
The noise level in my evroment is not too hig, based on what i have seen
the three weeks i have been running the geophone. But i am still
learning proplery on this hardware. That is why i will ask questions.
However, yesterday was rather windy day and the noise levels where above
the usual level.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: ebay auction
From: Bob Barns royb1@...........
Date: Sat, 07 Jan 2006 09:58:11 -0500
Hi gang,
Vintage Seismograph Seiscor Telephone Test Set - L@@k!
Item number: 6595047948
ends 1/13
Can someone post what this thing is? It looks capable of almost anything??
Bob
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Range of 4,5Hz geophone
From: ian ian@...........
Date: Sat, 07 Jan 2006 15:21:39 +0000
Hi,
it can also depend on the depth and other factors, whether you pick it
up or not. I record my data continuously. Disk space is cheap. I only
learned of the Fort William quake about a week after it happened. I
went back to the files (I record 30 minutes per file) for the time and
date and there it was.
Cheers
Ian
Jón Frímann wrote:
>Hi Ian and others.
>
>I did ask becose i didn't pickup a 3,5 mag earthquake that did happen
>yesterday about 100 - 180 Km nne of where i life. You can get more info
>on that earthquake here >
>http://hraun.vedur.is/ja/englishweb/eqlist.html the automatic system
>that i.m.o has marks it as a 3,8Ml in size, the quality was rather poor
>on the i.m.o system. But for some reasion i didn't pick it up, i might
>have setup the warning system in winsdr too hig or something in the
>ground did prevent me from picking it up, but i did change the setting
>after i did notice this. To prevent me from recording noise, i did set
>the sla/tla ratio to 8.0, but far as i understand it. That controls the
>warning levels pickups.
>
>The earthquake that where happening yesterday where on the 2 - 4Hz
>(problay higher) bands, as can be seen here >
>http://hraun.vedur.is/ja/oroi/hrn.gif there are more stations
>http://hraun.vedur.is/ja/englishweb/tremor.html here.
>
>The noise level in my evroment is not too hig, based on what i have seen
>the three weeks i have been running the geophone. But i am still
>learning proplery on this hardware. That is why i will ask questions.
>However, yesterday was rather windy day and the noise levels where above
>the usual level.
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Range of 4,5Hz geophone
From: "Steve Hammond" shammon1@.............
Date: Sat, 7 Jan 2006 09:59:50 -0800
Jon, My station ID is ATx and I have a lot of geophone data on Larry's
system under ATE, ATN and ATX that is from three HS-10 geophones with a gain
of 2,100. As a rule, I don't look for event data if the event is less than a
3.0 and more than 200 km away, 4.0 and more than 300 km, 5.0 and more than
400 km. Smaller local events less than 2.0 can be lost in the local noise
because I live near the Monterey Bay in Central California.
Regards, Steve Hammond PSN San Jose, Aptos, California
-----Original Message-----
From: psn-l-request@..............
[mailto:psn-l-request@................. Behalf Of Jón Frímann
Sent: Saturday, January 07, 2006 4:38 AM
To: PSN-Postlist
Subject: Range of 4,5Hz geophone
Hi all
What is the estimated range of 4,5Hz Geophone to detect earthquakes,
three axis ? Then i am counting in kilometers.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Range of 4,5Hz geophone
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 07 Jan 2006 21:02:20 +0000
Hi all
I do think i found the source of the problem, i think that the ampling
of the psnamp board was too low. I did change it, but i am not sure how
much i did change it, it has the jumper on and the gain is from 175 -
1750. I did turn them clockwise and i think the settings now at maximum
settings. I see bit more noise then i did before.
If the range of a 4,5Hz geophone is up to 640 km max, then i problay
will not have problems picking up most small quakes that happen near me,
or at least up to 200km away from me.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Range of 4,5Hz geophone
From: ian ian@...........
Date: Sun, 08 Jan 2006 12:40:07 +0000
I'm getting an amazing trace on my Lehman of the Greek quake, still in
progress. Interestingly, there is a small event on my geophone which
seems to co-incide with the P wave. Is this likely? See
http://www.iasmith.com/realtime.htm
I'm just about to fit a permanent set of heaters in the box. The
temporary desk lamp has been great since I put it in, cured the problem
completely. I'll have to wait a bit now so as to not disturb the trace
in progress....
Ian Smith
Jón Frímann wrote:
>Hi all
>
>I do think i found the source of the problem, i think that the ampling
>of the psnamp board was too low. I did change it, but i am not sure how
>much i did change it, it has the jumper on and the gain is from 175 -
>1750. I did turn them clockwise and i think the settings now at maximum
>settings. I see bit more noise then i did before.
>
>If the range of a 4,5Hz geophone is up to 640 km max, then i problay
>will not have problems picking up most small quakes that happen near me,
>or at least up to 200km away from me.
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Range of 4,5Hz geophone
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sun, 08 Jan 2006 16:27:11 +0000
Hi Ian and others.
I didn't recored or see this earthquake on my geophone, something
probaly shatters the wave before it reaches me or trims it down below
the local noise. I know it was detected by the i.m.o siesmonitors. I
have alot bigger amplitude on my geophone then before, so i hope to
pickup earthquakes when they happen. I now record alot of noise, for
instance i see alot more wind being picked up by my geophone, even if it
is inside and well isolated.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Range of 4,5Hz geophone
From: John or Jan Lahr JohnJan@........
Date: Sun, 08 Jan 2006 08:32:57 -0800
Hi Ian,
It's possible that the small event was triggered by the arriving
seismic waves, although this usually occurs later when the surface
waves are arriving. See, for example, this page by USGS seismologist
Andy Michael:
http://quake.wr.usgs.gov/~michael/surprises.html
This has been observed in may volcanic and hydrothermal areas, where
presumable there are some "spots" that are so close to failure that
the added strain produced by the waves of a distant earthquake can
set some of them off.
Andy's main page is:
http://quake.wr.usgs.gov/~michael/
This "event" is more likely just the high frequency component of the
P wave. It's hard to tell from the seismograms, but if it starts at
exactly the same time as P on the Lehman, then it's probably not a
triggered event.
Cheers,
John
At 04:40 AM 1/8/2006, you wrote:
>I'm getting an amazing trace on my Lehman of the Greek quake, still
>in progress. Interestingly, there is a small event on my geophone
>which seems to co-incide with the P wave. Is this likely? See
>http://www.iasmith.com/realtime.htm
>
>I'm just about to fit a permanent set of heaters in the box. The
>temporary desk lamp has been great since I put it in, cured the
>problem completely. I'll have to wait a bit now so as to not
>disturb the trace in progress....
>
>Ian Smith
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Range of 4,5Hz geophone
From: ian ian@...........
Date: Sun, 08 Jan 2006 16:39:27 +0000
Hi,
I wouldn't really expect to pick up a quake from Greece with a geophone
at the distance you are at. You really have to have a longer period
device to detect it. I'm not sure if the spike on my geophone was the P
wave or just something local.
Either way, the geophone spike was brief compared to the 90 minutes or
so that the quake grumbled on for. Maybe you should have a go at making
something like a Lehman. They're not too difficult and you probably
have a spare channel on your amp and A/D.
I've spent the afternoon replacing the desk lamp in the enclosure with 3
car lights. I'm starting off by feeding them 5 volts from an old PC
power supply. If that isn't warm enough then I'll switch to 12 volts.
Thanks to Chris Chapman for pointing this out, it's made a huge difference.
Cheers
Ian
Jón Frímann wrote:
>Hi Ian and others.
>
>I didn't recored or see this earthquake on my geophone, something
>probaly shatters the wave before it reaches me or trims it down below
>the local noise. I know it was detected by the i.m.o siesmonitors. I
>have alot bigger amplitude on my geophone then before, so i hope to
>pickup earthquakes when they happen. I now record alot of noise, for
>instance i see alot more wind being picked up by my geophone, even if it
>is inside and well isolated.
>
>Regards.
>
>
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Subject: The earthquake in Greece
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sun, 08 Jan 2006 16:45:46 +0000
Hi all
John, thanks for mension this. Becose there has been a increase in
earthquakes in Silicy, Italy after the Greece earthquake. It did start
about three hours after the main quake in Greece. You can get the
earthquake data here.
http://www.emsc-csem.org/cgi-bin/QDM_all.sh?1
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
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Subject: Re: Range of 4,5Hz geophone
From: ian ian@...........
Date: Sun, 08 Jan 2006 16:48:07 +0000
Hi,
thanks for the links. Interesting thought. If the BGS was working I'd
be able to check if it was real or local. BGS sensors have been off
since the 24th of December, outrageous and embarrassing. Presumably
Monday may bring some hope. I'm tempted to email a complaint to them
(it's my taxes!).
Thanks
Ian
John or Jan Lahr wrote:
> Hi Ian,
>
> It's possible that the small event was triggered by the arriving
> seismic waves, although this usually occurs later when the surface
> waves are arriving. See, for example, this page by USGS seismologist
> Andy Michael:
> http://quake.wr.usgs.gov/~michael/surprises.html
> This has been observed in may volcanic and hydrothermal areas, where
> presumable there are some "spots" that are so close to failure that
> the added strain produced by the waves of a distant earthquake can set
> some of them off.
>
> Andy's main page is:
> http://quake.wr.usgs.gov/~michael/
>
> This "event" is more likely just the high frequency component of the P
> wave. It's hard to tell from the seismograms, but if it starts at
> exactly the same time as P on the Lehman, then it's probably not a
> triggered event.
>
> Cheers,
> John
>
>
> At 04:40 AM 1/8/2006, you wrote:
>
>> I'm getting an amazing trace on my Lehman of the Greek quake, still
>> in progress. Interestingly, there is a small event on my geophone
>> which seems to co-incide with the P wave. Is this likely? See
>> http://www.iasmith.com/realtime.htm
>>
>> I'm just about to fit a permanent set of heaters in the box. The
>> temporary desk lamp has been great since I put it in, cured the
>> problem completely. I'll have to wait a bit now so as to not disturb
>> the trace in progress....
>>
>> Ian Smith
>
>
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
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Subject: Re: Range of 4,5Hz geophone,Greek quake
From: "Thomas Dick" dickthomas01@.............
Date: Sun, 8 Jan 2006 11:13:28 -0600
My vertical geophone detected this quake. I am 82 degrees away.
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Public Seismic Network Mailing List (PSN-L)
Subject: Re: Range of 4,5Hz geophone
From: ChrisAtUpw@.......
Date: Sun, 8 Jan 2006 13:29:59 EST
In a message dated 08/01/2006, ian@........... writes:
I've spent the afternoon replacing the desk lamp in the enclosure with 3
car lights. I'm starting off by feeding them 5 volts from an old PC
power supply. If that isn't warm enough then I'll switch to 12 volts.
Hi Ian,
There are two problems with using light bulbs. You need to run them at
3/4 the rated voltage to get a very long life from them and the glass
envelopes need to be kept cool. If the glass gets too hot, oxygen may diffuse through
it and shorten the filament life. The other problem is that insects, spiders
and small animals are attracted to a warmed environment, particularly if it
is also illuminated.
Power resistors with an Al case which can be bolted onto an earthed Al
top plate in the enclosure and provided with soldered connections are likely
to give the most satisfactory permanent solution. Farnell and RS sell them.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 08/01/2006, ian@........... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>I've=20
spent the afternoon replacing the desk lamp in the enclosure with 3 <BR>ca=
r=20
lights. I'm starting off by feeding them 5 volts from an old PC <BR>p=
ower=20
supply. If that isn't warm enough then I'll switch to 12 volts. =20
<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Ian,</DIV>
<DIV> </DIV>
<DIV> There are two problems with using light bulbs.=20=
You=20
need to run them at 3/4 the rated voltage to get a very long life from them=20=
and=20
the glass envelopes need to be kept cool. If the glass gets too hot, oxygen=20=
may=20
diffuse through it and shorten the filament life. The other problem is that=20
insects, spiders and small animals are attracted to a warmed=20
environment, particularly if it is also=20
illuminated. </DIV>
<DIV> Power resistors with an Al case which can be bo=
lted=20
onto an earthed Al top plate in the enclosure and provided with soldered=20
connections are likely to give the most satisfactory permanent solution=
..=20
Farnell and RS sell them. </DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Range of 4,5Hz geophone
From: ian ian@...........
Date: Sun, 08 Jan 2006 18:58:50 +0000
Hi,
thanks for the warnings. As always, I've taken a short cut (lack of
time). I also had to get the desk lamp out by today as my family return
tomorrow and will want the desk lamp back(!) and wouldn't want a mains
lead stretching across the garden/back yard. It was nice and cosy
inside the box when I opened it up, so the thermal insulation isn't too
bad. It was around 0C outside at the time.
I ripped out the flasher, stop and tail light string from our old Honda
and attached that to the inside ceiling of the enclosure. I'm only
sending 5 volts dc to them (down 30m of mains lead) so they don't get
very hot at all, just a warming glow. Unfortunately I won't have much
more time until the summer. So I'll have to wait until then before
changing over to resistors. Unless of course it starts going bump in
the night!
Cheers
Ian
ChrisAtUpw@....... wrote:
> In a message dated 08/01/2006, ian@........... writes:
>
> I've spent the afternoon replacing the desk lamp in the enclosure
> with 3
> car lights. I'm starting off by feeding them 5 volts from an old PC
> power supply. If that isn't warm enough then I'll switch to 12
> volts.
>
> Hi Ian,
>
> There are two problems with using light bulbs. You need to run
> them at 3/4 the rated voltage to get a very long life from them and
> the glass envelopes need to be kept cool. If the glass gets too hot,
> oxygen may diffuse through it and shorten the filament life. The other
> problem is that insects, spiders and small animals are attracted to a
> warmed environment, particularly if it is also illuminated.
> Power resistors with an Al case which can be bolted onto an
> earthed Al top plate in the enclosure and provided with soldered
> connections are likely to give the most satisfactory permanent
> solution. Farnell and RS sell them.
>
> Regards,
>
> Chris Chapman
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
Hi,<br>
<br>
thanks for the warnings. As always, I've taken a short cut (lack of
time). I also had to get the desk lamp out by today as my family
return tomorrow and will want the desk lamp back(!) and wouldn't want a
mains lead stretching across the garden/back yard. It was nice and
cosy inside the box when I opened it up, so the thermal insulation
isn't too bad. It was around 0C outside at the time.<br>
<br>
I ripped out the flasher, stop and tail light string from our old Honda
and attached that to the inside ceiling of the enclosure. I'm only
sending 5 volts dc to them (down 30m of mains lead) so they don't get
very hot at all, just a warming glow. Unfortunately I won't have much
more time until the summer. So I'll have to wait until then before
changing over to resistors. Unless of course it starts going bump in
the night!<br>
<br>
Cheers<br>
<br>
Ian<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:ChrisAtUpw@.......">ChrisAtUpw@.......</a> wrote:<br>
<blockquote cite="mid24b.4e506ae.30f2b427@......." type="cite">
<meta http-equiv="Content-Type" content="text/html; ">
<meta content="MSHTML 6.00.2900.2802" name="GENERATOR">
<font id="role_document" color="#000000" face="Arial" size="2">
<div>
<div>In a message dated 08/01/2006, <a class="moz-txt-link-abbreviated" href="mailto:ian@...........">ian@...........</a> writes:</div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">I've spent the afternoon replacing the desk lamp in the
enclosure with 3 <br>
car lights. I'm starting off by feeding them 5 volts from an old PC <br>
power supply. If that isn't warm enough then I'll switch to 12 volts. <br>
</font></blockquote>
</div>
<div>Hi Ian,</div>
<div> </div>
<div> There are two problems with using light bulbs. You need to
run them at 3/4 the rated voltage to get a very long life from them and
the glass envelopes need to be kept cool. If the glass gets too hot,
oxygen may diffuse through it and shorten the filament life. The other
problem is that insects, spiders and small animals are attracted to a
warmed environment, particularly if it is also illuminated. </div>
<div> Power resistors with an Al case which can be bolted onto an
earthed Al top plate in the enclosure and provided with soldered
connections are likely to give the most satisfactory permanent
solution. Farnell and RS sell them. </div>
<div> </div>
<div> Regards,</div>
<div> </div>
<div> Chris Chapman</div>
</font></blockquote>
</body>
</html>
Subject: Re: Range of 4,5Hz geophone
From: "Geoff" gmvoeth@...........
Date: Sun, 8 Jan 2006 13:05:42 -0700
I understand the physics of wave propagation through
water or ground or anything allows for shadow areas
where there is little or no energy.
It seems reasonable to assume such shadow areas
can affect small areas closer to the event
and not just 103 or so degrees away.
maybe you were just in one of these shadow zones ???
> I didn't recored or see this earthquake on my geophone, something
> probaly shatters the wave before it reaches me or trims it down below
> the local noise. I know it was detected by the i.m.o siesmonitors. I
But then I am no geophysicist, the person most likely to know.
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Subject: Online seismonitor graphs are offline
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 09 Jan 2006 01:11:38 +0000
Hi all.
My online seismonitors graphs are currently offline due to technical
problems. I hope to have them back online tomorrow, but i will have to
move them to my own server at my home, so the address will change. I
will setup a forward page also on the old place tomorrow (where my page
is), so you will get redireced to the new location automaticlly.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
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Subject: Updated link
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 09 Jan 2006 13:08:21 +0000
Hi all
I finally got my seismographs online agen (hopefully). There has been
minor updated in the link. The current link is
http://www.simnet.is/jonfr500/earthquake/ and that this is a backup link
number two, the main backup link is this one
http://earthquake.homeip.net/~jonfr/ , the main link is going to be
http://www.jonfr.com/earthquake/ But at current time i am having
problems peforming a update to that location.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
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Subject: Earthquake in the North Atlantic Ocen, 5,3mb
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 09 Jan 2006 17:11:53 +0000
Hi all
Today (9th Jan, 2006) there was a earthquake of 5.3 mb in the North
Atlantic Ocen, the depth was 2 km. There are more info at esmc-cmes.org
and here http://www.emsc-csem.org/cgi-bin/QDM_link_content.sh?HB644&CSEM
The link might stop working anytime.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
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Subject: $200 microbarograph first light
From: "David Saum" DSaum@............
Date: Mon, 9 Jan 2006 15:08:10 -0500
I finally got my $200 home-brew microbarograph running yesterday,
and here are some pictures:
Here is last night's data logged and plotted hourly with the seismic
freeware AMASEIS. Time is GMT. Bandpass 0.01 Hz to 4.5 Hz.
http://www.infiltec.com/Infrasound@.................
The microbarograph was in a cooler, outside on the 4th
floor deck of my condo, with no spatial wind averaging array.
I am about 10 miles from Washington Reagan airport, and
they reported 9-15mph winds, so the peaks are probably
wind and not seismic events, nuclear tests, meteors, etc. :(
Here is some fine structure of one of last night's events:
http://www.infiltec.com/Infrasound@.................
The adc pressure resolution is about 0.004 Pa, so a 200 adc
count peak is about 0.8 Pa. AMASEIS allows you to block any time
segment and examine it in detail, including fourier transform
and bandpass filtering.
Exterior of microbarograph with serial cable:
http://www.infiltec.com/Infrasound@.................
Interior of microbarograph:
http://www.infiltec.com/Infrasound@.................
PCB removed from box
http://www.infiltec.com/Infrasound@.................
PCB and high-pass pneumatic filter removed from box:
http://www.infiltec.com/Infrasound@.................
System specs:
System Bandpass: 0.01 to 4 Hz.
High-Pass filter: ~100 sec or 0.01 Hz using volume/capillary tube.
Low pass filter: 4 Hz anti-alias, 8 pole Bessel filter (MAX4701)
Differential pressure sensor: silicon, bridge type, 1"wc (DUXL01D)
Pres Resolution: ~0.004 Pa - possibly lower depending offsets
Range: +/- 120 Pa (32768 times pressure resolution)
Amp: instrumentation,1000x,single supply,micropower,RTR out(INA122P)
Power: ~2ma 5VDC, derived from PC serial port, no exernal power supply
Regulator: 5VDC, low dropout micropower, precision (LP2950-5.0)
Amplifer Reference Voltage: 2.5VDC fixed, precision reference (LT1004-2.5)
Microprocessor: 4mhz, onboard 16 bit ADC and serial I/O (PIC14000)
Firmware: ADC sampling at ~35 SPS, zero drift tracking ~5 min TC.
Enclosure: diecast aluminum box for shielding (Hammond 1590P)
Serial Out: RS232, 9600 baud, 8N1, ascii records, -32767 to +32767
Wind Spatial Averaging: array of micro-perforated garden tubing
Data Log/Display: freeware PC AMASEIS seismic log/analysis software
Improvements?: Offset voltages in the instrumentation amp and pressure
sensor seem to limit the maximum gain. I may try a variable amp reference
voltage to eliminate these offsets. I bought some pressure transmitters
from eBay to see if their noise levels are lower: an MKS Baratron 223B and
an Ashcroft XLDP. Unfortunately these transmitters use a lot more power
and voltage than I can steal from the PC serial port.
Kits: If there is some interest I will offer a kit for this
microbarograph. It would be similar to my seismometer kit that
is described below, including step-by-step building instructions :
http://www.infiltec.com/seismo/infkqm10.htm
The seismometer kit was recently built by an 8th grader for her
science project.
Dave
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Subject: RE: $200 microbarograph first light
From: "John D Nelson" jnelson@.................
Date: Mon, 9 Jan 2006 14:19:19 -0600
I would certainly be interested in seeing a kit offered, or at least the
circuit board.
John Nelson
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@...............
On Behalf Of David Saum
Sent: Monday, January 09, 2006 2:08 PM
To: Undisclosed-Recipient:;
Subject: $200 microbarograph first light
I finally got my $200 home-brew microbarograph running yesterday,
and here are some pictures:
Here is last night's data logged and plotted hourly with the seismic
freeware AMASEIS. Time is GMT. Bandpass 0.01 Hz to 4.5 Hz.
http://www.infiltec.com/Infrasound@.................
The microbarograph was in a cooler, outside on the 4th=20
floor deck of my condo, with no spatial wind averaging array.=20
I am about 10 miles from Washington Reagan airport, and
they reported 9-15mph winds, so the peaks are probably
wind and not seismic events, nuclear tests, meteors, etc. :(
Here is some fine structure of one of last night's events:
http://www.infiltec.com/Infrasound@.................
The adc pressure resolution is about 0.004 Pa, so a 200 adc=20
count peak is about 0.8 Pa. AMASEIS allows you to block any time
segment and examine it in detail, including fourier transform
and bandpass filtering.
Exterior of microbarograph with serial cable:
http://www.infiltec.com/Infrasound@.................
Interior of microbarograph:
http://www.infiltec.com/Infrasound@.................
PCB removed from box
http://www.infiltec.com/Infrasound@.................
PCB and high-pass pneumatic filter removed from box:
http://www.infiltec.com/Infrasound@.................
System specs:=20
System Bandpass: 0.01 to 4 Hz.
High-Pass filter: ~100 sec or 0.01 Hz using volume/capillary tube.
Low pass filter: 4 Hz anti-alias, 8 pole Bessel filter (MAX4701)
Differential pressure sensor: silicon, bridge type, 1"wc (DUXL01D)
Pres Resolution: ~0.004 Pa - possibly lower depending offsets
Range: +/- 120 Pa (32768 times pressure resolution)
Amp: instrumentation,1000x,single supply,micropower,RTR out(INA122P)=20
Power: ~2ma 5VDC, derived from PC serial port, no exernal power supply
Regulator: 5VDC, low dropout micropower, precision (LP2950-5.0) =20
Amplifer Reference Voltage: 2.5VDC fixed, precision reference
(LT1004-2.5)
Microprocessor: 4mhz, onboard 16 bit ADC and serial I/O (PIC14000)
Firmware: ADC sampling at ~35 SPS, zero drift tracking ~5 min TC.
Enclosure: diecast aluminum box for shielding (Hammond 1590P)
Serial Out: RS232, 9600 baud, 8N1, ascii records, -32767 to +32767
Wind Spatial Averaging: array of micro-perforated garden tubing=20
Data Log/Display: freeware PC AMASEIS seismic log/analysis software
Improvements?: Offset voltages in the instrumentation amp and pressure
sensor seem to limit the maximum gain. I may try a variable amp
reference
voltage to eliminate these offsets. I bought some pressure transmitters
from eBay to see if their noise levels are lower: an MKS Baratron 223B
and
an Ashcroft XLDP. Unfortunately these transmitters use a lot more power
and voltage than I can steal from the PC serial port.
Kits: If there is some interest I will offer a kit for this
microbarograph. It would be similar to my seismometer kit that
is described below, including step-by-step building instructions :
http://www.infiltec.com/seismo/infkqm10.htm
The seismometer kit was recently built by an 8th grader for her
science project.
Dave=20
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Subject: Re: $200 microbarograph first light
From: "James Hannon" jmhannon@.........
Date: Mon, 9 Jan 106 14:26:33 CST
Dave,
Looks real nice.
I was wondering about the high pass filter. The capillary tube seems large. Did you arrive at the volume/ tube dia/ length by calculation or experiment? Do you have any data on these parameters vs response?
Jim Hannon
--
Jim Hannon
http://www.fmtcs.com/web/jmhannon/
42,11.90N,91,39.26W
WB0TXL
--
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Subject: Recorded two 3 ricther scale earthquakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Tue, 10 Jan 2006 02:09:29 +0000
Hi all
Thanks to comment on how to increase the amptiude i did finally record
earthquakes. This earthquakes are two, with just a few seconds time
between them. The size according to i.m.o is 3,0Ml and 3,4Ml. The range
from my station is about ~220 km. Below are gif image of the earthquake
and the psn file.
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn.gif
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
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Subject: Re: $200 microbarograph first light
From: ChrisAtUpw@.......
Date: Mon, 9 Jan 2006 22:56:18 EST
In a message dated 09/01/2006, DSaum@............ writes:
Improvements? Offset voltages in the instrumentation amp and pressure
sensor seem to limit the maximum gain.
If you use a low noise differential input amplifier, but keep the gain
at a level at which it does not saturate, you can add a high pass filter and
then additional amplification and filtering. It can be a bit difficult to zero
the sensor without increasing it's noise.
In the equipment shown, the reference pressure is a very small volume
connected to atmosphere with a leak tube. The temperature of the reference
volume usually needs to be stabilised, to reduce ambient drift, especially when
using a fairly long time constant, like 100 sec. A half pint thermos flask
filled with the lightest grade of polyurethane foam makes quite a good
reference. This allows the pressure sensing to be ~isothermal rather than semi
adiabatic and increases the sensitivity. The ambient thermal response time of an
empty flask is usually over 30 mins. The 'thermal mass' can be increased by
adding candle wax inside the flask.
The sensor shown will pick up wide band ambient noise from the wind,
passing aircraft, helicopters, vehicles..... Unless you want to observe these
sorts of signal, you can use a single stage pneumatic low pass filter, with a
leak tube and a reference volume, to reduce the input noise. This may be quite
helpful in keeping the output 'on scale', particularly in very windy / noisy
conditions.
Wind noise can be reduced by using a large sensor array of porous
irrigation hose. This may be protected from rain to keep the acoustic properties
fairly constant. A large circle of hose connected to a sensor at the centre by
four to eight hard wall connecting tubes has been used for infrasound arrays,
with diameters up to several hundred feet. Radial spokes of porous hose are
also used, usually connected to the sensor with lengths of solid tube.
It is also possible to use a single sensor head with a multi hole entry
in between horizontal disks. This can significantly reduce the wind noise.
Buildings, isolated trees, water towers, pylons etc will all have downwind
vortices associated with them which can greatly increase the input signal
amplitude at a 'miss-placed' sensor, usually to over twice the crosswind dimension.
The turbulence generated by a structure like a wall or a hedge may be
detected at distances over 50x the height downwind.
Regards,
Chris Chapman
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<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
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<DIV>
<DIV>In a message dated 09/01/2006, DSaum@............ writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20
size=3D2>Improvements? Offset voltages in the instrumentation amp and=20
pressure<BR>sensor seem to limit the maximum=20
gain. </FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV> If you use a low noise differential input=20
amplifier, but keep the gain at a level at which it does not saturate, you c=
an=20
add a high pass filter and then additional amplification and filtering. =
;It=20
can be a bit difficult to zero the sensor without increasing it's=20
noise. </DIV>
<DIV> </DIV>
<DIV> In the equipment shown, the reference pressure=20=
is a=20
very small volume connected to atmosphere with a leak tube. The tempera=
ture=20
of the reference volume usually needs to be stabilised, to reduce ambient dr=
ift,=20
especially when using a fairly long time constant, like 100 sec. A half=
=20
pint thermos flask filled with the lightest grade of polyurethane foam makes=
=20
quite a good reference. This allows the pressure sensing to be ~isother=
mal=20
rather than semi adiabatic and increases the sensitivity. The ambient therma=
l=20
response time of an empty flask is usually over 30 mins. The 'thermal m=
ass'=20
can be increased by adding candle wax inside the flask. </DIV>
<DIV> </DIV>
<DIV> The sensor shown will pick up wide band ambient=
=20
noise from the wind, passing aircraft, helicopters, vehicles..... Unless you=
=20
want to observe these sorts of signal, you can use a single stage pneumatic=20=
low=20
pass filter, with a leak tube and a reference volume, to reduce the inp=
ut=20
noise. This may be quite helpful in keeping the output 'on scale', particula=
rly=20
in very windy / noisy conditions. </DIV>
<DIV> </DIV>
<DIV> Wind noise can be reduced by using a large sens=
or=20
array of porous irrigation hose. This may be protected from rain to keep the=
=20
acoustic properties fairly constant. A large circle of hose connected to a=20
sensor at the centre by four to eight hard wall connecting tubes has be=
en=20
used for infrasound arrays, with diameters up to several hundred feet. Radia=
l=20
spokes of porous hose are also used, usually connected to the sensor with=20
lengths of solid tube. </DIV>
<DIV> </DIV>
<DIV> It is also possible to use a single sensor head=
=20
with a multi hole entry in between horizontal disks. This can significa=
ntly=20
reduce the wind noise. Buildings, isolated trees, water towers, pylons=20=
etc=20
will all have downwind vortices associated with them which can greatly incre=
ase=20
the input signal amplitude at a 'miss-placed' sensor, usually to over twice=20=
the=20
crosswind dimension. The turbulence generated by a structure like a wal=
l or=20
a hedge may be detected at distances over 50x the height downwind. </DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: ebay auction
From: Bob Barns royb1@...........
Date: Tue, 10 Jan 2006 10:38:15 -0500
GeoSonics SSU Micro Seismograph Earthquake System Unit
Item number: 7579963838
ends 1/16
Bob
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Locating P and S wave, suggestions needed
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Tue, 10 Jan 2006 17:53:25 +0000
Hi all
As I did say in my early post today, I did record a earthquake at 00:25
today. The earthquake mag was 3,0 on the ricther scale according to the
icelandic met office. My problem is this that i don't think i have found
the p and s wave properly, since this earthquake wave has two spikes,
not one. I did think that i had correctly located the p and s waves, but
based on the wave form I am not totally sure.
Here is the gif file and the psn file of the recording.
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn.gif
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn
(p and s markers are not set in this psn file)
Here is a picture of the earthquake with the p and s markers as i did
set them.
http://alvaran.com/forum/index.php?act=Attach&type=post&id=11
If nothing else, I welcome suggestions on this matter.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: $200 microbarograph first light
From: ChrisAtUpw@.......
Date: Tue, 10 Jan 2006 21:49:34 EST
In a message dated 09/01/2006, DSaum@............ writes:
System Bandpass: 0.01 to 4 Hz.
High-Pass filter: ~100 sec or 0.01 Hz using volume/capillary tube.
Low pass filter: 4 Hz anti-alias, 8 pole Bessel filter (MAX4701)
This gives a drop of 40 dB at 4 Hz, an average signal delay of 0.2 sec
and 0.35 sec peak.
Differential pressure sensor: silicon, bridge type, 1"wc (DUXL01D)
Pres Resolution: ~0.004 Pa - possibly lower depending offsets
Range: +/- 120 Pa (32768 times pressure resolution)
For a 5 V supply, this sensor has an output of 6 mV per inch water and a
span of 6 mV. You might do better with a DUXL05D. This has an output of 4.5
mV per inch water and a span of 22.5 mV.
1" water gauge corresponds to a pitot speed of about 45 mph. This does
not leave much, if any, safety margin for storm conditions.
Amp: instrumentation,1000x,single supply,micropower,RTR out(INA122P)
While the INA122 has rail to rail output, it also has a 0.1 to 10 Hz
noise of 2 micro V pp. This is poor in comparison with an INA118 which has a
noise level of 0.28 micro V pp - roughly 1/7th. There are other low noise opamps
available.
Power: ~2ma 5VDC, derived from PC serial port, no exernal power supply
Regulator: 5VDC, low dropout micropower, precision (LP2950-5.0)
Firmware: ADC sampling at ~35 SPS, zero drift tracking ~5 min TC.
Serial Out: RS232, 9600 baud, 8N1, ascii records, -32767 to +32767
Wind Spatial Averaging: array of micro-perforated garden tubing
Data Log/Display: freeware PC AMASEIS seismic log/analysis software
Improvements? Offset voltages in the instrumentation amp and pressure
sensor seem to limit the maximum gain. I may try a variable amp reference
voltage to eliminate these offsets.
Use the average signal level as your zero?
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>In a message dated 09/01/2006, DSaum@............ writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>System=20
Bandpass: 0.01 to 4 Hz.<BR>High-Pass filter: ~100 sec or 0.01 Hz using=20
volume/capillary tube.<BR>Low pass filter: 4 Hz anti-alias, 8 pole Bessel=20
filter (MAX4701)</FONT></BLOCKQUOTE>
<DIV> This gives a drop of 40 dB at 4 Hz, an average=20
signal delay of 0.2 sec and 0.35 sec peak. </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20
size=3D2>Differential pressure sensor: silicon, bridge type, 1"wc=20
(DUXL01D)<BR>Pres Resolution: ~0.004 Pa - possibly lower depending=20
offsets<BR>Range: +/- 120 Pa (32768 times pressure=20
resolution)</FONT></BLOCKQUOTE>
<DIV> For a 5 V supply, this sensor has an output of=20=
6 mV=20
per inch water and a span of 6 mV. You might do better with a DUXL05D.=20=
This=20
has an output of 4.5 mV per inch water and a span of 22.5 mV.</DIV>
<DIV> </DIV>
<DIV> 1" water gauge corresponds to a pitot speed of=20
about 45 mph. This does not leave much, if any, safety margin for storm=
=20
conditions.</DIV>
<DIV><FONT style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000=
000=20
size=3D2><BR>Amp: instrumentation,1000x,single supply,micropower,RTR out(INA=
122P)=20
</DIV>
<DIV> </DIV>
<DIV> While the INA122 has rail to rail output, it al=
so=20
has a 0.1 to 10 Hz noise of 2 micro V pp. This is poor in comparison with an=
=20
INA118 which has a noise level of 0.28 micro V pp - roughly 1/7th. There are=
=20
other low noise opamps available.</DIV>
<DIV><BR>Power: ~2ma 5VDC, derived from PC serial port, no exernal power=20
supply<BR>Regulator: 5VDC, low dropout micropower, precision (LP2950-5.0)&nb=
sp;=20
<BR>Firmware: ADC sampling at ~35 SPS, zero drift tracking ~5 min TC.<BR>Ser=
ial=20
Out: RS232, 9600 baud, 8N1, ascii records, -32767 to +32767<BR>Wind Spatial=20
Averaging: array of micro-perforated garden tubing <BR>Data Log/Display:=20
freeware PC AMASEIS seismic log/analysis software<BR><BR>Improvements? Offse=
t=20
voltages in the instrumentation amp and pressure<BR>sensor seem to limit the=
=20
maximum gain. I may try a variable amp reference<BR>voltage to elimina=
te=20
these offsets.</DIV>
<DIV> </DIV>
<DIV></FONT> Use the average signal level as your=20
zero?</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV>
<DIV></DIV>
<DIV> </DIV></FONT></BODY></HTML>
Subject: Re: Locating P and S wave, suggestions needed
From: Paul elegant_dice@.........
Date: Wed, 11 Jan 2006 09:44:25 +0800
According to my friend, he reckons they look good. Your S looks good to
him, but your P could be moved to coincide with the peak of the first
pulse, it seems to be a few samples earlier than the peak.
I'm new at this myself, so I'd like to hear some feedback too
Jón Frímann wrote:
> Hi all
>
> As I did say in my early post today, I did record a earthquake at 00:25
> today. The earthquake mag was 3,0 on the ricther scale according to the
> icelandic met office. My problem is this that i don't think i have found
> the p and s wave properly, since this earthquake wave has two spikes,
> not one. I did think that i had correctly located the p and s waves, but
> based on the wave form I am not totally sure.
>
> Here is the gif file and the psn file of the recording.
> http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn.gif
> http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn
> (p and s markers are not set in this psn file)
>
> Here is a picture of the earthquake with the p and s markers as i did
> set them.
> http://alvaran.com/forum/index.php?act=Attach&type=post&id=11
>
> If nothing else, I welcome suggestions on this matter.
>
> Regards.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Locating P and S wave, suggestions needed
From: "Bob Hancock" carpediem1@.........
Date: Tue, 10 Jan 2006 21:40:09 -0700
I downloaded the file and then looked at it with the FFT option in =
WinQuake.
I tried several different filtering options and then settled on =
filtering
out all data with a frequency longer than 1 hz. I was unable to see
anything that looked like an earthquake in the longer frequencies.
This appears to be two separate earthquakes such as a primary event and
aftershock, rather than a P wave and S wave. In addition, based upon =
the
higher frequencies of both events, they are relatively close to the =
station,
although I would not want to hazard a guess at distance. I have noticed
similar frequencies from nearby events both in New Jersey where I used =
to
live and now in Arizona. =20
The initial direction of what I perceived as the P wave is visible and =
moves
up on both events. As I see it, the first event occurred at 25:53.270 =
and
the amplitude on the P wave was 20.3. The second event occurred at
26:13.120, and the amplitude on the P wave was 34.6.
This all becomes visible when you filter out the lower frequency data, =
and
expand the X axis to 10 seconds.
However, if an expert has a better answer, I will bow to them.
Bob Hancock
Three Points, AZ
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... =
On
Behalf Of Paul
Sent: Tuesday, January 10, 2006 18:44
To: psn-l@..............
Subject: Re: Locating P and S wave, suggestions needed
According to my friend, he reckons they look good. Your S looks good to =
him, but your P could be moved to coincide with the peak of the first=20
pulse, it seems to be a few samples earlier than the peak.
I'm new at this myself, so I'd like to hear some feedback too
J=F3n Fr=EDmann wrote:
> Hi all
>=20
> As I did say in my early post today, I did record a earthquake at =
00:25
> today. The earthquake mag was 3,0 on the ricther scale according to =
the
> icelandic met office. My problem is this that i don't think i have =
found
> the p and s wave properly, since this earthquake wave has two spikes,
> not one. I did think that i had correctly located the p and s waves, =
but
> based on the wave form I am not totally sure.
>=20
> Here is the gif file and the psn file of the recording.
>
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn.g=
if
> =
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn
> (p and s markers are not set in this psn file)
>=20
> Here is a picture of the earthquake with the p and s markers as i did
> set them.
> http://alvaran.com/forum/index.php?act=3DAttach&type=3Dpost&id=3D11
>=20
> If nothing else, I welcome suggestions on this matter.
>=20
> Regards.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Locating P and S wave, suggestions needed
From: John or Jan Lahr JohnJan@........
Date: Tue, 10 Jan 2006 21:01:36 -0800
Hi J=F3n,
To get better resolution in time, change the time=20
window (x scale) to 40 seconds.
Then use the Display/Modify system to enter the=20
known location, origin time, and magnitude from=20
the Iceland network (http://hraun.vedur.is/ja/englishweb/eqlist.html).
Click on the Loc button and the P and S markers=20
will be positioned automatically. When I did=20
this they were close to the start of the phases,=20
but a one or two seconds late. This could mean=20
that your clock is a few seconds fast, or that=20
the velocity model does not fit exactly for Iceland.
When I position the P and S markers, the implied=20
distance is 162 km, whereas the computed distance=20
is 166 km. This is pretty close.
I think you recorded the 3.4 event rather than=20
the 3.0 event, but it can be hard to untangle=20
events that are this close together in space and time.
<http://hraun.vedur.is/cgi-bin/eqloc.cgi?x/2006/jan/10/00:20:00/25:29:258>20=
06-01-1000:25:26,563,964-21,8541,13,490,03=20
5,1 kmSof Helgafell
<http://hraun.vedur.is/cgi-bin/eqloc.cgi?x/2006/jan/10/00:20:00/25:26:750>20=
06-01-1000:25:24,963,955-22,1133,23,090,05=20
7,9 kmNNWof Kr=EDsuv=EDk
I posted my WinQuake windows showing the way I would pick this earthquake=
here:
http://jclahr.com/science/psn/misc/jon.html
Cheers,
John
At 09:53 AM 1/10/2006, you wrote:
>Hi all
>
>As I did say in my early post today, I did record a earthquake at 00:25
>today. The earthquake mag was 3,0 on the ricther scale according to the
>icelandic met office. My problem is this that i don't think i have found
>the p and s wave properly, since this earthquake wave has two spikes,
>not one. I did think that i had correctly located the p and s waves, but
>based on the wave form I am not totally sure.
>
>Here is the gif file and the psn file of the recording.
>http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn.gif
>http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn
>(p and s markers are not set in this psn file)
>
>Here is a picture of the earthquake with the p and s markers as i did
>set them.
>http://alvaran.com/forum/index.php?act=3DAttach&type=3Dpost&id=3D11
>
>If nothing else, I welcome suggestions on this matter.
>
>Regards.
>--
>J=F3n Fr=EDmann J=F3nsson
>http://www.jonfr.com
>
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with
>the body of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
##################################/ John C. Lahr
#################################/ Emeritus Seismologist
################################/ U.S. Geological Survey
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D/ Geologic Hazards Team
##############################/ Golden, Colorado
#############################//##############################
############################//###############################
PO Box 548 /################################
Corvallis, Oregon 97339 /##################################
Phone: (541) 758-2699 /=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Cell: (541) 740-4844 /###################################
Fax: (928) 569-0113 /##################################
jjpub@........ /####################################
http://jclahr.com/science/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Locating P and S wave, suggestions needed
From: John or Jan Lahr JohnJan@........
Date: Tue, 10 Jan 2006 21:08:42 -0800
Bob may be right about this being two events. As soon as there is
another 3.5 event within 175 km of Jon's station, it will be clear if
he is able to see it clearly. If not, then that would argue for the
two-event interpretation. The separation of the two phases is very
close to what would be expected for the S-P interval from the distant
events, so that argues for my interpretation.
John
At 08:40 PM 1/10/2006, you wrote:
>This appears to be two separate earthquakes such as a primary event and
>aftershock, rather than a P wave and S wave.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Locating P and S wave, suggestions needed
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Wed, 11 Jan 2006 06:14:37 +0000
Hi all
Thanks for the comments and suggestions, i am sure that i will learn
this with time. I did go over the final resaults of this earthquake on
the Icelandic met Office homepage and according to that resaults they
only register one earthquake at that exact time, the size of the evenent
was 3.07 M. Here is the final resaults from I.M.O.
I took also few smaller earthquakes that i didn't detect. Those
earthquakes where few seconds before the earthquake that i did detect.
Depth M Ml
9 20060110 002459.128 63.94168 -22.10622 5.094 0.76 0.16
10 20060110 002506.566 63.94402 -22.10538 4.168 0.46 -0.02
11 20060110 002525.044 63.94730 -22.11069 5.103 3.07 2.57
12 20060110 002641.410 63.93540 -22.11102 6.147 1.32 0.42
The page that has this info is in Icelandic, it is not on there engish web.
Why this earthquake shows two spikes is something i don't understand.
But that is problay the reasion why IMO automatic system shows two earthquakes.
The p and s wave diffrance is 20.7 sec, when i did put in the final resaults from the Icelandic
met Office.
At this range i seems to be able to detect earthquakes down to 3 on the ricther scale. The area
where this earthquake was, often has earthquakes that are from 3 - 5 on the ricther scale. So i might not have to
wait so long for other earthquake to happen, in order to see the diffrance on earthquakes.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Locating P and S wave, suggestions needed
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Wed, 11 Jan 2006 08:43:53 +0000
Hi all
I have all the psn files and gifs for those who don't have winquake.
Just follow the urls. This is with the data from IMO and p and s markers
set.
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424p.s.mark.ch1.gif
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424p.s.mark.ch2.gif
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424p.s.mark.ch3.gif
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch3.psn
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch2.psn
http://www.simnet.is/jonfr500/earthquake/winquake/060110.002424.ch1.psn
When looked at the N-S file (ch3) the wave appears just to have one
earthquake the same applyes to E-W (ch2), boths channels pattern is alot
diffrent then from Z (ch1).
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: $200 microbarograph first light
From: "Arie Verveer" greensky@..............
Date: Wed, 11 Jan 2006 21:48:55 +0800
David,
A few year ago I ran an infra-sound detector and found
the air currents caused a great deal of problems.
Basically most of the signal. Only having a limited
space, I opted for a long length of thin wall silicon tube
coiled in a spiral. This tube was purchased from a medical
supplier. It acted a a large diaphragm reducing the air
currents at the detectors input. I managed to detect
the air pressure induced by the movement of a small local
quake (100 km away) that shook the ground under the detector.
A few observed meteors were detected plus some interesting
yearly changes in the background noise (ocean). I do think the
radial arm on porous tubes close to the ground would be
the best way forward assuming you have the space. My
detector operated 10 hz and lower.
On the drawing board is mark three of the detector but
before I attempted this I wrote a program that calculated
the propagation of infra-sound in the earth's atmosphere.
It's a working program but not polished enough for production.
If you are interested I can send you some image plots on wave
propagation. It explains why a local quakes infra-sound may
bounce right over your location and why thunderstorms can
only be heard a certain distance and so on.
Question: can image files be posted to this site ? Its been
a while since I last posted anything.
It would be good to have a network of these sensors. Great
work.
Cheers Arie
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Can i use any of those programs ?
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Wed, 11 Jan 2006 13:56:22 +0000
Hi all
Can is use any of those programs on this list with the psn board that i
have or with winsdr.
http://quake.wr.usgs.gov/research/software/
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: $200 microbarograph first light
From: John Popelish jpopelish@........
Date: Wed, 11 Jan 2006 15:14:14 -0500
Arie Verveer wrote:
> David,
>
> A few year ago I ran an infra-sound detector and found
> the air currents caused a great deal of problems.
> Basically most of the signal. Only having a limited
> space, I opted for a long length of thin wall silicon tube
> coiled in a spiral. This tube was purchased from a medical
> supplier. It acted a a large diaphragm reducing the air
> currents at the detectors input. I managed to detect
> the air pressure induced by the movement of a small local
> quake (100 km away) that shook the ground under the detector.
> A few observed meteors were detected plus some interesting
> yearly changes in the background noise (ocean). I do think the
> radial arm on porous tubes close to the ground would be
> the best way forward assuming you have the space. My
> detector operated 10 hz and lower.
(snip)
Do you have any idea what your pressure transducer's sensitivity to
acceleration is? Unless it is a balanced design that specifically
cancels the effects of acceleration, you may have seen a signal that
was a combination of pressure and sensor movement.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: $200 microbarograph first light
From: "Arie Verveer" greensky@..............
Date: Thu, 12 Jan 2006 20:05:16 +0800
Hi, The Pressure sensor is a MKS Bartatron Type 223B
0.2 mmHg Full scale range. It's taut metal diaphragm
was placed parallel to the ground and I would guess
it's response to acceleration is quickly dampened, far
above the 10 Hz response. As my station was some 120km
from our local seismic field direct (distant) measurement
from a local quake was not possible. The infra-sound will
propagate up-wards and then refracts back to the detector
some 200 - 250 km away. I only detected events as the
atmosphere was displaced above the sensor.
Cheers Arie
On Thu, 12 Jan 2006 04:14:14 +0800, John Popelish <jpopelish@........> wrote:
> Arie Verveer wrote:
>> David,
>>
>> A few year ago I ran an infra-sound detector and found
>> the air currents caused a great deal of problems.
>> Basically most of the signal. Only having a limited
>> space, I opted for a long length of thin wall silicon tube
>> coiled in a spiral. This tube was purchased from a medical
>> supplier. It acted a a large diaphragm reducing the air
>> currents at the detectors input. I managed to detect
>> the air pressure induced by the movement of a small local
>> quake (100 km away) that shook the ground under the detector.
>> A few observed meteors were detected plus some interesting
>> yearly changes in the background noise (ocean). I do think the
>> radial arm on porous tubes close to the ground would be
>> the best way forward assuming you have the space. My
>> detector operated 10 hz and lower.
> (snip)
>
> Do you have any idea what your pressure transducer's sensitivity to
> acceleration is? Unless it is a balanced design that specifically
> cancels the effects of acceleration, you may have seen a signal that
> was a combination of pressure and sensor movement.
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with
> the body of the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
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Subject: Finetuning L15B geophone
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Thu, 12 Jan 2006 14:29:01 +0000
Hi all
The new guy in this earthquake stuff needs help agen. I want to finish
setup my geophone settings in winsdr, but i don't know what values i
need to insert in this settings box in winsdr.
Azimuth, currently set to 0, Incident, set to 0, Output Voltage, set to
0, Amp gain, set to 0, A/D input, set to 0, Sensitivity, set to 0,
WinQuake Mag Corr, set to 0, Filter delay, set to 0, DC offset, set to
0. I need to know how to fill those 0 with numbers that are useful to
me. Or a good how-to on it. (I have read the help files, but i am still
shorta lost on this)
I also need to know what unit is on the mesurment, when earthquakes are
detected. Since i was sending my recording to one geologist at the
Icelandic met Office and she did want to know what the setting was on
the detection when earthquake is detected. Then the units that are used,
she did come with this numbers, "24, 48, 72 .....".
I hate know almost nothing about this at this time, i hope pepole here
can tolirate my endless questions. Becose i am learning this day by day.
Greetings.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Earthquake monitoring in Iceland/Scotland/ and the US
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Thu, 12 Jan 2006 15:49:03 +0000
Hi all
Sorry for bringin this old disccuion back up from the darkness of time.
I have found out how far away from a solid rock my geophone is, it is
not deeper then 2m at the most, we are speaking about 2m of sand below
the concret floor then just solid rock. It problay is a lot less then
that below my apartment (i am on ground floor), but it is hard to say
for sure.
Greetings.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Earthquake monitoring in Iceland/Scotland/ and the US
From: "Thomas Dick" dickthomas01@.............
Date: Thu, 12 Jan 2006 12:27:00 -0600
I wish I had only 2 meters to bed rock. I'd take a shovel and dig that far.
It is at least 60 meters to bedrock here at my location. I have to worry
more about liquifraction!
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Earthquake monitoring in Iceland/Scotland/ and the US
From: "Geoff" gmvoeth@...........
Date: Thu, 12 Jan 2006 17:44:23 -0700
You think you got troubles
I am like 240 meters from beadrock
and I have a major road only 30 or so
meters away. I have heard you do not
want roads any closer then the
bedrock is deep.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: microbarograph sensor arrays
From: ChrisAtUpw@.......
Date: Thu, 12 Jan 2006 22:27:16 EST
Hi,
There is a very useful Jan 2005 Revue Article by A J Bedard on
Infrasonic Signals of many sorts and their characteristics at
_http://www.etl.noaa.gov/et1/infrasound/Monthly_Weather_Rev_Paper_Jan05.pdf_
(http://www.etl.noaa.gov/et1/infrasound/Monthly_Weather_Rev_Paper_Jan05.pdf)
There are other useful links at _http://www.etl.noaa.gov/et1/infrasound/_
(http://www.etl.noaa.gov/et1/infrasound/)
Apparatus is described at
_http://www.tornadochaser.net/research/infasonicdetector.pdf_ (http://www.tornadochaser.net/research/infasonicdetector.pdf)
The reduction of wind noise is the major problem when trying to receive
infrasound signals. Large sensor arrays of 'leaky tube' of up to several
hundred feet in diameter may be used. For a single sensor head see US Patent No
4,838,087 June 1989, Bedard and Nishiyama, 'Quad Disk Static Pressure Probe'.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>Hi,</DIV>
<DIV> </DIV>
<DIV> There is a very useful Jan 2005 Revue Article b=
y A=20
J Bedard on Infrasonic Signals of many sorts and their characteristics at=20
<A=20
href=3D"http://www.etl.noaa.gov/et1/infrasound/Monthly_Weather_Rev_Paper_Jan=
05.pdf">http://www.etl.noaa.gov/et1/infrasound/Monthly_Weather_Rev_Paper_Jan=
05.pdf</A></DIV>
<DIV> </DIV>
<DIV> There are other useful links at <A=20
href=3D"http://www.etl.noaa.gov/et1/infrasound/">http://www.etl.noaa.gov/et1=
/infrasound/</A></DIV>
<DIV> </DIV>
<DIV> Apparatus is described at <A=20
title=3Dhttp://www.tornadochaser.net/research/infasonicdetector.pdf=20
href=3D"http://www.tornadochaser.net/research/infasonicdetector.pdf">http://=
www.tornadochaser.net/research/infasonicdetector.pdf</A></DIV>
<DIV> </DIV>
<DIV> The reduction of wind noise is the major proble=
m=20
when trying to receive infrasound signals. Large sensor arrays of 'leaky tub=
e'=20
of up to several hundred feet in diameter may be used. For a single sen=
sor=20
head see US Patent No 4,838,087 June 1989, Bedard and Nishiyama, 'Quad=20=
Disk=20
Static Pressure Probe'.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: I did record a 3,6Ml earthquake, 198 Km away from me.
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 13 Jan 2006 16:19:06 +0000
Hi all
I did just record a 3,6Ml earthquake at 15:19 today. You can get the psn
file here.
http://www.simnet.is/jonfr500/earthquake/winquake/060113.151900.ch1.psn
Here is the gif file. At the moment it does not have any p and s
markers.
http://www.simnet.is/jonfr500/earthquake/winquake/060113.151900.ch1.psn.gif
I have inserted the early time data from IMO into the psn file. I have
not done so with N-S, E-W files. But i will do so later tonight. It is
intresting to compare this one with the mag 3,0 that did happen 10th of
January that was south of me at distance of 171 km. This one was east of
me and 198km away from me. It is also clearly visable on my raw
seismographs.
Greetings.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: I did record a 3,6Ml earthquake, 198 Km away from me.
From: John or Jan Lahr JohnJan@........
Date: Fri, 13 Jan 2006 08:53:27 -0800
J=F3n,
You're lucky to be in an active area (at least in=20
terms of recording lots of local activity).
In your gif images, if you expand the time scale=20
by setting the time interval to something=20
shorter, such as 30 seconds, the event details=20
will be more easily seen and picks will be more accurate.
Cheers,
John
At 08:19 AM 1/13/2006, you wrote:
>Hi all
>
>I did just record a 3,6Ml earthquake at 15:19 today. You can get the psn
>file here.
>
>http://www.simnet.is/jonfr500/earthquake/winquake/060113.151900.ch1.psn
>
>Here is the gif file. At the moment it does not have any p and s
>markers.
>
>http://www.simnet.is/jonfr500/earthquake/winquake/060113.151900.ch1.psn.gif
>
>I have inserted the early time data from IMO into the psn file. I have
>not done so with N-S, E-W files. But i will do so later tonight. It is
>intresting to compare this one with the mag 3,0 that did happen 10th of
>January that was south of me at distance of 171 km. This one was east of
>me and 198km away from me. It is also clearly visable on my raw
>seismographs.
>
>Greetings.
>--
>J=F3n Fr=EDmann J=F3nsson
>http://www.jonfr.com
>
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with
>the body of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
##################################/ John C. Lahr
#################################/ Emeritus Seismologist
################################/ U.S. Geological Survey
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D/ Geologic Hazards Team
##############################/ Golden, Colorado
#############################//##############################
############################//###############################
PO Box 548 /################################
Corvallis, Oregon 97339 /##################################
Phone: (541) 758-2699 /=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Cell: (541) 740-4844 /###################################
Fax: (928) 569-0113 /##################################
jjpub@........ /####################################
http://jclahr.com/science/
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Public Seismic Network Mailing List (PSN-L)
Subject: Re: I did record a 3,6Ml earthquake, 198 Km away from me.
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 13 Jan 2006 17:00:43 +0000
Hi John or Jan Lahr
Updated gif image with p and s markers will be online in just a moments
time (few min after i send this email). I have used early data from IMO
to set the p and s markers.
Greetings.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: I did record a 3,6Ml earthquake, 198 Km away from me.
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 13 Jan 2006 17:15:28 +0000
Hi all
I have updated the files with final data from IMO webapge. I haven't
posted E-W or N-S files. If you want them, just let me know.
Bye.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: I did record a 3,6Ml earthquake, 198 Km away from me.
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 13 Jan 2006 22:52:25 +0000
Hi John
There has not been a earthquake swarm in past three weeks since i got
the geophone (not large anyway), but they are common here in Iceland.
Most of them happen in the Tjörnes Fracture Zone (TFZ), but they are
also common on the Reykjanes ridge and the Reykjanes it self (where
Reykjavik is located) and other locations in Iceland on the volcano
ridge. Sometimes earthquakes that go to 5mb happen. But most common are
earthquakes in the range of 3 - 4,9Ml. I am speaking of earthquake
swarms with hundreds of earthquakes pr hour and sometimes thousunds of
earthquakes pr hour and more then a dosent of earthquakes that rech 3 -
4Ml in size, sometims more.
That has not happened, but when it happens my online graphs are going to
look quite inresting. :-)
Greetings.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: I did record a 3,6Ml earthquake, 198 Km away from me.
From: "Bob Shannon" earth@...........
Date: Fri, 13 Jan 2006 15:05:36 -0800
Just out of curiosity, were you able to pick this up?:
4.0 2006/01/13 04:10:18 18.685 -65.038 54.5 PUERTO RICO REGION
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@...............
On Behalf Of J=F3n Fr=EDmann
Sent: Friday, January 13, 2006 2:52 PM
To: psn-l@..............
Subject: Re: I did record a 3,6Ml earthquake, 198 Km away from me.
Hi John
There has not been a earthquake swarm in past three weeks since i got
the geophone (not large anyway), but they are common here in Iceland.
Most of them happen in the Tj=F6rnes Fracture Zone (TFZ=20
--=20
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.371 / Virus Database: 267.14.16 - Release Date: 1/9/2006
=20
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Public Seismic Network Mailing List (PSN-L)
Subject: RE: I did record a 3,6Ml earthquake, 198 Km away from me.
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 13 Jan 2006 23:14:02 +0000
Hi Bob Shannon
No, i don't have a teleseismic sensor yet. I only have a short range
geophone, that works on 4,5Hz and has a max distance of ~640km.
My online seismographs are here, the earthquake today is clearly visable
even there is a alot of noise that the geophone picks up.
http://www.simnet.is/jonfr500/earthquake/
The earthquake was at 15:19
Greetings.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: ebay auction
From: Bob Barns royb1@...........
Date: Sat, 14 Jan 2006 09:40:17 -0500
Hi gang,
Impact-O-Graph - Recording Accelerometer - Seismograph?
Item number: 7581594696
ends 1/18
Bob
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Subject: Earthquake in Beaufort Sea, 4.9mb
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 14 Jan 2006 14:59:02 +0000
Hi all
I did notice that according to emsc-csem that today there was a
earthquake in Beaufort Sea, the size of the earthquake was at least
4,9mb. I find the location of the earthquake intresting, since there is
no active faultline there or other type of active area that know of.
Here is the info on the earthquake from emsc-csem.
http://www.emsc-csem.org/cgi-bin/QDM_link_content.sh?HC308&2006
Bye.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: ebay auction
From: Bob Barns royb1@...........
Date: Mon, 16 Jan 2006 10:05:21 -0500
Hi gang,
SEISMOGRAPH MINI -MATE
Item number: 6245357035
ends 1/22
Bob
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Public Seismic Network Mailing List (PSN-L)
Subject: ebay auction
From: Bob Barns royb1@...........
Date: Tue, 17 Jan 2006 09:37:02 -0500
Hi gang,
Vintage Seismograph Seiscor Telephone Test Set - L@@k!
Item number: 6597839335
ends 1/23
I have no idea what this is.
Bob
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: follow-up
From: "Thomas Dick" dickthomas01@.............
Date: Wed, 18 Jan 2006 16:55:40 -0600
I understand from witnesses of the Nov 6 tornado over here in Evansville =
that as many as four from your office came to the area. Was a formal =
report of their findings ever released?
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>I understand from witnesses of the Nov =
6 tornado=20
over here in Evansville that as many as four from your office came to =
the area.=20
Was a formal report of their findings ever released?</FONT></DIV>
<DIV> </DIV></BODY></HTML>
Subject: Earthquake swarm
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Thu, 19 Jan 2006 16:21:28 +0000
Hi all
At the current moment there appears to be earthquake swarm going on in
North East of Iceland, north of Krafla volcano system. The biggest
earthquake so far is 4,1Ml. But unfortunally i was moving my geophone
outside when the earthquake did happen, so i did only got the tail of
it. Also, becose i did move the geophone outside the dection is alot
better and i can now see car traffic alot "better" then i did before.
But it hopefully will not be alot of problem for me.
Bye.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Stand Alone A/D converter
From: "Geoff" gmvoeth@...........
Date: Thu, 19 Jan 2006 19:15:19 -0700
Hello you eggheads;
Not trying to offend anyone it is just
an affectionate term I use for academically
oriented person/persons.
The results following this question might be of interest
for newbie Amateurs just getting into
this sport I would like to have known
the answer to this question 10 years ago.
I got this problem that can only be
solved by someone with experience
with the exact/precise thing of which
I speak here.
I am in need of a stand alone 16 bit
A/D converter that can interface with
an IBM style laptop via parallel/serial/USB ports.
It must be totally controllable via the
laptop for sample rates meaning the trigger
for each sample to be read is to be ordered
by the laptop running a custom built program.
It needs to acquire data at the rate of 100
samples per second or slower.
It needs to be quiet down to the last
LSb so the entire 16 bit word can be used.
It needs to provide -120dbv or so isolation
between (the computer and/or the power supply)
and the input to the converter.
I have tried only one A/D converter
a model 40-12 by a company called Prairie Digital
out of Du Sac, WI this device seems to
lack the isolation I need and also radiates
terribly its color burst clock frequency.
It is relatively noisy forcing me to use
only the top 9 bits of its 12 bit capability.
This device is pretty much what I am looking
for in a converter but just too darn noisy.
If any of you kind folks out there will
please take mercy on my soul and tell me
where I can find a device like this
Prairie Digital but designed for serious (quiet)
data collection I sure would like to know.
Please feel free to answer me direct
via gmvoeth<at>hotmail.com .
I have looked around and found a mess of
internal cards to plug into a computer
but What I am looking for is a stand alone
device which one of you seismic gurus have
used before with excellent results.
One which can be outfitted with battery backup.
Thanx Ahead Of Time;
gmv
p.s. this question is not designed to cause any
troubles I was just wondering if any of you
out there know this off the top of your head.
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Subject: Re: Stand Alone A/D converter
From: John or Jan Lahr JohnJan@........
Date: Thu, 19 Jan 2006 20:06:00 -0800
At 06:15 PM 1/19/2006, you wrote:
>I am in need of a stand alone 16 bit
>A/D converter
Geoff,
One option worth considering is the 24-bit A/D made by Symetric
Technology. The owner is Kip Wyss and he's been designing A/D
converters for 20 years. He sells a 1-channel system that connects
via the parallel port and the cost is only
$150. See: http://www.symres.com/products/seldaq.htm
If you want very precise timing, then you can also get a GPS module,
but that jumps the price up quite a bit.
I've only spent a little time trying out the sample program that
comes with the 1-channel system. You definitely have complete
control over all aspects of the A/D, but I haven't gotten into any of
the details.
Hope this helps,
John
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Noise that my geophone picks up
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 20 Jan 2006 21:59:34 +0000
Hi all
I am wondering about noise on my geophone. I have moved my geophone
outside so i have mostly got rid of the noise from inside the house. But
now i get the noise from the weather, traffic and so on alot more then
when it was inside my apartment. However i hope to detect earthquake
better then i did before. But that remanins to be seen.
I appreceate any comments on my noise level. The seismographs plot are
set to setting 8 in winsdr, so it is not too crude.
Bye.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Noise that my geophone picks up
From: ChrisAtUpw@.......
Date: Fri, 20 Jan 2006 18:25:37 EST
In a message dated 20/01/2006, jonfr500@......... writes:
I am wondering about noise on my geophone. I have moved my geophone
outside so I have mostly got rid of the noise from inside the house. But
now I get the noise from the weather, traffic and so on a lot more then
when it was inside my apartment. However I hope to detect earthquake
better then I did before.
Hi Jon,
Have you sealed the plastic case? Are the geophones above the ground
surface, on the surface, or below the surface? Is there a container over the
top?
Is there any possibilty of digging a hole maybe 1 m deep and putting in
a large diameter plastic pipe or similar, sealed at the top and the bottom?
It needs to be completely weather proof.
How do the actual noise levels compare with those when the geophones
were in the apartment? Can you compare 'before' and 'after' recordings?
A professional seismometer pit is described at
_http://www.guralp.net/services/stations/eskdalemuir/_
(http://www.guralp.net/services/stations/eskdalemuir/)
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 20/01/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>I am=20
wondering about noise on my geophone. I have moved my geophone<BR>outside=20=
so I=20
have mostly got rid of the noise from inside the house. But<BR>now I=20=
get=20
the noise from the weather, traffic and so on a lot more then<BR>when it w=
as=20
inside my apartment. However I hope to detect earthquake<BR>better=20
then I did before.</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> Have you sealed the plastic case? Are the geoph=
ones=20
above the ground surface, on the surface, or below the surface? Is there a=20
container over the top? </DIV>
<DIV> </DIV>
<DIV> Is there any possibilty of digging a hole maybe=
1 m=20
deep and putting in a large diameter plastic pipe or similar, sealed at the=20=
top=20
and the bottom? It needs to be completely weather proof. </DIV>
<DIV> </DIV>
<DIV> How do the actual noise levels compare with tho=
se=20
when the geophones were in the apartment? Can you compare 'before' and 'afte=
r'=20
recordings? </DIV>
<DIV> </DIV>
<DIV> A professional seismometer pit is described at=20=
<A=20
href=3D"http://www.guralp.net/services/stations/eskdalemuir/">http://www.gur=
alp.net/services/stations/eskdalemuir/</A></DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Noise that my geophone picks up
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 20 Jan 2006 23:48:17 +0000
Hi Chris
The geophone is above ground, with double box on it, inside is a plastic
box and on top of that is a wood box that has isolation material, i also
have two heavy rocks on the box to prevent it from moving in bad
weather. It is well sealed from the weather (as well it can be done).
Digging a hole 1m deep is not an option for me, becose my lawn is shared
and the there is a bedrock problay about 1m deep down, also the ground
freezing line is about 1m deep.
The noise pickup is diffrent, i see more wind but fewer spikes that
start a warning in winsdr. Only the higest noise inside the block is now
picked up in such way it starts a warning in winsdr (like when someone
closes a door). Unlike before when i did pickup almost everything. It
also seems when the weather is good, and there is no or little traffic
the noise level go down to almost nothing (that seems to be the case at
the moment). The only thing that creates alot of spikes is when the snow
is cleared off the roads near me. But only when it is done close to my
location, less then 500m away from me.
So far the geophone has withstand a heat change from -5C to 3C in the
past 24 hours.
I can send a picture of my setup, if you are intrested in seeing it.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Digital Inverse Filter
From: Bobhelenmcclure@.......
Date: Fri, 20 Jan 2006 22:50:58 EST
In my email of December 31, 2005, I was pessimistic about digitally =20
extending the low frequency response of a geophone to a value useful for te=
leseisms.=20
However, I have been encouraged by my experiments on data recorded by J=F3n=
=20
Fr=EDmann J=F3nsson of Iceland. Please inspect the volume file=20
=20
"060117.015700.hvtzlp Mb4.5 259km from Hvammstangi, Iceland (Inverse=20
Filtered): REYKJANES RIDGE"=20
=20
which I have submitted to the New PSN Earthquake Data Files list. This is a=
=20
volume file consisting of two traces. The upper trace is the result of =20
applying "WQFilter.exe" to the data of the bottom trace. You will see that =20=
inverse=20
filtering has brought out microseisms and the longer period components of t=
he=20
event. I set the Long Period filter to extend the sensor period from 0.22=20
seconds to 4.0 seconds.
=20
Bob McClure
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DISO-8859-1">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2><FONT id=3Drole_document face=3DArial=20=
color=3D#000000=20
size=3D2>
<DIV> In my email of December 31, 2005, I was pessimistic about digita=
lly=20
extending the low frequency response of a geophone to a value useful for=20
teleseisms. However, I have been encouraged by my experiments=20
on data recorded by J=F3n Fr=EDmann J=F3nsson of Iceland. Please i=
nspect the=20
volume file </DIV>
<DIV> </DIV>
<DIV>"<U>060117.015700.hvtzlp</U> Mb4.5 259km from Hvammstangi, Icelan=
d=20
(Inverse Filtered): REYKJANES RIDGE" </DIV>
<DIV> </DIV>
<DIV>which I have submitted to the New PSN Earthquake Data Files list.=20=
This=20
is a volume file consisting of two traces. The upper trace is the result of=20
applying "WQFilter.exe" to the data of the bottom trace. You will see that=20
inverse filtering has brought out microseisms and the longer period=20
components of the event. I set the Long Period filter to extend th=
e=20
sensor period from 0.22 seconds to 4.0 seconds.</DIV>
<DIV> </DIV>
<DIV>Bob McClure</DIV></FONT></FONT></BODY></HTML>
Subject: Re: Noise that my geophone picks up
From: "Geoff" gmvoeth@...........
Date: Fri, 20 Jan 2006 22:20:50 -0700
Are you the Frimann (Freeman) of Half Life two ???
If you are looking higher than two
hertz you are probably plagued
by all kinds of man made noises
and if you are looking under
one hertz you should find
terrible microseisms about
point two hertz.
I find it best to limit things
between point four hertz and
two hertz if at all possible
you want a flat response range
in this area to see P waves.
If you want to see P,S,L waves
you need a flat response between
point oh five and two hertz
but then you will need to turn down your gain
to avoid the added noise of a wide
band receiver from all sources.
I am in a terrible bad noisy place
and considering trying a high gain
narrow band receiver with a Q
of 10 or so and centered on or just
below 1 Hz to see only the
P waves of teleseismic events.
I would be interested in hearing
from people who have battled the
man made noises.
I understand the quietest place you can put your
Geophone is directly on bedrock but since
bedrock might be 800 feet deep it is not
an option I can try.
All the noise I speak of is in the
Southwest Desert of Arizona and
(I understand)
the noise profile is highly dependent
upon geographics.
For all you experts, I just want to
share my personal experiences here
as a layman I am not trying to
supersede your efforts to maintain
a scientifically pure world
of Amateur Seismology.
gmv
----- Original Message -----
From: "Jón Frímann" <jonfr500@.........>
To: "PSN-Postlist" <PSN-L@..............>
Sent: Friday, January 20, 2006 2:59 PM
Subject: Noise that my geophone picks up
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Noise that my geophone picks up
From: ian ian@...........
Date: Sat, 21 Jan 2006 09:19:51 +0000
Hi,
is there a wall that you could sit the geophone on top of? The wall
might be sitting on the underlying bedrock. This is what I did in my
last house. I drilled a hole on the top of the wall and hammered the
geophone spike into it ( the spike was first unscrewed from the
geophone!). This worked well along with a very similar double cover and
rocks that you describe.
I didn't have a problem with wind and rain, just gekos and their egg
planting!
Cheers
Ian
Jón Frímann wrote:
>Hi Chris
>
>The geophone is above ground, with double box on it, inside is a plastic
>box and on top of that is a wood box that has isolation material, i also
>have two heavy rocks on the box to prevent it from moving in bad
>weather. It is well sealed from the weather (as well it can be done).
>Digging a hole 1m deep is not an option for me, becose my lawn is shared
>and the there is a bedrock problay about 1m deep down, also the ground
>freezing line is about 1m deep.
>
>The noise pickup is diffrent, i see more wind but fewer spikes that
>start a warning in winsdr. Only the higest noise inside the block is now
>picked up in such way it starts a warning in winsdr (like when someone
>closes a door). Unlike before when i did pickup almost everything. It
>also seems when the weather is good, and there is no or little traffic
>the noise level go down to almost nothing (that seems to be the case at
>the moment). The only thing that creates alot of spikes is when the snow
>is cleared off the roads near me. But only when it is done close to my
>location, less then 500m away from me.
>
>So far the geophone has withstand a heat change from -5C to 3C in the
>past 24 hours.
>
>I can send a picture of my setup, if you are intrested in seeing it.
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Noise that my geophone picks up
From: "David Saum" DSaum@............
Date: Sat, 21 Jan 2006 10:23:48 -0500 (EST)
Hi Jón
I have a similar noise problem with my 4.5 hz geophone
system that is resting on my basement office slab about
20m from a major highway.
I am using Amaseis freeware for data logging and display,
and I generally set the helicorder display low-pass filter
to 1 Hz, and that gets rid of a lot of the local noise.
When I receive and email notice of a teleseismic event,
I look at the data segment even if it does not show
up on my helicorder display. Often I can FFT the data
segment, see the quake spectral peak, and apply a bandpass
filter to bring the quake out.
One test to see if your electronics is working well is to
see if you can pick up the ~0.2 Hz microseism peak on
your geophone system. My system can generally pick
this up since I started using an AD8626 autozero opamp,
a pcb with star ground configuration, and a shielded
enclosure for my electronics and geophone.
Ciao,
Dave
http://www.infiltec.com/seismo
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: winsdr auto start
From: Barry Lotz barry_lotz@.............
Date: Mon, 23 Jan 2006 16:55:59 -0800 (PST)
Hi all
I'm not that versed with windows inner workings. I was using SDR (DOS) currently. I was interested in using WINSDR but was concerned about it's starting. My power goes out a few times per year. I want to have WINSDR start automaticly when the computer comes back . Larry suggested I put WINSDR in my start up file list. I tried that but when I turn the computer off and on the program is not up and runninjg ( at lease I think). When the computer comes on, I have to log onto windows networking, then I get my desktop display. I'm not sure what is actually running. Should I see WINSDR in the maximized form or minimized?
Regards
Barry
<DIV id=RTEContent>Hi all</DIV> <DIV> I'm not that versed with windows inner workings. I was using SDR (DOS) currently. I was interested in using WINSDR but was concerned about it's starting. My power goes out a few times per year. I want to have WINSDR start automaticly when the computer comes back . Larry suggested I put WINSDR in my start up file list. I tried that but when I turn the computer off and on the program is not up and runninjg ( at lease I think). When the computer comes on, I have to log onto windows networking, then I get my desktop display. I'm not sure what is actually running. Should I see WINSDR in the maximized form or minimized? </DIV> <DIV>Regards</DIV> <DIV>Barry</DIV>
Subject: Re: Noise that my geophone picks up
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Tue, 24 Jan 2006 02:11:57 +0000
Hi Geoff and others.
I am not the Freeman of the game Half Life, hoever few guys in my old
school did call me that becose they did figure that i did look like that
game caracter. :-)
The problem with earthquakes here in Iceland is this, they are mostly in
the range of 2 - 60Hz and problay higer. Since many of them are of
volcanic nature.
I am directly above bedrock, it is about 1 to 2 meters at the most down
to it.
Bye
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: winsdr auto start
From: apsn apsn@...........
Date: Mon, 23 Jan 2006 18:22:54 -0900
Barry,
What I do is disable the need for an administrator name and password
thus bypassing the login prompt upon startup.
In Windows 2000, you can find it under Start, Control Panel, Users
and Passwords, and ensure that the checkbox for "Users must enter a
user name and password to use this computer" is unchecked. Realize,
of course, that doing this means your PC is wide open to everyone who
has physical access to it. Also, make sure the screen saver is not
password protected as it also interfered with proper operation.
With these changes, I got WinSDR (in the startup list) working. And
it runs maximized upon cold boot up.
This is the only way I found to get WinSDR to run upon cold boot in
Windows 2000. If there are other ways, I'd like to hear them.
Good luck,
Bob
http://apsn.awcable.com
At 03:55 PM 1/23/2006, you wrote:
>Hi all
> I'm not that versed with windows inner workings. I was using SDR
> (DOS) currently. I was interested in using WINSDR but was concerned
> about it's starting. My power goes out a few times per year. I want
> to have WINSDR start automaticly when the computer comes back .
> Larry suggested I put WINSDR in my start up file list. I tried that
> but when I turn the computer off and on the program is not up and
> runninjg ( at lease I think). When the computer comes on, I have
> to log onto windows networking, then I get my desktop display. I'm
> not sure what is actually running. Should I see WINSDR in the
> maximized form or minimized?
>Regards
>Barry
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: winsdr auto start
From: Barry Lotz barry_lotz@.............
Date: Mon, 23 Jan 2006 21:37:52 -0800 (PST)
Bob
I'm using windows 98. It has a little different setup in the control panel. The password and users are in separate locations. It seems that what I need to disable is the network password prompt.
Regards
Barry
apsn <apsn@...........> wrote:
Barry,
What I do is disable the need for an administrator name and password
thus bypassing the login prompt upon startup.
In Windows 2000, you can find it under Start, Control Panel, Users
and Passwords, and ensure that the checkbox for "Users must enter a
user name and password to use this computer" is unchecked. Realize,
of course, that doing this means your PC is wide open to everyone who
has physical access to it. Also, make sure the screen saver is not
password protected as it also interfered with proper operation.
With these changes, I got WinSDR (in the startup list) working. And
it runs maximized upon cold boot up.
This is the only way I found to get WinSDR to run upon cold boot in
Windows 2000. If there are other ways, I'd like to hear them.
Good luck,
Bob
http://apsn.awcable.com
<DIV>Bob</DIV> <DIV> I'm using windows 98. It has a little different setup in the control panel. The password and users are in separate locations. It seems that what I need to disable is the network password prompt.</DIV> <DIV>Regards</DIV> <DIV>Barry<BR><BR><B><I>apsn <apsn@...........></I></B> wrote:</DIV> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Barry,<BR><BR>What I do is disable the need for an administrator name and password <BR>thus bypassing the login prompt upon startup.<BR>In Windows 2000, you can find it under Start, Control Panel, Users <BR>and Passwords, and ensure that the checkbox for "Users must enter a <BR>user name and password to use this computer" is unchecked. Realize, <BR>of course, that doing this means your PC is wide open to everyone who <BR>has physical access to it. Also, make sure the screen saver is not <BR>password protected as it also interfered with proper operation.<BR><BR>With
these changes, I got WinSDR (in the startup list) working. And <BR>it runs maximized upon cold boot up.<BR><BR>This is the only way I found to get WinSDR to run upon cold boot in <BR>Windows 2000. If there are other ways, I'd like to hear them.<BR><BR>Good luck,<BR><BR>Bob<BR>http://apsn.awcable.com<BR><BR><BR></BLOCKQUOTE>
Subject: Re: Noise that my geophone picks up
From: Kevin McCue asc@...............
Date: Tue, 24 Jan 2006 21:28:53 +1100
Jon
I have been enjoying this exchange of information.
The frequency range of local earthquakes in Iceland is typical of the=20
frequency range of small earthquakes recorded on rock near to the=20
source. You just have to sample at a high rate 100 or preferably 200s/s=20=
to see it. For monitoring of mining rock bursts up close you have to=20
increase this rate by a factor of 10 or more.
In the Lachlan Foldbelt in southeastern Australia we typically record=20
ground shaking near 50 Hz for small earthquakes up to ML 4 and there=20
isn't a recently active volcano for 500 km or so.
Regards
Kevin
On 24/01/2006, at 1:11 PM, J=F3n Fr=EDmann wrote:
> Hi Geoff and others.
>
> I am not the Freeman of the game Half Life, hoever few guys in my old
> school did call me that becose they did figure that i did look like=20
> that
> game caracter. :-)
>
> The problem with earthquakes here in Iceland is this, they are mostly=20=
> in
> the range of 2 - 60Hz and problay higer. Since many of them are of
> volcanic nature.
>
> I am directly above bedrock, it is about 1 to 2 meters at the most =
down
> to it.
>
> Bye
> --=20
> J=F3n Fr=EDmann J=F3nsson
> http://www.jonfr.com
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with
> the body of the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
>
Kevin McCue
Director
Australian Seismological Centre
PO Box 324 Jamison Centre
ACT 2614
Australia
ph: 61 (0)2 6251 1291
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re[2]: winsdr auto start
From: Angel sismos@..............
Date: Tue, 24 Jan 2006 12:23:49 +0000
Hello Barry,
You can try to run WinSDR as a service and give it permission to
interact with the desktop. Microsoft makes a tool that works
sometimes to make programs run a service. I think it is call "srvany"
I have used it successfully with Seislog and other programs that
needed to run before user credential were entered.
In the end I would get away from W98.
Angel
Tuesday, January 24, 2006, 5:37:52 AM, you wrote:
> Bob
> I'm using windows 98. It has a little different setup in the
> control panel. The password and users are in separate locations. It
> seems that what I need to disable is the network password prompt.
> Regards
> Barry
> apsn <apsn@...........> wrote:
> Barry,
> What I do is disable the need for an administrator name and password
> thus bypassing the login prompt upon startup.
> In Windows 2000, you can find it under Start, Control Panel, Users
> and Passwords, and ensure that the checkbox for "Users must enter a
> user name and password to use this computer" is unchecked. Realize,
> of course, that doing this means your PC is wide open to everyone who
> has physical access to it. Also, make sure the screen saver is not
> password protected as it also interfered with proper operation.
> With these changes, I got WinSDR (in the startup list) working. And
> it runs maximized upon cold boot up.
> This is the only way I found to get WinSDR to run upon cold boot in
> Windows 2000. If there are other ways, I'd like to hear them.
> Good luck,
> Bob
> http://apsn.awcable.com
--
Best regards,
Angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Noise that my geophone picks up
From: ChrisAtUpw@.......
Date: Tue, 24 Jan 2006 07:48:15 EST
In a message dated 24/01/2006, asc@............... writes:
Jon
I have been enjoying this exchange of information. The frequency range of
local earthquakes in Iceland is typical of the frequency range of small
earthquakes recorded on rock near to the source. You just have to sample at a high
rate 100 or preferably 200s/s to see it. For monitoring of mining rock bursts
up close you have to increase this rate by a factor of 10 or more.
In the Lachlan Foldbelt in south-eastern Australia we typically record
ground shaking near 50 Hz for small earthquakes up to ML 4 and there isn't a
recently active volcano for 500 km or so.
Regards
Kevin
Hi Jon, Kevin,
Jon is using one of Larrys's four channel amplifier boards. These have a
nominal bandwidth of 20 sec to 10 Hz, with an 8 pole Butterworth roll off.
It is 20 dB down by 20 Hz and 40 dB down by 30 Hz. I doubt if there is any
point in sampling beyond 50 sps, and 30 sps would probably would be
satisfactory. See _http://psn.quake.net/serialamp.html_
(http://psn.quake.net/serialamp.html)
Jon also has sea noise and local environmental noise to cope with.
Your comments, please, Kevin?
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 24/01/2006, asc@............... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Jon<BR>I=20
have been enjoying this exchange of information. The frequency range of lo=
cal=20
earthquakes in Iceland is typical of the frequency range of small earthqua=
kes=20
recorded on rock near to the source. You just have to sample at a high rat=
e=20
100 or preferably 200s/s to see it. For monitoring of mining rock bursts u=
p=20
close you have to increase this rate by a factor of 10 or more.<BR>In the=20
Lachlan Foldbelt in south-eastern Australia we typically record ground sha=
king=20
near 50 Hz for small earthquakes up to ML 4 and there isn't a recently act=
ive=20
volcano for 500 km or so.<BR>Regards<BR>Kevin<BR></FONT></BLOCKQUOTE></DIV=
>
<DIV></DIV>
<DIV>Hi Jon, Kevin,</DIV>
<DIV> </DIV>
<DIV> Jon is using one of Larrys's four channel ampli=
fier=20
boards. These have a nominal bandwidth of 20 sec to 10 Hz, with an 8 pole=20
Butterworth roll off. It is 20 dB down by 20 Hz and 40 dB down by 30 Hz. I d=
oubt=20
if there is any point in sampling beyond 50 sps, and 30 sps would proba=
bly=20
would be satisfactory. See <A=20
href=3D"http://psn.quake.net/serialamp.html">http://psn.quake.net/serialamp.=
html</A></DIV>
<DIV> Jon also has sea noise and local environmental=20
noise to cope with. </DIV>
<DIV> Your comments, please, Kevin?</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: from Angel
From: Angel sismos@..............
Date: Tue, 24 Jan 2006 13:24:09 +0000
Hi Larry,
Please give me a price on an 8 channel serial ADC with two amp boards
with mounting kit with cables. In a box if you have one.
I want to take 8 VHF/UHF telemetry channels and take them to and
Earthworm system. I am assuming that I need to amplify these channels
after the demodualtor. I have not used telemetry station before.
It would be shipped to Seattle and needs to be there by Feb. 2nd.
Regards,
angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: from Angel
From: Angel sismos@..............
Date: Tue, 24 Jan 2006 14:18:31 +0000
Larry,
please add a GPS to the last quote.
1 serial board
2 four channel amp boards
mounting kit
gps
all in a box if possible with longest GPS cable you can provide.
angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: My apologies to the list
From: Angel sismos@..............
Date: Tue, 24 Jan 2006 14:39:57 +0000
Sorry to everyone,
Those last two messages were meant privately for Larry. I have sworn
before not to use reply on this list. :(
Angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Windows auto start
From: "Thomas Dick" dickthomas01@.............
Date: Tue, 24 Jan 2006 11:05:05 -0600
I used it on Windows 98. Now using it on Windows 2000. I had to wait for my
techie son to put it in simple terms but here it is
1.one solution
TweakUI, a widely available program forWindows, has this feature built-in,
for automatically signing on.
2.second solution
If one is brave enough to take on registry editting, then you
Start-Run->Regedit
3. third solution and the one I resorted to ...
Goto:
Local Machine->Software->Microsoft->Windows NT->Current Version->Winlogon
In this part of the tree, new or existing string keys need to be set thusly:
Key: Values:
AutoAdminLogon 1
DefaultUserName WhateverYourSignonNameGoesHere
DefaultPassword YourPasswordAtStartupGoesHere
DefaultDomainName NameOfYourComputerHere
DisableCAD 1
You can find out the name of your computer from the "Computer Name" tab of
the System control panel.
Watch out! Twice I lost data because the hard drive ran out of memory.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: tornadoes and earthquake detection
From: "Thomas Dick" dickthomas01@.............
Date: Wed, 25 Jan 2006 14:03:27 -0600
Geoff, where did you get these figures you made on the net on this date?
Sent: Friday, December 02, 2005 2:47 PM
Subject: Re: tornadoes and earthquake detection
>
> You should do a FFT analysis of your raw digital
> data and see if you can extract the rotational rate of the funnel cloud
> from the data.
> I would expect the rotational rate of a .75 mile
> wide funnel with 100 mph wind speed to have
> a rotational period near 84 seconds or less.
>
> If the tornado was traveling at 60mph
> then the rotational speed was probably
> only about 100mph.
>
> It made me sad that was unable to see the
> seismic data, but what the hey, thats the story of my life.
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Fault zones in Iceland
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Thu, 26 Jan 2006 05:54:24 +0000
Hi all
Here is a map that shows the fault zones and the hotspot of Iceland, if
my loaction is marked on that map it is clear that i hopefully will be
able to detect earthquakes that are <2.5 on the ricther scale. I am
close to most of the fault zones here in Iceland, but not too close.
http://home1.gte.net/res04as8/Grimsvtn/map.html
I am also near (less then 20 km) a old rupture zone that was active at
least 3,3 million years ago. But i do now know if earthquakes happens
there at all or some other type of activti (it looks pretty dead). I
have seen earthquakes that are less then 40 km away from where i life
(south of me, but in both cases the trigger was activiti near
Hveravöllum with earthquakes from 1 - 3.5 mag), but they where small,
around 1,5 - 2,8 on the ricther scale (minimal that Icelandic met Office
detects at that range, based on the location of there stations). There
have been large earthquakes near where i life, the last one was in 1973
and was 5,5 on the ricther scale (South-West of me). The largest one
mesured was a mag 7 on the ricther scale in 1963 and was about 60 - 80
km where i life (North-East of where i life). I fear that when there is
going to me a earthquake above 6 on the ricther scale that my geophone
will move in the tremor (like get displaced from it's location). However
a earthquake at that size and that close to me is unlikley, but not
impossible. But both of those earthquakes did happen before i was born
and i did miss the big earthquakes (two 6,5 mag) in the year 2000 that
did happen in south of Iceland.
I also have one question to ask this time. Does anyone know how the ocen
wave appears on seismograph ? Becose i was doing some work on my
geophone early this night and after that i see wave top appear on my
seismographs (preventing the geophone from moving by increase the
pressure on him with plastic bags inside of the box that is on top of
him, also to minimize the wind noise as i can), those tops are "smooth"
and don't look like wind noise. I doubt that this is the plastic bags
fault.
There appars to be increased activiti at Hveravöllum. Two earthquakes
recored by the Iceland met Office in past 24 hours or so.
Thanks.
Bye.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Fault zones in Iceland
From: ChrisAtUpw@.......
Date: Thu, 26 Jan 2006 09:30:13 EST
In a message dated 26/01/2006, jonfr500@......... writes:
I also have one question to ask this time. Does anyone know how the ocean
wave appears on seismograph? Because I was doing some work on my
geophone early this night and after that I saw wave top appear on my
seismographs (preventing the geophone from moving by increase the
pressure on him with plastic bags inside of the box that is on top of
him, also to minimise the wind noise as I can), those tops are "smooth"
and don't look like wind noise. I doubt that this is the plastic bags
fault.
Hi Jon,
The Atlantic ocean microseisms may be 0.5 to 15 microns with a period of
6 to 7 seconds. I very much doubt if your geophones will see this. The waves
are usually short sections of rather rough sine form. Since you are fairly
close to the sea, you may pick up wave noise. You are likely to see storm
noise.
If you have any air filled plastic bags in your seismometer box, I
suggest that you remove them immediatly. They are likely to react quite strongly
both to changes in atmospheric pressure and to wind speed!
The accelerations that you normally observe should not move a geophone
case set on the ground. If you want to provide a more firm fixing, I suggest
that you get some children's 'plasticene' (like a non sticky putty) and use
this to 'join' the geophone case to the concrete.
See _http://www.bostik.com.au/pdf/datasheet/bostik_blu_tack.pdf_
(http://www.bostik.com.au/pdf/datasheet/bostik_blu_tack.pdf) I can buy Blu-Tack and
White-Tack adhesive putty from stationers. It is now available in the US. See
_http://www.artech-electronics.com/us/products/accesso/blutack.html_
(http://www.artech-electronics.com/us/products/accesso/blutack.html) It is a semi
elastic non drying adhesive mastic which hardens over a period of weeks, but
may be kneaded again by hand and re-used. Very useful for making demountable
seals, sticking posters to walls without damaging the finish etc..
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 26/01/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>I also=20
have one question to ask this time. Does anyone know how the ocean<BR>wave=
=20
appears on seismograph? Because I was doing some work on my<BR>geophone ea=
rly=20
this night and after that I saw wave top appear on my<BR>seismographs=
=20
(preventing the geophone from moving by increase the<BR>pressure on him wi=
th=20
plastic bags inside of the box that is on top of<BR>him, also to minimise=20=
the=20
wind noise as I can), those tops are "smooth"<BR>and don't look like=20=
wind=20
noise. I doubt that this is the plastic=20
bags<BR>fault.<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> The Atlantic ocean microseisms may be 0.5 to 15=
=20
microns with a period of 6 to 7 seconds. I very much doubt if your geophones=
=20
will see this. The waves are usually short sections of rather rough sine for=
m.=20
Since you are fairly close to the sea, you may pick up wave noise. You are=20
likely to see storm noise.</DIV>
<DIV> If you have any air filled plastic bags in your=
=20
seismometer box, I suggest that you remove them immediatly. They are li=
kely=20
to react quite strongly both to changes in atmospheric pressure an=
d to=20
wind speed! </DIV>
<DIV> The accelerations that you normally observe sho=
uld=20
not move a geophone case set on the ground. If you want to provide a more fi=
rm=20
fixing, I suggest that you get some children's 'plasticene' (like a non stic=
ky=20
putty) and use this to 'join' the geophone case to=20
the concrete. </DIV>
<DIV> See <A=20
href=3D"http://www.bostik.com.au/pdf/datasheet/bostik_blu_tack.pdf">http://w=
ww.bostik.com.au/pdf/datasheet/bostik_blu_tack.pdf</A> I=20
can buy Blu-Tack and White-Tack adhesive putty from stationers. It is now=20
available in the US. See</DIV>
<DIV><A=20
href=3D"http://www.artech-electronics.com/us/products/accesso/blutack.html">=
http://www.artech-electronics.com/us/products/accesso/blutack.html</A> =
It=20
is a semi elastic non drying adhesive mastic which hardens over a period of=20
weeks, but may be kneaded again by hand and re-used. Very useful for making=20
demountable seals, sticking posters to walls without damaging the finish=20
etc..</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: ebay auction
From: Bob Barns royb1@...........
Date: Thu, 26 Jan 2006 10:00:52 -0500
Hi gang,
Seismograph Earthquake Vibration Seismic Geophone Kit
Item number: 7585030314
ends 2/1
Might be a way to introduce kids to seismology.
Bob
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Fault zones in Iceland
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Thu, 26 Jan 2006 21:25:58 +0000
Hi all
I did remove the plastic bags as Chris Chapman did advice me, but i did
also move my geophone back inside. Becose the noise inside the house is
less then the noise that is outside and the house also tamper the wind
noise down alot. I have been wondering about lowpassfilter and
higpassfilter, i do know where i can detect the earthquakes. But that is
from 2Hz to 10Hz that can work for me. But i don't know if they
lowpassfreq cutoff is 2Hz or 4Hz and other way around regarding the
higpassfreq cutoff. I have been reading help for winsdr regarding that,
but i don't understand what is what.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Fault zones in Iceland
From: ChrisAtUpw@.......
Date: Thu, 26 Jan 2006 21:38:56 EST
In a message dated 26/01/2006, jonfr500@......... writes:
I have been wondering about low pass filter and
high pass filter, I do know where I can detect the earthquakes. But that is
from 2Hz to 10Hz that can work for me. But I don't know if they
low pass freq cut-off is 2Hz or 4Hz and other way around regarding the
high pass freq. cut-off. I have been reading help for winsdr regarding that,
but I don't understand what is what.
Hi Jon,
A low pass filter is one which passes all frequencies up to about the
cut-off frequency without loss. The amplitude of any signal above the cut-off
frequency drops very quickly and it is depends on the number of 'poles' or
filter sections.
A high pass filter passes frequencies above the cut-off frequency.
The low pass filter on your amplifier board should be 10 Hz and have 8
poles. In practice, a signal at 13.4 Hz will be reduced to 1/10 and one at 18
Hz to 1/100.
The amplifier has a high pass filter set at 0.05 Hz = 20 sec., which is
well below the lowest response of your geophones.
The low frequency response is set by the geophone, 4.5 Hz in this case.
From 4.5 to 60 Hz, the response is nearly constant. Below 4.5 Hz the response
falls off roughly proportional to the square of the frequency ratio. So a 2
Hz signal can give ~1/5 the amplitude, but you may still see it. A 1 Hz
signal will only give ~1/20 the amplitude and this is likely to be lost in the
noise. A 0.5 Hz signal will give ~1/100 the amplitude.
So, putting this signal into your system, you will see a flat response
between 4.5 an 10 Hz. The response falls very quickly for signals above 10 Hz,
but much less quickly for signals below 4.5 Hz.
The local quakes which you are likely to observe have a lot of higher
frequency components, certainly to 10 Hz and maybe to over 40 Hz, which is good
for your system. Unfortunately the environmental noise also increases with
frequency in this range, which will limit your ability to detect the quakes.
Choosing the quietest place for your geophones is important. This is best done
by taking several 24 hr recordings, observing the weather and wind strength
and estimating how the noise signal changes with time. There are likely to be
higher noise levels when residents leave for work in the morning and return
in the evening. Snow clearance vehicles and heavy lorries can make quite a
noise. The wind noise is likely to increase with the square of the wind speed.
Buildings are shaken by the wind and the vibrations are coupled into the
ground nearby. Placing the geophone on a basement floor, but away from the
outside walls may help.
Hope that this is of help. Please say if there is anything you don't
understand.
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 26/01/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>I have=20
been wondering about low pass filter and<BR>high pass filter, I do kn=
ow=20
where I can detect the earthquakes. But that is<BR>from 2Hz to 10Hz t=
hat=20
can work for me. But I don't know if they<BR>low pass freq cut-off is=
2Hz=20
or 4Hz and other way around regarding the<BR>high pass freq. cut-off. I ha=
ve=20
been reading help for winsdr regarding that,<BR>but I don't understan=
d=20
what is what.<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> A low pass filter is one which passes all=20
frequencies up to about the cut-off frequency without loss. The amplitude of=
any=20
signal above the cut-off frequency drops very quickly and it is depends=20
on the number of 'poles' or filter sections.</DIV>
<DIV> A high pass filter passes frequencies above the=
=20
cut-off frequency.</DIV>
<DIV> The low pass filter on your amplifier board sho=
uld=20
be 10 Hz and have 8 poles. In practice, a signal at 13.4 Hz will be reduced=20=
to=20
1/10 and one at 18 Hz to 1/100.</DIV>
<DIV> The amplifier has a high pass filter set at 0.0=
5 Hz=20
=3D 20 sec., which is well below the lowest response of your geophones.</DIV=
>
<DIV> </DIV>
<DIV> The low frequency response is set by the=20
geophone, 4.5 Hz in this case. From 4.5 to 60 Hz, the response is=20
nearly constant. Below 4.5 Hz the response falls off roughly proportional to=
the=20
square of the frequency ratio. So a 2 Hz signal can give ~1/5=
the=20
amplitude, but you may still see it. A 1 Hz signal will only give ~1/20=
the=20
amplitude and this is likely to be lost in the noise. A 0.5 H=
z=20
signal will give ~1/100 the amplitude.</DIV>
<DIV> </DIV>
<DIV> So, putting this signal into your system,=20
you will see a flat response between 4.5 an 10 Hz. The response fa=
lls=20
very quickly for signals above 10 Hz, but much less quickly for signals=
=20
below 4.5 Hz. </DIV>
<DIV> </DIV>
<DIV> The local quakes which you are likely to observ=
e=20
have a lot of higher frequency components, certainly to 10 Hz and maybe=
to=20
over 40 Hz, which is good for your system. Unfortunately the environmental n=
oise=20
also increases with frequency in this range, which will limit your=20
ability to detect the quakes. Choosing the quietest place for your=20
geophones is important. This is best done by taking several 24 hr=20
recordings, observing the weather and wind strength and estimating how the n=
oise=20
signal changes with time. There are likely to be higher noise levels when=20
residents leave for work in the morning and return in the evening. Snow=20
clearance vehicles and heavy lorries can make quite a noise. The wind noise=20=
is=20
likely to increase with the square of the wind speed. Buildings are shaken b=
y=20
the wind and the vibrations are coupled into the ground nearby. Placing the=20
geophone on a basement floor, but away from the outside walls may=20
help.</DIV>
<DIV> </DIV>
<DIV> Hope that this is of help. Please say if there=20=
is=20
anything you don't understand.</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV>
<DIV> </DIV>
<DIV> </DIV></FONT></BODY></HTML>
Subject: Re: Fault zones in Iceland
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 27 Jan 2006 03:00:08 +0000
Hi Chris
Thanks for the info. I did set the low pass cutoff freq to 4.5Hz (i
might have turned that setting off when you read this email, just to
compare the resaults), since most of the noise is above that level as
you say. But i wonder if i am right on doing that. The noise level is
alot less sinice i did move my geophone back in, execpt from the noise
from me and strong wind that was going on to night. It has been rather
flat line. I will need a earthquake to see if my low pass cutoff
settings are correct or not. I still detect the noise from my movements,
but at they are alot more lower then before.
I am looking into moving the geophone into my storage room, it can be
done. But not until i get a specal computer for it. Since i can't draw a
wire from that location and into my apartment. I will have to use wlan
and two winsdr to do this. Connected together over the wlan. If that
can be done to start with.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: exact frequencies for arrival of different seismic waves ??
From: "Geoff" gmvoeth@...........
Date: Thu, 26 Jan 2006 20:29:31 -0700
Hello;
Can anyone tell me ?
Are there exact frequencies for the first
arrival time of P and S waves ?
I have only seen ranges of frequencies.
If I could pin down exact frequencies I could
make a summation of maybe three narrow band pass
filters with a relatively high Q to look for
each of these waves.
I suspect the ground may behave in a
predictable fashion with the leading edge
of a wave train.
Has anyone ever researched this in any depth
with test equipment that can show reality ?
I know for a fact that the government has
incredible test equipment because I have seen
some of it but not that which is designed
for geological work.
I have seen charts showing ranges of freqs
but here I am only interested in exact
frequencies or slew rates of the first
time of arrival and not the train that follows.
also;
If you are looking for seismic waves
created by nuclear explosions, what
would you be looking for ?
gmv
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: exact frequencies for arrival of different seismic waves ??
From: Dave Nelson davenn@...............
Date: Fri, 27 Jan 2006 15:30:47 +1100
Hi Geoff
there are NO exact frequencies ... the frequency of the
different waves arriving at the sensor are dependant on many factors.
1) type and depth of rupture
2) distance between the sensor and the rupture
3) sensor location relative to the ruprture
to name a few
take 2) .. distance between your sensor and the rupture.....
as distance increases you loose the higher freq component of the signal
because of attenuation/absorption just as you do with sound waves over
distance eg. think of a rumble of thunder in a storm ....
if you are close to the lightning strike you hear the sharp crack of the
thunder
as distance increases you only get to hear the low freq rumblings
or another pratical example .... think of that loud music being played
by your noisy neighbour what do you hear ?? ... the thump thump of the
bass and drums the hi freq has all but gone ( they are all there at the
source!)
when refering to sensor location I am referring to compass bearing to the
rupture
from the sensor ( or visa versa) eg on a strike slip fault ... if you are
in the compressional quadrant of the outgoing waves you are likely to see a
far different waveform than if you are in the dilation quadrant. see my
brief discussion of this on my www page
...... http://www.sydneystormcity.com/fomec.htm
if you look at diag B you can see the 4 quadrants 2 compressional and 2
dilational and the sensor location within those quadrants will have a
determination on the amplitude and freq of the received waveform
this all applies to teleseisms as well .... note how they lack much in the
way of P and S wave signal MOST of it is the lower freq surface waves
basically then, the closer the quake, the more hi freq component your
sensor will detect
hence why professional stations use broadband sensors ... record
EVERYTHING, then filter accordingly to retrieve the wanted data
cheers
Dave N
Sydney
Australia
At 20:29 26/01/2006 -0700, you wrote:
>Hello;
>Can anyone tell me ?
>Are there exact frequencies for the first
>arrival time of P and S waves ?
>I have only seen ranges of frequencies.
>If I could pin down exact frequencies I could
>make a summation of maybe three narrow band pass
>filters with a relatively high Q to look for
>each of these waves.
>
>I suspect the ground may behave in a
>predictable fashion with the leading edge
>of a wave train.
>Has anyone ever researched this in any depth
>with test equipment that can show reality ?
>I know for a fact that the government has
>incredible test equipment because I have seen
>some of it but not that which is designed
>for geological work.
>I have seen charts showing ranges of freqs
>but here I am only interested in exact
>frequencies or slew rates of the first
>time of arrival and not the train that follows.
>
>also;
>If you are looking for seismic waves
>created by nuclear explosions, what
>would you be looking for ?
>
>gmv
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: exact frequencies for arrival of different seismic waves ??
From: "Geoff" gmvoeth@...........
Date: Thu, 26 Jan 2006 23:34:45 -0700
Thanks Dave;
I just got three EQs from Baja California looks like
two foreshocks and the main, they are a little over three
degrees away and 4,0 or less in magnitude.
It looks to me like the P waves are in the hertz range
which is beyond the rolloff of my current filter.
The other day I received Teleseismic event from New Zealand
that was said to be 90deg away and only 5.2 mag which
was inband..it looked like the freq was down around
5 hertz or so.
You pointd out something I never saw before with the link
you provided, thank you very much. I never understood
what those spheres represented till now.
I am currently using a two octave filter which provides
flatness below 1 Hz and am able to see both regional
and teleseismic P waves.
My filter is down to three opamps now where it used to
be 8 or so :-) and I get better results.
I got this penpal over in England that believes
in a KISS philosophy (Keep it Simple Stupid)
that philosophy has proven to be true.
Once Again Thanks to PSN and people like
yourself I am an old dog learning new tricks.
gmv
----- Original Message -----
From: "Dave Nelson" <davenn@...............>
To: <psn-l@..............>
Sent: Thursday, January 26, 2006 9:30 PM
Subject: Re: exact frequencies for arrival of different seismic waves ??
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Intrest in Volcano activiti ?
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 27 Jan 2006 22:54:37 +0000
Hi all
I am wondering if anyone that is on the psn postlist has intrest in
volcano activiti. But that is my main intrest along with earthquakes.
Greetings.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Fault zones in Iceland
From: Larry Cochrane lcochrane@..............
Date: Fri, 27 Jan 2006 18:14:21 -0800
Hi Everyone,
Chris wrote:
> The low pass filter on your amplifier board should be 10 Hz and have 8
> poles. In practice, a signal at 13.4 Hz will be reduced to 1/10 and one at 18
> Hz to 1/100.
> The amplifier has a high pass filter set at 0.05 Hz = 20 sec., which is
> well below the lowest response of your geophones.
Actually Jon's Amp/Filter board has a 20 Hz 7 pole low pass filter. I usually set the
filter to 20 Hz instead of the 10 Hz if I know that the filter board will be used
with a geophone to record local events.
Regards,
Larry Cochrane
Redwood City, PSN
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Fault zones in Iceland
From: Tamati chief.cook.nz@............
Date: Sun, 29 Jan 2006 04:40:58 +1300
TAMATI's WORD's OF WISDOM
FOR THE GOOD OF ALL MANKIND
HTTP://LIVE-PLANET.BLOGSPOT.COM
http://www.webspawner.com/users/chiefcooknz/index.html
Please give me feed back on what you think
chief.cook.nz.@............
NZ-021-150-33-59 or NZ-07-855-0195
Good Morning from NZ (2-53am)
Can you send my a circut diagram and a Pic of the Amplifer please I've =
thought of a way of making pickup
1/ A plastic Jam jar with a screw lid full of jelly or grease or fat or =
sand or even sugar with the screw lid screwed down tight
2/ take an old computer case with the speaker still mount in it
3/ Run a couple of long wires from the speaker in inside comuputer case =
outside the cas (I have about 5 or 6 of them) =20
4/ Put he comuter case inside a trash bag with the wires from the =
speaker outside the trash bag and then seal it with packing tape
5/ dig a hole in the ground about a metre deep and bury the computer =
case=20
6/ The speaker would act as Microphone to your ampilfier (perampifier)=20
7/ Run the wires to the microphone jack on my computer or a laptop use a =
software music mixer/editor prg with shows the music as waves
8/ Then PRINT IT or export inputed data to a file compatable with a prg =
that would show the wave and PRINT IT
What do you think of my idea as I'm a Member of:-=20
"THE NUMBER 8 WIRE KIWI CLUB" (Inventor)
Cheers Tamati
From the Castle of Tamati, Hinemoa and Karauwa the Dog
From the Castle of Tom, Robyn and the Dog
I'm Just a Stone's Throw Away:- NZ-021-150-33-59 or NZ-07-855-0195
Bush Telegragh:- =
chief.cook.nz@............
My Regular Pitstop:- Tamati
P.O.BOX 19-356 CENTRAL
HAMILTON
NEW =
ZEALAND
----- Original Message -----=20
From: "Larry Cochrane" <lcochrane@..............>
To: <psn-l@..............>
Sent: Saturday, January 28, 2006 3:14 PM
Subject: Re: Fault zones in Iceland
> Hi Everyone,
>=20
> Chris wrote:
>> The low pass filter on your amplifier board should be 10 Hz and have =
8=20
>> poles. In practice, a signal at 13.4 Hz will be reduced to 1/10 and =
one at 18=20
>> Hz to 1/100.
>> The amplifier has a high pass filter set at 0.05 Hz =3D 20 sec., =
which is=20
>> well below the lowest response of your geophones.
>=20
> Actually Jon's Amp/Filter board has a 20 Hz 7 pole low pass filter. I =
usually set the=20
> filter to 20 Hz instead of the 10 Hz if I know that the filter board =
will be used=20
> with a geophone to record local events.
>=20
> Regards,
> Larry Cochrane
> Redwood City, PSN
>=20
> __________________________________________________________
>=20
> Public Seismic Network Mailing List (PSN-L)
>=20
> To leave this list email PSN-L-REQUEST@.............. with=20
> the body of the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<BODY>
<DIV><STRONG><FONT face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dcenter><STRONG><FONT face=3DGeorgia>TAMATI's WORD's OF =
WISDOM<BR>FOR=20
THE GOOD OF ALL MANKIND<BR></FONT></STRONG><A=20
href=3D"http://LIVE-PLANET.BLOGSPOT.COM"><STRONG><FONT=20
face=3DGeorgia>HTTP://LIVE-PLANET.BLOGSPOT.COM</FONT></STRONG></A><BR><A =
href=3D"http://www.webspawner.com/users/chiefcooknz/index.html"><STRONG><=
FONT=20
face=3DGeorgia>http://www.webspawner.com/users/chiefcooknz/index.html</FO=
NT></STRONG></A><BR><STRONG><FONT=20
face=3DGeorgia>Please give me feed back on what you =
think<BR></FONT></STRONG><A=20
href=3D"mailto:chief.cook.nz.@............"><STRONG><FONT=20
face=3DGeorgia>chief.cook.nz.@............</FONT></STRONG></A><BR><STRONG=
><FONT=20
face=3DGeorgia>NZ-021-150-33-59 or NZ-07-855-0195</FONT></STRONG></DIV>
<DIV align=3Dcenter><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG><STRONG><FONT=20
face=3DGeorgia>Good Morning from NZ (2-53am)</FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>Can you send my a circut =
diagram and=20
a Pic of the Amplifer please I've thought of a way of making=20
pickup</FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>1/ A plastic Jam =
jar with a=20
screw lid full of jelly or grease or fat or sand or even sugar with the =
screw=20
lid screwed down tight</FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>2/ take an old computer =
case with the=20
</FONT></STRONG><STRONG><FONT face=3DGeorgia>speaker still mount =
in=20
it</FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>3/=20
Run </FONT></STRONG><STRONG><FONT face=3DGeorgia>a couple =
of long=20
wires from the speaker in inside comuputer case outside the cas (I =
have=20
about 5 or 6 of them) </FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>4/ Put he comuter case =
inside a trash=20
bag with the wires from the speaker outside the trash bag and then seal =
it with=20
packing tape</FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG><STRONG><FONT=20
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>5/ dig a hole in the =
ground about a=20
metre deep and bury the computer case </FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>6/ The=20
speaker would act as<STRONG><FONT face=3DGeorgia> Microphone =
to your=20
ampilfier (perampifier) </FONT></STRONG></FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia>7/</FONT></STRONG><STRONG><FONT=20
face=3DGeorgia> Run the wires to the microphone jack on my computer =
or a=20
laptop use a software music mixer/editor prg with shows the =
music as=20
waves</FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>8/ Then PRINT IT =
or export=20
inputed data to a file compatable with a prg that would show the wave =
and PRINT=20
IT</FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>What do you think of my =
idea as I'm a=20
Member of:- </FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>"THE NUMBER 8 WIRE KIWI =
CLUB"=20
(Inventor)</FONT></STRONG></DIV>
<DIV align=3Dleft><STRONG><FONT =
face=3DGeorgia></FONT></STRONG> </DIV>
<DIV align=3Dleft><STRONG><FONT face=3DGeorgia>Cheers Tamati<BR>From the =
Castle of=20
Tamati, Hinemoa and Karauwa the Dog<BR>From the Castle of Tom, Robyn and =
the=20
Dog</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia></FONT></STRONG> </DIV>
<DIV><STRONG><FONT face=3DGeorgia>I'm Just a Stone's Throw Away:- =
NZ-021-150-33-59=20
or=20
NZ-07-855-0195<BR> &=
nbsp; &n=
bsp; =20
Bush Telegragh:- </FONT></STRONG><A=20
href=3D"mailto:chief.cook.nz@............"><STRONG><FONT=20
face=3DGeorgia>chief.cook.nz@............</FONT></STRONG></A><BR><STRONG>=
<FONT=20
face=3DGeorgia> =20
&=
nbsp; =20
My Regular Pitstop:- Tamati<BR> </FONT></STRONG><STRONG><FONT =
face=3DGeorgia> &nbs=
p;  =
; =20
P.O.BOX 19-356=20
CENTRAL<BR> &n=
bsp; &nb=
sp; &nbs=
p;  =
; =
=20
HAMILTON<BR> &=
nbsp; &n=
bsp; &nb=
sp; &nbs=
p;  =
; =20
NEW ZEALAND</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia>----- Original Message ----- =
</FONT></STRONG>
<DIV><STRONG><FONT face=3DGeorgia>From: "Larry Cochrane" =
<</FONT></STRONG><A=20
href=3D"mailto:lcochrane@.............."><STRONG><FONT=20
face=3DGeorgia>lcochrane@..............</FONT></STRONG></A><STRONG><FONT =
face=3DGeorgia>></FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia>To: <</FONT></STRONG><A=20
href=3D"mailto:psn-l@.............."><STRONG><FONT=20
face=3DGeorgia>psn-l@..............</FONT></STRONG></A><STRONG><FONT=20
face=3DGeorgia>></FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia>Sent: Saturday, January 28, 2006 3:14=20
PM</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia>Subject: Re: Fault zones in=20
Iceland</FONT></STRONG></DIV></DIV>
<DIV><STRONG><BR><FONT =
face=3DGeorgia></FONT></STRONG></DIV><STRONG><FONT=20
face=3DGeorgia>> Hi Everyone,<BR>> <BR>> Chris =
wrote:<BR>>> The low=20
pass filter on your amplifier board should be 10 Hz and have 8=20
<BR>>> poles. In practice, a signal at 13.4 Hz will be reduced =
to =20
1/10 and one at 18 <BR>>> Hz to =
1/100.<BR>>> =20
The amplifier has a high pass filter set at 0.05 Hz =3D 20 sec., =
which is=20
<BR>>> well below the lowest response of your geophones.<BR>> =
<BR>>=20
Actually Jon's Amp/Filter board has a 20 Hz 7 pole low pass filter. I =
usually=20
set the <BR>> filter to 20 Hz instead of the 10 Hz if I know that the =
filter=20
board will be used <BR>> with a geophone to record local =
events.<BR>>=20
<BR>> Regards,<BR>> Larry Cochrane<BR>> Redwood City, =
PSN<BR>>=20
<BR>> =
__________________________________________________________<BR>>=20
<BR>> Public Seismic Network Mailing List (PSN-L)<BR>> <BR>> To =
leave=20
this list email </FONT></STRONG><A=20
href=3D"mailto:PSN-L-REQUEST@.............."><STRONG><FONT=20
face=3DGeorgia>PSN-L-REQUEST@..............</FONT></STRONG></A><STRONG><F=
ONT=20
face=3DGeorgia> with <BR>> the body of the message (first line only): =
unsubscribe<BR>> See </FONT></STRONG><A=20
href=3D"http://www.seismicnet.com/maillist.html"><STRONG><FONT=20
face=3DGeorgia>http://www.seismicnet.com/maillist.html</FONT></STRONG></A=
><STRONG><FONT=20
face=3DGeorgia> for more information.</FONT></STRONG></BODY></HTML>
Subject: force gauge/transducer
From: Jan Froom JDarwin@.............
Date: Mon, 30 Jan 2006 12:12:21 -0800
Anyone know of a simple... quick... force gauge or force transducer...
20 - 30 grams max with a resolution of .1 gram. that I could make or buy?
I'm working on a wind tunnel for my grandson's science fair project and
we need a way to measure the lift and drag.
I can measure lift with a beam balance scale... but the drag is in a
horizontal direction and because the force is so low, I hate using a
pulley arrangement to change the direction from horizontal to vertical.
Oh... and did I say cheap?
I'd settle for a spring gauge if I could find a source... that's
accurate at this low a force.
Thanks.... Jan in Gilroy
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: force gauge/transducer
From: "Jack Ivey" ivey@..........
Date: Mon, 30 Jan 2006 15:49:52 -0500
How about a piece of "feeler gauge" material (10 mm X 50-150 mm strip of
thin springy steel), clamped at one end and hanging vertically. You may
be able to get some from an auto or machine shop supply place or
mcmastercarr.com. You can get a nice little tool that comprises a bunch
of these strips of different thicknesses, arranged to open up like a
fan. That way you could just pick the thickness that works best and
take it
out of the set.
Jack =20
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@...............
On Behalf Of Jan Froom
Sent: Monday, January 30, 2006 3:12 PM
To: psn-l@..............
Subject: force gauge/transducer
Anyone know of a simple... quick... force gauge or force transducer...
20 - 30 grams max with a resolution of .1 gram. that I could make or
buy?
I'm working on a wind tunnel for my grandson's science fair project and=20
we need a way to measure the lift and drag.
I can measure lift with a beam balance scale... but the drag is in a=20
horizontal direction and because the force is so low, I hate using a=20
pulley arrangement to change the direction from horizontal to vertical.
Oh... and did I say cheap?
I'd settle for a spring gauge if I could find a source... that's=20
accurate at this low a force.
Thanks.... Jan in Gilroy
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: force gauge/transducer
From: Jan Froom JDarwin@.............
Date: Mon, 30 Jan 2006 13:20:08 -0800
Thanks Jack...
Had to think about it for a minute or two....
I assume you're suggesting that you then put a sheet of paper behind the
strip, and then using a beam balance scale, calibrate the amount of bend
and mark that on the paper. Simple and neat.
Jan
Jack Ivey wrote:
>How about a piece of "feeler gauge" material (10 mm X 50-150 mm strip of
>thin springy steel), clamped at one end and hanging vertically. You may
>
>be able to get some from an auto or machine shop supply place or
>mcmastercarr.com. You can get a nice little tool that comprises a bunch
>
>of these strips of different thicknesses, arranged to open up like a
>fan. That way you could just pick the thickness that works best and
>take it
>out of the set.
>
>Jack
>
>-----Original Message-----
>From: psn-l-request@.............. [mailto:psn-l-request@...............
>On Behalf Of Jan Froom
>Sent: Monday, January 30, 2006 3:12 PM
>To: psn-l@..............
>Subject: force gauge/transducer
>
>Anyone know of a simple... quick... force gauge or force transducer...
>20 - 30 grams max with a resolution of .1 gram. that I could make or
>buy?
>
>I'm working on a wind tunnel for my grandson's science fair project and
>we need a way to measure the lift and drag.
>I can measure lift with a beam balance scale... but the drag is in a
>horizontal direction and because the force is so low, I hate using a
>pulley arrangement to change the direction from horizontal to vertical.
>
>Oh... and did I say cheap?
>
>I'd settle for a spring gauge if I could find a source... that's
>accurate at this low a force.
>
>Thanks.... Jan in Gilroy
>
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with
>the body of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with
>the body of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
>
>
>
>
>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
<font size="+1">Thanks Jack... <br>
Had to think about it for a minute or two.... <br>
I assume you're suggesting that you then put a sheet of paper behind
the strip, and then using a beam balance scale, calibrate the amount of
bend and mark that on the paper. Simple and neat.</font><br>
<br>
<big> Jan</big><br>
<br>
Jack Ivey wrote:
<blockquote
cite="mid91FBE7AEE91B454282AE05FE79413A4A02141BB2@......................"
type="cite">
<pre wrap="">How about a piece of "feeler gauge" material (10 mm X 50-150 mm strip of
thin springy steel), clamped at one end and hanging vertically. You may
be able to get some from an auto or machine shop supply place or
mcmastercarr.com. You can get a nice little tool that comprises a bunch
of these strips of different thicknesses, arranged to open up like a
fan. That way you could just pick the thickness that works best and
take it
out of the set.
Jack
-----Original Message-----
From: <a class="moz-txt-link-abbreviated" href="mailto:psn-l-request@..............">psn-l-request@..............</a> [<a class="moz-txt-link-freetext" href="mailto:psn-l-request@..............">mailto:psn-l-request@..............</a>]
On Behalf Of Jan Froom
Sent: Monday, January 30, 2006 3:12 PM
To: <a class="moz-txt-link-abbreviated" href="mailto:psn-l@..............">psn-l@..............</a>
Subject: force gauge/transducer
Anyone know of a simple... quick... force gauge or force transducer...
20 - 30 grams max with a resolution of .1 gram. that I could make or
buy?
I'm working on a wind tunnel for my grandson's science fair project and
we need a way to measure the lift and drag.
I can measure lift with a beam balance scale... but the drag is in a
horizontal direction and because the force is so low, I hate using a
pulley arrangement to change the direction from horizontal to vertical.
Oh... and did I say cheap?
I'd settle for a spring gauge if I could find a source... that's
accurate at this low a force.
Thanks.... Jan in Gilroy
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
To leave this list email <a class="moz-txt-link-abbreviated" href="mailto:PSN-L-REQUEST@..............">PSN-L-REQUEST@..............</a> with
the body of the message (first line only): unsubscribe
See <a class="moz-txt-link-freetext" href="http://www.seismicnet.com/maillist.html">http://www.seismicnet.com/maillist.html</a> for more information.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
To leave this list email <a class="moz-txt-link-abbreviated" href="mailto:PSN-L-REQUEST@..............">PSN-L-REQUEST@..............</a> with
the body of the message (first line only): unsubscribe
See <a class="moz-txt-link-freetext" href="http://www.seismicnet.com/maillist.html">http://www.seismicnet.com/maillist.html</a> for more information.
</pre>
</blockquote>
</body>
</html>
Subject: RE: force gauge/transducer
From: "Jack Ivey" ivey@..........
Date: Mon, 30 Jan 2006 17:37:28 -0500
Thanks for clarifying my post, I was even more cryptic than usual.
=20
Jack
=20
________________________________
From: psn-l-request@.............. [mailto:psn-l-request@...............
On Behalf Of Jan Froom
Sent: Monday, January 30, 2006 4:20 PM
To: psn-l@..............
Subject: Re: force gauge/transducer
=20
Thanks Jack...=20
Had to think about it for a minute or two.... =20
I assume you're suggesting that you then put a sheet of paper behind the
strip, and then using a beam balance scale, calibrate the amount of bend
and mark that on the paper. Simple and neat.
Jan
Jack Ivey wrote:=20
How about a piece of "feeler gauge" material (10 mm X 50-150 mm strip of
thin springy steel), clamped at one end and hanging vertically. You may
=20
be able to get some from an auto or machine shop supply place or
mcmastercarr.com. You can get a nice little tool that comprises a bunch
=20
of these strips of different thicknesses, arranged to open up like a
fan. That way you could just pick the thickness that works best and
take it
out of the set.
=20
Jack =20
=20
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@...............
On Behalf Of Jan Froom
Sent: Monday, January 30, 2006 3:12 PM
To: psn-l@..............
Subject: force gauge/transducer
=20
Anyone know of a simple... quick... force gauge or force transducer...
20 - 30 grams max with a resolution of .1 gram. that I could make or
buy?
=20
I'm working on a wind tunnel for my grandson's science fair project and=20
we need a way to measure the lift and drag.
I can measure lift with a beam balance scale... but the drag is in a=20
horizontal direction and because the force is so low, I hate using a=20
pulley arrangement to change the direction from horizontal to vertical.
=20
Oh... and did I say cheap?
=20
I'd settle for a spring gauge if I could find a source... that's=20
accurate at this low a force.
=20
Thanks.... Jan in Gilroy
=20
__________________________________________________________
=20
Public Seismic Network Mailing List (PSN-L)
=20
__________________________________________________________
=20
Public Seismic Network Mailing List (PSN-L)
=20
=20
=20
=20
=20
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<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Thanks for clarifying my post, I =
was even
more cryptic than usual.<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Jack<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
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10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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size=3D2 color=3Dblack face=3DTahoma><span =
style=3D'font-size:10.0pt;font-family:Tahoma;
color:windowtext'> psn-l-request@..............
[mailto:psn-l-request@............... <b><span =
style=3D'font-weight:bold'>On
Behalf Of </span></b>Jan Froom<br>
<b><span style=3D'font-weight:bold'>Sent:</span></b> Monday, January 30, =
2006
4:20 PM<br>
<b><span style=3D'font-weight:bold'>To:</span></b> <st1:PersonName =
w:st=3D"on">psn-l@..............</st1:PersonName><br>
<b><span style=3D'font-weight:bold'>Subject:</span></b> Re: force
gauge/transducer</span></font><font color=3Dblack><span =
style=3D'color:windowtext'><o:p></o:p></span></font></p>
</div>
<p class=3DMsoNormal><font size=3D3 color=3Dblack face=3D"Times New =
Roman"><span
style=3D'font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D4 color=3Dblack face=3D"Times New =
Roman"><span
style=3D'font-size:13.5pt'>Thanks Jack... <br>
Had to think about it for a minute or two.... <br>
I assume you're suggesting that you then put a sheet of paper behind the =
strip,
and then using a beam balance scale, calibrate the amount of bend and =
mark that
on the paper. Simple and neat.</span></font><br>
<br>
<font size=3D4><span =
style=3D'font-size:13.5pt'> Jan</span></font><br>
<br>
Jack Ivey wrote: <o:p></o:p></p>
<pre wrap=3D""><font size=3D2 color=3Dblack face=3D"Courier New"><span
style=3D'font-size:10.0pt'>How about a piece of "feeler gauge" =
material (10 mm X 50-150 mm strip =
of<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>thin springy steel), clamped at one end and =
hanging vertically. You =
may<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>be able to get some from an auto or machine =
shop supply place or<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>mcmastercarr.com. You can get a nice =
little tool that comprises a =
bunch<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>of these strips of different thicknesses, =
arranged to open up like a<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>fan. That way you could just pick the =
thickness that works best and<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>take =
it<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>out of the =
set.<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>Jack =
<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>-----Original =
Message-----<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>From: <a
href=3D"mailto:psn-l-request@..............">psn-l-request@...............
</a> [<a
href=3D"mailto:psn-l-request@..............">mailto:psn-l-request@webtron=
ics.com</a>]<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>On Behalf Of Jan =
Froom<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>Sent: Monday, January 30, 2006 3:12 =
PM<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>To: <a
href=3D"mailto:psn-l@..............">psn-l@..............</a><o:p></o:p><=
/span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>Subject: force =
gauge/transducer<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>Anyone know of a simple... quick... force =
gauge or force transducer...<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>20 - 30 grams max with a resolution of .1 =
gram. that I could make =
or<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>buy?<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>I'm working on a wind tunnel for my =
grandson's science fair project and =
<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>we need a way to measure the lift and =
drag.<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>I can measure lift with a beam balance =
scale... but the drag is in a <o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>horizontal direction and because the force is =
so low, I hate using a <o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>pulley arrangement to change the direction =
from horizontal to vertical.<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>Oh... and did I say =
cheap?<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>I'd settle for a spring gauge if I could find =
a source... that's <o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>accurate at this low a =
force.<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>Thanks.... Jan in <st1:City
w:st=3D"on"><st1:place =
w:st=3D"on">Gilroy</st1:place></st1:City><o:p></o:p></span></font></pre><=
pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>______________________________________________=
____________<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>Public Seismic Network Mailing List =
(PSN-L)<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>To leave this list email <a
href=3D"mailto:PSN-L-REQUEST@..............">PSN-L-REQUEST@...............
</a> with <o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>the body of the message (first line only): =
unsubscribe<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>See <a
href=3D"http://www.seismicnet.com/maillist.html">http://www.seismicnet.co=
m/maillist.html</a> for more =
information.<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>______________________________________________=
____________<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>Public Seismic Network Mailing List =
(PSN-L)<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>To leave this list email <a
href=3D"mailto:PSN-L-REQUEST@..............">PSN-L-REQUEST@...............
</a> with <o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>the body of the message (first line only): =
unsubscribe<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>See <a
href=3D"http://www.seismicnet.com/maillist.html">http://www.seismicnet.co=
m/maillist.html</a> for more =
information.<o:p></o:p></span></font></pre><pre><font
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'><o:p> </o:p></span></font></pre><pre><fon=
t
size=3D2 color=3Dblack face=3D"Courier New"><span =
style=3D'font-size:10.0pt'> <o:p></o:p></span></font></pre></div>
</body>
</html>
Subject: Re: Digest from 01/30/2006 00:01:27
From: Roger Sparks rsparks@..........
Date: Tue, 31 Jan 2006 08:55:47 -0800
Hi Jan,
A hacksaw blade can become a very sensitive spring. Other sources of
good spring material are the recoil springs from lawn mower motors, or
even smaller, the recoil spring from a tape measure.
You could calibrate horizontal beam deflection with the use of weights
previously measured with your vertical balance scale. Install the beam
for vertical measurement. Establish a fixed distance from the beam
support for a calibrated displacement line which will become your
scale. Then place the previously measured weights on the beam and mark
the deflected position of the beam. One previously measured weight
would be enough but you could test for linearity and accuracy if more
than one previously measured weight was used for calibration.
It sounds like an interesting project. Good luck.
Roger
psn-l-digest-request@.............. wrote:
> <>.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> | Message 1 |
> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> Subject: force gauge/transducer
> From: Jan Froom <JDarwin@.............>
> Date: Mon, 30 Jan 2006 12:12:21 -0800
> Anyone know of a simple... quick... force gauge or force transducer...
> 20 - 30 grams max with a resolution of .1 gram. that I could make or buy?
>
> I'm working on a wind tunnel for my grandson's science fair project and
> we need a way to measure the lift and drag.
> I can measure lift with a beam balance scale... but the drag is in a
> horizontal direction and because the force is so low, I hate using a
> pulley arrangement to change the direction from horizontal to vertical.
>
> Oh... and did I say cheap?
>
> I'd settle for a spring gauge if I could find a source... that's
> accurate at this low a force.
>
> Thanks.... Jan in Gilroy
>
>
>
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Suggestion for a seismograph program
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Tue, 31 Jan 2006 18:02:28 +0000
Hi all
I plan to write a linux / *nix compatable program for working out data
from a psn station. I currently don't know how to program in C++ or
other programming languages (nothign useful anyway), but i plan to learn
it on my own. But i will need suggestions and help with that prodect. I
will have this program of mine in GPL licenace when the time comes.
Here is what i have planned so far, and plan to put this in a Open
Office document soon (and pdf).
* The program is in two parts, server (datalogging) (gui optimcal) and
client (working on the data, only gui). Both parts will have networks
abliti (communication over lan or the internet). I will define this part
better later on.
* Automatic magnitue calculation, from one or many stations.
* Network and Internet abilty. Both to remote connect stations into one
or more server.
* Low and hig pass digital filtering, along side with raw data mode
(setup of many windows as needed). This is can be done on the client,
that actually displays the data as it gets send from the server program.
* Post prosessing of earthquakes.
* Automatic detection of earthquakes, and removal of envromental noise.
* Webserver abilti. This is going to be detailed later.
* Map abliti, for more then three station. But also for location of
earthquakes if remote data is used. For example time and location data
used from emsc-cmes and others.
* GPS timeing and location. Timeing also awable trugh the internet by
using ntp (ntp client) will then have to be installed if used.
* Hig resultion details of earthquakes. More detail on this later.
* Wide support of hardware, both from psn and others.
* Tremor plot in a window on user defined freq.
* Telesemic earthquake detection. Local earthquake detection.
There is problay more that belongs on this list (and problay few things
that i have forgot to put on this list), but that is going to be added
with time.
I want my program to be compatable with the *.psn format and the windsr
dataloggin program (server) but also to contain it's own dataloggin
program. I also want my program to be able to save in the *.psn format.
I also want my program to be awable to professonal seismographs networks
out there, along side with pepole who have intrest in earthquakes and
volcanos.
In few words. Suggestions, ideas, comments and so on needed. So i know
where to start.
I haven't started anything yet, but my learning on C++ and other
programming languages is going to start soon. I need good books on the
matter. But i am more broke then usual so that might get delayed. I am
going to use what i have at the moment to learn this.
Sorry for spelling errors.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Suggestion for a seismograph program
From: ian ian@...........
Date: Tue, 31 Jan 2006 18:41:15 +0000
Being old fashioned, I would choose C rather than C++ but you may be
correct.
The scope you describe is very wide and admirable. It might be suited
to doing a full specification which would then allow the software to be
written by a collaboration of people.
Cheers
Ian
Jón Frímann wrote:
>Hi all
>
>I plan to write a linux / *nix compatable program for working out data
>from a psn station. I currently don't know how to program in C++ or
>other programming languages (nothign useful anyway), but i plan to learn
>it on my own. But i will need suggestions and help with that prodect. I
>will have this program of mine in GPL licenace when the time comes.
>
>Here is what i have planned so far, and plan to put this in a Open
>Office document soon (and pdf).
>
>* The program is in two parts, server (datalogging) (gui optimcal) and
>client (working on the data, only gui). Both parts will have networks
>abliti (communication over lan or the internet). I will define this part
>better later on.
>* Automatic magnitue calculation, from one or many stations.
>* Network and Internet abilty. Both to remote connect stations into one
>or more server.
>* Low and hig pass digital filtering, along side with raw data mode
>(setup of many windows as needed). This is can be done on the client,
>that actually displays the data as it gets send from the server program.
>* Post prosessing of earthquakes.
>* Automatic detection of earthquakes, and removal of envromental noise.
>* Webserver abilti. This is going to be detailed later.
>* Map abliti, for more then three station. But also for location of
>earthquakes if remote data is used. For example time and location data
>used from emsc-cmes and others.
>* GPS timeing and location. Timeing also awable trugh the internet by
>using ntp (ntp client) will then have to be installed if used.
>* Hig resultion details of earthquakes. More detail on this later.
>* Wide support of hardware, both from psn and others.
>* Tremor plot in a window on user defined freq.
>* Telesemic earthquake detection. Local earthquake detection.
>
>There is problay more that belongs on this list (and problay few things
>that i have forgot to put on this list), but that is going to be added
>with time.
>
>I want my program to be compatable with the *.psn format and the windsr
>dataloggin program (server) but also to contain it's own dataloggin
>program. I also want my program to be able to save in the *.psn format.
>
>I also want my program to be awable to professonal seismographs networks
>out there, along side with pepole who have intrest in earthquakes and
>volcanos.
>
>In few words. Suggestions, ideas, comments and so on needed. So i know
>where to start.
>
>I haven't started anything yet, but my learning on C++ and other
>programming languages is going to start soon. I need good books on the
>matter. But i am more broke then usual so that might get delayed. I am
>going to use what i have at the moment to learn this.
>
>Sorry for spelling errors.
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Suggestion for a seismograph program
From: ian ian@...........
Date: Tue, 31 Jan 2006 18:41:15 +0000
Being old fashioned, I would choose C rather than C++ but you may be
correct.
The scope you describe is very wide and admirable. It might be suited
to doing a full specification which would then allow the software to be
written by a collaboration of people.
Cheers
Ian
Jón Frímann wrote:
>Hi all
>
>I plan to write a linux / *nix compatable program for working out data
>from a psn station. I currently don't know how to program in C++ or
>other programming languages (nothign useful anyway), but i plan to learn
>it on my own. But i will need suggestions and help with that prodect. I
>will have this program of mine in GPL licenace when the time comes.
>
>Here is what i have planned so far, and plan to put this in a Open
>Office document soon (and pdf).
>
>* The program is in two parts, server (datalogging) (gui optimcal) and
>client (working on the data, only gui). Both parts will have networks
>abliti (communication over lan or the internet). I will define this part
>better later on.
>* Automatic magnitue calculation, from one or many stations.
>* Network and Internet abilty. Both to remote connect stations into one
>or more server.
>* Low and hig pass digital filtering, along side with raw data mode
>(setup of many windows as needed). This is can be done on the client,
>that actually displays the data as it gets send from the server program.
>* Post prosessing of earthquakes.
>* Automatic detection of earthquakes, and removal of envromental noise.
>* Webserver abilti. This is going to be detailed later.
>* Map abliti, for more then three station. But also for location of
>earthquakes if remote data is used. For example time and location data
>used from emsc-cmes and others.
>* GPS timeing and location. Timeing also awable trugh the internet by
>using ntp (ntp client) will then have to be installed if used.
>* Hig resultion details of earthquakes. More detail on this later.
>* Wide support of hardware, both from psn and others.
>* Tremor plot in a window on user defined freq.
>* Telesemic earthquake detection. Local earthquake detection.
>
>There is problay more that belongs on this list (and problay few things
>that i have forgot to put on this list), but that is going to be added
>with time.
>
>I want my program to be compatable with the *.psn format and the windsr
>dataloggin program (server) but also to contain it's own dataloggin
>program. I also want my program to be able to save in the *.psn format.
>
>I also want my program to be awable to professonal seismographs networks
>out there, along side with pepole who have intrest in earthquakes and
>volcanos.
>
>In few words. Suggestions, ideas, comments and so on needed. So i know
>where to start.
>
>I haven't started anything yet, but my learning on C++ and other
>programming languages is going to start soon. I need good books on the
>matter. But i am more broke then usual so that might get delayed. I am
>going to use what i have at the moment to learn this.
>
>Sorry for spelling errors.
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Suggestion for a seismograph program
From: Angel sismos@..............
Date: Tue, 31 Jan 2006 20:07:47 +0000
Hello Jón,
I think that that is an admirable endeavor to start on but most of
what you describe there has already be done by several groups and at
least two of them are in the public domain and free.
I think that it would be far easier to write the missing modules for
the core Earthworm system than to reinvent something that already works
well and is in wide use.
Right now you can take the data from the PSN serial card (and others)
and go directly into Earthworm or Seiscomp over a TCP/IP and in either
of those systems you can do most of the things you list.
Jon, you can find more information for the two systems I mention at
these URLs:
http://folkworm.ceri.memphis.edu/ew-doc/
http://www.gfz-potsdam.de/geofon/new/scp.html
Warmly,
Angel
Tuesday, January 31, 2006, 6:02:28 PM, you wrote:
> Hi all
> I plan to write a linux / *nix compatable program for working out data
> from a psn station. I currently don't know how to program in C++ or
> other programming languages (nothign useful anyway), but i plan to learn
> it on my own. But i will need suggestions and help with that prodect. I
> will have this program of mine in GPL licenace when the time comes.
> Here is what i have planned so far, and plan to put this in a Open
> Office document soon (and pdf).
> * The program is in two parts, server (datalogging) (gui optimcal) and
> client (working on the data, only gui). Both parts will have networks
> abliti (communication over lan or the internet). I will define this part
> better later on.
> * Automatic magnitue calculation, from one or many stations.
> * Network and Internet abilty. Both to remote connect stations into one
> or more server.
> * Low and hig pass digital filtering, along side with raw data mode
> (setup of many windows as needed). This is can be done on the client,
> that actually displays the data as it gets send from the server program.
> * Post prosessing of earthquakes.
> * Automatic detection of earthquakes, and removal of envromental noise.
> * Webserver abilti. This is going to be detailed later.
> * Map abliti, for more then three station. But also for location of
> earthquakes if remote data is used. For example time and location data
> used from emsc-cmes and others.
> * GPS timeing and location. Timeing also awable trugh the internet by
> using ntp (ntp client) will then have to be installed if used.
> * Hig resultion details of earthquakes. More detail on this later.
> * Wide support of hardware, both from psn and others.
> * Tremor plot in a window on user defined freq.
> * Telesemic earthquake detection. Local earthquake detection.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: force gauge/transducer
From: ChrisAtUpw@.......
Date: Tue, 31 Jan 2006 16:47:00 EST
In a message dated 30/01/2006, JDarwin@............. writes:
Anyone know of a simple... quick... force gauge or force transducer...
20 - 30 grams max with a resolution of .1 gram. that I could make or buy?
I'm working on a wind tunnel for my grandson's science fair project and
we need a way to measure the lift and drag.
I can measure lift with a beam balance scale..
Oh... and did I say cheap?
Hi Jan,
You can buy 1 mm thick sheets of a rubbery like material called QTC -
Quantum Tunneling Composite. You sandwich it between two metal plates and
measure the resistance between them. With zero force you have a near insulator. As
the force increases, the electrical resistance drops. This is a cheap way of
making a force transducer.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 30/01/2006, JDarwin@............. writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Anyone=20
know of a simple... quick... force gauge or force transducer...<BR>20 - 30=
=20
grams max with a resolution of .1 gram. that I could make or=20
buy?<BR><BR>I'm working on a wind tunnel for my grandson's science fair=20
project and <BR>we need a way to measure the lift and drag.<BR>I can=
=20
measure lift with a beam balance scale..<BR><BR>Oh... and did I say=20
cheap?<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jan,</DIV>
<DIV> </DIV>
<DIV> You can buy 1 mm thick sheets of a rubbery=
=20
like material called QTC - Quantum Tunneling Composite. You sandwich it betw=
een=20
two metal plates and measure the resistance between them. With zero force yo=
u=20
have a near insulator. As the force increases, the electrical resistance dro=
ps.=20
This is a cheap way of making a force transducer.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Suggestion for a seismograph program
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Wed, 01 Feb 2006 01:30:25 +0000
Hi Angel
(and others)
I did try test those programs that you did recommend. But i was unable
to get them running, becose i did find them rather hard to both start
and the lack of usefuls guides was hig and there was no way to install
them properly on my linux system, both from source or by binary install.
I am used to complex things (after all, i do run Gentoo Linux) so
understanding is only a tempuary problem if things works as suppose to.
However i do find the structure of the programs to be confusing and
lacking. I don't want to offent the pepole who take there time to write
those programs, there effort is good. But i do belive that there is a
need for better more modern program to do this work, that is also more
flexable and more routeburst (can withstand failures). I also agree with
you that there is no need to invent the programs, but i belive that
improvments is needed.
I can try and failed, i want that rather then not to try and not knowing
if it was possible. After all, that is why i did get me geophone to
start with. :-)
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Suggestion for a seismograph program
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Wed, 01 Feb 2006 01:34:53 +0000
Hi Ian
(and others)
It is save to say that this prodject will need more pepole then just me.
But i will see how this works out. I have alot to learn, and it is going
to take some time to learn it.
I also want more suggestions or ideas if possible. Since there are so
many things about recording earthquakes that i don't know about.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: exact frequencies for arrival of different seismic waves ??
From: Tamati chief.cook.nz@............
Date: Thu, 02 Feb 2006 09:53:08 +1300
TAMATI's WORD's OF WISDOM
FOR THE GOOD OF ALL MANKIND
HTTP://LIVE-PLANET.BLOGSPOT.COM
http://www.webspawner.com/users/chiefcooknz/index.html
Please give me feed back on what you think
chief.cook.nz.@............
NZ-021-150-33-59 or NZ-07-855-0195
Morning from New Zealand
I'm one of those WHAT,WHERE & HOW people I don't know at your talking about
but:-
I've got a question in your Email you said that you I recieved a
Teleseismic event from New Zealand
What is a Teleseismic event?
Where did the Teleseimic event happen?
How long was the Teleseimic Event?
How did you or they measuring the Hz rates? are you talking about radio
noise your measuring or Wind or what?
I understand and know "tele" means visial affect and seismic is the resolt
of waves radiating outwards from a centre of force release eg: a stone
thrown into water generates a seismic affect
Cheers Tamati
From the Castle of Tamati, Hinemoa and Karauwa the Dog
From the Castle of Tom, Robyn and the Dog
I'm Just a Stone's Throw Away:- NZ-021-150-33-59 or NZ-07-855-0195
Bush Telegragh:- chief.cook.nz@............
My Regular Pitstop:- Tamati
P.O.BOX
19-356 CENTRAL
HAMILTON
NEW
ZEALAND
----- Original Message -----
From: "Geoff" <gmvoeth@...........>
To: <psn-l@..............>
Sent: Friday, January 27, 2006 7:34 PM
Subject: Re: exact frequencies for arrival of different seismic waves ??
> Thanks Dave;
>
> I just got three EQs from Baja California looks like
> two foreshocks and the main, they are a little over three
> degrees away and 4,0 or less in magnitude.
> It looks to me like the P waves are in the hertz range
> which is beyond the rolloff of my current filter.
> The other day I received Teleseismic event from New Zealand
> that was said to be 90deg away and only 5.2 mag which
> was inband..it looked like the freq was down around
> 5 hertz or so.
>
> You pointd out something I never saw before with the link
> you provided, thank you very much. I never understood
> what those spheres represented till now.
>
> I am currently using a two octave filter which provides
> flatness below 1 Hz and am able to see both regional
> and teleseismic P waves.
>
> My filter is down to three opamps now where it used to
> be 8 or so :-) and I get better results.
> I got this penpal over in England that believes
> in a KISS philosophy (Keep it Simple Stupid)
> that philosophy has proven to be true.
>
> Once Again Thanks to PSN and people like
> yourself I am an old dog learning new tricks.
>
> gmv
>
> ----- Original Message -----
> From: "Dave Nelson" <davenn@...............>
> To: <psn-l@..............>
> Sent: Thursday, January 26, 2006 9:30 PM
> Subject: Re: exact frequencies for arrival of different seismic waves ??
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with the body of the
> message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
__________________________________________________________
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Subject: digital filtering
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Thu, 02 Feb 2006 04:13:13 +0000
Hi all
I have started digital filtering my gif files online. With a lowpass
filter cutoff of 10Hz. Any suggestion on that move is welcomed by me,
since i am still learning on this.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: digital filtering
From: ChrisAtUpw@.......
Date: Thu, 2 Feb 2006 06:07:18 EST
In a message dated 02/02/2006, jonfr500@......... writes:
Hi all
I have started digital filtering my gif files online. With a lowpass
filter cutoff of 10Hz. Any suggestion on that move is welcomed by me,
since i am still learning on this.
Hi Jon,
Your amplifier Low Pass Filter is actually set to 20 Hz, so there should
be very little data above about 22 Hz. This should be well suited to you
local quakes.
Sorry that I got it wrong, but I was reading the characteristics from
the psn website.
Regards,
Chris Chapman
In a message dated 28/01/2006, lcochrane@.............. writes:
Chris wrote:
> The low pass filter on your amplifier board should be 10 Hz and have 8
> poles. In practice, a signal at 13.4 Hz will be reduced to 1/10 and one
at 18
> Hz to 1/100.
> The amplifier has a high pass filter set at 0.05 Hz = 20 sec., which
is
> well below the lowest response of your geophones.
Actually Jon's Amp/Filter board has a 20 Hz 7 pole low pass filter. I
usually set the
filter to 20 Hz instead of the 10 Hz if I know that the filter board will be
used
with a geophone to record local events.
Regards,
Larry Cochrane
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 02/02/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Hi=20
all<BR>I have started digital filtering my gif files online. With a=20
lowpass<BR>filter cutoff of 10Hz. Any suggestion on that move is welcomed=20=
by=20
me,<BR>since i am still learning on this.<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon, </DIV>
<DIV> </DIV>
<DIV> Your amplifier Low Pass Filter is actually set=20=
to=20
20 Hz, so there should be very little data above about 22 Hz. This should be=
=20
well suited to you local quakes.</DIV>
<DIV> Sorry that I got it wrong, but I was reading th=
e=20
characteristics from the psn website.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV>
<DIV> </DIV>
<DIV> =20
<DIV>In a message dated 28/01/2006, lcochrane@.............. writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Chris=20
wrote:<BR>> The low pass filter on your amplifier board should be=
10=20
Hz and have 8 <BR>> poles. In practice, a signal at 13.4 Hz will be red=
uced=20
to 1/10 and one at 18 <BR>> Hz to 1/100.<BR>> &nbs=
p;=20
The amplifier has a high pass filter set at 0.05 Hz =3D 20 sec., whi=
ch is=20
<BR>> well below the lowest response of your geophones.<BR><BR>Actually=
=20
Jon's Amp/Filter board has a 20 Hz 7 pole low pass filter. I usually set t=
he=20
<BR>filter to 20 Hz instead of the 10 Hz if I know that the filter board w=
ill=20
be used <BR>with a geophone to record local events.<BR><BR>Regards,<BR>Lar=
ry=20
Cochrane</FONT></BLOCKQUOTE></DIV></FONT></BODY></HTML>
Subject: Re: digital filtering
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Thu, 02 Feb 2006 22:40:42 +0000
Hi Chris
I have set the raw data on digital filtering, but that one is on 5.5Hz
but the online graphs are now on 4Hz. It appears that the noise is
somewhat above 10Hz (there is noise on 10Hz, but alot less then if i
record from 2Hz to 60Hz), maybe above 6Hz. I just haven tested it
properly yet. I do not know how this filtering will effect my abliti to
detect earthquakes. But i hope that the won't be any effect of this in
regarding detecing earthquakes.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: digital filtering
From: Mark Robinson mark.robinson@...............
Date: Fri, 03 Feb 2006 11:48:19 +1300
Jón Frímann wrote:
> I have set the raw data on digital filtering, but that one is on 5.5Hz
> but the online graphs are now on 4Hz. It appears that the noise is
> somewhat above 10Hz (there is noise on 10Hz, but alot less then if i
> record from 2Hz to 60Hz), maybe above 6Hz. I just haven tested it
> properly yet. I do not know how this filtering will effect my abliti to
> detect earthquakes. But i hope that the won't be any effect of this in
> regarding detecing earthquakes.
The more you filter the higher frequencies out the less small local events you
will see.
If you look at http://www.geonet.org.nz/drums/snzo-drum.gif and
http://aslwww.cr.usgs.gov/Seismic_Data/telemetry_data/SNZO_24hr.gif you will
see that the first one shows local events while the second shows teleseisms.
Both traces come from the same sensor, the Geonet display showing the data with
all the long period stuff filtered out and the usgs one showing the same data
with all the high frequencies filtered out.
regards
Mark
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Public Seismic Network Mailing List (PSN-L)
Subject: Re: digital filtering
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Thu, 02 Feb 2006 23:11:11 +0000
Hi Mark
I do now know the frequencies of the earthquakes that happen here in
Iceland, but it is hig (most of the time). I have taken the digital
filtering off the raw data and i will see how earthquake appears on the
online graphs. Now i just need a earthquake.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: digital filtering
From: ChrisAtUpw@.......
Date: Thu, 2 Feb 2006 22:07:38 EST
In a message dated 02/02/2006, jonfr500@......... writes:
I have set the raw data on digital filtering, but that one is on 5.5Hz
but the online graphs are now on 4Hz. It appears that the noise is
somewhat above 10Hz (there is noise on 10Hz, but alot less then if i
record from 2Hz to 60Hz), maybe above 6Hz. I just haven tested it
properly yet. I do not know how this filtering will effect my abliti to
detect earthquakes.
Hi Jon,
Record 'sample' traces at the maximum bandwidth of 20 Hz, including
noise at various times and a few local quakes.
If you only view from maybe 3 to 5.5 Hz, you may miss some quakes.
Then view these traces putting in varying frequency low pass digital
filters, using Winquake and see how to make the quake traces easier to read
against the background noise.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 02/02/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>I have=20
set the raw data on digital filtering, but that one is on 5.5Hz<BR>but the=
=20
online graphs are now on 4Hz. It appears that the noise is<BR>somewhat abo=
ve=20
10Hz (there is noise on 10Hz, but alot less then if i<BR>record from 2Hz t=
o=20
60Hz), maybe above 6Hz. I just haven tested it<BR>properly yet. I do=
not=20
know how this filtering will effect my abliti to<BR>detect=20
earthquakes.</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> Record 'sample' traces at the maximum bandwidth=
of=20
20 Hz, including noise at various times and a few local quakes.</DIV>
<DIV> </DIV>
<DIV> If you only view from maybe 3 to 5.5 Hz, you ma=
y=20
miss some quakes. </DIV>
<DIV> </DIV>
<DIV> Then view these traces putting in varying=20
frequency low pass digital filters, using Winquake and see how to make the q=
uake=20
traces easier to read against the background noise.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: digital filtering
From: Barry Lotz barry_lotz@.............
Date: Thu, 2 Feb 2006 20:01:16 -0800 (PST)
Hi Jon
I agree with Chris. I record my quakes as raw data then filter them with winquake. If you don't like the pass band you can change it. For teleseismic events on my system I use a pass band between 0.03 & 0.3 hz. For local events I use a high pass around .5 to 1 hz.
ChrisAtUpw@....... wrote:
In a message dated 02/02/2006, jonfr500@......... writes:
I have set the raw data on digital filtering, but that one is on 5.5Hz
but the online graphs are now on 4Hz. It appears that the noise is
somewhat above 10Hz (there is noise on 10Hz, but alot less then if i
record from 2Hz to 60Hz), maybe above 6Hz. I just haven tested it
properly yet. I do not know how this filtering will effect my abliti to
detect earthquakes.
Hi Jon,
Record 'sample' traces at the maximum bandwidth of 20 Hz, including noise at various times and a few local quakes.
If you only view from maybe 3 to 5.5 Hz, you may miss some quakes.
Then view these traces putting in varying frequency low pass digital filters, using Winquake and see how to make the quake traces easier to read against the background noise.
Regards,
Chris Chapman
<DIV>Hi Jon</DIV> <DIV> I agree with Chris. I record my quakes as raw data then filter them with winquake. If you don't like the pass band you can change it. For teleseismic events on my system I use a pass band between 0.03 & 0.3 hz. For local events I use a high pass around .5 to 1 hz.<BR><BR><B><I>ChrisAtUpw@.......</I></B> wrote:</DIV> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid"> <META content="MSHTML 6.00.2900.2802" name=GENERATOR><FONT id=role_document face=Arial color=#000000 size=2> <DIV> <DIV>In a message dated 02/02/2006, jonfr500@......... writes:</DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT style="BACKGROUND-COLOR: transparent" face=Arial color=#000000 size=2>I have set the raw data on digital filtering, but that one is on 5.5Hz<BR>but the online graphs are now on 4Hz. It appears that the noise is<BR>somewhat above 10Hz (there is noise on 10Hz, but
alot less then if i<BR>record from 2Hz to 60Hz), maybe above 6Hz. I just haven tested it<BR>properly yet. I do not know how this filtering will effect my abliti to<BR>detect earthquakes.</FONT></BLOCKQUOTE></DIV> <DIV></DIV> <DIV>Hi Jon,</DIV> <DIV> </DIV> <DIV> Record 'sample' traces at the maximum bandwidth of 20 Hz, including noise at various times and a few local quakes.</DIV> <DIV> </DIV> <DIV> If you only view from maybe 3 to 5.5 Hz, you may miss some quakes. </DIV> <DIV> </DIV> <DIV> Then view these traces putting in varying frequency low pass digital filters, using Winquake and see how to make the quake traces easier to read against the background noise.</DIV> <DIV> </DIV> <DIV> Regards,</DIV> <DIV> </DIV> <DIV> Chris Chapman</DIV></FONT></BLOCKQUOTE> <DIV><BR></DIV>
Subject: Re: digital filtering
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 03 Feb 2006 04:30:44 +0000
Hi
I have turned off digital filtering for raw data. However i am going to
keep it on for the online tremor graphs that i have. I did check data on
the earthquake that i have recorded and they appear good on 4Hz freq. So
they will appear on my online graphs. The freq. there is 4.5Hz, i had
posted the wrong freq setup before.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Detecting earthquake of a distiance of 855 km
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 04 Feb 2006 15:52:23 +0000
Hi all
I think i did manage to detect a earthquake at the distace of 855 km,
the earthquake was on the Reykjanes ridge, i had to manually register
the earthquake. I can see the seismatic wave (at least i think it is the
seismetic wave) if i filter the raw data down to 4Hz with winquake or
lower. I am going to send the raw data to the psn file list. But before
i do that i want to be sure that i did detected the earthquake. The
trace is 10 min long, but i don't know if i did need to make a longer
trace or not.
The files can be downloaded from here.
http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt1z.psn
http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt2e.psn
http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt3n.psn
Thanks and regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting earthquake of a distiance of 855 km
From: ian ian@...........
Date: Sat, 04 Feb 2006 18:56:42 +0000
Hi,
I picked it up on my Lehman. My geopone is still suffering from that
channel's electrical problem, so I can't do a comparison for you.
You can see a nice traces of the quake at
http://www.guralp.net/realtime/ and a good map at
http://www.iris.edu/seismon/zoom/?view=eveday&lon=-29&lat=51
I'm currently off line. My satellite broadband provider, Aramiska, went
bankrupt last week :-(
Cheers
Ian
Jón Frímann wrote:
>Hi all
>
>I think i did manage to detect a earthquake at the distace of 855 km,
>the earthquake was on the Reykjanes ridge, i had to manually register
>the earthquake. I can see the seismatic wave (at least i think it is the
>seismetic wave) if i filter the raw data down to 4Hz with winquake or
>lower. I am going to send the raw data to the psn file list. But before
>i do that i want to be sure that i did detected the earthquake. The
>trace is 10 min long, but i don't know if i did need to make a longer
>trace or not.
>
>The files can be downloaded from here.
>
>http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt1z.psn
>http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt2e.psn
>http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt3n.psn
>
>Thanks and regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting earthquake of a distiance of 855 km
From: Dave Nelson davenn@...............
Date: Sun, 05 Feb 2006 08:51:52 +1100
Hi Jon
yup looks like u fot it but when comparing to Ian's=20
recording it loks like u got the P and S in the wrong place where u have=
=20
the P marker should be where the S marker position and the P marker in=20
front of that
when u filter ur seismogram in winquake this becomes much more obvious
cheers
Dave
At 15:52 4/02/2006 +0000, you wrote:
>Hi all
>I think i did manage to detect a earthquake at the distace of 855 km,
>the earthquake was on the Reykjanes ridge, i had to manually register
>the earthquake. I can see the seismatic wave (at least i think it is the
>seismetic wave) if i filter the raw data down to 4Hz with winquake or
>The files can be downloaded from here.
>http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt1z.psn
>http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt2e.psn
>http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt3n.psn
>
>Thanks and regards.
>--
>J=F3n Fr=EDmann J=F3nsson
__________________________________________________________
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Subject: Re: Detecting earthquake of a distance of 855 km
From: Dave Nelson davenn@...............
Date: Sun, 05 Feb 2006 08:57:01 +1100
Hi Jon
yet where u have the markers coincides with the event timing
so maybe you only did pick up the P wave
I know over the years there are many many distant events I recorded that=
=20
only the P wave showed up on the seismogram
cheers
Dave Nelson
Sydney
At 15:52 4/02/2006 +0000, you wrote:
>Hi all
>I think i did manage to detect a earthquake at the distace of 855 km,
>the earthquake was on the Reykjanes ridge, i had to manually register
>the earthquake. I can see the seismatic wave (at least i think it is the
>seismetic wave) if i filter the raw data down to 4Hz with winquake or
>The files can be downloaded from here.
>http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt1z.psn
>http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt2e.psn
>http://www.simnet.is/jonfr500/earthquake/winquake/060204.142900.hvt3n.psn
>
>Thanks and regards.
>--
>J=F3n Fr=EDmann J=F3nsson
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting earthquake of a distance of 855 km
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sun, 05 Feb 2006 04:08:49 +0000
Hi all
I did also detect a 4.5mb earthquake that did happen today (i think).
But that detection was worse then the detection of the 4.9mb earthquake.
I do not know if i was able to detect the s wave from those quakes, but
i think that it is there, even if it is almost not visable. When i got
down to 2Hz with winquake. I think that i see the surface waves. But I
am not sure.
I made a new trace of the 4.9mb earthquake, it about 20 min long. The
trace of the 4.5mb earthquake is 19 min long.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Detecting earthquake of a distance of 855 km
From: "Kareem at HeyJooJoo" system98765@.............
Date: Sat, 4 Feb 2006 20:20:32 -0800
Where are you guys located where you're recording these events?
Kareem=20
Western Contra Costa County - CA, USA
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... =
On
Behalf Of J=F3n Fr=EDmann
Sent: Saturday, February 04, 2006 8:09 PM
To: psn-l@..............
Subject: Re: Detecting earthquake of a distance of 855 km
Hi all
I did also detect a 4.5mb earthquake that did happen today (i think).
But that detection was worse then the detection of the 4.9mb earthquake.
I do not know if i was able to detect the s wave from those quakes, but =
i
think that it is there, even if it is almost not visable. When i got =
down to
2Hz with winquake. I think that i see the surface waves. But I am not =
sure.
I made a new trace of the 4.9mb earthquake, it about 20 min long. The =
trace
of the 4.5mb earthquake is 19 min long.
Regards.
--
J=F3n Fr=EDmann J=F3nsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
http://www.seismicnet.com/maillist.html for more information.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting earthquake of a distance of 855 km
From: ian ian@...........
Date: Sun, 05 Feb 2006 07:53:19 +0000
I'm in East Lothian, Scotland, UK.
Ian
Kareem at HeyJooJoo wrote:
>Where are you guys located where you're recording these events?
>
>Kareem
>Western Contra Costa County - CA, USA
>
>
>
>-----Original Message-----
>From: psn-l-request@.............. [mailto:psn-l-request@............... On
>Behalf Of Jón Frímann
>Sent: Saturday, February 04, 2006 8:09 PM
>To: psn-l@..............
>Subject: Re: Detecting earthquake of a distance of 855 km
>
>Hi all
>
>I did also detect a 4.5mb earthquake that did happen today (i think).
>But that detection was worse then the detection of the 4.9mb earthquake.
>I do not know if i was able to detect the s wave from those quakes, but i
>think that it is there, even if it is almost not visable. When i got down to
>2Hz with winquake. I think that i see the surface waves. But I am not sure.
>
>I made a new trace of the 4.9mb earthquake, it about 20 min long. The trace
>of the 4.5mb earthquake is 19 min long.
>
>Regards.
>--
>Jón Frímann Jónsson
>http://www.jonfr.com
>
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with the body of the
>message (first line only): unsubscribe See
>http://www.seismicnet.com/maillist.html for more information.
>
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with
>the body of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
>
>
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Detecting micro-earthquakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sun, 05 Feb 2006 13:49:16 +0000
Hi all
I am wondering what is the best way for me to detect micro-earthquakes
that i might record, manually or automatic. Since i have to have a way
to detect them from the noise. I already know that i have to filter the
data down to at least 3Hz to get rid of the noise. But i am not sure how
to detect the wave pattern of such small earthquake (not smaller then
2Ml) after such filtering.
Thanks and regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting earthquake of a distance of 855 km
From: Bobhelenmcclure@.......
Date: Sun, 5 Feb 2006 13:51:14 EST
I applied my WQFilter utility to the data submitted by J=F3n Fr=EDmann J=F3n=
sson =20
for the event
=20
M5.4 2006/02/04 14:29:55 59.058 -30.896 10.0 REYKJANES RIDGE
=20
He did record the event, as evident in the filtered result, although there =20
are also some artifacts present as well. WQFilter was used to extend the lon=
g =20
period response of the geophone sensor from 0.22 seconds to 4.0 seconds.
=20
I have submitted the filtered and raw data for the Z sensor as the volume=20
file 060204.142901.hvt1.psn
=20
Bob
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DISO-8859-1">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>I applied my WQFilter utility to the data submitted by J=F3n Fr=EDmann=20=
J=F3nsson=20
for the event</DIV>
<DIV> </DIV>
<DIV>M5.4 2006/02/04 14:29:55 59.058 -30.896 10.0&nb=
sp;=20
REYKJANES RIDGE</DIV>
<DIV> </DIV>
<DIV>He did record the event, as evident in the filtered result, although th=
ere=20
are also some artifacts present as well. WQFilter was used to extend the lon=
g=20
period response of the geophone sensor from 0.22 seconds to 4.0 seconds.</DI=
V>
<DIV> </DIV>
<DIV>I have submitted the filtered and raw data for the Z=20
sensor as the volume file 060204.142901.hvt1.psn</DIV>
<DIV> </DIV>
<DIV>Bob</DIV></FONT></BODY></HTML>
Subject: 12 bits for $39
From: Bobhelenmcclure@.......
Date: Sun, 5 Feb 2006 14:35:39 EST
Hi all,
I use the 12-bit Dataq DI-154RS for data acquisition. I am on my second
one, and I paid $150 for each. Go to
_www.dataq.com/products/startkit/di154rs.htm_
(http://www.dataq.com/products/startkit/di154rs.htm)
and you will see that the price is now only $39.
I have all the software you need to use this device for data logging,
filtering, and conversion to PSN event files.
Regards,
Bob
Bob McClure
PSN Network Station REM
Locust Valley, NY USA
40.882N 73.5817W
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>Hi all,</DIV>
<DIV> </DIV>
<DIV> I use the 12-bit Dataq DI-154RS for data acquisition. I am on my=
=20
second one, and I paid $150 for each. Go to</DIV>
<DIV> </DIV>
<DIV><A=20
href=3D"http://www.dataq.com/products/startkit/di154rs.htm">www.dataq.com/pr=
oducts/startkit/di154rs.htm</A> </DIV>
<DIV> </DIV>
<DIV>and you will see that the price is now only $39.</DIV>
<DIV> </DIV>
<DIV> I have all the software you need to use this device for data=20
logging, filtering, and conversion to PSN event files.</DIV>
<DIV> </DIV>
<DIV>Regards,</DIV>
<DIV> </DIV>
<DIV>Bob</DIV>
<DIV> </DIV>
<DIV><FONT lang=3D0 face=3DArial size=3D2 FAMILY=3D"SANSSERIF" PTSIZE=3D"10"=
>Bob=20
McClure<BR>PSN Network Station REM<BR>Locust Valley, NY USA<BR>40.882N=20
73.5817W</FONT></DIV></FONT></BODY></HTML>
Subject: Re: Detecting earthquake of a distance of 855 km
From: Tamati chief.cook.nz@............
Date: Mon, 06 Feb 2006 10:10:45 +1300
chief.cook.nz.@............
NZ-021-150-33-59 or NZ-07-855-0195
Hi John
with your trace recordings can you put the location(s) of Country and/or
your State plus time time or is the time stamp on the Email at same time as
tour recording(s)
BTW:- how do I display your website in english please
Cheers Tamati
From the Castle of Tamati, Hinemoa and Karauwa the Dog
From the Castle of Tom, Robyn and the Dog
I'm Just a Stone's Throw Away:- NZ-021-150-33-59 or NZ-07-855-0195
Bush Telegragh:- chief.cook.nz@............
My Regular Pitstop:- Tamati
P.O.BOX
19-356 CENTRAL
HAMILTON
NEW
ZEALAND
----- Original Message -----
From: "Jón Frímann" <jonfr500@.........>
To: <psn-l@..............>
Sent: Sunday, February 05, 2006 5:08 PM
Subject: Re: Detecting earthquake of a distance of 855 km
> Hi all
>
> I did also detect a 4.5mb earthquake that did happen today (i think).
> But that detection was worse then the detection of the 4.9mb earthquake.
> I do not know if i was able to detect the s wave from those quakes, but
> i think that it is there, even if it is almost not visable. When i got
> down to 2Hz with winquake. I think that i see the surface waves. But I
> am not sure.
>
> I made a new trace of the 4.9mb earthquake, it about 20 min long. The
> trace of the 4.5mb earthquake is 19 min long.
>
> Regards.
> --
> Jón Frímann Jónsson
> http://www.jonfr.com
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with
> the body of the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Fwd: [o4r] Superb resource
From: John or Jan Lahr JohnJan@........
Date: Sun, 05 Feb 2006 14:38:37 -0800
I just learned the MIT has posted a lot of information on their
courses (see below). In the case of seismology, there are even
lecture notes (see:
http://ocw.mit.edu/OcwWeb/Earth--Atmospheric--and-Planetary-Sciences/12-510Spring-2005/LectureNotes/).
I haven't looked at many of them, but this is a good place to learn
about the theory.
Cheers,
John
>From: George Slusher
>
>MIT has put the course materials for most of their courses online--and
>it's FREE.
>
>http://ocw.mit.edu/index.html
>
>This does not include lectures, contact with the faculty, nor credit,
>of course. (Ya gotta pay for that.) It also doesn't include the texts,
>but it often does have lecture notes, assignments (homework),
>solutions, tests and exams, and study materials.
>
>
>
>
>George Slusher
>Eugene, OR
>
>
>
>
>Yahoo! Groups Links
>
><*> To visit your group on the web, go to:
> http://groups.yahoo.com/group/or4think-members/
>
><*> To unsubscribe from this group, send an email to:
> or4think-members-unsubscribe@...............
>
><*> Your use of Yahoo! Groups is subject to:
> http://docs.yahoo.com/info/terms/
>
##################################/ John C. Lahr
#################################/ Emeritus Seismologist
################################/ U.S. Geological Survey
===========================/ Geologic Hazards Team
##############################/ Golden, Colorado
#############################//##############################
############################//###############################
PO Box 548 /################################
Corvallis, Oregon 97339 /##################################
Phone: (541) 758-2699 /=============================
Cell: (541) 740-4844 /###################################
Fax: (928) 569-0113 /##################################
jjpub@........ /####################################
http://jclahr.com/science/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting micro-earthquakes
From: Roger Sparks rsparks@..........
Date: Mon, 06 Feb 2006 06:23:36 -0800
Hi Jon,
I live about 150 km east of Seattle, Washington where we have a lot of
quakes less than magnitude 3.0. I wanted to see some of those quakes.
When I first began this hobby, I filtered hard to remove the high
frequency noise but soon found that I was also removing the signals from
the small local quakes. That was because the small quakes were
generating signals at a frequency above 1 Hz, up to 10 Hz and higher.
I found my seismic noise floor to be the ocean wave generated noise near
0.2 Hz. Therefore, I expected that the small local quakes would be
seen as high frequency deviations from the fairly smooth curve generated
by the 0.2 Hz background noise. This expectation turned out to be correct.
I presently have my computer screen filters set to high pass above 0.7
Hz. Using a sample rate of about 10.8 Hz, I can see quakes from
magnitude 1.2 on up depending upon distance. I also have the ability
to low pass the data which is helpful on the larger teleseismic
quakes. Nearly all the teleseismic quakes also have energy at
frequencies above my 0.7 Hz high pass filter cutoff so I can usually see
them without the low pass filtering.
Your problem might be different from mine if your noise floor is not
from the ocean wave background. If your noise floor is from your
electronics, seismometer hinge or wind, then your filtering needs would
be different.
You may have noticed that you can download the data from the quakes
posted on PSN so that you can examine it carefully with Winquake. You
can see what data operations have been used, what equipment the station
is using, and examine the background noise for frequency. This can be
very helpful in comparing the results from your station with the results
of other station operators.
I post on PSN from Ellensburg, Wash., and use the station signature "ebgz".
When I began this hobby, I spent a lot of time looking for known events
in my data. Now I mostly manually look for the event only if I think
it is within my sensitivity and distance range but it is not obvious on
my screen.
Best wishes,
Roger
----- ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 1 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Detecting micro-earthquakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= <jonfr500@.........>
Date: Sun, 05 Feb 2006 13:49:16 +0000
Hi all
I am wondering what is the best way for me to detect micro-earthquakes
that i might record, manually or automatic. Since i have to have a way
to detect them from the noise. I already know that i have to filter the
data down to at least 3Hz to get rid of the noise. But i am not sure how
to detect the wave pattern of such small earthquake (not smaller then
2Ml) after such filtering.
Thanks and regards.
-- Jón Frímann Jónsson http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting micro-earthquakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 06 Feb 2006 17:54:03 +0000
Hi all
To Roger.
I have 4.5Hz geophone, becose of that i don't detect the ocen wave most
of the time (maybe during storm).
Other matter.
I think that i might have recorded a small earthquake, but there was a
mining expotion at distance of 119km away from me around the same time,
that i might have been able to pickup. However the p and s wave are so
close to gether that i doubt that i was recording the mining explotion
as i did first think, becose if i apply that timeing of the subspected
mining, the p and s wave are behind the top that i see. There is a other
option regarding this, this event might have been created when the earth
freezes over and it cracks when that happens. But the current temp is
-3.5C and the ground is freezing over. This might also just be noise.
Here are the files for those intrested.
www.simnet.is/jonfr500/earthquake/winquake/060206.163401.hvt1z.psn
www.simnet.is/jonfr500/earthquake/winquake/060206.163401.hvt2e.psn
www.simnet.is/jonfr500/earthquake/winquake/060206.163401.hvt3n.psn
Thanks and regards. (sorry for spelling errors)
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: ebay auction
From: Bob Barns royb1@...........
Date: Tue, 07 Feb 2006 09:45:42 -0500
Hi gang,
Vintage Seismograph Seiscor Telephone Test Set - L@@k!
Item number: 6603668893
ends 2/13
I have no idea what this is. :-\
Bob
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: ebay auction
From: "Jack Ivey" ivey@..........
Date: Tue, 7 Feb 2006 10:47:31 -0500
It's a telephone test set. I'm assuming the seller is going from the=20
company name (Seiscor).
Jack
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@...............
On Behalf Of Bob Barns
Sent: Tuesday, February 07, 2006 9:46 AM
To: psn mail
Subject: ebay auction
Hi gang,
=20
Vintage Seismograph Seiscor Telephone Test Set - L@@k!
Item number: 6603668893 =09
=09
ends 2/13
I have no idea what this is. :-\
Bob
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: ebay auction
From: "Jack Ivey" ivey@..........
Date: Tue, 7 Feb 2006 10:47:31 -0500
It's a telephone test set. I'm assuming the seller is going from the=20
company name (Seiscor).
Jack
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@...............
On Behalf Of Bob Barns
Sent: Tuesday, February 07, 2006 9:46 AM
To: psn mail
Subject: ebay auction
Hi gang,
=20
Vintage Seismograph Seiscor Telephone Test Set - L@@k!
Item number: 6603668893 =09
=09
ends 2/13
I have no idea what this is. :-\
Bob
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Shackleford-Gundersen Seismometer, is it long period ?
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Tue, 07 Feb 2006 17:07:27 +0000
Hi all
Is the Shackleford-Gundersen Seismometer long period seismometer or
short period seismometer. I was looking at the info on the psn page
regarding this seismometer.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Shackleford-Gundersen Seismometer, is it long period ?
From: ChrisAtUpw@.......
Date: Tue, 7 Feb 2006 12:30:00 EST
In a message dated 07/02/2006, jonfr500@......... writes:
Is the Shackleford-Gundersen Seismometer long period seismometer or
short period seismometer. I was looking at the info on the psn page
regarding this seismometer.
Hi Jon,
It is a long period seismometer with a second channel high frequency
output. You start with a vertical pendulum of maybe 1 sec period and extend the
period using a linear distance transducer and electronic force feedback. See
_http://psn.quake.net/freqtest.html_ (http://psn.quake.net/freqtest.html)
Being a vertical pendulum, it does not have the precision tilt setup
requirements of a Lehman. It is also physically smaller.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 07/02/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Is the=20
Shackleford-Gundersen Seismometer long period seismometer or<BR>short peri=
od=20
seismometer. I was looking at the info on the psn page<BR>regarding this=20
seismometer.</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> It is a long period seismometer with a second=20
channel high frequency output. You start with a vertical pendulum of maybe 1=
sec=20
period and extend the period using a linear distance transducer and electron=
ic=20
force feedback. See <A=20
href=3D"http://psn.quake.net/freqtest.html">http://psn.quake.net/freqtest.ht=
ml</A> Being=20
a vertical pendulum, it does not have the precision tilt setup requirements=20=
of a=20
Lehman. It is also physically smaller.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Noise and earthquakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Thu, 09 Feb 2006 20:44:36 +0000
Hi all
Tomorrow (hopefully) i will send few recordings of earthquakes that i
did record today (i am still wating for the final size and location etc,
data from the Icelandic met Office), however there is a lot of noise in
those recordings. Since the earhquakes did happen during the day. There
is also a diffrent type of noise in the recordings, but it appears that
when the ground is frosen it makes hig pulse period (both short and long
period) noise that i sometimes records. One such noise did happen at the
same time as i did record a earthquake. I did try to downfilter the
files, but that didn't work well. Since the trace of the earhquakes is
weak.
I did send today the psn file list page two earthquakes that i did
record yesterday and today. I got a trace of a 2.48 mag on Reykjanes, it
was decent. Also a recording of a mag 3.3 earthquake, but it was really
poor.
Suggestions are always welcomed. Sorry for the spelling errors.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting micro-earthquakes
From: Roger Sparks rsparks@..........
Date: Thu, 09 Feb 2006 17:27:00 -0800
Hi All,
Hi Jon,
I took a look at your files. Thanks for making them available.
While I have become familiar with my own seismometer and capabilities, I
am looking at a different world when looking at your files. First is
the 200 samples per second which provides resolution of events as high
as 100 Hz. That is very good.
Next is the 4.5 Hz geophone which has a peak response at about 4.5 Hz.
I expect it to detect local quakes very well. The expectations for
large distant quakes are less.
What surprised me was the large amount of energy found at 10 Hz,
declining up to about 20 Hz. I did not expect to see that when I
applied the FFT algorithm from Winquake to each file, and for the most
part, to each subdivided time period within each file. What I expected
to see was the ocean wave noise at 0.2 Hz but at a much reduced peak
compared to my own seismometer which has a natural period of about 3 1/5
to 4 seconds. I am curious to know if you can explain the 10 Hz energy
source? Also ocean waves? Maybe a nearby flag pole and flag waving in
the wind?
The second surprise was the large noise count, up in the +/- 300 unit
range. It is nothing to be alarmed about, only different from my
system. I wonder what the noise floor is when the seismometer is
disconnected from the electronics?
After looking at the files, the trace that most looked like a quake to
me, occurred at about 36:11. I have a lot of local (people walking)
quakes and occasionally see a trace like the 36:11 trace that is not a
quake, so I would not go so far as to say it was one. I always check
to see if other stations have also recorded the event before having
confidence in my own results.
It takes a while to learn the capabilities and limits of new equipment.
Best wishes, Roger
>.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
>| Message 2 |
>'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
>Subject: Re: Detecting micro-earthquakes
>From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= <jonfr500@.........>
>Date: Mon, 06 Feb 2006 17:54:03 +0000
>
>Hi all
>
>To Roger.
>
>I have 4.5Hz geophone, becose of that i don't detect the ocen wave most
>of the time (maybe during storm).
>
>Other matter.
>I think that i might have recorded a small earthquake, but there was a
>mining expotion at distance of 119km away from me around the same time,
>that i might have been able to pickup. However the p and s wave are so
>close to gether that i doubt that i was recording the mining explotion
>as i did first think, becose if i apply that timeing of the subspected
>mining, the p and s wave are behind the top that i see. There is a other
>option regarding this, this event might have been created when the earth
>freezes over and it cracks when that happens. But the current temp is
>-3.5C and the ground is freezing over. This might also just be noise.
>
>Here are the files for those intrested.
>
>www.simnet.is/jonfr500/earthquake/winquake/060206.163401.hvt1z.psn
>www.simnet.is/jonfr500/earthquake/winquake/060206.163401.hvt2e.psn
>www.simnet.is/jonfr500/earthquake/winquake/060206.163401.hvt3n.psn
>
>Thanks and regards. (sorry for spelling errors)
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: work light switch
From: Barry Lotz barry_lotz@.............
Date: Thu, 9 Feb 2006 20:21:27 -0800 (PST)
Hi all
I have a reasonably related question. I have a flourescent magnifying desk lamp that I use to solder my seismic circuitry . The switch has gone out and I can't seem to find a "off-on-momentary" replacement rocker switch for it (push til the light is warm then release to start position. push the other way to shut off.). Any thoughts? I've checked in digikey,mouser and serched on line with no success. It seems like it would be a simple & common item.....
regards
barry
<DIV id=RTEContent>Hi all</DIV> <DIV> I have a reasonably related question. I have a flourescent magnifying desk lamp that I use to solder my seismic circuitry . The switch has gone out and I can't seem to find a "off-on-momentary" replacement rocker switch for it (push til the light is warm then release to start position. push the other way to shut off.). Any thoughts? I've checked in digikey,mouser and serched on line with no success. It seems like it would be a simple & common item.....</DIV> <DIV>regards</DIV> <DIV>barry</DIV> <DIV> </DIV> <DIV> </DIV> <DIV> </DIV>
Subject: Re: work light switch
From: "Kim Roland" KROL@............
Date: Fri, 10 Feb 2006 00:44:42 -0800
Hi,
Try this company:=20
http://www.switchchannel.com/=20
Located in Los Angles,CA. USA
Part # DR-42A-BB is a momentary on -off-on rocker switch.
That might work.
Kim =20
----- Original Message -----=20
From: Barry Lotz=20
To: psn-l@.................
Sent: Thursday, February 09, 2006 8:21 PM
Subject: work light switch
Hi all
I have a reasonably related question. I have a flourescent magnifying =
desk lamp that I use to solder my seismic circuitry . The switch has =
gone out and I can't seem to find a "off-on-momentary" replacement =
rocker switch for it (push til the light is warm then release to start =
position. push the other way to shut off.). Any thoughts? I've checked =
in digikey,mouser and serched on line with no success. It seems like it =
would be a simple & common item.....
regards
barry
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2800.1528" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Hi,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Try this company: </FONT></DIV>
<DIV><FONT face=3DArial size=3D2><A=20
href=3D"http://www.switchchannel.com/">http://www.switchchannel.com/</A>&=
nbsp;</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Located in Los Angles,CA. =
USA</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Part # DR-42A-BB is a momentary on =
-off-on rocker=20
switch.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2> That might work.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Kim </FONT></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Dbarry_lotz@............. =
href=3D"mailto:barry_lotz@.............">Barry=20
Lotz</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dpsn-l@.................
href=3D"mailto:psn-l@..............">psn-l@..............</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Thursday, February 09, =
2006 8:21=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> work light =
switch</DIV>
<DIV><BR></DIV>
<DIV id=3DRTEContent>Hi all</DIV>
<DIV> I have a reasonably related question. I have a=20
flourescent magnifying desk lamp that I use to solder my seismic=20
circuitry . The switch has gone out and I can't seem to find a=20
"off-on-momentary" replacement rocker switch for it (push til the =
light is=20
warm then release to start position. push the other way to shut off.). =
Any=20
thoughts? I've checked in digikey,mouser and serched on line with no =
success.=20
It seems like it would be a simple & common=20
item.....</DIV>
<DIV>regards</DIV>
<DIV>barry</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV></BLOCKQUOTE></BODY></HTML>
Subject: Re: Detecting micro-earthquakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 10 Feb 2006 10:38:13 +0000
Hi
To Roger.
I did in the end figure out that i didn't detect the earthquake at that
range. It was out of my range, after all i didn't see any change in the
graph as i did go down to 10 seconds on the X scale. I also now got a
comparison, i did detect a mag 2.2Ml (unconfirmed size) earthquake this
morning (05:01 GMT), it did happen when there is minimal noise from
traffic and other cultrual noise sources. I was able to detect the S
wave of the quake, but the recording is really poor.
As for the 10 to 20Hz noise, i am unsure what you mean.But i am close to
the ocen, about 300 meters from the beach. There are many noise sources
where the geophone is located at the moment (for instant the wind noise
is hig, even if the geophone is located inside the house), at the moment
i can't move the geophone to better location, becose of house i life in.
But i plan to move the geophone in next 6 to 8 months, when i can buy
the needed hardware to move the geophone.
If i rember correctly, the noise level is almost none when i do
disconnect the geophone from the psn board. But i am not sure, i will
check this when i move the geophone. The geophone is also located 2
meters (max) from a solid bedrock. That problay goes down to ~35km into
the crust, becose it is an old volcano that the town is build on top of
(in the side of it).
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting micro-earthquakes
From: ChrisAtUpw@.......
Date: Fri, 10 Feb 2006 13:28:54 EST
In a message dated 10/02/2006, rsparks@.......... writes:
While I have become familiar with my own seismometer and capabilities, I am
looking at a different world when looking at your files. First is the 200
samples per second which provides resolution of events as high as 100 Hz. That
is very good.
Hi Jon,
Your amplifiers have a cut-off at ~20 Hz. The minimum sample rate is 40
sps. 200 sps is not necessary and could use a lot of memory. Can you use 60
to 100 sps?
Next is the 4.5 Hz geophone which has a peak response at about 4.5 Hz. I
expect it to detect local quakes very well. The expectations for large distant
quakes are less.
It will not have a peaked response if it is correctly loaded. There
should be a ~2.7 K Ohm resistor soldered across the output terminals of each
geophone.
What surprised me was the large amount of energy found at 10 Hz, declining
up to about 20 Hz. I did not expect to see that when I applied the FFT
algorithm from Winquake to each file, and for the most part, to each subdivided time
period within each file. What I expected to see was the ocean wave noise at
0.2 Hz but at a much reduced peak compared to my own seismometer which has a
natural period of about 3 1/5 to 4 seconds.
You don't see microseisms at about 6 sec with a 4.5 Hz geophone. The
response will be down by a factor of over 700. If you are on the coast you will
likely see higher frequency noise associated with breaking waves.
I am curious to know if you can explain the 10 Hz energy source? Also ocean
waves? Maybe a nearby flag pole and flag waving in the wind?
The Strouhal number is between 0.2 and 0.4, depending on the 'bluntness'
of the object; S=fxD/v, where f is the vortex shedding frequency, D is the
width of the object and v is the velocity. Vortices are shed alternately from
either side of the object. The force on an object is at f/2 Hz, so a strong
20 m/sec, 76 kph wind will give D = 20 / 100, D ~ 0.2 m.
I suspect that the 10 Hz could be resonances in air ducts in a central
heating system? Maybe a fan? The velocity of sound is about 330 m/s, so 10 Hz
has a wavelength of about 33 m. Do you have any ducts or corridors about 33,
16.5 or 8.25 m long?
To see the response, choose a section of recording with no quake and
click on the FFT tab in the top tool bar. You will see a plot of the amplitude
against the period.
The second surprise was the large noise count, up in the +/- 300 unit range.
It is nothing to be alarmed about, only different from my system. I wonder
what the noise floor is when the seismometer is disconnected from the
electronics?
You need to substitute 390 Ohm metal film resistors for the geophones to do
this test. Can you buy electronic components easily?
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>In a message dated 10/02/2006, rsparks@.......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>While I=20
have become familiar with my own seismometer and capabilities, I am lookin=
g at=20
a different world when looking at your files. First is the 200 sample=
s=20
per second which provides resolution of events as high as 100 Hz. Tha=
t is=20
very good.</FONT></BLOCKQUOTE>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> Your amplifiers have a cut-off at ~20 Hz. The=20
minimum sample rate is 40 sps. 200 sps is not necessary and could use a lot=20=
of=20
memory. Can you use 60 to 100 sps?</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Next is=20
the 4.5 Hz geophone which has a peak response at about 4.5 Hz. I expe=
ct=20
it to detect local quakes very well. The expectations for large distant qu=
akes=20
are less.</FONT></BLOCKQUOTE>
<DIV> It will not have a peaked response if it is=20
correctly loaded. There should be a ~2.7 K Ohm resistor soldered across the=20
output terminals of each geophone.</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>What=20
surprised me was the large amount of energy found at 10 Hz, declining=
up=20
to about 20 Hz. I did not expect to see that when I applied the FFT algori=
thm=20
from Winquake to each file, and for the most part, to each subdivided time=
=20
period within each file. What I expected to see was the ocean wave no=
ise=20
at 0.2 Hz but at a much reduced peak compared to my own seismometer which=20=
has=20
a natural period of about 3 1/5 to 4 seconds. </FONT></BLOCKQU=
OTE>
<DIV> You don't see microseisms at about 6 sec with a=
4.5=20
Hz geophone. The response will be down by a factor of over 700. If you=20=
are=20
on the coast you will likely see higher frequency noise associated with brea=
king=20
waves. </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>I am=20
curious to know if you can explain the 10 Hz energy source? Also ocean wav=
es?=20
Maybe a nearby flag pole and flag waving in the wind?</FONT></BLOCKQUOTE>
<DIV> The Strouhal number is between 0.2 and 0.4=
,=20
depending on the 'bluntness' of the object; S=3DfxD/v, where f is the vortex=
=20
shedding frequency, D is the width of the object and v is the velocity. Vort=
ices=20
are shed alternately from either side of the object. The force on an object=20=
is=20
at f/2 Hz, so a strong 20 m/sec, 76 kph wind will give D =3D 20 /=20=
100, D=20
~ 0.2 m. </DIV>
<DIV> I suspect that the 10 Hz could be resonanc=
es=20
in air ducts in a central heating system? Maybe a fan? The velocity of=20
sound is about 330 m/s, so 10 Hz has a wavelength of about 33 m. Do you have=
any=20
ducts or corridors about 33, 16.5 or 8.25 m long?</DIV>
<DIV> </DIV>
<DIV> To see the response, choose a section of=20
recording with no quake and click on the FFT tab in the top t=
ool=20
bar. You will see a plot of the amplitude against the period. </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>The=20
second surprise was the large noise count, up in the +/- 300 unit ran=
ge.=20
It is nothing to be alarmed about, only different from my system. I wonder=
=20
what the noise floor is when the seismometer is disconnected from the=20
electronics?<BR></FONT></BLOCKQUOTE>
<DIV></DIV>
<DIV> You need to substitute 390 Ohm metal film resis=
tors=20
for the geophones to do this test. Can you buy electronic components=20
easily?</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Alot of earthquakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 10 Feb 2006 18:50:34 +0000
Hi all
As you might have noticed i have been sending in alot of psn files. I
hope that doesn't bother anyone. But there has been a slow earthquake
swarm going on East of Grímsey for the last 24 hours. There also appears
that earthquakes are picking up in other areas of TFZ, for instace
Northwest of Grímsey. The largest earthquake so far detect is 3.6Ml
earthquake that did happen at 18:00 UTC. For the last files i forgot to
change there Description, it is ment to say TFZ, but it says Icelandic
Region. I just forgot to change it before i did send the files (doh!).
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Alot of earthquakes
From: "Kareem at HeyJooJoo" system98765@.............
Date: Fri, 10 Feb 2006 18:29:04 -0800
Hi Jon and the others...
Where is the area of Grimsey? I'm in the U.S. on the west coast but not
familiar with the area you speak of. Is this in Germany, France, etc?
Kareem
=20
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... =
On
Behalf Of J=F3n Fr=EDmann
Sent: Friday, February 10, 2006 10:51 AM
To: PSN-Postlist
Subject: Alot of earthquakes
Hi all
As you might have noticed i have been sending in alot of psn files. I =
hope
that doesn't bother anyone. But there has been a slow earthquake swarm =
going
on East of Gr=EDmsey for the last 24 hours. There also appears that
earthquakes are picking up in other areas of TFZ, for instace Northwest =
of
Gr=EDmsey. The largest earthquake so far detect is 3.6Ml earthquake that =
did
happen at 18:00 UTC. For the last files i forgot to change there
Description, it is ment to say TFZ, but it says Icelandic Region. I just
forgot to change it before i did send the files (doh!).
Regards.
--
J=F3n Fr=EDmann J=F3nsson
http://www.jonfr.com
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
http://www.seismicnet.com/maillist.html for more information.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Alot of earthquakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 11 Feb 2006 05:12:10 +0000
Hi
Question: Where is the area of Grimsey?
This is located in Iceland, about ~200km away from me. There has been
alot of activiti there now, and problay will continue today.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Massive earthquakea activite
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 11 Feb 2006 07:58:15 +0000
Hi all
There is alot of earthquakea activitie going on now in Iceland, please
look at this map. http://hraun.vedur.is/ja/englishweb/index.html
Some earthquakes are problay mis locatated by the automatic system, but
this is huge number of earthquakes.
Regards, sorry for double emailing this.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting micro-earthquakes
From: Roger Sparks rsparks@..........
Date: Sat, 11 Feb 2006 10:53:29 -0800
Hi All,
Hi Jon,
You definitely have detected some events. Congratulations.
We had a M2.9 event about 102 km from Ellensburg last night. I posted
both a filtered and unfiltered version on the PSN site.
http://www.seismicnet.com/cgi-dos/makegif.exe?/quakes/0602/060211.114712.ebgz.psn
http://www.seismicnet.com/cgi-dos/makegif.exe?/quakes/0602/060211.114712.efil.psn
The unfiltered recording vividly demonstrates how the high frequency
local quake can ride on the noise from ocean waves. Ellensburg is very
roughly 200 miles from the ocean.
Your location at 300 meters from the ocean must be very noisy as you
have indicated. Your problems are far different from mine.
Best wishes, Roger
psn-l-digest-request@.............. wrote:
>.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
>| Message 1 |
>'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
>Subject: Re: Detecting micro-earthquakes
>From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= <jonfr500@.........>
>Date: Fri, 10 Feb 2006 10:38:13 +0000
>
>Hi
>
>To Roger.
>
>I did in the end figure out that i didn't detect the earthquake at that
>range. It was out of my range, after all i didn't see any change in the
>graph as i did go down to 10 seconds on the X scale. I also now got a
>comparison, i did detect a mag 2.2Ml (unconfirmed size) earthquake this
>morning (05:01 GMT), it did happen when there is minimal noise from
>traffic and other cultrual noise sources. I was able to detect the S
>wave of the quake, but the recording is really poor.
>
>As for the 10 to 20Hz noise, i am unsure what you mean.But i am close to
>the ocen, about 300 meters from the beach. There are many noise sources
>where the geophone is located at the moment (for instant the wind noise
>is hig, even if the geophone is located inside the house), at the moment
>i can't move the geophone to better location, becose of house i life in.
>But i plan to move the geophone in next 6 to 8 months, when i can buy
>the needed hardware to move the geophone.
>
>If i rember correctly, the noise level is almost none when i do
>disconnect the geophone from the psn board. But i am not sure, i will
>check this when i move the geophone. The geophone is also located 2
>meters (max) from a solid bedrock. That problay goes down to ~35km into
>the crust, becose it is an old volcano that the town is build on top of
>(in the side of it).
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Detecting micro-earthquakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 11 Feb 2006 19:45:07 +0000
Hi all
Hi Roger
There was an earthquake warm last night and it did last until 11:37 (i
think there where about ~200 earthquakes that did happen in this
earthquake swarm), the earthquakes that i did record where all in poor
qualiti. I think that might come from the depth that they where
happening on, but also how they where breaking up in the crust.
Today i did change my setup a little bit, i did increase the gain and
did set the sps to 50, this move was based on a advice that i got
earlyar today. That is also the reasion why my online graphs are so
eampty.
Now i just have to wait for a earthquake to see how good or bad change
it was that i did do today. I don't think that i am going to have to
wait for a long time before i record a earthquake at this new settings.
I already know that i was able to detect earthquakes down to ~2.4Ml at
the range of ~200km max, if the earthquake had good recording on the
Icelandic Met office seismic network.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Icelandic SIL network document (document from the Icelandic met
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 11 Feb 2006 20:17:26 +0000
Hi all
I want to point out, for those how are intrested in this document, but
it is about the Icelandic SIL network and how it was setup, this
document is farly old and is problay in some parts outdated. But it is
intresting non the less.
http://hraun.vedur.is/ja/skyrslur/silresp/index.html
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Icelandic SIL network document (document from the Icelandic met office)
From: ChrisAtUpw@.......
Date: Sat, 11 Feb 2006 21:55:33 EST
In a message dated 11/02/2006, jonfr500@......... writes:
http://hraun.vedur.is/ja/skyrslur/silresp/index.html
Hi Jon,
Can you check this reference, please? I get website unavailable...
` Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 11/02/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20
size=3D2>http://hraun.vedur.is/ja/skyrslur/silresp/index.html</FONT></BLOC=
KQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> Can you check this reference, please? =
;I=20
get website unavailable...</DIV>
<DIV> </DIV>
<DIV>` Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman </DIV></FONT></BODY></HTML>
Subject: Re: Icelandic SIL network document (document from the Icelandic
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sun, 12 Feb 2006 03:08:40 +0000
Hi
The Icelandic met Office web, at least the earthquake part of there web
appears to be down at the moment. I don't know what did happen, but it
went offline sometimes around from 2:03 - 3:00UTC. They hopefully will
fix this when the morning comes. Just check later if you can't connect
right now.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: snow storm
From: ian ian@...........
Date: Mon, 13 Feb 2006 16:52:09 +0000
are the current micro seisms the snow storm on the East Coast (of USA)?
See http://www.guralp.net/aboutus/index.php#live . My trace is the same
too.
Ian
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
<font color="#000000"><font size="2"><font face="Arial">are the current
micro seisms the snow storm on the East Coast (of USA)? See
<a class="moz-txt-link-freetext" href="http://www.guralp.net/aboutus/index.php#live">http://www.guralp.net/aboutus/index.php#live</a> . My trace is the same
too.<br>
<br>
Ian<br>
</font></font></font>
</body>
</html>
Subject: RE: snow storm
From: "Bob Hancock" carpediem1@.........
Date: Mon, 13 Feb 2006 09:59:26 -0700
You can check out the current ocean activity, a major source of this type of
noise with the following link:
https://www.fnmoc.navy.mil/PUBLIC/WAM/all_glbl.html
Bob Hancock
_____
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of ian
Sent: Monday, February 13, 2006 09:52
To: psn-l@..............
Subject: snow storm
are the current micro seisms the snow storm on the East Coast (of USA)? See
http://www.guralp.net/aboutus/index.php#live . My trace is the same too.
Ian
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<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>You can check out the current ocean
activity, a major source of this type of noise with the following =
link:<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'> =
<a
href=3D"https://www.fnmoc.navy.mil/PUBLIC/WAM/all_glbl.html">https://www.=
fnmoc.navy.mil/PUBLIC/WAM/all_glbl.html</a><o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Bob =
Hancock<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
<div class=3DMsoNormal align=3Dcenter style=3D'text-align:center'><font =
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color=3Dblack face=3D"Times New Roman"><span =
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<hr size=3D2 width=3D"100%" align=3Dcenter tabindex=3D-1>
</span></font></div>
<p class=3DMsoNormal><b><font size=3D2 color=3Dblack face=3DTahoma><span
style=3D'font-size:10.0pt;font-family:Tahoma;color:windowtext;font-weight=
:bold'>From:</span></font></b><font
size=3D2 color=3Dblack face=3DTahoma><span =
style=3D'font-size:10.0pt;font-family:Tahoma;
color:windowtext'> psn-l-request@..............
[mailto:psn-l-request@............... <b><span =
style=3D'font-weight:bold'>On
Behalf Of </span></b>ian<br>
<b><span style=3D'font-weight:bold'>Sent:</span></b> Monday, February =
13, 2006
09:52<br>
<b><span style=3D'font-weight:bold'>To:</span></b> <st1:PersonName =
w:st=3D"on">psn-l@..............</st1:PersonName><br>
<b><span style=3D'font-weight:bold'>Subject:</span></b> snow =
storm</span></font><font
color=3Dblack><span =
style=3D'color:windowtext'><o:p></o:p></span></font></p>
</div>
<p class=3DMsoNormal><font size=3D3 color=3Dblack face=3D"Times New =
Roman"><span
style=3D'font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dblack face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial'>are the current micro seisms the snow storm on =
the
East Coast (of <st1:country-region w:st=3D"on"><st1:place =
w:st=3D"on">USA</st1:place></st1:country-region>)?
See <a =
href=3D"http://www.guralp.net/aboutus/index.php#live">http://www.guralp.n=
et/aboutus/index.php#live</a>
.. My trace is the same too.<br>
<br>
Ian</span></font><o:p></o:p></p>
</div>
</body>
</html>
Subject: Re: snow storm
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 13 Feb 2006 17:23:07 +0000
Hi Ian
According to the wave pattern, this is a wind hammering on the building
where the seismonitor is located. I get this type of pattern all the
time. Becose i have so many storms.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: what formats?
From: "Thomas Dick" dickthomas01@.............
Date: Mon, 13 Feb 2006 11:46:50 -0600
Anybody know .. what formats like weed and spyder will WinQuake handle?
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: snow storm
From: ian ian@...........
Date: Mon, 13 Feb 2006 18:15:50 +0000
Hi,
thanks for the link. The maps show waves in the atlantic which are at
the end of the scale(huge)!
Ian
Bob Hancock wrote:
> You can check out the current ocean activity, a major source of this
> type of noise with the following link:
>
>
>
> https://www.fnmoc.navy.mil/PUBLIC/WAM/all_glbl.html
>
>
>
> Bob Hancock
>
>
>
> ------------------------------------------------------------------------
>
> From: psn-l-request@..............
> [mailto:psn-l-request@............... On Behalf Of ian
> Sent: Monday, February 13, 2006 09:52
> To: psn-l@..............
> Subject: snow storm
>
>
>
> are the current micro seisms the snow storm on the East Coast (of
> USA)? See http://www.guralp.net/aboutus/index.php#live . My trace is
> the same too.
>
> Ian
>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
Hi,<br>
<br>
thanks for the link. The maps show waves in the atlantic which are at
the end of the scale(huge)!<br>
<br>
Ian<br>
<br>
Bob Hancock wrote:<br>
<blockquote cite="midB0000455033@..................." type="cite">
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<div class="Section1">
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial; color: navy;">You can
check out the current ocean
activity, a major source of this type of noise with the following link:<o:p></o:p></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial; color: navy;"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial; color: navy;"> <a
href="https://www.fnmoc.navy.mil/PUBLIC/WAM/all_glbl.html">https://www.fnmoc.navy.mil/PUBLIC/WAM/all_glbl.html</a><o:p></o:p></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial; color: navy;"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial; color: navy;">Bob Hancock<o:p></o:p></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial; color: navy;"><o:p> </o:p></span></font></p>
<div>
<div class="MsoNormal" style="text-align: center;" align="center"><font
color="black" face="Times New Roman" size="3"><span
style="font-size: 12pt; color: windowtext;">
<hr tabindex="-1" align="center" size="2" width="100%"></span></font></div>
<p class="MsoNormal"><b><font color="black" face="Tahoma" size="2"><span
style="font-size: 10pt; font-family: Tahoma; color: windowtext; font-weight: bold;">From:</span></font></b><font
color="black" face="Tahoma" size="2"><span
style="font-size: 10pt; font-family: Tahoma; color: windowtext;">
<a class="moz-txt-link-abbreviated" href="mailto:psn-l-request@..............">psn-l-request@..............</a>
[<a class="moz-txt-link-freetext" href="mailto:psn-l-request@..............">mailto:psn-l-request@..............</a>] <b><span
style="font-weight: bold;">On
Behalf Of </span></b>ian<br>
<b><span style="font-weight: bold;">Sent:</span></b> Monday, February
13, 2006
09:52<br>
<b><span style="font-weight: bold;">To:</span></b> <st1:PersonName
w:st="on"><a class="moz-txt-link-abbreviated" href="mailto:psn-l@..............">psn-l@..............</a></st1:PersonName><br>
<b><span style="font-weight: bold;">Subject:</span></b> snow storm</span></font><font
color="black"><span style="color: windowtext;"><o:p></o:p></span></font></p>
</div>
<p class="MsoNormal"><font color="black" face="Times New Roman"
size="3"><span style="font-size: 12pt;"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font color="black" face="Arial" size="2"><span
style="font-size: 10pt; font-family: Arial;">are the current micro
seisms the snow storm on the
East Coast (of <st1:country-region w:st="on"><st1:place w:st="on">USA</st1:place></st1:country-region>)?
See <a href="http://www.guralp.net/aboutus/index.php#live">http://www.guralp.net/aboutus/index.php#live</a>
.. My trace is the same too.<br>
<br>
Ian</span></font><o:p></o:p></p>
</div>
</blockquote>
</body>
</html>
Subject: Alot of earthquake in a week
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 13 Feb 2006 22:13:05 +0000
Hi all
Last week was today the most busy week that i have had in recording
earthquakes since i got my Geophone in December. I have sent my psn
files to the psn data list. I hope that it doesn't bother pepole that i
have sent in large number of files.
This however was rater normal week in Iceland, only about 300 - 500
earthquakes recored in total this week.
I think the psn file list is going to be intresting when there is going
to be a large scale earthquake swarm in part of Iceland. With mag 5 as a
main earthquake and about ~20 earthquakes that are mag 3 or bigger and
alot of smaller earthquakes.
I hope that i don't bother pepole with this.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Google maps
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Tue, 14 Feb 2006 16:28:20 +0000
Hi all
I want to point out wonders of google maps. This link is almost directy
above my town.
http://maps.google.com/maps?f=q&hl=en&t=k&ll=65.407731,-20.926895&spn=0.524632,1.955566&t=k
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Google maps
From: Dave Willey davewilley@.............
Date: Tue, 14 Feb 2006 15:35:34 -0800 (PST)
Ha! If you have a fast computer you better take some Dramamine first!
It is a very impressive tool. But I'm only good for about 10 minutes of flying
around before my head starts spinning & I stagger off like a drunk as go
to toss my lunch...
Dave - N6DSW
Jón Frímann <jonfr500@.........> wrote: Hi all
I want to point out wonders of google maps. This link is almost directy
above my town.
http://maps.google.com/maps?f=q&hl=en&t=k&ll=65.407731,-20.926895&spn=0.524632,1.955566&t=k
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
<div id="RTEContent">Ha! If you have a fast computer you better take some Dramamine first!<br> <br> It is a very impressive tool. But I'm only good for about 10 minutes of flying<br> around before my head starts spinning & I stagger off like a drunk as go<br> to toss my lunch...<br> <br> Dave - N6DSW<br><br><b><i>Jón Frímann <jonfr500@.........></i></b> wrote:<blockquote class="replbq" style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"> Hi all<br><br>I want to point out wonders of google maps. This link is almost directy<br>above my town.<br><br>http://maps.google.com/maps?f=q&hl=en&t=k&ll=65.407731,-20.926895&spn=0.524632,1.955566&t=k<br><br>Regards.<br>-- <br>Jón Frímann Jónsson<br>http://www.jonfr.com<br>http://www.simnet.is/jonfr500/earthquake/<br><br>__________________________________________________________<br><br>Public Seismic Network Mailing List (PSN-L)<br><br>To leave this list email
PSN-L-REQUEST@SEISMICNET.COM with <br>the body of the message (first line only): unsubscribe<br>See http://www.seismicnet.com/maillist.html for more information.<br></blockquote><br></div>
Subject: Detecting earthquake trugh a wind noise
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Wed, 15 Feb 2006 14:05:02 +0000
Hi all
Last 24 hours have been bad for me in terms of detecting earthquakes,
there has been a storm going on and my geophone picks up the wind and
the ocen movements on the beach, even if it is inside the house. Last
night at 03:19 UTC was a earthquake at size 2.88Ml at distance of 246km,
i think that might have been able to detect that earthquake, however
becose of the wind i am not sure if that i did detect the earthquake,
becose the noise from the wind might simple have drowned the signal from
the earthquake. Is there any good way for me to see if there is a
earthquake in the noise or not.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: good leveling screw source
From: Barry Lotz barry_lotz@.............
Date: Wed, 15 Feb 2006 20:30:20 -0800 (PST)
jim
I have found that surplus surveying transit/level leveling screws have worked well for me, plus they come with an adjusting knob/wheel and bottom swivel (maybe not good, ie. possible minute horizontal free play) . Surveying repair businesses usually carry spare parts.
regards
Barry
James Hannon <jmhannon@.........> wrote:
I have not found the need to use extra fine pitch screws for leveling. I use national fine pitch socket head screws and grind the end to a dome shape. By using a long handle allen wrench to turn the screws I can get all the fineness in the adjustment I need.
Jim Hannon
--
Jim Hannon
http://www.fmtcs.com/web/jmhannon/
42,11.90N,91,39.26W
WB0TXL
--
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
<DIV>jim</DIV> <DIV> I have found that surplus surveying transit/level leveling screws have worked well for me, plus they come with an adjusting knob/wheel and bottom swivel (maybe not good, ie. possible minute horizontal free play) . Surveying repair businesses usually carry spare parts.</DIV> <DIV>regards</DIV> <DIV>Barry</DIV> <DIV><BR><BR><B><I>James Hannon <jmhannon@.........></I></B> wrote:</DIV> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">I have not found the need to use extra fine pitch screws for leveling. I use national fine pitch socket head screws and grind the end to a dome shape. By using a long handle allen wrench to turn the screws I can get all the fineness in the adjustment I need.<BR><BR>Jim Hannon<BR>--<BR>Jim Hannon<BR>http://www.fmtcs.com/web/jmhannon/<BR>42,11.90N,91,39.26W<BR>WB0TXL<BR>--<BR><BR>__________________________________________________________<BR><BR>Public Seismic Network
Mailing List (PSN-L)<BR><BR>To leave this list email PSN-L-REQUEST@SEISMICNET.COM with <BR>the body of the message (first line only): unsubscribe<BR>See http://www.seismicnet.com/maillist.html for more information.<BR></BLOCKQUOTE> <DIV><BR></DIV>
Subject: WinQuake volume files
From: Roger Sparks rsparks@..........
Date: Thu, 16 Feb 2006 10:23:42 -0800
Hi All,
Bob McClure suggested that I post the contents of an email that I sent
he and others yesterday concerning WinQuake volume files. Here it is.
Volume files are a new WinQuake feature that Bob has used for a while
now. It is available in WinQuake 2.9.8 beta which can be found here.
http://www.seismicnet.com/software/wq298.zip
Volume files allow two or three traces to appear in one window, each
placed above the other. Each file must be the same length and contain
some of the same header information before it can be placed in a
volume. The File/Add menu is intended as an aid to making volume files
but does not yet work reliably.
Here is a work-around to make a volume file. Assume the goal is to
filter a recording and display both the filtered and unfiltered trace in
one window.
The steps in WinQuake:
1. WinQuake opens with files listed in the "Open" screen. Select the
quake to be displayed and click on "Open File" button
2. Perform the filter operation and save the filtered file with a new
name. This is done in the "File Save" menu by modifying the name in the
"File Name" window. Click the "OK" button.
3. Close the window containing the filtered file. That should put you
back to the "Open" screen with the list of event files which now
contains the filtered file.
4. Select both the filtered and unfiltered files by using the shift key
while selecting the second file. Both files should be highlighted.
Click the "Open File" button.
5. You should now see the traces from both files in the main WinQuake
window. Click the "Save" button.
6. In the "File Save" window, you will see both names in separate
"File Name" windows. Find the "Dataset Volume" check/button and click
to place a check in the box One of the file names will disappear,
leaving only one file name. Modify the name (if desired) and click the
"OK" button. Both files will be saved as a volume with the modified name.
7. Here is a link to the volume that I made as I typed these
instructions.
http://www.seismicnet.com/quakes/0602/060211.114712.ebgztwo.psn
Once opened, you can look at either individual file by clicking the
"View" button. The drop-down menu choice "Display Record" or "Select
Record" both give drop-down menu choices to examine the traces
individually.
My thanks to Bob who helped and inspired me to learn how to use this new
WinQuake feature. Thanks also to Larry Cochrane who wrote WinQuake with
all its useful features.
Roger
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject:
From: 1goss@...........
Date: Fri, 17 Feb 2006 08:54:25 +0000
Hi all I am trying to find a used geophone for recording micro earthquakes in the central US.
Mainly in the New Madrid Fault Zone. I have a Lehmann sensor, but I would like a Geophone.
I am not sure what I need, Maybe something like Larry had on his website but is sold out of the GeoSpace HS 10-1 1 Hz Vertical Sensor. Where would I look to find one or does anyone have one they would part with for the right price.
Thanks Bryan S Goss
Corinth Ms
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Geophones on ebay
From: Bob Barns royb1@...........
Date: Fri, 17 Feb 2006 10:12:47 -0500
Bryan,
Ebay often offers geophones. They are rarely the 1 sec. period vareity.
Bob
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Geophones on ebay
From: "Geoffrey" gmvoeth@...........
Date: Fri, 17 Feb 2006 10:59:29 -0700
I have to say that such a 1 sec geophone new
will cost you in the neighborhood of
$3000 USD so I think people who buy them
are not too eager to give them up
at a reduced price. I think those
geophone people would be doing all us
amateures a favor to create a lesser quality
device at 1/10 the cost.
Maybe if the chinese were to make them
they could make them cheaper and sell
them at Walmart in the toy section for the
Jimmy Neutrons of this Earth.
gmvoeth
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Geophones on ebay
From: John or Jan Lahr JohnJan@........
Date: Fri, 17 Feb 2006 15:08:06 -0800
It's not that hard to make a short period sensor with a period of
about 1 second. I've event been experimenting with one made mostly
of wood! I've posted pictures here:
http://jclahr.com/science/psn/wooden/
The period is just over 3 seconds, but at 1 second period it would be
even more stable under
changed in temperature.
I actually like the toy store idea and think it would be easy to mass
produce a very inexpensive
system.
Cheers,
John
At 09:59 AM 2/17/2006, you wrote:
>I have to say that such a 1 sec geophone new
>will cost you in the neighborhood of
>$3000 USD so I think people who buy them
>are not too eager to give them up
>at a reduced price. I think those
>geophone people would be doing all us
>amateures a favor to create a lesser quality
>device at 1/10 the cost.
>Maybe if the chinese were to make them
>they could make them cheaper and sell
>them at Walmart in the toy section for the
>Jimmy Neutrons of this Earth.
>gmvoeth
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with the body
>of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Recording Micro Quakes
From: Roger Sparks rsparks@..........
Date: Sat, 18 Feb 2006 08:08:00 -0800
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
Hi Bryan,<br>
<br>
You should find that your Lehmann would be more sensitive than a
Geophone at the higher frequencies expected from micro quakes. This
would be because the longer period instruments would use less damping
than the higher frequency units.<br>
<br>
Think of it this way. The shorter the period of a seismometer, the
larger the damper will be to achieve critical damping. The damper
always reduces the motion induced in the seismometer by the passing
wave. Larger damper for a higher frequency sensor so less sensitivity
(than the longer period sensor) at the higher frequencies.<br>
<br>
You might consider if the damping and filters you are using on the
Lehmann are seriously attenuating the higher frequency waves that could
be expected from micro quakes. You are probably sensing the micro
quakes now, but losing the information in the filters and damper.<br>
<br>
Several people are posting recordings of micro quakes on <a
href="http://psn.quake.net/">The PSN web site</a> . A WinQuake FFT
analysis of the posted micro quakes helps give a perspective of the
bandpass requirements needed of the equipment.<br>
<br>
Best wishes, Roger<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:psn-l-digest-request@..............">psn-l-digest-request@..............</a> wrote:
<blockquote cite="midB0000457102@..................." type="cite">
<pre wrap="">.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 1 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
From: <a class="moz-txt-link-abbreviated" href="mailto:1goss@...........">1goss@...........</a>
Date: Fri, 17 Feb 2006 08:54:25 +0000
Hi all I am trying to find a used geophone for recording micro earthquakes in the central US.
Mainly in the New Madrid Fault Zone. I have a Lehmann sensor, but I would like a Geophone.
I am not sure what I need, Maybe something like Larry had on his website but is sold out of the GeoSpace HS 10-1 1 Hz Vertical Sensor. Where would I look to find one or does anyone have one they would part with for the right price.
Thanks Bryan S Goss
Corinth Ms
</pre>
<pre wrap="">
</pre>
</blockquote>
</body>
</html>
Subject: RE: Recording Micro Quakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 18 Feb 2006 17:02:06 +0000
Hi Bryan
I use 4.5Hz Geophone to detect local and regional earthquakes, at this
moment i don't have a long period seismonitor. This geophone can, if the
condsions are good, you can detect earthquakes down to ~2.4ML at the
range of ~200 km. The frequancy of a local earthquake is from 2Hz to
60Hz, problay higer if you can recorod it. The problem is however that
above 4Hz there is alot of noise. Both from nature and human traffic.
You can check my recordings at the psn webpage.
http://seismicnet.com/cgi-dos/event.exe
They are the one with the name "Hvammstangi".
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Geo-phone
From: Tamati chief.cook.nz@............
Date: Sun, 19 Feb 2006 08:04:32 +1300
TAMATI's WORD's OF WISDOM
FOR THE GOOD OF ALL MANKIND
HTTP://LIVE-PLANET.BLOGSPOT.COM
http://www.webspawner.com/users/chiefcooknz/index.html
Please give me feed back on what you think
chief.cook.nz.@............
NZ-021-150-33-59 or NZ-07-855-0195
have you got a circut diagram of your geo-phone
Cheers Tamati
From the Castle of Tamati, Hinemoa and Karauwa the Dog
From the Castle of Tom, Robyn and the Dog
I'm Just a Stone's Throw Away:- NZ-021-150-33-59 or NZ-07-855-0195
Bush Telegragh:- =
chief.cook.nz@............
My Regular Pitstop:- Tamati
=
P.O.BOX 19-356 CENTRAL
=
HAMILTON
NEW =
ZEALAND
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV align=3Dcenter><STRONG><FONT face=3DGeorgia>TAMATI's WORD's OF =
WISDOM<BR>FOR=20
THE GOOD OF ALL MANKIND<BR><A=20
href=3D"http://LIVE-PLANET.BLOGSPOT.COM">HTTP://LIVE-PLANET.BLOGSPOT.COM<=
/A><BR><A=20
href=3D"http://www.webspawner.com/users/chiefcooknz/index.html">http://ww=
w.webspawner.com/users/chiefcooknz/index.html</A><BR>Please=20
give me feed back on what you think<BR><A=20
href=3D"mailto:chief.cook.nz.@............">chief.cook.nz.@............</=
A><BR>NZ-021-150-33-59=20
or NZ-07-855-0195</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia></FONT></STRONG> </DIV>
<DIV><STRONG><FONT face=3DGeorgia>have you got a circut diagram of your=20
geo-phone</FONT></STRONG></DIV>
<DIV> </DIV>
<DIV><STRONG><FONT face=3DGeorgia>Cheers Tamati<BR>From the Castle of =
Tamati,=20
Hinemoa and Karauwa the Dog<BR>From the Castle of Tom, Robyn and the=20
Dog</FONT></STRONG></DIV>
<DIV> </DIV>
<DIV><STRONG><FONT face=3DGeorgia>I'm Just a Stone's Throw Away:- =
NZ-021-150-33-59=20
or=20
NZ-07-855-0195<BR> &=
nbsp; &n=
bsp; =20
Bush Telegragh:- <A=20
href=3D"mailto:chief.cook.nz@............">chief.cook.nz@............</A>=
<BR> &nb=
sp; =20
My Regular Pitstop:-=20
Tamati<BR> &nb=
sp; &nbs=
p;  =
; =
&=
nbsp; =20
P.O.BOX 19-356=20
CENTRAL<BR> &n=
bsp; &nb=
sp; &nbs=
p;  =
; =
=20
HAMILTON<BR> &=
nbsp; &n=
bsp; &nb=
sp; &nbs=
p;  =
; =20
NEW ZEALAND</FONT></STRONG></DIV></BODY></HTML>
Subject: Recording Micro Quakes
From: 1goss@...........
Date: Sun, 19 Feb 2006 07:00:59 +0000
Thanks for all the reply’s. I don’t have 3,000 for a geophone laying around, so I will shorten the period on one of my Lehman’s to see how well It can record local events.
Thanks again Bryan S Goss
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Recording Micro Quakes
From: ChrisAtUpw@.......
Date: Sun, 19 Feb 2006 11:07:29 EST
=20
In a message dated 19/02/2006, 1goss@........... writes:
Thanks for all the reply=E2=80=99s. I don=E2=80=99t have 3,000 for a geopho=
ne laying=20
around, so I will shorten the period on one of my Lehman=E2=80=99s to see h=
ow well It can=20
record local events.=20
Thanks again Bryan S Goss
Hi Bryan,
=20
No! This is not necessary and it will actually REDUCE the output, since=
=20
you will have to increase the damping. For local events you need to look at=
P=20
& S freqencies well over 1 Hz. I expect that your amplifier will roll off a=
t=20
10 Hz. Just use Winquake to set the upper and lower frequencies displayed.
=20
Regards,
=20
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUTF-8">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 19/02/2006, 1goss@........... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Thanks=20
for all the reply=E2=80=99s. I don=E2=80=99t have 3,000 for a geophone lay=
ing around, so I=20
will shorten the period on one of my Lehman=E2=80=99s to see how well It c=
an record=20
local events. <BR> Thanks again Bryan S Goss<BR></FONT></BLOCKQUOTE>=
</DIV>
<DIV></DIV>
<DIV>Hi Bryan,</DIV>
<DIV> </DIV>
<DIV> No! This is not necessary and it will actually=20
REDUCE the output, since you will have to increase the damping. For local ev=
ents=20
you need to look at P & S freqencies well over 1 Hz. I expect that your=20
amplifier will roll off at 10 Hz. Just use Winquake to set the upper and low=
er=20
frequencies displayed.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Educational seisograph construction details
From: Jatin Pandya jatinip@.........
Date: Sun, 19 Feb 2006 09:20:31 -0800 (PST)
I was pointed at the following site to get details of their educational seisograph. I have sent them requests at least three times, but haven't heard back from them. Has anyone received any construction details of their educational seismograph from them?
The site is at: http://www.mgm.monschau.de/seismic/
Jatin
===============
<html><head><style type="text/css"><!-- DIV {margin:0px} --></style></head><body><div style="font-family:courier, monaco, monospace, sans-serif;font-size:10pt">I was pointed at the following site to get details of their educational
seisograph. I have sent them requests at least three times, but haven't
heard back from them. Has anyone received any construction details of
their educational seismograph from them? <br><br><span>The site is at: <a id="bodyLinks" target="_blank" href="http://www.mgm.monschau.de/seismic/">http://www.mgm.monschau.de/seismic/</a></span><br><br>Jatin<br>===============<div><br></div></div></body></html>
Subject: Geophone Schematic for anyone interested
From: "Geoffrey" gmvoeth@...........
Date: Sun, 19 Feb 2006 10:53:29 -0700
Here is a link to the schematic I am currently using here in Apache junction, I was just wondering possibly if there is anyone out
there interested in breadboarding and testing this same idea ?? It is only for P/S waves. My area is terribly noisy so I trust just
about no signals I see here.
http://users.isp.com/gmvoethb293690/geo001.gif
Tamati asked me to show him what I am using
so I told him to look here to find it.
Cheers :-)
gmvoeth
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Educational seisograph construction details
From: ChrisAtUpw@.......
Date: Sun, 19 Feb 2006 15:50:35 EST
In a message dated 19/02/2006, jatinip@......... writes:
I was pointed at the following site to get details of their educational
seisograph. I have sent them requests at least three times, but haven't heard
back from them. Has anyone received any construction details of their
educational seismograph from them?
The site is at: _http://www.mgm.monschau.de/seismic/_
(http://www.mgm.monschau.de/seismic/)
Hi Jatin,
I also put in a request, but I did not get either an acknowledgement or
any information.
Regards,
Chris
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 19/02/2006, jatinip@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DCourier color=3D#000000 siz=
e=3D2>I was=20
pointed at the following site to get details of their educational seisogra=
ph.=20
I have sent them requests at least three times, but haven't heard back fro=
m=20
them. Has anyone received any construction details of their educational=20
seismograph from them? <BR><BR><SPAN>The site is at: <A id=3DbodyLinks=20
title=3Dhttp://www.mgm.monschau.de/seismic/=20
href=3D"http://www.mgm.monschau.de/seismic/"=20
target=3D_blank>http://www.mgm.monschau.de/seismic/</A></SPAN><BR></FONT><=
/BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jatin,</DIV>
<DIV> </DIV>
<DIV> I also put in a request, but I did not get eith=
er=20
an acknowledgement or any information.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris</DIV></FONT></BODY></HTML>
Subject: earthquake p and s wave fracturing ?
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 20 Feb 2006 00:57:42 +0000
Hi all
This morning i did recorod a earthquake that was a 3.0ML based on early
resaults, it problay is larger in size then the automatic resaults
indicate. However, i have noticed something strange about this
earthquake. This earthquake has a energy componment down to 2Hz and down
to 1Hz, however i just don't recorod that frequancy (1Hz) that low good
with my geophone. There also appears to be sometype of a fraction in the
earthquake p and s waves. It appears more in the p wave, but is also
visable in the s wave. This might be becose there is a large volcano
between my location and where the earthquake did happen, i am not sure
about that however.
The files are here. http://seismicnet.com/cgi-dos/event.exe
They are named Ml3 189km from Hvammstangi, Iceland, Vatnajökull
I think that this might indcate that there is something in the making in
the area where this earthqauke did happen. But the area is inside a
volcano fissure swarm. The volcano in questions is named Bárðarbúnga
(Bárdarbunga), here are info about it.
http://www.volcano.si.edu/world/volcano.cfm?vnum=1703-03=
Those volcanos are in between my location and where the earthquake did
happen.
http://www.volcano.si.edu/world/volcano.cfm?vnum=1701-09= - Hofsjökull
http://www.volcano.si.edu/world/volcano.cfm?vnum=1703-04= -
Tungnafellsjökull
I just wonder why this is, that's all.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: earthquake p and s wave fracturing ?
From: ChrisAtUpw@.......
Date: Mon, 20 Feb 2006 07:07:55 EST
In a message dated 20/02/2006, jonfr500@......... writes:
This earthquake has an energy component down to 2Hz and down to 1Hz, however
i just don't record that frequency (1Hz) that low good with my geophone.
There also appears to be some type of a fraction in the earthquake p and s
waves. It appears more in the p wave, but is also visible in the s wave.
HI Jon,
From the distance, this looks like a near regional quake. Your geophone
will see ~1/20 sensitivity at 1 Hz, 1/5 sensitivity at 2 Hz. If the waves are
strong enough you can see them. You may also see two sets of P & S waves
which have travelled by different paths. There is a discontinuity called the
Moho about 35 km down under land, 10 km down under the sea. The volcanic
structures may interfere.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 20/02/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>This=20
earthquake has an energy component down to 2Hz and down to 1Hz, however i=20=
just=20
don't record that frequency (1Hz) that low good with my geophone. There al=
so=20
appears to be some type of a fraction in the earthquake p and s waves. It=20
appears more in the p wave, but is also visible in the s wave.=20
</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>HI Jon,</DIV>
<DIV> </DIV>
<DIV> From the distance, this looks like a near regio=
nal=20
quake. Your geophone will see ~1/20 sensitivity at 1 Hz, 1/5 sensitivity at=20=
2=20
Hz. If the waves are strong enough you can see them. You may also see two se=
ts=20
of P & S waves which have travelled by different paths. There is a=20
discontinuity called the Moho about 35 km down under land, 10 km down u=
nder=20
the sea. The volcanic structures may interfere.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Educational seisograph construction details
From: geodynamics@.......
Date: Mon, 20 Feb 2006 15:07:56 +0000
I just looked at the site. Seems that you might be able to figure out the details by studing the three posted documents.
http://www.mgm.monschau.de/seismic/english/downloads.php
Regards,
-Tim-
Timothy Carpenter
-------------- Original message from ChrisAtUpw@........ --------------
In a message dated 19/02/2006, jatinip@......... writes:
I was pointed at the following site to get details of their educational seisograph. I have sent them requests at least three times, but haven't heard back from them. Has anyone received any construction details of their educational seismograph from them?
The site is at: http://www.mgm.monschau.de/seismic/
Hi Jatin,
I also put in a request, but I did not get either an acknowledgement or any information.
Regards,
Chris
<html>
<!-- BEGIN WEBMAIL STATIONERY -->
<head></head>
<body>
<!-- WEBMAIL STATIONERY noneset -->
<DIV></DIV>
<P>I just looked at the site. Seems that you might be able to figure out the details by studing the three posted documents.</P>
<P> </P>
<P><A href="http://www.mgm.monschau.de/seismic/english/downloads.php">http://www.mgm.monschau.de/seismic/english/downloads.php</A><BR></P>
<P>Regards,</P>
<P>-Tim-</P>
<P>Timothy Carpenter</P>
<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">-------------- Original message from ChrisAtUpw@........ -------------- <BR><BR>
<META content="MSHTML 6.00.2900.2802" name=GENERATOR><FONT id=role_document face=Arial color=#000000 size=2>
<DIV>
<DIV>In a message dated 19/02/2006, jatinip@......... writes:</DIV>
<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT style="BACKGROUND-COLOR: transparent" face=Courier color=#000000 size=2>I was pointed at the following site to get details of their educational seisograph. I have sent them requests at least three times, but haven't heard back from them. Has anyone received any construction details of their educational seismograph from them? <BR><BR><SPAN>The site is at: <A id=bodyLinks title=http://www.mgm.monschau.de/seismic/ href="http://www.mgm.monschau.de/seismic/" target=_blank>http://www.mgm.monschau.de/seismic/</A></SPAN><BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jatin,</DIV>
<DIV> </DIV>
<DIV> I also put in a request, but I did not get either an acknowledgement or any information.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris</DIV></FONT></BLOCKQUOTE>
<!-- END WEBMAIL STATIONERY -->
</body>
</html>
Subject: RE: Geophones on ebay
From: "Jack Ivey" ivey@..........
Date: Mon, 20 Feb 2006 12:48:13 -0500
John,
What are you using for a spring? Is it a special magic "zero length"
spring
or just something from the hardware store?
Thanks,
Jack
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@...............
On Behalf Of John or Jan Lahr
Sent: Friday, February 17, 2006 6:08 PM
To: psn-l@..............
Subject: Re: Geophones on ebay
It's not that hard to make a short period sensor with a period of=20
about 1 second. I've event been experimenting with one made mostly=20
of wood! I've posted pictures here:
http://jclahr.com/science/psn/wooden/
The period is just over 3 seconds, but at 1 second period it would be=20
even more stable under
changed in temperature.
I actually like the toy store idea and think it would be easy to mass=20
produce a very inexpensive
system.
Cheers,
John
At 09:59 AM 2/17/2006, you wrote:
>I have to say that such a 1 sec geophone new
>will cost you in the neighborhood of
>$3000 USD so I think people who buy them
>are not too eager to give them up
>at a reduced price. I think those
>geophone people would be doing all us
>amateures a favor to create a lesser quality
>device at 1/10 the cost.
>Maybe if the chinese were to make them
>they could make them cheaper and sell
>them at Walmart in the toy section for the
>Jimmy Neutrons of this Earth.
>gmvoeth
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with the body=20
>of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Educational seisograph construction details
From: ChrisAtUpw@.......
Date: Mon, 20 Feb 2006 13:02:57 EST
In a message dated 20/02/2006, geodynamics@....... writes:
I just looked at the site. Seems that you might be able to figure out the
details by studing the three posted documents.
_http://www.mgm.monschau.de/seismic/english/downloads.php_
(http://www.mgm.monschau.de/seismic/english/downloads.php)
Hi Tim,
Thanks for the suggestion. I have done this, but there is no information
on their vertical sensor, just outline information on the two Lehmans. I was
hoping to get drawings and dimensions. They do offer to send you a complete
CD!
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 20/02/2006, geodynamics@....... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>
<P>I just looked at the site. Seems that you might be able to figure out t=
he=20
details by studing the three posted documents. <A=20
title=3Dhttp://www.mgm.monschau.de/seismic/english/downloads.php=20
href=3D"http://www.mgm.monschau.de/seismic/english/downloads.php">http://w=
ww.mgm.monschau.de/seismic/english/downloads.php</A><BR></P></FONT></BLOCKQU=
OTE></DIV>
<DIV></DIV>
<DIV>Hi Tim,</DIV>
<DIV> </DIV>
<DIV> Thanks for the suggestion. I have done this, bu=
t=20
there is no information on their vertical sensor, just outline information o=
n=20
the two Lehmans. I was hoping to get drawings and dimensions. They do offer=20=
to=20
send you a complete CD! </DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: RE: Geophones on ebay
From: John or Jan Lahr JohnJan@........
Date: Mon, 20 Feb 2006 11:19:35 -0800
Hi Jack,
I'm just using a spring from the hardware store.
John
At 09:48 AM 2/20/2006, you wrote:
>John,
>What are you using for a spring? Is it a special magic "zero length"
>spring
>or just something from the hardware store?
>
>Thanks,
>Jack
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Recording Micro Quakes
From: Roger Sparks rsparks@..........
Date: Mon, 20 Feb 2006 13:54:46 -0800
This is a re-post. I mistakenly originally posted in HTML format,
which does not reproduce well on PSN. I locked my E-mail to "text" for
this posting and all future postings.
Hi Bryan,
You should find that your Lehmann would be more sensitive than a
Geophone at the higher frequencies expected from micro quakes. This
would be because the longer period instruments would use less damping
than the higher frequency units.
Think of it this way. The shorter the period of a seismometer, the
larger the damper will be to achieve critical damping. The damper
always reduces the motion induced in the seismometer by the passing
wave. Larger damper for a higher frequency sensor so less sensitivity
(than the longer period sensor) at the higher frequencies.
You might consider if the damping and filters you are using on the
Lehmann are seriously attenuating the higher frequency waves that could
be expected from micro quakes. You are probably sensing the micro
quakes now, but losing the information in the filters and damper.
Several people are posting recordings of micro quakes on
http://psn.quake.net. A WinQuake FFT analysis of the posted micro
quakes helps give a perspective of the bandpass requirements needed of
the equipment.
Best wishes, Roger
psn-l-digest-request@.............. wrote:
>.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
>| Message 1 |
>'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
>From: 1goss@...........
>Date: Fri, 17 Feb 2006 08:54:25 +0000
>
>Hi all I am trying to find a used geophone for recording micro earthquakes in the central US.
>Mainly in the New Madrid Fault Zone. I have a Lehmann sensor, but I would like a Geophone.
>I am not sure what I need, Maybe something like Larry had on his website but is sold out of the GeoSpace HS 10-1 1 Hz Vertical Sensor. Where would I look to find one or does anyone have one they would part with for the right price.
>Thanks Bryan S Goss
>Corinth Ms
>
>
>
>
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: two home-made vertical seismometers
From: "Gerencher, Joseph J" gerencher@............
Date: Tue, 21 Feb 2006 15:09:27 -0500
I have photographs of two vertical seismometers that were made by Jim
Lehman and given to me. Both have been in continuous operation for
several years and both have a natural period of about one second. The
smaller unit is in my classroom and the larger one is in the basement
beneath the classroom. I modified the damping of the smaller unit using
copper plumbing fittings, which makes it both easier to construct and
easier to operate than the larger one. The web address for going
directly to the photographs is too long to post on an e-mail, so if you
want to see images of both these seismometers go to my opening web page
at=20
http://home.moravian.edu/users/phys/mejjg01/
then click "homemade seismographs," click "Illustrated history of the
seismometer system, 1991 to 1998" and click the links on that page.
Additional detailed photographs of the construction design of the
smaller home-made seismometer can be found at the following web site:
http://www.netquake.org/seismometers/vertical.htm Unfortunately, I have
not yet gotten around to annotating these photographs, but intend to do
so in the next several days.
=20
Joe Gerencher
=20
=20
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<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>I have photographs of two vertical seismometers that =
were
made by Jim Lehman and given to me. Both have been in continuous
operation for several years and both have a natural period of about one =
second.
The smaller unit is in my classroom and the larger one is in the =
basement
beneath the classroom. I modified the damping of the smaller unit =
using
copper plumbing fittings, which makes it both easier to construct and =
easier to
operate than the larger one. The web address for going directly to =
the photographs
is too long to post on an e-mail, so if you want to see images of both =
these
seismometers go to my opening web page at <o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'><a =
href=3D"http://home.moravian.edu/users/phys/mejjg01/">http://home.moravia=
n.edu/users/phys/mejjg01/</a><o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'>then click “homemade seismographs,” click =
“Illustrated
history of the seismometer system, 1991 to 1998” and click the =
links on
that page. Additional detailed photographs of the construction =
design of
the smaller home-made seismometer can be found at the following web =
site:
</span></font><a =
href=3D"http://www.netquake.org/seismometers/vertical.htm">http://www.net=
quake.org/seismometers/vertical.htm</a>
Unfortunately, I have not yet gotten around to annotating these =
photographs,
but intend to do so in the next several days.<o:p></o:p></p>
<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'>Joe Gerencher<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
</div>
</body>
</html>
Subject: RE: two home-made vertical seismometers
From: "Steve Hammond" shammon1@.............
Date: Wed, 22 Feb 2006 09:02:10 -0800
If you want to build a simple seismograph, here is a URL of a very simple
vertical seismograph that was designed by a fellow in Pasadena in the early
1990's.
http://pw2.netcom.com/~shammon1/compressed/VERTICAL.GIF
It uses a screen door spring and cost under $20. It is made from common
parts in a local hardware store and produces good results. It does lack the
electronics however, so if you check the same site,
http://pw2.netcom.com/~shammon1/equip.htm#Electronics
you will find a pre-amp using OP-07's that can be used with this. The coil
can be built from #44 wire on a plastic frame. You can get the frame from
Radio Shack if you just purchase a spool of their red/black/green #22
construction wire. Hand wind about 4,000 turns of the #44 wire onto a frame.
Warp the coil in black electrical tape to protect it. The magnet is a cow
magnet sold in an animal feed stores but other magnets will also work. I
used these plans to build a system for a 5th grade classroom and the
students were able to locate local events with it.
Regards, Steve Hammond PSN San Jose, Aptos California
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@.................
Behalf Of Gerencher, Joseph J
Sent: Tuesday, February 21, 2006 12:09 PM
To: PSN-L@..............
Subject: two home-made vertical seismometers
I have photographs of two vertical seismometers that were made by Jim
Lehman and given to me. Both have been in continuous operation for several
years and both have a natural period of about one second. The smaller unit
is in my classroom and the larger one is in the basement beneath the
classroom. I modified the damping of the smaller unit using copper plumbing
fittings, which makes it both easier to construct and easier to operate than
the larger one. The web address for going directly to the photographs is
too long to post on an e-mail, so if you want to see images of both these
seismometers go to my opening web page at
http://home.moravian.edu/users/phys/mejjg01/
then click "homemade seismographs," click "Illustrated history of the
seismometer system, 1991 to 1998" and click the links on that page.
Additional detailed photographs of the construction design of the smaller
home-made seismometer can be found at the following web site:
http://www.netquake.org/seismometers/vertical.htm Unfortunately, I have not
yet gotten around to annotating these photographs, but intend to do so in
the next several days.
Joe Gerencher
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<BODY lang=3DEN-US vLink=3Dpurple link=3Dblue>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2>If you=20
want to build a simple seismograph, here is a URL of a very simple =
vertical=20
seismograph that was designed by a fellow in Pasadena in the early=20
1990's.</FONT></SPAN></DIV>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2><A=20
href=3D"http://pw2.netcom.com/~shammon1/compressed/VERTICAL.GIF">http://p=
w2.netcom.com/~shammon1/compressed/VERTICAL.GIF</A></FONT></SPAN></DIV>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2>It=20
uses a screen door spring and cost under $20. It is made from =
common parts=20
in a local hardware store and produces good results. It does lack the=20
electronics however, so if you check the same site,</FONT></SPAN></DIV>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2> <A=20
href=3D"http://pw2.netcom.com/~shammon1/equip.htm#Electronics">http://pw2=
..netcom.com/~shammon1/equip.htm#Electronics</A> </FONT></SPAN></DIV>=
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2>you=20
will find a pre-amp using OP-07's that can be used with this. The coil =
can be=20
built from #44 wire on a plastic frame. You can get the frame from Radio =
Shack=20
if you just purchase a spool of their red/black/green #22 construction =
wire.=20
Hand wind about 4,000 turns of the #44 wire onto a frame. Warp the =
coil in=20
black electrical tape to protect it. The magnet is a cow magnet =
sold in an=20
animal feed stores but other magnets will also work. I used these =
plans to=20
build a system for a 5th grade classroom and the students were =
able to=20
locate local events with it.</FONT></SPAN></DIV>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2>Regards, Steve Hammond PSN San Jose, Aptos =
California</FONT></SPAN></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> =
psn-l-request@.................
[mailto:psn-l-request@...............<B>On Behalf Of </B>Gerencher, =
Joseph=20
J<BR><B>Sent:</B> Tuesday, February 21, 2006 12:09 PM<BR><B>To:</B>=20
PSN-L@..............<BR><B>Subject:</B> two home-made vertical=20
seismometers<BR><BR></FONT></DIV>
<DIV class=3DSection1>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">I have photographs of =
two vertical=20
seismometers that were made by Jim Lehman and given to me. Both =
have=20
been in continuous operation for several years and both have a natural =
period=20
of about one second. The smaller unit is in my classroom and the =
larger=20
one is in the basement beneath the classroom. I modified the =
damping of=20
the smaller unit using copper plumbing fittings, which makes it both =
easier to=20
construct and easier to operate than the larger one. The web =
address for=20
going directly to the photographs is too long to post on an e-mail, so =
if you=20
want to see images of both these seismometers go to my opening web =
page at=20
<o:p></o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial"><A=20
=
href=3D"http://home.moravian.edu/users/phys/mejjg01/">http://home.moravia=
n.edu/users/phys/mejjg01/</A><o:p></o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">then click =
“homemade=20
seismographs,” click “Illustrated history of the =
seismometer system, 1991 to=20
1998” and click the links on that page. Additional =
detailed photographs=20
of the construction design of the smaller home-made seismometer can be =
found=20
at the following web site: </SPAN></FONT><A=20
=
href=3D"http://www.netquake.org/seismometers/vertical.htm">http://www.net=
quake.org/seismometers/vertical.htm</A> =20
Unfortunately, I have not yet gotten around to annotating these =
photographs,=20
but intend to do so in the next several days.<o:p></o:p></P>
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN=20
style=3D"FONT-SIZE: 12pt"><o:p> </o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN=20
style=3D"FONT-SIZE: 12pt">Joe Gerencher<o:p></o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial"><o:p> </o:p></SPAN></FONT></P></DIV></BLOCKQUOTE></BODY></HTM=
L>
Subject: RE: two home-made vertical seismometers
From: "Steve Hammond" shammon1@.............
Date: Wed, 22 Feb 2006 09:02:10 -0800
If you want to build a simple seismograph, here is a URL of a very simple
vertical seismograph that was designed by a fellow in Pasadena in the early
1990's.
http://pw2.netcom.com/~shammon1/compressed/VERTICAL.GIF
It uses a screen door spring and cost under $20. It is made from common
parts in a local hardware store and produces good results. It does lack the
electronics however, so if you check the same site,
http://pw2.netcom.com/~shammon1/equip.htm#Electronics
you will find a pre-amp using OP-07's that can be used with this. The coil
can be built from #44 wire on a plastic frame. You can get the frame from
Radio Shack if you just purchase a spool of their red/black/green #22
construction wire. Hand wind about 4,000 turns of the #44 wire onto a frame.
Warp the coil in black electrical tape to protect it. The magnet is a cow
magnet sold in an animal feed stores but other magnets will also work. I
used these plans to build a system for a 5th grade classroom and the
students were able to locate local events with it.
Regards, Steve Hammond PSN San Jose, Aptos California
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@.................
Behalf Of Gerencher, Joseph J
Sent: Tuesday, February 21, 2006 12:09 PM
To: PSN-L@..............
Subject: two home-made vertical seismometers
I have photographs of two vertical seismometers that were made by Jim
Lehman and given to me. Both have been in continuous operation for several
years and both have a natural period of about one second. The smaller unit
is in my classroom and the larger one is in the basement beneath the
classroom. I modified the damping of the smaller unit using copper plumbing
fittings, which makes it both easier to construct and easier to operate than
the larger one. The web address for going directly to the photographs is
too long to post on an e-mail, so if you want to see images of both these
seismometers go to my opening web page at
http://home.moravian.edu/users/phys/mejjg01/
then click "homemade seismographs," click "Illustrated history of the
seismometer system, 1991 to 1998" and click the links on that page.
Additional detailed photographs of the construction design of the smaller
home-made seismometer can be found at the following web site:
http://www.netquake.org/seismometers/vertical.htm Unfortunately, I have not
yet gotten around to annotating these photographs, but intend to do so in
the next several days.
Joe Gerencher
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML xmlns=3D"http://www.w3.org/TR/REC-html40" xmlns:o =3D=20
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<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2>If you=20
want to build a simple seismograph, here is a URL of a very simple =
vertical=20
seismograph that was designed by a fellow in Pasadena in the early=20
1990's.</FONT></SPAN></DIV>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2><A=20
href=3D"http://pw2.netcom.com/~shammon1/compressed/VERTICAL.GIF">http://p=
w2.netcom.com/~shammon1/compressed/VERTICAL.GIF</A></FONT></SPAN></DIV>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2>It=20
uses a screen door spring and cost under $20. It is made from =
common parts=20
in a local hardware store and produces good results. It does lack the=20
electronics however, so if you check the same site,</FONT></SPAN></DIV>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2> <A=20
href=3D"http://pw2.netcom.com/~shammon1/equip.htm#Electronics">http://pw2=
..netcom.com/~shammon1/equip.htm#Electronics</A> </FONT></SPAN></DIV>=
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2>you=20
will find a pre-amp using OP-07's that can be used with this. The coil =
can be=20
built from #44 wire on a plastic frame. You can get the frame from Radio =
Shack=20
if you just purchase a spool of their red/black/green #22 construction =
wire.=20
Hand wind about 4,000 turns of the #44 wire onto a frame. Warp the =
coil in=20
black electrical tape to protect it. The magnet is a cow magnet =
sold in an=20
animal feed stores but other magnets will also work. I used these =
plans to=20
build a system for a 5th grade classroom and the students were =
able to=20
locate local events with it.</FONT></SPAN></DIV>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D828344316-22022006><FONT face=3DArial color=3D#0000ff =
size=3D2>Regards, Steve Hammond PSN San Jose, Aptos =
California</FONT></SPAN></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> =
psn-l-request@.................
[mailto:psn-l-request@...............<B>On Behalf Of </B>Gerencher, =
Joseph=20
J<BR><B>Sent:</B> Tuesday, February 21, 2006 12:09 PM<BR><B>To:</B>=20
PSN-L@..............<BR><B>Subject:</B> two home-made vertical=20
seismometers<BR><BR></FONT></DIV>
<DIV class=3DSection1>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">I have photographs of =
two vertical=20
seismometers that were made by Jim Lehman and given to me. Both =
have=20
been in continuous operation for several years and both have a natural =
period=20
of about one second. The smaller unit is in my classroom and the =
larger=20
one is in the basement beneath the classroom. I modified the =
damping of=20
the smaller unit using copper plumbing fittings, which makes it both =
easier to=20
construct and easier to operate than the larger one. The web =
address for=20
going directly to the photographs is too long to post on an e-mail, so =
if you=20
want to see images of both these seismometers go to my opening web =
page at=20
<o:p></o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial"><A=20
=
href=3D"http://home.moravian.edu/users/phys/mejjg01/">http://home.moravia=
n.edu/users/phys/mejjg01/</A><o:p></o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: Arial">then click =
“homemade=20
seismographs,” click “Illustrated history of the =
seismometer system, 1991 to=20
1998” and click the links on that page. Additional =
detailed photographs=20
of the construction design of the smaller home-made seismometer can be =
found=20
at the following web site: </SPAN></FONT><A=20
=
href=3D"http://www.netquake.org/seismometers/vertical.htm">http://www.net=
quake.org/seismometers/vertical.htm</A> =20
Unfortunately, I have not yet gotten around to annotating these =
photographs,=20
but intend to do so in the next several days.<o:p></o:p></P>
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN=20
style=3D"FONT-SIZE: 12pt"><o:p> </o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3D"Times New Roman" size=3D3><SPAN=20
style=3D"FONT-SIZE: 12pt">Joe Gerencher<o:p></o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; FONT-FAMILY: =
Arial"><o:p> </o:p></SPAN></FONT></P></DIV></BLOCKQUOTE></BODY></HTM=
L>
Subject: balancing motor timing
From: Barry Lotz barry_lotz@.............
Date: Wed, 22 Feb 2006 16:58:19 -0800 (PST)
Hi All
I have three long period homemade sensors with balancing motors, I check their position voltage manually every 2-3 days and if they are to far off center I send a 5 vt + or - signal to the sensor's low rpm(1 rpm) balancing motor for a few seconds to send it back towards zero. I would like to do this automatically. I could do this with a microprocessor but I thought it might be done with something more simple like some gates,switches and possibly 555 timers. I have not tried to create a 555 timing circuit with such a inballanced duty cycle ( on for ~ 1/2 to 1 sec and off for ~24 hrs). Any thoughts?
regards
Barry
<DIV id=RTEContent> <DIV id=RTEContent> <DIV id=RTEContent> <DIV id=RTEContent>Hi All</DIV> <DIV> I have three long period homemade sensors with balancing motors, I check their position voltage manually every 2-3 days and if they are to far off center I send a 5 vt + or - signal to the sensor's low rpm(1 rpm) balancing motor for a few seconds to send it back towards zero. I would like to do this automatically. I could do this with a microprocessor but I thought it might be done with something more simple like some gates,switches and possibly 555 timers. I have not tried to create a 555 timing circuit with such a inballanced duty cycle ( on for ~ 1/2 to 1 sec and off for ~24 hrs). Any thoughts?</DIV> <DIV>regards</DIV> <DIV>Barry</DIV> <DIV> </DIV></DIV></DIV></DIV>
Subject: RE: two home-made vertical seismometers
From: "Kareem at HeyJooJoo" system98765@.............
Date: Wed, 22 Feb 2006 17:28:23 -0800
Hi Steve,
Are there any simple plans for building a horizontal, long period
seismograph? (I know that there are tons of places online but figured you or
the others may know of some real-time plans.)
Kareem
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Steve Hammond
Sent: Wednesday, February 22, 2006 9:02 AM
To: psn-l@............... PSN-L@..............
Subject: RE: two home-made vertical seismometers
If you want to build a simple seismograph, here is a URL of a very simple
vertical seismograph that was designed by a fellow in Pasadena in the early
1990's.
http://pw2.netcom.com/~shammon1/compressed/VERTICAL.GIF
It uses a screen door spring and cost under $20. It is made from common
parts in a local hardware store and produces good results. It does lack the
electronics however, so if you check the same site,
http://pw2.netcom.com/~shammon1/equip.htm#Electronics
you will find a pre-amp using OP-07's that can be used with this. The coil
can be built from #44 wire on a plastic frame. You can get the frame from
Radio Shack if you just purchase a spool of their red/black/green #22
construction wire. Hand wind about 4,000 turns of the #44 wire onto a frame.
Warp the coil in black electrical tape to protect it. The magnet is a cow
magnet sold in an animal feed stores but other magnets will also work. I
used these plans to build a system for a 5th grade classroom and the
students were able to locate local events with it.
Regards, Steve Hammond PSN San Jose, Aptos California
-----Original Message-----
From: psn-l-request@..............
[mailto:psn-l-request@................. Behalf Of Gerencher, Joseph J
Sent: Tuesday, February 21, 2006 12:09 PM
To: PSN-L@..............
Subject: two home-made vertical seismometers
I have photographs of two vertical seismometers that were made by
Jim Lehman and given to me. Both have been in continuous operation for
several years and both have a natural period of about one second. The
smaller unit is in my classroom and the larger one is in the basement
beneath the classroom. I modified the damping of the smaller unit using
copper plumbing fittings, which makes it both easier to construct and easier
to operate than the larger one. The web address for going directly to the
photographs is too long to post on an e-mail, so if you want to see images
of both these seismometers go to my opening web page at
http://home.moravian.edu/users/phys/mejjg01/
then click "homemade seismographs," click "Illustrated history of
the seismometer system, 1991 to 1998" and click the links on that page.
Additional detailed photographs of the construction design of the smaller
home-made seismometer can be found at the following web site:
http://www.netquake.org/seismometers/vertical.htm Unfortunately, I have not
yet gotten around to annotating these photographs, but intend to do so in
the next several days.
Joe Gerencher
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: two home-made vertical seismometers
From: Barry Lotz barry_lotz@.............
Date: Wed, 22 Feb 2006 19:56:00 -0800 (PST)
Hi Kareem
This maybe a little to involved but I made a long period horizontal ( ~10" long ) from information read from Sean Thomas Morrissey's web site http://www.eas.slu.edu/People/STMorrissey/index.html. I built the vertical he described first then tried a horizontal next. It looks like the W.F. Sprengnether figure at the "PSN info" location.It's natural period was about 5 sec without the feedback circuitry. I used his circuitry with his description of the speaker coil and the VRDT construction for the feedback. I think the period was increased to about 20-30 sec but I haven't been able to check the base frequency vs response yet. the construction was not expensive but it was time consuming. I chose the component values from his Mcad equations but I'm not sure they are optimum (part of the required input was the coil output G and the sensors natural frequency) . I'm still working on a few bugs in the external amplifier/filter and balancing motor circuitry. It did record the recent
Mozambique event but so did my simple Lehman ( pretty large event).
I have wanted to try a horizontal lehman type sensor but with two long springs (one on each side) meeting at a heavy weight and slightly apart at the base of the boom. For a vertical like John Lahr showed previously, if the spring angle is brought more horizontal (parallel with the boom ) my understanding is the period is increased. I thought the same might apply with the horizontal and one would not have to worry as much about the drift the Lehman can produce as the boom assemble approaches the non returning position ( ie trying to increase the lehman period).
Sorry I got so wordy
Regards
Barry.
Kareem at HeyJooJoo <system98765@.............> wrote:
Hi Steve,
Are there any simple plans for building a horizontal, long period
seismograph? (I know that there are tons of places online but figured you or
the others may know of some real-time plans.)
Kareem
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Steve Hammond
Sent: Wednesday, February 22, 2006 9:02 AM
To: psn-l@............... PSN-L@..............
Subject: RE: two home-made vertical seismometers
If you want to build a simple seismograph, here is a URL of a very simple
vertical seismograph that was designed by a fellow in Pasadena in the early
1990's.
http://pw2.netcom.com/~shammon1/compressed/VERTICAL.GIF
It uses a screen door spring and cost under $20. It is made from common
parts in a local hardware store and produces good results. It does lack the
electronics however, so if you check the same site,
http://pw2.netcom.com/~shammon1/equip.htm#Electronics
you will find a pre-amp using OP-07's that can be used with this. The coil
can be built from #44 wire on a plastic frame. You can get the frame from
Radio Shack if you just purchase a spool of their red/black/green #22
construction wire. Hand wind about 4,000 turns of the #44 wire onto a frame.
Warp the coil in black electrical tape to protect it. The magnet is a cow
magnet sold in an animal feed stores but other magnets will also work. I
used these plans to build a system for a 5th grade classroom and the
students were able to locate local events with it.
Regards, Steve Hammond PSN San Jose, Aptos California
-----Original Message-----
From: psn-l-request@..............
[mailto:psn-l-request@................. Behalf Of Gerencher, Joseph J
Sent: Tuesday, February 21, 2006 12:09 PM
To: PSN-L@..............
Subject: two home-made vertical seismometers
I have photographs of two vertical seismometers that were made by
Jim Lehman and given to me. Both have been in continuous operation for
several years and both have a natural period of about one second. The
smaller unit is in my classroom and the larger one is in the basement
beneath the classroom. I modified the damping of the smaller unit using
copper plumbing fittings, which makes it both easier to construct and easier
to operate than the larger one. The web address for going directly to the
photographs is too long to post on an e-mail, so if you want to see images
of both these seismometers go to my opening web page at
http://home.moravian.edu/users/phys/mejjg01/
then click "homemade seismographs," click "Illustrated history of
the seismometer system, 1991 to 1998" and click the links on that page.
Additional detailed photographs of the construction design of the smaller
home-made seismometer can be found at the following web site:
http://www.netquake.org/seismometers/vertical.htm Unfortunately, I have not
yet gotten around to annotating these photographs, but intend to do so in
the next several days.
Joe Gerencher
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
<DIV>Hi Kareem</DIV> <DIV> This maybe a little to involved but I made a long period horizontal ( ~10" long ) from information read from Sean Thomas Morrissey's web site <A href="http://www.eas.slu.edu/People/STMorrissey/index.html">http://www.eas.slu.edu/People/STMorrissey/index.html</A>. I built the vertical he described first then tried a horizontal next. It looks like the W.F. Sprengnether figure at the "PSN info" location.It's natural period was about 5 sec without the feedback circuitry. I used his circuitry with his description of the speaker coil and the VRDT construction for the feedback. I think the period was increased to about 20-30 sec but I haven't been able to check the base frequency vs response yet. the construction was not expensive but it was time consuming. I chose the component values from his Mcad equations but I'm not sure they are optimum (part of the required input was the coil output G and the sensors
natural frequency) . I'm still working on a few bugs in the external amplifier/filter and balancing motor circuitry. It did record the recent Mozambique event but so did my simple Lehman ( pretty large event). </DIV> <DIV> I have wanted to try a horizontal lehman type sensor but with two long springs (one on each side) meeting at a heavy weight and slightly apart at the base of the boom. For a vertical like John Lahr showed previously, if the spring angle is brought more horizontal (parallel with the boom ) my understanding is the period is increased. I thought the same might apply with the horizontal and one would not have to worry as much about the drift the Lehman can produce as the boom assemble approaches the non returning position ( ie trying to increase the lehman period). </DIV> <DIV> </DIV> <DIV>Sorry I got so wordy</DIV> <DIV> </DIV> <DIV>Regards</DIV>
<DIV>Barry.<BR><BR><B><I>Kareem at HeyJooJoo <system98765@.............></I></B> wrote:</DIV> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Hi Steve,<BR><BR>Are there any simple plans for building a horizontal, long period<BR>seismograph? (I know that there are tons of places online but figured you or<BR>the others may know of some real-time plans.)<BR><BR><BR>Kareem <BR><BR>-----Original Message-----<BR>From: psn-l-request@.............. [mailto:psn-l-request@............... On<BR>Behalf Of Steve Hammond<BR>Sent: Wednesday, February 22, 2006 9:02 AM<BR>To: psn-l@............... PSN-L@..............<BR>Subject: RE: two home-made vertical seismometers<BR><BR>If you want to build a simple seismograph, here is a URL of a very simple<BR>vertical seismograph that was designed by a fellow in Pasadena in the early<BR>1990's.<BR>http://pw2.netcom.com/~shammon1/compressed/VERTICAL.GIF<BR>It uses a screen door spring and cost under
$20. It is made from common<BR>parts in a local hardware store and produces good results. It does lack the<BR>electronics however, so if you check the same site,<BR>http://pw2.netcom.com/~shammon1/equip.htm#Electronics<BR>you will find a pre-amp using OP-07's that can be used with this. The coil<BR>can be built from #44 wire on a plastic frame. You can get the frame from<BR>Radio Shack if you just purchase a spool of their red/black/green #22<BR>construction wire. Hand wind about 4,000 turns of the #44 wire onto a frame.<BR>Warp the coil in black electrical tape to protect it. The magnet is a cow<BR>magnet sold in an animal feed stores but other magnets will also work. I<BR>used these plans to build a system for a 5th grade classroom and the<BR>students were able to locate local events with it.<BR><BR>Regards, Steve Hammond PSN San Jose, Aptos California<BR><BR>-----Original Message-----<BR>From: psn-l-request@..............<BR>[mailto:psn-l-request@................. Behalf Of
Gerencher, Joseph J<BR>Sent: Tuesday, February 21, 2006 12:09 PM<BR>To: PSN-L@..............<BR>Subject: two home-made vertical seismometers<BR><BR><BR><BR>I have photographs of two vertical seismometers that were made by<BR>Jim Lehman and given to me. Both have been in continuous operation for<BR>several years and both have a natural period of about one second. The<BR>smaller unit is in my classroom and the larger one is in the basement<BR>beneath the classroom. I modified the damping of the smaller unit using<BR>copper plumbing fittings, which makes it both easier to construct and easier<BR>to operate than the larger one. The web address for going directly to the<BR>photographs is too long to post on an e-mail, so if you want to see images<BR>of both these seismometers go to my opening web page at <BR><BR>http://home.moravian.edu/users/phys/mejjg01/<BR><BR>then click "homemade seismographs," click "Illustrated history of<BR>the seismometer system, 1991 to 1998" and click the links
on that page.<BR>Additional detailed photographs of the construction design of the smaller<BR>home-made seismometer can be found at the following web site:<BR>http://www.netquake.org/seismometers/vertical.htm Unfortunately, I have not<BR>yet gotten around to annotating these photographs, but intend to do so in<BR>the next several days.<BR><BR><BR><BR>Joe Gerencher<BR><BR><BR><BR><BR><BR><BR>__________________________________________________________<BR><BR>Public Seismic Network Mailing List (PSN-L)<BR><BR>To leave this list email PSN-L-REQUEST@SEISMICNET.COM with <BR>the body of the message (first line only): unsubscribe<BR>See http://www.seismicnet.com/maillist.html for more information.<BR></BLOCKQUOTE> <DIV><BR></DIV>
Subject: Re: balancing motor timing
From: ChrisAtUpw@.......
Date: Wed, 22 Feb 2006 22:57:33 EST
In a message dated 23/02/2006, barry_lotz@............. writes:
Any thoughts?
Hi Barry,
Have a look at Allan's circuit at
_http://physics.mercer.edu/petepag/MKXVIII.pdf_ (http://physics.mercer.edu/petepag/MKXVIII.pdf) He has done
automatic levelling - and a lot more!
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 23/02/2006, barry_lotz@............. writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Any=20
thoughts?</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Barry,</DIV>
<DIV> </DIV>
<DIV> Have a look at Allan's circuit at <A=20
href=3D"http://physics.mercer.edu/petepag/MKXVIII.pdf">http://physics.mercer=
..edu/petepag/MKXVIII.pdf</A> He=20
has done automatic levelling - and a lot more!</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Mozambique 7.5 quake
From: Jan Froom JDarwin@.............
Date: Thu, 23 Feb 2006 08:07:14 -0800
We recorded it in Gilroy CA at South Valley Middle School.
http://www.gusd.k12.ca.us/southvalley/seismic
For those of us in California, Mozambique is on the opposite side of the
earth... so when we receive the seismic waves... from which direction
are they coming and if from multiple paths, why don't they interfere or
cancel each other out?
Jan in Gilroy....
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Mozambique 7.5 quake -- global view of wave migration
From: "Timothy Carpenter" geodynamics@.......
Date: Thu, 23 Feb 2006 12:37:45 -0500
The following program provides an excellent representation of how =
seismic
waves travel through and around the globe. Watch the propagation of the
waves and you should be able to answer your own question.
Go to:
http://www.geol.binghamton.edu/faculty/jones/jones.html
Scroll down to: "Seismic Waves: A program for the visualization of wave
propagation" (About 1/2 way down the page).
Download seiswave.readme and SeismicWavesSetup.exe.
Read the readme file and then Run the setup program.
When the installation is finished, run the animation and select the =
Sumatra
Quake. After it has finished with one quake, the program moves on to
another.
According to Dr. Jones' site, "It is possible to add new events by using =
the
Wilbur II facility at the IRIS Electronic Bulletin Board"
Regards,
-Tim-
Timothy Carpenter, P.E., Pres.,
GeoDynamics Consultants, Inc.
5043 Whitlow Ct.
Commerce Twp., Mi 48382
248-363-4529 (voice & fax)
248-766-1629 (cell)
geodynamics@........... (primary)
geodynamics@....... (secondary)
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... =
On
Behalf Of Jan Froom
Sent: Thursday, February 23, 2006 11:07 AM
To: psn-l@..............
Subject: Mozambique 7.5 quake
We recorded it in Gilroy CA at South Valley Middle School.=20
http://www.gusd.k12.ca.us/southvalley/seismic
For those of us in California, Mozambique is on the opposite side of the =
earth... so when we receive the seismic waves... from which direction=20
are they coming and if from multiple paths, why don't they interfere or=20
cancel each other out?
Jan in Gilroy....
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: two home-made vertical seismometers
From: Bobhelenmcclure@.......
Date: Thu, 23 Feb 2006 13:53:21 EST
If you are looking for a simple vertical seismometer, take a look at the one
built by Roger Sparks.
_http://www.elltel.net/sparksite/CSpring%20Seismometer.html_
(http://www.elltel.net/sparksite/CSpring%20Seismometer.html)
It has a period of several seconds, which I has been able to digitally
extend to many seconds.
It is virtually impossible to get a long period simply by hanging a mass
from a vertical spring. For example, the spring has to stretch one meter to get
a natural period of two seconds. The period of such a sensor is the same as a
pendulum of the same length as the extension of a vertical spring.
Bob
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<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
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bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>If you are looking for a simple vertical seismometer, take a look at th=
e=20
one built by Roger Sparks.</DIV>
<DIV> </DIV>
<DIV><A=20
href=3D"http://www.elltel.net/sparksite/CSpring%20Seismometer.html">http://w=
ww.elltel.net/sparksite/CSpring%20Seismometer.html</A></DIV>
<DIV> </DIV>
<DIV>It has a period of several seconds, which I has been able to digit=
ally=20
extend to many seconds.</DIV>
<DIV> </DIV>
<DIV>It is virtually impossible to get a long period simply by hanging a mas=
s=20
from a vertical spring. For example, the spring has to stretch one meter to=20=
get=20
a natural period of two seconds. The period of such a sensor is the same as=20=
a=20
pendulum of the same length as the extension of a vertical spring.</DIV>
<DIV> </DIV>
<DIV>Bob</DIV></FONT></BODY></HTML>
Subject: Re: Recording Micro Quakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 24 Feb 2006 01:53:46 +0000
Hi all
I have managed to record a earthquake that was 2.2Ml in magnitue at the
range of 155Km, this is smallest earthquake i have been able to detect
so far. I don't expect to recorod anything smaller at this distance. I
assume that i will be able to detect earthquake smaller then 2.2Ml in
magnitue if they are closer to my location.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Recording Micro Quakes
From: "Kareem at HeyJooJoo" system98765@.............
Date: Thu, 23 Feb 2006 18:23:33 -0800
Joe,
That's impressive. Are you using a short period sensor or long?
Kareem
California, U.S.A.=20
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... =
On
Behalf Of J=F3n Fr=EDmann
Sent: Thursday, February 23, 2006 5:54 PM
To: psn-l@..............
Subject: Re: Recording Micro Quakes
Hi all
I have managed to record a earthquake that was 2.2Ml in magnitue at the
range of 155Km, this is smallest earthquake i have been able to detect =
so
far. I don't expect to recorod anything smaller at this distance. I =
assume
that i will be able to detect earthquake smaller then 2.2Ml in magnitue =
if
they are closer to my location.
Regards.
--
J=F3n Fr=EDmann J=F3nsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
http://www.seismicnet.com/maillist.html for more information.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: two home-made vertical seismometers
From: "Kareem at HeyJooJoo" system98765@.............
Date: Thu, 23 Feb 2006 18:31:07 -0800
Hey Barry,
Thanks for the info. I'll have a look. I actually have a PS2 recording
system by Kinemetrics. It's a portable system which came with a vertical
geophone (L4). It's great for local events as imagined but not so good for
distant more common events. So I figured that it may be time to attempt to
build one. Message is certainly not too wordy but rather appreciated. I'm
still quite knew on the concepts of short period versus long period.
Kareem
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Barry Lotz
Sent: Wednesday, February 22, 2006 7:56 PM
To: psn-l@..............
Subject: RE: two home-made vertical seismometers
Hi Kareem
This maybe a little to involved but I made a long period horizontal ( ~10"
long ) from information read from Sean Thomas Morrissey's web site
http://www.eas.slu.edu/People/STMorrissey/index.html. I built the vertical
he described first then tried a horizontal next. It looks like the W.F.
Sprengnether figure at the "PSN info" location.It's natural period was about
5 sec without the feedback circuitry. I used his circuitry with his
description of the speaker coil and the VRDT construction for the feedback.
I think the period was increased to about 20-30 sec but I haven't been able
to check the base frequency vs response yet. the construction was not
expensive but it was time consuming. I chose the component values from his
Mcad equations but I'm not sure they are optimum (part of the required input
was the coil output G and the sensors natural frequency) . I'm still working
on a few bugs in the external amplifier/filter and balancing motor
circuitry. It did record the recent Mozambique event but so did my simple
Lehman ( pretty large event).
I have wanted to try a horizontal lehman type sensor but with two
long springs (one on each side) meeting at a heavy weight and slightly apart
at the base of the boom. For a vertical like John Lahr showed previously, if
the spring angle is brought more horizontal (parallel with the boom ) my
understanding is the period is increased. I thought the same might apply
with the horizontal and one would not have to worry as much about the drift
the Lehman can produce as the boom assemble approaches the non returning
position ( ie trying to increase the lehman period).
Sorry I got so wordy
Regards
Barry.
Kareem at HeyJooJoo <system98765@.............> wrote:
Hi Steve,
Are there any simple plans for building a horizontal, long period
seismograph? (I know that there are tons of places online but
figured you or
the others may know of some real-time plans.)
Kareem
-----Original Message-----
From: psn-l-request@..............
[mailto:psn-l-request@............... On
Behalf Of Steve Hammond
Sent: Wednesday, February 22, 2006 9:02 AM
To: psn-l@............... PSN-L@..............
Subject: RE: two home-made vertical seismometers
If you want to build a simple seismograph, here is a URL of a very
simple
vertical seismograph that was designed by a fellow in Pasadena in
the early
1990's.
http://pw2.netcom.com/~shammon1/compressed/VERTICAL.GIF
It uses a screen door spring and cost under $20. It is made from
common
parts in a local hardware store and produces good results. It does
lack the
electronics however, so if you check the same site,
http://pw2.netcom.com/~shammon1/equip.htm#Electronics
you will find a pre-amp using OP-07's that can be used with this.
The coil
can be built from #44 wire on a plastic frame. You can get the frame
from
Radio Shack if you just purchase a spool of their red/black/green
#22
construction wire. Hand wind about 4,000 turns of the #44 wire onto
a frame.
Warp the coil in black electrical tape to protect it. The magnet is
a cow
magnet sold in an animal feed stores but other magnets will also
work. I
used these plans to build a system for a 5th grade classroom and the
students were able to locate local events with it.
Regards, Steve Hammond PSN San Jose, Aptos California
-----Original Message-----
From: psn-l-request@..............
[mailto:psn-l-request@................. Behalf Of Gerencher, Joseph
J
Sent: Tuesday, February 21, 2006 12:09 PM
To: PSN-L@..............
Subject: two home-made vertical seismometers
I have photographs of two vertical seismometers that were made by
Jim Lehman and given to me. Both have been in continuous operation
for
several years and both have a natural period of about one second.
The
smaller unit is in my classroom and the larger one is in the
basement
beneath the classroom. I modified the damping of the smaller unit
using
copper plumbing fittings, which makes it both easier to construct
and easier
to operate than the larger one. The web address for going directly
to the
photographs is too long to post on an e-mail, so if you want to see
images
of both these seismometers go to my opening web page at
http://home.moravian.edu/users/phys/mejjg01/
then click "homemade seismographs," click "Illustrated history of
the seismometer system, 1991 to 1998" and click the links on that
page.
Additional detailed photographs of the construction design of the
smaller
home-made seismometer can be found at the following web site:
http://www.netquake.org/seismometers/vertical.htm Unfortunately, I
have not
yet gotten around to annotating these photographs, but intend to do
so in
the next several days.
Joe Gerencher
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To leave this list email PSN-L-REQUEST@.............. with
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Subject: RE: Recording Micro Quakes
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 24 Feb 2006 02:50:02 +0000
Hi Kareem
I am using short period sensor, an 4.5Hz Geophone that i got from here,
http://seismicnet.com/geophone/index.html#L15B
This geophone has the range of 860 - 1000km (my estimate).
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Winquake command line
From: Larry Conklin lconklin@............
Date: Fri, 24 Feb 2006 15:47:19 -0500
I know that if you select two compatible (ie. two files from the same
event with the same header info, etc.) files from the file dialog box at
the same time, that Winquake will open them together in a single window.
Winquake will also open a single file specified as a command line
argument. Is there a command line syntax that will open more than one
file at once with a single command? I tried several plausible
alternatives with no success.
Larry Conklin
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Winquake command line
From: Larry Cochrane lcochrane@..............
Date: Fri, 24 Feb 2006 19:28:01 -0800
Larry,
WinQuake only processes one file on the command line so currently there is no way to
open two or more event files.
Regards,
Larry Cochrane
Redwood City, PSN
Larry Conklin wrote:
> I know that if you select two compatible (ie. two files from the same
> event with the same header info, etc.) files from the file dialog box at
> the same time, that Winquake will open them together in a single window.
> Winquake will also open a single file specified as a command line
> argument. Is there a command line syntax that will open more than one
> file at once with a single command? I tried several plausible
> alternatives with no success.
>
> Larry Conklin
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with
> the body of the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: The Canada earthquake, instresing location
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 25 Feb 2006 05:47:08 +0000
Hi all
The Canada earthquake, that did happen at 01:39 tonight (UTC) (25th
feb.2006) is at intresting location. See map here,
http://www.emsc-csem.org/index.php?page=current&sub=detail&id=HM304;NEIR
I do not know the earthquake history of this reagion. But i wonders if
there is a possibliti for this to be a pre-earthquake for a maybe a
bigger event. I do not know if there was some aftershocks from this
event, i don't see any signs of it on the usgs webpage. Far as i know,
there aren't any fault lines in this region, but my knowlage is lacking
regarding this area in terms of geological features.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: The Canada earthquake, instresing location
From: Canie canie@...........
Date: Fri, 24 Feb 2006 22:08:08 -0800
Here's a page on it from USGS - talks of historic seismicity
http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/usjpad.php
Canie
At 09:47 PM 2/24/2006, you wrote:
>Hi all
>
>The Canada earthquake, that did happen at 01:39 tonight (UTC) (25th
>feb.2006) is at intresting location. See map here,
>http://www.emsc-csem.org/index.php?page=3Dcurrent&sub=3Ddetail&id=3DHM304;N=
EIR
>
>I do not know the earthquake history of this reagion. But i wonders if
>there is a possibliti for this to be a pre-earthquake for a maybe a
>bigger event. I do not know if there was some aftershocks from this
>event, i don't see any signs of it on the usgs webpage. Far as i know,
>there aren't any fault lines in this region, but my knowlage is lacking
>regarding this area in terms of geological features.
>
>Regards.
>--
>J=F3n Fr=EDmann J=F3nsson
>http://www.jonfr.com
>http://www.simnet.is/jonfr500/earthquake/
>
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with
>the body of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: The Canada earthquake, instresing location
From: Dave Nelson davenn@...............
Date: Sat, 25 Feb 2006 22:01:59 +1100
Hi Jon
the nth american/canadian continent is very old and is heavily faulted
and regular small to medium quakes are common including the occassional
large event
as the link that Carnie gave shows there is plent of activity in this=
region
one thing you will find is that many of the river channels ...
eg the St Lawrence River follow faultlines as the rock along the=20
faultlines is softer and easily erroded
this is a common feature along older landscapes and is a feature I=20
learnt to recognise quickly during my geological studies in new zealand
the rivers of the tibetan plateau in the himilayan mountains in asia is=
=20
a classic example of this feature
cheers
At 05:47 AM 2/25/2006 +0000, you wrote:
>Hi all
>I do not know the earthquake history of this reagion. But i wonders if
>there is a possibliti for this to be a pre-earthquake for a maybe a
>bigger event. I do not know if there was some aftershocks from this
>event, i don't see any signs of it on the usgs webpage. Far as i know,
>there aren't any fault lines in this region, but my knowlage is lacking
>regarding this area in terms of geological features.
>Regards.
>J=F3n Fr=EDmann J=F3nsson
Dave Nelson VK2TDN
Sydney
Australia
www.sydneystormcity.com
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Public Seismic Network Mailing List (PSN-L)
Subject: Winquake Ascii Text File
From: "Geoffrey" gmvoeth@...........
Date: Sat, 25 Feb 2006 22:54:38 -0700
Hello PSN:
Could someone please send me a Winquake
Ascii text file so I may check my conversion
from a raw 8 bit format to Winquake ascii.
This is what I think it should look like:
----------------START of File------------------
! PSN ASCII Event File Format 1.0
Start Time: yyyy/dd/mm hh:mm:ss.s
Number of Samples: nnnn
SPS: 18.205556
Comment:
A/D Converter Bits:
Data Minimum: -127
Data Maximum: 128
! Sensor Information:
Sensor Location: Apache Junction, Arizona
Sensor Latitude: 33.421380
Sensor Longitude: -111.574770
Sensor Orientation: Z
! Event Information:
Event Latitude:
Event Longitude:
Event Time:
Event Magnitude:
Event Depth:
! WinQuake Information:
Magnitude Correction:
Mb Magnitude Correction:
Ms Period: 20.000000
Mb Period: 1.000000
Md Duration:
PS Pick Information:
! SDR Information:
Lock Indicator:
Data:
-2 <------------- First Data Point
-8
--------------END Of File--------------------
I am guessing those are minus signs
in front of the two data points.
I am not certain what the file extension
should be or if I am missing something else.
I am too cheap to buy Winquake at this time
but I would like to be able to share my files
with people who have this program.
I understand only the first four lines are necessary.
This text file is one I tried to convert:
http://users.isp.com/gmvoethb293690/WQFIJI00.TXT
If you have Winquake you can try it out
and please tell me what happens.
Regards;
gmvoeth
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Two earthquakes at the same time
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Tue, 28 Feb 2006 06:03:54 +0000
Hi all
Yesterday i did record a earthquake at mag 3.07ML at 02:42 UTC. Today i
was updateing the time and location with the final resault from the
Icelandic met office regarding this earthquake when i did notice that
where actually two earthquaks at that same time, happening with less
then 1 sec (they where just less then 100ms apart in time) time
diffrance. I problay did detect both of those earthquakes, but becose
how close they are in time it is hard for me to tell what earthquake is
what in the trace. This also leads to the fact the trace is a bit
diffrence since there where two earthquakes almost at the same loaction
at the same time. The trace is on the Psn event file list, the automatic
location that i did use did give up the size 2.9ML.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Room Temp Super Conductor coil
From: "Geoffrey" gmvoeth@...........
Date: Wed, 1 Mar 2006 08:32:01 -0700
Would a room temperature superconductor make a good coil for coil-magnet seismic sensor ?
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Does Anyone know how to get ahold of Larry
From: "Geoffrey" gmvoeth@...........
Date: Wed, 1 Mar 2006 09:59:46 -0700
I was interested in registering Winquake but when I sent a
message to Larry this is what came back
************* See Below ************
This is the Postfix program at host mail13.mdx.safepages.com.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to <postmaster>
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The Postfix program
<cochrane@..............>: host mail1.webtronics.com[66.92.4.80] said: 550
5.1.1 <cochrane@..............> is not a valid mailbox (in reply to RCPT TO
command)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Does Anyone know how to get ahold of Larry
From: "Steve Hammond" shammon1@.............
Date: Wed, 1 Mar 2006 10:08:45 -0800
He should see this.
Steve Hammond
-----Original Message-----
From: psn-l-request@..............
[mailto:psn-l-request@................. Behalf Of Geoffrey
Sent: Wednesday, March 01, 2006 9:00 AM
To: PSN
Subject: Does Anyone know how to get ahold of Larry
I was interested in registering Winquake but when I sent a
message to Larry this is what came back
************* See Below ************
This is the Postfix program at host mail13.mdx.safepages.com.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to <postmaster>
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The Postfix program
<cochrane@..............>: host mail1.webtronics.com[66.92.4.80] said: 550
5.1.1 <cochrane@..............> is not a valid mailbox (in reply to RCPT
TO
command)
__________________________________________________________
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Subject: Re: Room Temp Super Conductor coil
From: Ben Bradley benbradley@...............
Date: Wed, 01 Mar 2006 13:13:50 -0500
Geoffrey wrote:
> Would a room temperature superconductor make a good coil for coil-magnet
> seismic sensor ?
I don't see any advantage, as the coil resistance in a coil used for
a seismic sensor is of little significance. The resistance may be fairly
high due to the thin wire and large number of turns of the coil, but
it's easy enough to make high-impedance circuitry to measure signal
voltage without loading down the coil.
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with the body of
> the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Room Temp Super Conductor coil
From: "Jack Ivey" ivey@..........
Date: Wed, 1 Mar 2006 13:39:40 -0500
The thermal noise produced by the resistance of the coil would go
to zero, but it's unlikely that this is the primary source of noise
in most seismometers.
Jack
> Would a room temperature superconductor make a good coil for
coil-magnet=20
> seismic sensor ?
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Room Temp Super Conductor coil
From: ChrisAtUpw@.......
Date: Wed, 1 Mar 2006 13:52:30 EST
In a message dated 01/03/2006, ivey@.......... writes:
The thermal noise produced by the resistance of the coil would go to zero,
but it's unlikely that this is the primary source of noise in most
seismometers.
Hi there,
Where do you get a room temperature superconductor? And what is it? Last
time I looked they had critical temperatures just above liquid O2, 90 K.
Coil / amplifier low noise combinations are designed on the coil
resistance, so if this did go to zero, you would need to develop a different
amplifier circuit - not use the same one.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 01/03/2006, ivey@.......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>The=20
thermal noise produced by the resistance of the coil would go to zero, but=
=20
it's unlikely that this is the primary source of noise in most=20
seismometers.<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi there,</DIV>
<DIV> </DIV>
<DIV> Where do you get a room temperature superconduc=
tor?=20
And what is it? Last time I looked they had critical temperatures just=20
above liquid O2, 90 K.</DIV>
<DIV> </DIV>
<DIV> Coil / amplifier low noise combinations are=20
designed on the coil resistance, so if this did go to zero, you would need t=
o=20
develop a different amplifier circuit - not use the same one.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Room Temp Super Conductor coil
From: ChrisAtUpw@.......
Date: Thu, 2 Mar 2006 08:09:18 EST
In a message dated 01/03/2006, gmvoeth@........... writes:
Would a room temperature superconductor make a good coil for coil-magnet
seismic sensor ?
The highest superconducting temperature to date is 138 K = -135 C
See _http://www.superconductors.org/_ (http://www.superconductors.org/)
There is still quite a long way to go before we get anywhere near room
temperature.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 01/03/2006, gmvoeth@........... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Would a=20
room temperature superconductor make a good coil for coil-magnet seismic=20
sensor ?<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV> The highest superconducting temperature to date=
is=20
138 K =3D -135 C</DIV>
<DIV> See <A=20
href=3D"http://www.superconductors.org/">http://www.superconductors.org/</A>=
There=20
is still quite a long way to go before we get anywhere near room=20
temperature.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: STM's VBB equations
From: Barry Lotz barry_lotz@.............
Date: Thu, 2 Mar 2006 19:26:40 -0800 (PST)
Hi All
I have constructed 3 long period seismographs which used info from STM's web site. They work well. What isn't working well is duplicating STM's equation results for the sensors response. I have tried my DOS version of mathcad and have just created the equations in Excel. I get the same results with both. However they differ from that STM got and also Al Coleman. I have been able to duplicate most of their results except for the response slope at both ends of the velocity graph, especially at the low end. My graphs drop off too dramatically. Has anyone run the equations and duplicated STM's results with his seismograph characteristics? I am an engineer and understand equations. I suppose that I'm not reproducing some subtle portion of the equations, though I have stared at them for days.
Regards
Barry
<DIV>Hi All</DIV> <DIV> I have constructed 3 long period seismographs which used info from STM's web site. They work well. What isn't working well is duplicating STM's equation results for the sensors response. I have tried my DOS version of mathcad and have just created the equations in Excel. I get the same results with both. However they differ from that STM got and also Al Coleman. I have been able to duplicate most of their results except for the response slope at both ends of the velocity graph, especially at the low end. My graphs drop off too dramatically. Has anyone run the equations and duplicated STM's results with his seismograph characteristics? I am an engineer and understand equations. I suppose that I'm not reproducing some subtle portion of the equations, though I have stared at them for days. </DIV> <DIV>Regards</DIV> <DIV>Barry</DIV> <DIV> </DIV>
Subject: Re: STM's VBB equations
From: Brett Nordgren Brett3kg@.............
Date: Fri, 03 Mar 2006 07:37:07 -0500
Barry,
If you haven't already, you may want to look at some of my data on
http://bnordgren.org/seismo/
In particular, the files 'loop3.pdf', 'lpmeas2.pdf', and probably some others.
If you can provide some more details, I'll be happy to try to help.
Regards
Brett
At 07:26 PM 3/2/2006 -0800, you wrote:
>Hi All
> I have constructed 3 long period seismographs which used info from
> STM's web site. They work well. What isn't working well is duplicating
> STM's equation results for the sensors response. I have tried my DOS
> version of mathcad and have just created the equations in Excel. I get
> the same results with both. However they differ from that STM got and
> also Al Coleman. I have been able to duplicate most of their results
> except for the response slope at both ends of the velocity graph,
> especially at the low end. My graphs drop off too dramatically. Has
> anyone run the equations and duplicated STM's results with his
> seismograph characteristics? I am an engineer and understand equations. I
> suppose that I'm not reproducing some subtle portion of the equations,
> though I have stared at them for days.
>Regards
>Barry
>
If my e-mail address above is not working
you can always reach my mail form at: http://bnordgren.org/contactB.html
using your Web browser.
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Subject: Re: STM's VBB equations
From: Brett Nordgren Brett3kg@.............
Date: Fri, 03 Mar 2006 08:27:16 -0500
Barry,
I see now that there is a newer version of the 'loop' pdf that's not shown
in the index. It corrects some errors, adds some clarifications and has
some notes to myself about what more needs to be worked
on. http://bnordgren.org/seismo/loop4.pdf is probably a better one to use.
Regards
Brett
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Subject: My Online seismographs are offline for the next 24 hours, computer
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 06 Mar 2006 14:01:21 +0000
Hi all
My online seismogrpahs are not going to update in the next 24 hours
becose of a computer failure. I had planned to change about hard drive
in the computer that work out the data from the geophone. However i did
suffer psu failure when i was changeing about the hard drive.I am going
to try to run winsdr in linux with wine API software in order to
continue recording earthquakes, but i won't update the online graphs in
such low level user mode.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
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Subject: speaking about bad luck
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 06 Mar 2006 15:52:06 +0000
Hi all
I had a really bad luck today. As i told you in my email early today i
had a psu failure in the computer that records earthquakes for me. But
also today there was a earthquake that was 4.5Mb on the Reykjanes ridge,
it was felt in Reykjavik. More info here,
http://www.emsc-csem.org/index.php?page=current&sub=detail&id=HP408;2006
But becose my earthquake computer is down i didn't record this
earthquake. :(
I really hate it when something like this happens.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
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Subject: Re: My Online seismographs are offline for the next 24 hours, computer hardwa...
From: ChrisAtUpw@.......
Date: Mon, 6 Mar 2006 21:47:56 EST
In a message dated 06/03/2006, jonfr500@......... writes:
However i did
suffer psu failure when i was changeing about the hard drive.
Hi Jon,
Look inside the PSU case, opening one side if necessary. They very often
have a fuse on the circuit board that they don't tell you about!
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 06/03/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>However=20
i did<BR>suffer psu failure when i was changeing about the hard=20
drive.</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> Look inside the PSU case, opening one side if=20
necessary. <U>They very often have a fuse on the circuit board that they don=
't=20
tell you about! </U></DIV>
<DIV><U></U> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: My Online seismographs are offline for the next 24 hours,
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Tue, 07 Mar 2006 16:10:01 +0000
Hi Chris
The psu did work agen this morning when i did test it. I didn't get new
psu today as expected, that is why i did test the psu that did fail
yesterday. I also did discover a problem with the new hard drive, i
found out that it wasn't so new as the store who sold it ment it to be.
I did send them the hard drive back and i will get new one after few
days. I am going to get new psu tomorrow and i expect the change to with
out a problem, one can only hope. I did try to open the psu box, but i
didn't find any clear way to open the box.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
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Subject: WinSDR crashing on single line display
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 11 Mar 2006 00:25:53 +0000
Hi all
In my computer the winSDR computer has the issue of crashing when i try
to use the single line display feature. Why this happens is unkown to
me, but i want to see if anyone else that is using Winsdr has this
problem. I don't think this is a memory releated problem, since i am not
haveing problem with other software or Windows 2000.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
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Subject: line driver question
From: Barry Lotz barry_lotz@.............
Date: Tue, 14 Mar 2006 20:59:58 -0800 (PST)
Hi All
I was planning to put a line driver on the position voltage output of my vbb style sensor. Currently I run it directly about 40' to my house but I think it affects the triple feedback circuit. The simple way is to put a non-inverting follower at the circuit output. The question is (lets see if I can explain this) the non-inverting opamp on the velocity output of the sensor has a small resistor between the output of the opamp (~10 ohms) and the line going back to the negative opamp input and a small (pf) capacitor between the opamp output and the negative input . I think this is for damping high frequency oscillations. Should I use this with the unity gain follower? I'm not sure if its necessary or how to do this. The only way I can think of is to put a high resistor (~100k) before the positive opamp input and a 100k in the line going back to the negative input and then put the small cap and resistor as noted above. I'm not sure that this will acomplish anything.
I didn't want to have a voltage divider before the non inverting opamp to reduce the voltage in half and then have a 2X noninverting opamp line driver. I think the voltage divider will affect the current flow to my feedback coil.
Regards
Barry
<div>Hi All</div> <div> I was planning to put a line driver on the position voltage output of my vbb style sensor. Currently I run it directly about 40' to my house but I think it affects the triple feedback circuit. The simple way is to put a non-inverting follower at the circuit output. The question is (lets see if I can explain this) the non-inverting opamp on the velocity output of the sensor has a small resistor between the output of the opamp (~10 ohms) and the line going back to the negative opamp input and a small (pf) capacitor between the opamp output and the negative input . I think this is for damping high frequency oscillations. Should I use this with the unity gain follower? I'm not sure if its necessary or how to do this. The only way I can think of is to put a high resistor (~100k) before the positive opamp input and a 100k in the line going back to the negative input and then put the small cap and resistor as noted above. I'm
not sure that this will acomplish anything.</div> <div>I didn't want to have a voltage divider before the non inverting opamp to reduce the voltage in half and then have a 2X noninverting opamp line driver. I think the voltage divider will affect the current flow to my feedback coil.</div> <div>Regards</div> <div>Barry </div>
Subject: Re: line driver question
From: John Popelish jpopelish@........
Date: Wed, 15 Mar 2006 00:26:18 -0500
Barry Lotz wrote:
> Hi All
> I was planning to put a line driver on the position voltage
> output of my vbb style sensor. Currently I run it directly
> about 40' to my house but I think it affects the triple feedback
> circuit. The simple way is to put a non-inverting follower
> at the circuit output.
The simple way to accomplish what?
> The question is (lets see if I can explain this)
> the non-inverting opamp on the velocity output of the sensor
> has a small resistor between the output of the opamp (~10 ohms)
> and the line going back to the negative opamp input
> and a small (pf) capacitor between the opamp output
> and the negative input. I think this is for damping high frequency
> oscillations.
It improves the opamps stability in the presence of a capacitive load,
like long wiring has. I seldom see this between opamps on the same board.
> Should I use this with the unity gain follower?
It probably can't hurt. But I don't understand the purpose of the
follower, to begin with.
> I'm not sure if its necessary or how to do this.
> The only way I can think of is to put a high resistor (~100k)
> before the positive opamp input and a 100k in the line going
> back to the negative input and then put the small cap and resistor
> as noted above.
The input resistor in the + input leg is necessary, only if the bias
current error of the opamp is significant to you. Some opamps have
such low bias current that the drop across the 100k feedback resistor
is less than the offset voltage of the input.
> I'm not sure that this will acomplish anything.
You may be solving a non problem. Will this follower drive a long wire?
> I didn't want to have a voltage divider before the
> non inverting opamp to reduce the voltage in half and then have
> a 2X noninverting opamp line driver.
I agree that this is not the way to go, if it can be avoided.
> I think the voltage divider will affect the current flow
> to my feedback coil.
It will not improve the accuracy of the follower. But, if this opamp
drives a feedback current, how 'bout configuring it as a voltage
controlled current source, so that wiring resistance will have little
effect on the accuracy?
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Subject: Re: line driver question
From: "Geoffrey" gmvoeth@...........
Date: Wed, 15 Mar 2006 05:39:51 -0700
> It will not improve the accuracy of the follower. But, if this opamp
> drives a feedback current, how 'bout configuring it as a voltage
> controlled current source, so that wiring resistance will have little
> effect on the accuracy?
Are you talking about something like they use in industry
and telephone called a 20 milliamp loop ?
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Subject: Re: line driver question
From: John Popelish jpopelish@........
Date: Wed, 15 Mar 2006 10:09:37 -0500
Geoffrey wrote:
>
>> It will not improve the accuracy of the follower. But, if this opamp
>> drives a feedback current, how 'bout configuring it as a voltage
>> controlled current source, so that wiring resistance will have little
>> effect on the accuracy?
>
>
>
> Are you talking about something like they use in industry
> and telephone called a 20 milliamp loop ?
Something like, yes, in that it is a circuit that regulates current,
rather than voltage. However, the teletype 20 mA loop had only two
output values, 0 and 20 mA, and was often only crudely regulated
(sometimes just with a big series resistor and a high voltage power
supply).
Voltage negative feedback (feedback from the output that is
proportional to the output voltage) tends to lower the output
impedance of an amplifier. That is, it tends to make the output
voltage almost independent of the load current.
But if the negative feedback is proportional to the load current,
instead of output voltage, it tends to raise the output impedance, and
make it almost independent of the voltage. Add resistance (wiring) in
series with the load,m and the output voltage increases to compensate
and keep the current as intended. This works well only at frequencies
below those where the wiring acts as a capacitive load that rolls off
the high frequencies, so there are limits to how fast the current at
the far end of a wire can be regulated. But at 40 feet of length, it
is probably high enough.
Whether or not a current regulator is a better idea than a voltage
regulator output, in this application, depends on details I don't have
in front of me.
If accurate voltage at a distance is needed, a feedback pair of wires
that act as long volt meter leads that return the voltage feedback
from the load are another possibility for improving accuracy.
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Subject: Re: line driver question
From: Brett Nordgren Brett3kg@.............
Date: Wed, 15 Mar 2006 10:17:33 -0500
Hi Barry,
At 08:59 PM 3/14/2006 -0800, you wrote:
>Hi All
> I was planning to put a line driver on the position voltage output of my
> vbb style sensor. Currently I run it directly about 40' to my house but I
> think it affects the triple feedback circuit.
That is possible, though not certain. I think that the position ouput
comes off from the capacitor of the integrator branch, putting the cable
capacitance in parallel with the relatively large integrator
capacitor. Adding a few (hundred) pf of cable capacitance to that,
shouldn't affect things much, unless the loop is already close to
oscillating. Small amounts of DC introduced back into the cable or
resistive loading would be a more serious problem.
>The simple way is to put a non-inverting follower at the circuit output.
>The question is (lets see if I can explain this) the non-inverting opamp
>on the velocity output of the sensor has a small resistor between the
>output of the opamp (~10 ohms) and the line going back to the negative
>opamp input and a small (pf) capacitor between the opamp output and the
>negative input . I think this is for damping high frequency oscillations.
The RC was possibly a trial and error solution to kill a high frequency
oscillation. A good analysis of why the loop was oscillating in the first
place might suggest some better solution for that issue.
>Should I use this with the unity gain follower? I'm not sure if its
>necessary or how to do this. The only way I can think of is to put a high
>resistor (~100k) before the positive opamp input and a 100k in the line
>going back to the negative input and then put the small cap and resistor
>as noted above. I'm not sure that this will acomplish anything.
A unity gain follower couldn't hurt and would isolate the signal path from
AC and DC leakage feeding back into it from the cable and load
circuits. Input signal from the integrator capacitor goes to the plus op
amp input, negative input connects to its output which also drives the
cable. You might want to add 1k or so in series between the op amp output
and cable input end to reduce the danger to the op amp from accidental
shorts or voltage transients fed back through the cable. At the low
frequencies involved, the added resistance shouldn't have much of an effect.
>I didn't want to have a voltage divider before the non inverting opamp to
>reduce the voltage in half and then have a 2X noninverting opamp line
>driver. I think the voltage divider will affect the current flow to my
>feedback coil.
>Regards
>Barry
It would help if I could see the circuit. Is there an image file
available? The circuit in my head may be far from what you have.
Regards,
Brett
If my e-mail address above is not working
you can always reach my mail form at: http://bnordgren.org/contactB.html
using your Web browser.
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Subject: Re: line driver question
From: Richard Gagnon richg_1998@.........
Date: Wed, 15 Mar 2006 07:27:00 -0800 (PST)
> Something like, yes, in that it is a circuit that regulates current,
> rather than voltage. However, the teletype 20 mA loop had only two
> output values, 0 and 20 mA, and was often only crudely regulated
> (sometimes just with a big series resistor and a high voltage power
> supply).
I work in industry in the USA that uses 20ma and it is 4ma to 20ma with
regulated power supplies. The signal can be any value between those two
numbers, quite often 0 signal is 4ma and maximum signal is 20ma. Machine
computer control is very effective at sending the exact values via a d/a
module.
This may have nothing to do with this thread but I wanted to comment on the
technology.
Cheers
Richard
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Subject: Re: line driver question
From: John Popelish jpopelish@........
Date: Wed, 15 Mar 2006 10:44:54 -0500
Richard Gagnon wrote:
> I work in industry
So do I. :-)
> in the USA that uses 20ma and it is 4ma to 20ma with
> regulated power supplies. The signal can be any value between those two
> numbers, quite often 0 signal is 4ma and maximum signal is 20ma. Machine
> computer control is very effective at sending the exact values via a d/a
> module.
> This may have nothing to do with this thread but I wanted to comment on the
> technology.
Yes, that is the analog extension of the old digital 20 mA teletype
current loop.
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Subject: Moonquakes, intresting artical by nasa
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Thu, 16 Mar 2006 04:03:01 +0000
Hi all
I want to point out this artical from nasa about moonquakes.
http://science.nasa.gov/headlines/y2006/15mar_moonquakes.htm?list131101
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
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Subject: Re: Moonquakes, intresting artical by nasa
From: "Geoffrey" gmvoeth@...........
Date: Wed, 15 Mar 2006 21:43:31 -0700
If you look hard enough you should also be able to find a design that they are considering for use on MARS. It is a capacitive
sensor I think with an X/Y motion mass suspended by a series of leaf springs. It looks like it would be great for amateurs if only
could get our hands on such a thing. They are putting considerable time and effort or so it seems into making a light weight
seismometer that would be very portable.
I can not remember where I saw the design but they had a photo of the guts to the thing.
I have always thought it would be nice to have a seismometer you could easily move from one place to another.
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Subject: Re: line driver question
From: Barry Lotz barry_lotz@.............
Date: Wed, 15 Mar 2006 20:45:50 -0800 (PST)
John,Brett,Richard&Geoffrey
Thanks for the "feedback" :). All I am trying to do is monitor a voltage in a feedback circuit from 40' from the circuit without affecting the performance of the feedback circuit. The monitored voltage goes to a LCD voltage display in my house.I think I will just try a follower with a resistor at the output , to prevent transient voltages from entering the feedback circuit from the shielded line.
regards
Barry
<div>John,Brett,Richard&Geoffrey</div> <div> Thanks for the "feedback" :). All I am trying to do is monitor a voltage in a feedback circuit from 40' from the circuit without affecting the performance of the feedback circuit. The monitored voltage goes to a LCD voltage display in my house.I think I will just try a follower with a resistor at the output , to prevent transient voltages from entering the feedback circuit from the shielded line.<BR>regards</div> <div>Barry</div> <div><BR> </div>
Subject: RE: line driver question
From: "Keith Payea" kpayea@...........
Date: Wed, 15 Mar 2006 21:12:12 -0800
Barry:
The circuit you describe is the classic way to deal with a large capacitive
load on an op-amp. The series resistor decouples the capacitance from the
op-amp output, and the local feedback capacitor keeps the whole thing
stable. There are also op-amps which are designed to drive highly
capacitive loads like this. It's not so critical if you don't need high
gain in addition to the line driving capability.
I use a part called the LM837 in my VBB output to drive the 70 or 80 feet of
cable back to the SDR system. See the schematic at:
http://www.bryantlabs.net/Images/SenseAmp.pdf You can see I have a small
resistor in series with the output also.
You are right to add a buffer between the internal "Analog Computer" and the
cable. I agree the issue is not so much the added capacitance as the
potential to feed noise into the process back up the cable. Opamps are
cheap...
Cheers,
Keith
_____
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Barry Lotz
Sent: Wednesday, March 15, 2006 8:46 PM
To: psn-l@..............
Subject: Re: line driver question
John,Brett,Richard&Geoffrey
Thanks for the "feedback" :). All I am trying to do is monitor a voltage
in a feedback circuit from 40' from the circuit without affecting the
performance of the feedback circuit. The monitored voltage goes to a LCD
voltage display in my house.I think I will just try a follower with a
resistor at the output , to prevent transient voltages from entering the
feedback circuit from the shielded line.
regards
Barry
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Dus-ascii">
<META content=3D"MSHTML 6.00.2800.1458" name=3DGENERATOR></HEAD>
<BODY>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D776560105-16032006><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>Barry: </FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D776560105-16032006><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D776560105-16032006><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>The circuit you describe is the classic way to =
deal with a=20
large capacitive load on an op-amp. The series resistor decouples =
the=20
capacitance from the op-amp output, and the local feedback capacitor =
keeps the=20
whole thing stable. There are also op-amps which are designed to =
drive=20
highly capacitive loads like this. It's not so critical if you =
don't need=20
high gain in addition to the line driving =
capability.</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D776560105-16032006><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D776560105-16032006><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>I use a part called the LM837 in my VBB output =
to drive the=20
70 or 80 feet of cable back to the SDR system. See the schematic =
at: <A=20
href=3D"http://www.bryantlabs.net/Images/SenseAmp.pdf">http://www.bryantl=
abs.net/Images/SenseAmp.pdf</A> =20
You can see I have a small resistor in series with the output=20
also.</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D776560105-16032006><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D776560105-16032006><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>You are right to add a buffer between the =
internal "Analog=20
Computer" and the cable. I agree the issue is not so much the =
added=20
capacitance as the potential to feed noise into the process back up the=20
cable. Opamps are cheap...</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D776560105-16032006><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D776560105-16032006><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>Cheers,</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D776560105-16032006><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN> </DIV>
<DIV dir=3Dltr align=3Dleft><SPAN =
class=3D776560105-16032006> <FONT=20
face=3DArial color=3D#0000ff size=3D2>Keith</FONT></SPAN></DIV><BR>
<DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr align=3Dleft>
<HR tabIndex=3D-1>
<FONT face=3DTahoma size=3D2><B>From:</B> psn-l-request@.................
[mailto:psn-l-request@............... <B>On Behalf Of </B>Barry=20
Lotz<BR><B>Sent:</B> Wednesday, March 15, 2006 8:46 PM<BR><B>To:</B>=20
psn-l@..............<BR><B>Subject:</B> Re: line driver=20
question<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV>John,Brett,Richard&Geoffrey</DIV>
<DIV> Thanks for the "feedback" :). All I am trying to do is =
monitor a=20
voltage in a feedback circuit from 40' from the circuit =
without=20
affecting the performance of the feedback circuit. The monitored voltage =
goes to=20
a LCD voltage display in my house.I think I will just try a follower =
with a=20
resistor at the output , to prevent transient voltages from =
entering the=20
feedback circuit from the shielded line.<BR>regards</DIV>
<DIV>Barry</DIV>
<DIV><BR> </DIV></BODY></HTML>
Subject: Op Amp circuits
From: Brett Nordgren Brett3kg@.............
Date: Thu, 16 Mar 2006 08:24:03 -0500
Barry,
In looking around for op-amp information, I just ran across the excellent
TI application note below.
http://focus.ti.com/lit/an/sboa092a/sboa092a.pdf
It has 93 pages of op-amp circuits and information on how to design with them.
Hope you or someone else here may find it useful.
Regards,
Brett
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: line driver question
From: "Steve Hammond" shammon1@.............
Date: Thu, 16 Mar 2006 08:07:53 -0800
Hi Berry, you might send this question to TJ Byers at tjbyers@....... . He
writes the Q&A column in Nuts&Volts. He likes unusual questions.
Steve Hammond
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@.................
Behalf Of Barry Lotz
Sent: Wednesday, March 15, 2006 8:46 PM
To: psn-l@..............
Subject: Re: line driver question
John,Brett,Richard&Geoffrey
Thanks for the "feedback" :). All I am trying to do is monitor a voltage
in a feedback circuit from 40' from the circuit without affecting the
performance of the feedback circuit. The monitored voltage goes to a LCD
voltage display in my house.I think I will just try a follower with a
resistor at the output , to prevent transient voltages from entering the
feedback circuit from the shielded line.
regards
Barry
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY>
<DIV><SPAN class=3D140330116-16032006><FONT face=3DArial color=3D#0000ff =
size=3D2>Hi=20
Berry, you might send this question to TJ Byers at <A=20
href=3D"mailto:tjbyers@.......">tjbyers@.......</A> . He writes the =
Q&A column=20
in Nuts&Volts. He likes unusual questions.</FONT></SPAN></DIV>
<DIV><SPAN class=3D140330116-16032006><FONT face=3DArial color=3D#0000ff =
size=3D2>Steve=20
Hammond</FONT></SPAN></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> =
psn-l-request@.................
[mailto:psn-l-request@...............<B>On Behalf Of </B>Barry=20
Lotz<BR><B>Sent:</B> Wednesday, March 15, 2006 8:46 PM<BR><B>To:</B>=20
psn-l@..............<BR><B>Subject:</B> Re: line driver=20
question<BR><BR></FONT></DIV>
<DIV>John,Brett,Richard&Geoffrey</DIV>
<DIV> Thanks for the "feedback" :). All I am trying to do is =
monitor a=20
voltage in a feedback circuit from 40' from the circuit =
without=20
affecting the performance of the feedback circuit. The monitored =
voltage goes=20
to a LCD voltage display in my house.I think I will just try a =
follower with a=20
resistor at the output , to prevent transient voltages from =
entering the=20
feedback circuit from the shielded line.<BR>regards</DIV>
<DIV>Barry</DIV>
<DIV><BR> </DIV></BLOCKQUOTE></BODY></HTML>
Subject: RE: line driver question
From: "Steve Hammond" shammon1@.............
Date: Thu, 16 Mar 2006 08:10:47 -0800
Ops... Sorry Barry-- (Not Berry) It's early and I'm still on coffee #1.
S--
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@.................
Behalf Of Steve Hammond
Sent: Thursday, March 16, 2006 8:08 AM
To: psn-l@..............
Subject: RE: line driver question
Hi Berry, you might send this question to TJ Byers at tjbyers@....... . He
writes the Q&A column in Nuts&Volts. He likes unusual questions.
Steve Hammond
-----Original Message-----
From: psn-l-request@..............
[mailto:psn-l-request@................. Behalf Of Barry Lotz
Sent: Wednesday, March 15, 2006 8:46 PM
To: psn-l@..............
Subject: Re: line driver question
John,Brett,Richard&Geoffrey
Thanks for the "feedback" :). All I am trying to do is monitor a
voltage in a feedback circuit from 40' from the circuit without affecting
the performance of the feedback circuit. The monitored voltage goes to a LCD
voltage display in my house.I think I will just try a follower with a
resistor at the output , to prevent transient voltages from entering the
feedback circuit from the shielded line.
regards
Barry
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY>
<DIV><SPAN class=3D437480816-16032006><FONT face=3DArial color=3D#0000ff =
size=3D2>Ops...=20
Sorry Barry-- (Not Berry) It's early and I'm still on coffee=20
#1.</FONT></SPAN></DIV>
<DIV><SPAN class=3D437480816-16032006><FONT face=3DArial color=3D#0000ff =
size=3D2>S--</FONT></SPAN></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> =
psn-l-request@.................
[mailto:psn-l-request@...............<B>On Behalf Of </B>Steve=20
Hammond<BR><B>Sent:</B> Thursday, March 16, 2006 8:08 AM<BR><B>To:</B> =
psn-l@..............<BR><B>Subject:</B> RE: line driver=20
question<BR><BR></FONT></DIV>
<DIV><SPAN class=3D140330116-16032006><FONT face=3DArial =
color=3D#0000ff size=3D2>Hi=20
Berry, you might send this question to TJ Byers at <A=20
href=3D"mailto:tjbyers@.......">tjbyers@.......</A> . He writes the =
Q&A=20
column in Nuts&Volts. He likes unusual =
questions.</FONT></SPAN></DIV>
<DIV><SPAN class=3D140330116-16032006><FONT face=3DArial =
color=3D#0000ff=20
size=3D2>Steve Hammond</FONT></SPAN></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B>=20
psn-l-request@.............. =
[mailto:psn-l-request@...............<B>On=20
Behalf Of </B>Barry Lotz<BR><B>Sent:</B> Wednesday, March 15, 2006 =
8:46=20
PM<BR><B>To:</B> psn-l@..............<BR><B>Subject:</B> Re: line =
driver=20
question<BR><BR></FONT></DIV>
<DIV>John,Brett,Richard&Geoffrey</DIV>
<DIV> Thanks for the "feedback" :). All I am trying to do is =
monitor a=20
voltage in a feedback circuit from 40' from the circuit =
without=20
affecting the performance of the feedback circuit. The monitored =
voltage=20
goes to a LCD voltage display in my house.I think I will just try a =
follower=20
with a resistor at the output , to prevent transient voltages =
from=20
entering the feedback circuit from the shielded =
line.<BR>regards</DIV>
<DIV>Barry</DIV>
<DIV><BR> </DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
Subject: RE: line driver question
From: Barry Lotz barry_lotz@.............
Date: Thu, 16 Mar 2006 20:05:04 -0800 (PST)
Hi Steve
Ah Nuts & Volts! I have about ten years worth. I didn't think of that. I like their new magazine format. I recommend it to all.
Regards
Barry
Steve Hammond <shammon1@.............> wrote:
Hi Berry, you might send this question to TJ Byers at tjbyers@....... . He writes the Q&A column in Nuts&Volts. He likes unusual questions.
Steve Hammond
<div>Hi Steve</div> <div> Ah Nuts & Volts! I have about ten years worth. I didn't think of that. I like their new magazine format. I recommend it to all.</div> <div>Regards</div> <div>Barry<BR><BR><B><I>Steve Hammond <shammon1@ix.netcom.com></I></B> wrote:</div> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid"> <META content="MSHTML 6.00.2900.2802" name=GENERATOR> <DIV><SPAN class=140330116-16032006><FONT face=Arial color=#0000ff size=2>Hi Berry, you might send this question to TJ Byers at <A href="mailto:tjbyers@aol.com">tjbyers@aol.com</A> . He writes the Q&A column in Nuts&Volts. He likes unusual questions.</FONT></SPAN></DIV> <DIV><SPAN class=140330116-16032006><FONT face=Arial color=#0000ff size=2>Steve Hammond</FONT></SPAN></DIV> <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> </BLOCKQUOTE></BLOCKQUOTE>
Subject: Long period seismonitor sensitivite ?
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 17 Mar 2006 17:28:02 +0000
Hi all
With long period seismonitor what is the smallest earthquake that can be
detected with such seismonitor ? Then i mean in teleseismic earthquake
range.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Drum recorders
From: "Steve Hammond" shammon1@.............
Date: Fri, 17 Mar 2006 10:49:05 -0800
I have two 75-100 lbs. drum recorders that I have been given over the years.
I would like to pass them on to somebody on the PSN list. They both need ink
pen / supply tanks. I live in the Santa Cruz area. If you are interested,
please send my a note off-line.
Regards, Steve Hammond PSN San Jose, Aptos, CA
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Long period seismonitor sensitivite ?
From: Angel sismos@..............
Date: Fri, 17 Mar 2006 20:06:10 +0000
Hello Jón,
Take a look at this page, it might help answer your question.
http://jclahr.com/science/psn/magnitude.html
Angel
Friday, March 17, 2006, 5:28:02 PM, you wrote:
> Hi all
> With long period seismonitor what is the smallest earthquake that can be
> detected with such seismonitor ? Then i mean in teleseismic earthquake
> range.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Drum recorders
From: Tamati chief.cook.nz@............
Date: Sat, 18 Mar 2006 09:05:01 +1300
TAMATI's WORD's OF WISDOM
FOR THE GOOD OF ALL MANKIND
HTTP://LIVE-PLANET.BLOGSPOT.COM
http://www.webspawner.com/users/chiefcooknz/index.html
Please give me feed back on what you think
chief.cook.nz.@............
NZ-021-150-33-59 or NZ-07-855-0195
Hi
What a b*((*&^ that I'm in NZ grrrrrrr'a
but that's the brakes, no-cash to pay frieght that a bigger GRRRRRRRR'A
Cheers Tamati
From the Castle of Tamati, Hinemoa and Karauwa the Dog
From the Castle of Tom, Robyn and the Dog
I'm Just a Stone's Throw Away:- NZ-021-150-33-59 or NZ-07-855-0195
Bush Telegragh:- =
chief.cook.nz@............
My Regular Pitstop:- Tamati
=
P.O.BOX 19-356 CENTRAL
=
HAMILTON
NEW =
ZEALAND
----- Original Message -----=20
From: "Steve Hammond" <shammon1@.............>
To: <psn-l@..............>
Sent: Saturday, March 18, 2006 7:49 AM
Subject: Drum recorders
>I have two 75-100 lbs. drum recorders that I have been given over the =
years.
> I would like to pass them on to somebody on the PSN list. They both =
need ink
> pen / supply tanks. I live in the Santa Cruz area. If you are =
interested,
> please send my a note off-line.
> Regards, Steve Hammond PSN San Jose, Aptos, CA
>=20
> __________________________________________________________
>=20
> Public Seismic Network Mailing List (PSN-L)
>=20
> To leave this list email PSN-L-REQUEST@.............. with=20
> the body of the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY>
<DIV align=3Dcenter><STRONG><FONT face=3DGeorgia>TAMATI's WORD's OF =
WISDOM<BR>FOR=20
THE GOOD OF ALL MANKIND<BR></FONT></STRONG><A=20
href=3D"http://LIVE-PLANET.BLOGSPOT.COM"><STRONG><FONT=20
face=3DGeorgia>HTTP://LIVE-PLANET.BLOGSPOT.COM</FONT></STRONG></A><BR><A =
href=3D"http://www.webspawner.com/users/chiefcooknz/index.html"><STRONG><=
FONT=20
face=3DGeorgia>http://www.webspawner.com/users/chiefcooknz/index.html</FO=
NT></STRONG></A><BR><STRONG><FONT=20
face=3DGeorgia>Please give me feed back on what you =
think<BR></FONT></STRONG><A=20
href=3D"mailto:chief.cook.nz.@............"><STRONG><FONT=20
face=3DGeorgia>chief.cook.nz.@............</FONT></STRONG></A><BR><STRONG=
><FONT=20
face=3DGeorgia>NZ-021-150-33-59 or NZ-07-855-0195</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia>Hi</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia>What a b*((*&^ that I'm in =
NZ =20
grrrrrrr'a</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia></FONT></STRONG> </DIV>
<DIV><STRONG><FONT face=3DGeorgia>but that's the brakes, no-cash to pay =
frieght=20
that a bigger GRRRRRRRR'A</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia></FONT></STRONG> </DIV>
<DIV><STRONG><FONT face=3DGeorgia></FONT></STRONG> </DIV>
<DIV><STRONG><FONT face=3DGeorgia>Cheers Tamati<BR>From the Castle of =
Tamati,=20
Hinemoa and Karauwa the Dog<BR>From the Castle of Tom, Robyn and the=20
Dog</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia></FONT></STRONG> </DIV>
<DIV><STRONG><FONT face=3DGeorgia>I'm Just a Stone's Throw Away:- =
NZ-021-150-33-59=20
or=20
NZ-07-855-0195<BR> &=
nbsp; &n=
bsp; =20
Bush Telegragh:- </FONT></STRONG><A=20
href=3D"mailto:chief.cook.nz@............"><STRONG><FONT=20
face=3DGeorgia>chief.cook.nz@............</FONT></STRONG></A><BR><STRONG>=
<FONT=20
face=3DGeorgia> &nbs=
p;  =
;=20
My Regular Pitstop:-=20
Tamati<BR> &nb=
sp; &nbs=
p;  =
; =
&=
nbsp; =20
P.O.BOX 19-356=20
CENTRAL<BR> &n=
bsp; &nb=
sp; &nbs=
p;  =
; =
=20
HAMILTON<BR> &=
nbsp; &n=
bsp; &nb=
sp; &nbs=
p;  =
; =20
NEW ZEALAND</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia>----- Original Message ----- =
</FONT></STRONG>
<DIV><STRONG><FONT face=3DGeorgia>From: "Steve Hammond" =
<</FONT></STRONG><A=20
href=3D"mailto:shammon1@............."><STRONG><FONT=20
face=3DGeorgia>shammon1@.............</FONT></STRONG></A><STRONG><FONT=20
face=3DGeorgia>></FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia>To: <</FONT></STRONG><A=20
href=3D"mailto:psn-l@.............."><STRONG><FONT=20
face=3DGeorgia>psn-l@..............</FONT></STRONG></A><STRONG><FONT=20
face=3DGeorgia>></FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia>Sent: Saturday, March 18, 2006 7:49=20
AM</FONT></STRONG></DIV>
<DIV><STRONG><FONT face=3DGeorgia>Subject: Drum=20
recorders</FONT></STRONG></DIV></DIV>
<DIV><STRONG><BR><FONT =
face=3DGeorgia></FONT></STRONG></DIV><STRONG><FONT=20
face=3DGeorgia>>I have two 75-100 lbs. drum recorders that I have =
been given=20
over the years.<BR>> I would like to pass them on to somebody on the =
PSN=20
list. They both need ink<BR>> pen / supply tanks. I live in the Santa =
Cruz=20
area. If you are interested,<BR>> please send my a note =
off-line.<BR>>=20
Regards, Steve Hammond PSN San Jose, Aptos, CA<BR>> <BR>>=20
__________________________________________________________<BR>> =
<BR>>=20
Public Seismic Network Mailing List (PSN-L)<BR>> <BR>> To leave =
this list=20
email </FONT></STRONG><A=20
href=3D"mailto:PSN-L-REQUEST@.............."><STRONG><FONT=20
face=3DGeorgia>PSN-L-REQUEST@..............</FONT></STRONG></A><STRONG><F=
ONT=20
face=3DGeorgia> with <BR>> the body of the message (first line only): =
unsubscribe<BR>> See </FONT></STRONG><A=20
href=3D"http://www.seismicnet.com/maillist.html"><STRONG><FONT=20
face=3DGeorgia>http://www.seismicnet.com/maillist.html</FONT></STRONG></A=
><STRONG><FONT=20
face=3DGeorgia> for more information.</FONT></STRONG></BODY></HTML>
Subject: Detecting small earthquakes, update
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 18 Mar 2006 00:54:00 +0000
Hi all
I have now been able to detect earthquakes down to 1.2ML at ~94 Km. I
did also record a 1.6ML earthquake at 82Km the other day. Yesterday i
did record a 2.47ML (clear) earthquake at 150Km, i did also record two
other earthquakes yesterday that where 1.5ML and 1.6ML at ~150Km range
but the signal that i got was poor.
I did submitt those recordings to the psn list, becose the automatic
system that Icelandic Met Office has did register both of those
earthquakes as 2.1ML in size. I don't submit earthquakes smaller then
2.0ML in size to the psn event file list, becose it is really hard to
see if there actually is a earthquake in the signal when earthquakes are
that small, also the fact that i am about ~80Km away from the closest
active seismitic zone here in Iceland, both South of my location, West
of my location and North-East of my location.
I am unsure of this, but i don't think WinSDR is desinged to detect this
small earthquakes. I have to manual register those earthquakes. But it
might also be that i have the noise setting so high that it doesn't
detect that small earthquakes automatic.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Drum recorders
From: "Kareem at HeyJooJoo" system98765@.............
Date: Fri, 17 Mar 2006 18:30:27 -0800
Hi Steve,
I'm interested but how do we get a hold of you off line? Contact me via my
website: http://www.heyjoojoo.com/contact/feedback.php
Kareem
El Sobrante (The Leftovers), Ca
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Steve Hammond
Sent: Friday, March 17, 2006 10:49 AM
To: psn-l@..............
Subject: Drum recorders
I have two 75-100 lbs. drum recorders that I have been given over the years.
I would like to pass them on to somebody on the PSN list. They both need ink
pen / supply tanks. I live in the Santa Cruz area. If you are interested,
please send my a note off-line.
Regards, Steve Hammond PSN San Jose, Aptos, CA
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Long period seismonitor sensitivity ?
From: ChrisAtUpw@.......
Date: Fri, 17 Mar 2006 22:56:18 EST
In a message dated 17/03/2006, jonfr500@......... writes:
With a long period seismometer what is the smallest earthquake that can be
detected with such a seismometer? I mean in the teleseismic earthquake range.
Hi Jon,
It depends on your instrument characteristics, the intrinsic equipment
noise and on the local ambient seismic noise levels. For a system using 4.5 Hz
geophones without period extension, you are likely to be frequency limited
to local and near regional quakes, less than 6 deg, maybe quite a lot less. If
you can detect 1.0, 0.5 Hz and longer period events either with different
instruments or with low frequency period extension, you should be able to
detect M6 quakes worldwide, but how much smaller will depend on the range of the
quake and on your local noise, which is weather, environment and time related.
Some data for an AS-1 can be found at
_http://www2.bc.edu/~kafka/SeismoEd_SRL/kr03_page1.html_ (http://www2.bc.edu/~kafka/SeismoEd_SRL/kr03_page1.html)
See page 6. I would expect a good quality Lehman or SG seismometer with a
period of 20 sec to do better than this - the long period waves are of
greater amplitude and the noise is likely to be less. Regional quakes are defined
as being from 6 to 16 deg and teleseismic from 16 to 180 deg. There are
several regions in the teleseismic range which have different characteristic and
many different paths possible
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 17/03/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>With a=20
long period seismometer what is the smallest earthquake that can=20
be<BR>detected with such a seismometer? I mean in the teleseismic earthqua=
ke=20
range.<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> It depends on your instrument characteristics,=20=
the=20
intrinsic equipment noise and on the local ambient seismic noise levels=
..=20
For a system using 4.5 Hz geophones without period extension, you are=20
likely to be frequency limited to local and near regional quakes, less than=20=
6=20
deg, maybe quite a lot less. If you can detect 1.0, 0.5 Hz and longer period=
=20
events either with different instruments or with low frequency period extens=
ion,=20
you should be able to detect M6 quakes worldwide, but how much smaller will=20
depend on the range of the quake and on your local noise, which is weather,=20
environment and time related.</DIV>
<DIV> </DIV>
<DIV> Some data for an AS-1 can be found at <A=20
href=3D"http://www2.bc.edu/~kafka/SeismoEd_SRL/kr03_page1.html">http://www2.=
bc.edu/~kafka/SeismoEd_SRL/kr03_page1.html</A> =20
See page 6. I would expect a good quality Lehman or SG seismometer with a pe=
riod=20
of 20 sec to do better than this - the long period waves are of greater=20
amplitude and the noise is likely to be less. Regional quakes are defined as=
=20
being from 6 to 16 deg and teleseismic from 16 to 180 deg. There are several=
=20
regions in the teleseismic range which have different characteristic and man=
y=20
different paths possible</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Long period seismonitor sensitivity ?
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sat, 18 Mar 2006 15:22:54 +0000
Hi Chris
Thanks for that info. I plan in the future to build two long period
seismonitors, one that is 1Hz and other that is 0.1Hz (SG seismonitor,
if possible) to monitor teleseimic earthquakes. With my current hardware
i can detect most regonal earthquakes that are 4.5Mb or larger along
with local earthquakes that i detect alot of.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Long period seismonitor sensitivite ?
From: Barry Lotz barry_lotz@.............
Date: Sat, 18 Mar 2006 07:37:48 -0800 (PST)
Hi Jon
S-T Morrissey sent PSN an email on 13 nov 1999 which had an equation relating magnitude,amplitude, period and distance. I made a log-log plot of this, the x-axis was distance (km) the y-axis was counts. Each line was one magnitude. It was then interesting to plot my events on this sheet to see how they co-related. The problem I see is one of sensor gain and a/d converter. If you increase the gain to get more distant events then you clip a larger event that may come. I think a higher count a/d with lower gain would give a larger event magnitude range but I'm not sure where the noise begins to enter the picture. this will depent on the electronics & site.
regards
Barry
regards
Barry
Jón Frímann <jonfr500@.........> wrote:
Hi all
With long period seismonitor what is the smallest earthquake that can be
detected with such seismonitor ? Then i mean in teleseismic earthquake
range.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
<DIV>Hi Jon</DIV> <DIV> S-T Morrissey sent PSN an email on 13 nov 1999 which had an equation relating magnitude,amplitude, period and distance. I made a log-log plot of this, the x-axis was distance (km) the y-axis was counts. Each line was one magnitude. It was then interesting to plot my events on this sheet to see how they co-related. The problem I see is one of sensor gain and a/d converter. If you increase the gain to get more distant events then you clip a larger event that may come. I think a higher count a/d with lower gain would give a larger event magnitude range but I'm not sure where the noise begins to enter the picture. this will depent on the electronics & site.</DIV> <DIV>regards</DIV> <DIV>Barry</DIV> <DIV> </DIV> <DIV>regards</DIV> <DIV>Barry<BR><BR><B><I>Jón Frímann <jonfr500@.........></I></B> wrote:</DIV> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Hi
all<BR><BR>With long period seismonitor what is the smallest earthquake that can be<BR>detected with such seismonitor ? Then i mean in teleseismic earthquake<BR>range.<BR><BR>Regards.<BR>-- <BR>Jón Frímann Jónsson<BR>http://www.jonfr.com<BR>http://www.simnet.is/jonfr500/earthquake/<BR><BR>__________________________________________________________<BR></BLOCKQUOTE>
Subject: RE: Drum recorders
From: "Steve Hammond" shammon1@.............
Date: Sat, 18 Mar 2006 09:35:43 -0800
Hi Kareem, I'll talk photos today and send them to you and Paul in Colorado.
Let's take this off-line, you can contact me at
shammon1@..............
To the members, I have two people that have contacted me for the drums. If
they are not taken I'll send another note to the list.
Thanks, Steve Hammond
-----Original Message-----
From: psn-l-request@..............
[mailto:psn-l-request@................. Behalf Of Kareem at HeyJooJoo
Sent: Friday, March 17, 2006 6:30 PM
To: psn-l@..............
Subject: RE: Drum recorders
Hi Steve,
I'm interested but how do we get a hold of you off line? Contact me via my
website: http://www.heyjoojoo.com/contact/feedback.php
Kareem
El Sobrante (The Leftovers), Ca
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Steve Hammond
Sent: Friday, March 17, 2006 10:49 AM
To: psn-l@..............
Subject: Drum recorders
I have two 75-100 lbs. drum recorders that I have been given over the years.
I would like to pass them on to somebody on the PSN list. They both need ink
pen / supply tanks. I live in the Santa Cruz area. If you are interested,
please send my a note off-line.
Regards, Steve Hammond PSN San Jose, Aptos, CA
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re[2]: Long period seismonitor sensitivity ?
From: Angel sismos@..............
Date: Sun, 19 Mar 2006 13:47:03 +0000
Hello Jón,
I have been following your progress in Iceland with interest, thanks
for all of the information.
I see that you mention that you want to build some long period devices
and I would to invite you (and anyone else) to the FMES list. We have
not been too active but the FMES (Fluid Mass Electolytic Seismograph)
is very easy to build and is good from about 5 hz to 50 seconds. It
has no moving parts except the fluid, which is water, anti-freeze and
a foam reducer.
You can join the list at http://groups.yahoo.com/group/fmes/
You can see some of the traces of different FMESes at
http://64.116.183.133/FMES/welcome.html
http://64.116.183.133/welcome.html
http://www.regioweer.info/seismo.php
two of those are mine and the other belongs to Marchal
Dave, Chris, Marchal and myself have working systems and I plan to
build more, we would welcome other to make some of these device so
that we can learn more faster and have more ideas come to all of use.
As the Perl perople say, "There is more than one way to do it"
regards,
Angel
Saturday, March 18, 2006, 3:22:54 PM, you wrote:
> Hi Chris
> Thanks for that info. I plan in the future to build two long period
> seismonitors, one that is 1Hz and other that is 0.1Hz (SG seismonitor,
> if possible) to monitor teleseimic earthquakes. With my current hardware
> i can detect most regonal earthquakes that are 4.5Mb or larger along
> with local earthquakes that i detect alot of.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Re[2]: Long period seismonitor sensitivity ?
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Sun, 19 Mar 2006 23:07:35 +0000
Hi Angel
I am happy to know that somebody is taking intrest in my earthquake
recordings. I don't get many large earthquakes, but i get alot of
smaller earthquakes. That is why i want to build teleseismic station, to
monitor the large distant earthquakes that happen, also to be able to
monitor regonal earthquakes better. I also plan to use the seismonitor
to monitor volcano activie better, since my current geophone is limited
by 2Hz cutoff. But volcano eruption tremors can go alot lower then that.
I am not ready for fluid seismonitors yet, but i find the consept
intresting. Since i have to learn more about normal seismonitors before
i can start to understand the working of a fluid seismonitors.
Everything takes time and i plan to take a good time to learn this type
of science. I also have limited space for seismonitors. As can been seen
on the noise of my geophone graphs.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: geophone location
From: "Geoffrey" gmvoeth@...........
Date: Sun, 19 Mar 2006 21:20:40 -0700
Hello;
Am I the only one or do others of you
out there have geophones in crowded
locations like this:
http://users.isp.com/gmvoethb293690/AJAZUSA.JPG
Regards;
gmvoeth
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: geophone location
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 20 Mar 2006 05:14:04 +0000
Hi Geoffrey
I live in a small town, with about ~680 ppl liveing in it. There isn't
alot of issue that i deal with. But car and other motor driven noise is
modrate and not exessive. I have my geophone inside to shield it from
weather noise. You can see the town where i live here
http://www.ismennt.is/not/jonasg/0landid/jg02/hvammstangi/hvammstangi-93-18507.jpg
The block where i live is North of the picture (left part of the
picture). It is the block north (with a white walls and a brown type of
roof) of the house with the two red roofs. This picture is a bit old,
few buildings are missing from it. I hope that you can find it, but this
is the town where i live.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: geophone location
From: ian ian@...........
Date: Mon, 20 Mar 2006 09:14:50 +0000
not to be out done(!), here's my location:
http://www.gohawaiian.net/northrigSatPic.jpg The pin points to my
house. Despite it all, I still get loads of noise from my 3 neighbours,
wind and the oceans. The gash behind my house is a pleasant narrow
valley, with a 6ft wide river (burn).
One day I'll dig a deep hole and build a proper vault.
Ian
Jón Frímann wrote:
>Hi Geoffrey
>
>I live in a small town, with about ~680 ppl liveing in it. There isn't
>alot of issue that i deal with. But car and other motor driven noise is
>modrate and not exessive. I have my geophone inside to shield it from
>weather noise. You can see the town where i live here
>http://www.ismennt.is/not/jonasg/0landid/jg02/hvammstangi/hvammstangi-93-18507.jpg
>
>The block where i live is North of the picture (left part of the
>picture). It is the block north (with a white walls and a brown type of
>roof) of the house with the two red roofs. This picture is a bit old,
>few buildings are missing from it. I hope that you can find it, but this
>is the town where i live.
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Unidentified Signal
From: "Geoffrey" gmvoeth@...........
Date: Mon, 20 Mar 2006 20:31:00 -0700
Hello PSN:
This seems to be an EQ but I can not get any confirmation.
Does anyone concurr ?
http://users.isp.com/gmvoethb293690/UEQ.BMP
http://users.isp.com/gmvoethb293690/UEQ.WAV
http://users.isp.com/gmvoethb293690/UEQ.PSN
Regards;
gmvoeth
__________________________________________________________
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Subject: Re: Unidentified Signal
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Tue, 21 Mar 2006 03:47:20 +0000
Hi Geoffrey
You might have recored a 5.0Mb earthquake in Mexico, see here
http://www.emsc-csem.org/index.php?page=current&sub=detail&id=HU976;2006
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Signal To Noise Ratio of a Seismic Sensor
From: "Geoffrey" gmvoeth@...........
Date: Sat, 25 Mar 2006 02:25:33 -0700
Hello PSN:
Can someone out there run down a list of
best ways to increase the signal to noise
ratio of a seismic sensor ?
Things like:
1. in a mass spring system use a larger mass
2. use a phased array
3. use low resistance's in the circuitry
4. use a narrow bandwidth
5. use a high Q
6. shield everything against anything not a seismic signal.
7. a high signal to noise ratio is not possible for the average amateur due to cost
it might take a bunch of amatures to pool their monies and talents to
create a decent seismic sensor, possibly such a thing is only possible
at a university where both money and talent exists.
Does any know of a system out there with the
highest signal to noise ratio...if so can we see it ?
More then likely it is in military hands
and is secret ?
In all the discussions I have seen in this group
none seem to concentrate on signal to noise ratio.
Sincerely;
gmvoeth
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: ian ian@...........
Date: Sat, 25 Mar 2006 10:19:32 +0000
I increased the s/n ratio by getting those small cubic super magnets,
arranging them in a column and have them sit inside the core of the
pickup coil. They move with the arm of the Lehman sensor (being
attached to it).
Ian
Geoffrey wrote:
> Hello PSN:
>
> Can someone out there run down a list of
> best ways to increase the signal to noise
> ratio of a seismic sensor ?
>
> Things like:
> 1. in a mass spring system use a larger mass
> 2. use a phased array
> 3. use low resistance's in the circuitry
> 4. use a narrow bandwidth
> 5. use a high Q
> 6. shield everything against anything not a seismic signal.
> 7. a high signal to noise ratio is not possible for the average
> amateur due to cost
> it might take a bunch of amatures to pool their monies and talents to
> create a decent seismic sensor, possibly such a thing is only possible
> at a university where both money and talent exists.
>
> Does any know of a system out there with the
> highest signal to noise ratio...if so can we see it ?
>
> More then likely it is in military hands
> and is secret ?
>
> In all the discussions I have seen in this group
> none seem to concentrate on signal to noise ratio.
>
> Sincerely;
> gmvoeth
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with the body of
> the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: ian ian@...........
Date: Sat, 25 Mar 2006 11:54:14 +0000
just to clarify what I said about magnets, I've drawn a simple sketch:
http://www.iasmith.com/pickup.gif
Hope that helps
Ian
Geoffrey wrote:
> Hello PSN:
>
> Can someone out there run down a list of
> best ways to increase the signal to noise
> ratio of a seismic sensor ?
>
> Things like:
> 1. in a mass spring system use a larger mass
> 2. use a phased array
> 3. use low resistance's in the circuitry
> 4. use a narrow bandwidth
> 5. use a high Q
> 6. shield everything against anything not a seismic signal.
> 7. a high signal to noise ratio is not possible for the average
> amateur due to cost
> it might take a bunch of amatures to pool their monies and talents to
> create a decent seismic sensor, possibly such a thing is only possible
> at a university where both money and talent exists.
>
> Does any know of a system out there with the
> highest signal to noise ratio...if so can we see it ?
>
> More then likely it is in military hands
> and is secret ?
>
> In all the discussions I have seen in this group
> none seem to concentrate on signal to noise ratio.
>
> Sincerely;
> gmvoeth
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with the body of
> the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: John Popelish jpopelish@........
Date: Sat, 25 Mar 2006 13:01:51 -0500
ian wrote:
> just to clarify what I said about magnets, I've drawn a simple sketch:
> http://www.iasmith.com/pickup.gif
You might crank the signal up a bit more by splitting that stack of
magnets in half, and clamping or gluing them on opposite sides of an
iron slug, with the magnets repelling each other at the attachment to
the slug. The slug should sit in the center of the coil.
The coil generates voltage in proportion to the flux that is passing
radially through the coil, and this arrangement crowds a lot more of
the flux in that direction. It also makes the total magnetic field
balanced, so that the Earth's magnetic field cannot push or pull on
the magnets as it changes. This reduces interference from things like
solar storms.
Your present design wasts a lot of flux that passes out the hole in
the coil and generates no signal. Making the change I am suggesting
might double your signal while reducing some sources of interference
and not increasing resistive noise at all.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: ChrisAtUpw@.......
Date: Sat, 25 Mar 2006 17:24:28 EST
In a message dated 25/03/2006, gmvoeth@........... writes:
Can someone out there run down a list of best ways to increase the signal to
noise
ratio of a seismic sensor?
Hi Geoff,
Wow, a BIG subject! Difficult to cover everything.
Things like:
1. in a mass spring system use a larger mass
Above about 35 gm, the intrinsic kT noise of the mass is less than
natural noise. For 'safety', use maybe 5x to 10x this as minimum.
For a spring / mass system the ends of the spring need to be straight
wires effectively clamped. The same applies to suspension systems. Good clamp
design is important.
The mass should preferably be non magnetic.
No horse shoe or open pole magnets should be mounted on the armature.
This is just asking for trouble and you will get it! Mount the sensor and
damping magnets on the baseplate and put the coils and damping plates on the arm.
Note that carefully designed 'potcore' magnets are used as the mass in some
seismometers. These do not have a high external magnetic field.
2. use a phased array
This would allow you to cancel much of the local environmental noise if
it is physically large, but it is a major undertaking.
3. use low resistance's in the circuitry
Choose the amplifier noise impedance to roughly match the sensor
resistance.
4. use a narrow bandwidth
This can be fairly critical. However it varies with the local noise and
the range of the signal that you want to detect. For local and near regional
signals you need maybe 10 to 20 Hz. For teleseismic quakes you may only need
2 to 3 Hz, or less.
In noisy situations you need properly matched fairly sharp cut-off
multipole filters.
You may also wish to provide a high pass filter to reduce VLF 1/f noise.
5. use a high Q
Oscillators for driving sensor systems need to have very good frequency
and amplitude stability.
6. shield everything against anything not a seismic signal.
Agreed, but you do need a single effective earthing point, usually
linked to the input of the first opamp where you have the minimum signal.
7. a high signal to noise ratio is not possible for the average amateur due
to cost
it might take a bunch of amateurs to pool their moneys and talents to
create a decent seismic sensor, possibly such a thing is only possible
at a university where both money and talent exists.
I disagree entirely.
Amateurs should be able to achieve instrument noise levels below their
local ambient seismic levels without great difficulty.
The more likely problems are interference, RF, magnetic or static
electric, poor earthing, poor shielding, utility supply signals and noise and local
environmental noise commonly due to wind, lightning and static electric
discharge, human activity including ordinary movement, cars, lorries and other
road traffic, trains, road and building work, quarrying, power plants, heavy
machinery, mining.... You need to try to identify the noise sources.
It may be that you need to treat your site as though it were a heavy
engineering factory and use isolating transformers and filters for supplying
your system and the computer, sealed metal cases, common point earthing and
braided screened connecting cables.
It is no accident that most seismic sites are well away from human
activity and fully encased borehole instruments are often used, buried maybe 100 m
below ground level. This eliminates a great deal of the surface and weather
related noise.
However, the design of sensor and damping systems is very important. It
is quite easy to increase the output of a system which used a coil and a
horse shoe magnet, by using a NdFeB magnet array and a smaller coil.
For a Lehman, I use two 1/4" thick mild steel plates, 3.5" long by 2"
wide. The corners are drilled to take 1/4" mild steel set screws 2.5" long with
mild steel washers and nuts. The two plates are held maybe 3/4" to 1" apart
for a sensor, using three nuts on every bolt. A bolt is firmly secured to one
plate using a nut. The second plate is mounted in between pairs of nuts on
the free thread, to allow the separation of the plates to be adjusted. Four
NdFeB magnets 1/8" thick by 1" square are mounted on the inside faces of the
plates. A N+S pair on one face is opposed by a S+N pair on the other. The
sensor coil is mounted in the high intensity magnetic field in the centre.
This construction gives quite an effective magnetic and electrostatic
screen around the coil. The external stray field is low. The sensitivity is
high due to the high field and the response is reasonably linear. If you use
rectangular instead of round coils, it can be made very highly linear over
+/-1/2" movement.
For induced current damping, I use four NdFeB bar magnets 1"x1/2"x1/4"
thick in two opposing squares, with the same 1/4" steel plate mounting. I use
a copper damping plate, 1/16" to 1/8" thick as appropriate, a bit over 2"
wide and 2.5" free length. This allows the arm to swing +/-1/2" without the edge
of the copper plate overlapping the edge of the 1" magnet square. The N+S
join of the magnet pairs is set perpendicular to the direction of motion. The
damping is adjusted by varying by the length of copper tongue overlapping the
magnet square and also by varying the separation of the 1/4" mild steel
plates and hence the magnet separations.
Does any know of a system out there with the
highest signal to noise ratio...if so can we see it ?
More then likely it is in military hands and is secret ?
More likely to be a commercial secret of the various seismometer
manufacturers! It takes quite a bit of effort to get the instrument noise below the
minimum earth noise levels. However, unless you are very fortunate with your
site, you are very unlikely to see seismic noise levels even approaching that
low.
Try either wedging your sensor in a fixed position or substituting a
resistor for it and running the whole system for 24 hrs on a weekday. This
should demonstrate the amplitude and timing of many interfering signals. But it
won't pick up sensor movement due to drafts, local magnetic field changes
(including the earth, your refrigerators, car, bicycle or mowing machine), ground
movement or tilt, insects or animals. Then you have the interesting task of
identifying these sources and eliminating the effects. Compare the signals and
timing with an active trace taken a seismically quiet day.
Get onto the www and see how ham radio operators deal with earthing in
your area, also the utility company. There are large areas of the US where the
rocks and soils are dry and have very poor electrical conductivity. Your
house or mobile home wiring may be sticking way up above the effective local
'earth' plane.
For noise coming in through the utility wiring, you can provide a
filter, but check that this has a good rejection from a few hundred Hz up and is
not simply an RF filter. The next stage is to use a 1:1 isolating transformer
with a metal case and an electrostatic screen in between the windings.
Consider providing a separate Earth for the screen, the case and the electronics.
The more extreme alternative is to use two batteries, one to drive the
equipment and a laptop computer while the other is charged on a separate power
circuit. An alternative is to use a large ferrite core transformer, similar to that
in a TV set, to provide a 15 kHz isolated charging circuit. You can also use
optical or radio links to transfer data to and from the phone system.
Hope that these comments / suggestions are of some help.
Regards,
Chris Chapman
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<DIV>In a message dated 25/03/2006, gmvoeth@........... writes:</DIV>
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<DIV>Hi Geoff,</DIV>
<DIV> </DIV>
<DIV> Wow, a BIG subject! Difficult to cover=20
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like:<BR>1. in a mass spring system use a larger mass</FONT></BLOCKQUOTE>
<DIV> Above about 35 gm, the intrinsic kT noise of th=
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<DIV> For a spring / mass system the ends of the spri=
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<DIV> The mass should preferably be non magnetic.</DI=
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<DIV> No horse shoe or open pole magnets should be=20
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will get it!</EM></STRONG> Mount the sensor and damping magnets on the basep=
late=20
and put the coils and damping plates on the arm. Note that carefully=20
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do not have a high external magnetic field.</DIV>
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phased array</FONT></BLOCKQUOTE>
<DIV> This would allow you to cancel much of the=20
local environmental noise if it is physically large, but it is a m=
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undertaking. </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>3. use=20
low resistance's in the circuitry</FONT></BLOCKQUOTE>
<DIV> Choose the amplifier noise impedance to=20
roughly match the sensor resistance. </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>4. use a=20
narrow bandwidth</FONT></BLOCKQUOTE>
<DIV> This can be fairly critical. However it varies=20=
with=20
the local noise and the range of the signal that you want to detect. For loc=
al=20
and near regional signals you need maybe 10 to 20 Hz. For teleseismic quakes=
you=20
may only need 2 to 3 Hz, or less.</DIV>
<DIV> In noisy situations you need properly matched=20
fairly sharp cut-off multipole filters. </DIV>
<DIV> You may also wish to provide a high pass filter=
to=20
reduce VLF 1/f noise.</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>5. use a=20
high Q</FONT></BLOCKQUOTE>
<DIV> Oscillators for driving sensor systems need to=20=
have=20
very good frequency and amplitude stability.</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>6.=20
shield everything against anything not a seismic signal.</FONT></BLOCKQUOT=
E>
<DIV> Agreed, but you do need a single effective eart=
hing=20
point, usually linked to the input of the first opamp where you have the min=
imum=20
signal. </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>7. a=20
high signal to noise ratio is not possible for the average amateur due to=20
cost<BR> it might take a bunch of amateurs to pool their money=
s=20
and talents to<BR> create a decent seismic sensor, possibly su=
ch a=20
thing is only possible<BR> at a university where both money an=
d=20
talent exists.</FONT></BLOCKQUOTE>
<DIV> I disagree entirely. </DIV>
<DIV> Amateurs should be able to achieve instrument n=
oise=20
levels below their local ambient seismic levels without great=20
difficulty. </DIV>
<DIV> The more likely problems are interference,=
RF,=20
magnetic or static electric, poor earthing, poor shielding, utility=20
supply signals and noise and local environmental noise commonly du=
e to=20
wind, lightning and static electric discharge, human activity including ordi=
nary=20
movement, cars, lorries and other road traffic, trains, road and building wo=
rk,=20
quarrying, power plants, heavy machinery, mining.... You need to try to iden=
tify=20
the noise sources.</DIV>
<DIV> It may be that you need to treat your site as=20
though it were a heavy engineering factory and use isolating transformers an=
d=20
filters for supplying your system and the computer, sealed metal cases, comm=
on=20
point earthing and braided screened connecting cables.</DIV>
<DIV> It is no accident that most seismic sites=20
are well away from human activity and fully encased borehole instrument=
s=20
are often used, buried maybe 100 m below ground level. This eliminates a gre=
at=20
deal of the surface and weather related noise. </DIV>
<DIV> </DIV>
<DIV> However, the design of sensor and damping syste=
ms=20
is very important. It is quite easy to increase the output of a system which=
=20
used a coil and a horse shoe magnet, by using a NdFeB magnet array and a sma=
ller=20
coil. </DIV>
<DIV> </DIV>
<DIV> For a Lehman, I use two 1/4" thick mild steel=20
plates, 3.5" long by 2" wide. The corners are drilled to take 1/4" mild stee=
l=20
set screws 2.5" long with mild steel washers and nuts. The two plates a=
re=20
held maybe 3/4" to 1" apart for a sensor, using three nuts on every bolt.=20
A bolt is firmly secured to one plate using a nut. The second plate is=20
mounted in between pairs of nuts on the free thread, to allow the separation=
of=20
the plates to be adjusted. Four NdFeB magnets 1/8" thick by 1" square are=20
mounted on the inside faces of the plates. A N+S pair on one face is=20
opposed by a S+N pair on the other. The sensor coil is mounted in the high=20
intensity magnetic field in the centre. </DIV>
<DIV> This construction gives quite an effective magn=
etic=20
and electrostatic screen around the coil. The external stray field is low. T=
he=20
sensitivity is high due to the high field and the response is reasonably lin=
ear.=20
If you use rectangular instead of round coils, it can be made very highly li=
near=20
over +/-1/2" movement.</DIV>
<DIV> For induced current damping, I=20
use four NdFeB bar magnets 1"x1/2"x1/4" thick in two opposing squa=
res,=20
with the same 1/4" steel plate mounting. I use a copper damping plate,=20
1/16" to 1/8" thick as appropriate, a bit over 2" wide and 2.=
5"=20
free length. This allows the arm to swing +/-1/2" without the edge of the co=
pper=20
plate overlapping the edge of the 1" magnet square. The N+S join of the magn=
et=20
pairs is set perpendicular to the direction of motion. The damping is adjust=
ed=20
by varying by the length of copper tongue overlapping the magnet square and=20=
also=20
by varying the separation of the 1/4" mild steel plates and hence the magnet=
=20
separations.</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Does any=20
know of a system out there with the<BR>highest signal to noise ratio...if=20=
so=20
can we see it ?<BR><BR>More then likely it is in military hands and is sec=
ret=20
?</FONT></BLOCKQUOTE>
<DIV> More likely to be a commercial secret of t=
he=20
various seismometer manufacturers! It takes quite a bit of effort to get the=
=20
instrument noise below the minimum earth noise levels. However, unless=20=
you=20
are very fortunate with your site, you are very unlikely to see seismic nois=
e=20
levels even approaching that low.</DIV>
<DIV></DIV>
<DIV> </DIV>
<DIV> Try either wedging your sensor in a fixed posit=
ion=20
or substituting a resistor for it and running the whole system for 24 hrs on=
a=20
weekday. This should demonstrate the amplitude and timing of many interferin=
g=20
signals. But it won't pick up sensor movement due to drafts, local magnetic=20
field changes (including the earth, your refrigerators, car, bicycle or mowi=
ng=20
machine), ground movement or tilt, insects or animals. Then you have the=20
interesting task of identifying these sources and eliminating the effects.=20
Compare the signals and timing with an active trace taken a seismically quie=
t=20
day.</DIV>
<DIV> </DIV>
<DIV> Get onto the www and see how ham radio operator=
s=20
deal with earthing in your area, also the utility company. There are large a=
reas=20
of the US where the rocks and soils are dry and have very poor electrical=20
conductivity. Your house or mobile home wiring may be sticking way up above=20=
the=20
effective local 'earth' plane. </DIV>
<DIV> </DIV>
<DIV> For noise coming in through the utility wiring,=
you=20
can provide a filter, but check that this has a good rejection from a few=20
hundred Hz up and is not simply an RF filter. The next stage is to use a 1:1=
=20
isolating transformer <STRONG>with a metal case and an electrostatic sc=
reen=20
in between the windings</STRONG>. Consider providing a separate Earth f=
or=20
the screen, the case and the electronics. The more extreme alterna=
tive=20
is to use two batteries, one to drive the equipment and a laptop computer wh=
ile=20
the other is charged on a separate power circuit. An alternative is to=20=
use=20
a large ferrite core transformer, similar to that in a TV set, to provide a=20=
15=20
kHz isolated charging circuit. You can also use optical or radio links=20=
to=20
transfer data to and from the phone system.</DIV>
<DIV> </DIV>
<DIV> Hope that these comments / suggestions are of s=
ome=20
help.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: Dave Nelson davenn@...............
Date: Sun, 26 Mar 2006 08:34:01 +1000
Agree with you John,
Ian, as shown in your drawing 1/2 of your magnets are outside the
coil area and only one side of the supporting bar. This severely reduces
the amount of voltage generated in the coils.
As to Geoffery's questions,
another good rule is ALWAYS use love noise components....
Bi-FET Op-Amps .... eg the OPA 027 and similar
series, rather 741 etc type
Metal Film resistors ... particularly are much lower noise producing than
standard carbon resistors
I have also always used coaxial cable for feedline between the sensor
and the
preamp board. and for the short period geophones ... Bury them ! even
6 inches below ground level cuts out a lot of stray RF field pickup and
other electrical noise.
cheers
Dave
At 01:01 PM 25/03/2006 -0500, you wrote:
>ian wrote:
>>just to clarify what I said about magnets, I've drawn a simple sketch:
>>http://www.iasmith.com/pickup.gif
>
>You might crank the signal up a bit more by splitting that stack of
>magnets in half, and clamping or gluing them on opposite sides of an iron
>slug, with the magnets repelling each other at the attachment to the
>slug. The slug should sit in the center of the coil.
>
>The coil generates voltage in proportion to the flux that is passing
>radially through the coil, and this arrangement crowds a lot more of the
>flux in that direction. It also makes the total magnetic field balanced,
>so that the Earth's magnetic field cannot push or pull on the magnets as
>it changes. This reduces interference from things like solar storms.
>
>Your present design wasts a lot of flux that passes out the hole in the
>coil and generates no signal. Making the change I am suggesting might
>double your signal while reducing some sources of interference and not
>increasing resistive noise at all.
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Public Seismic Network Mailing List (PSN-L)
Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: Dave Nelson davenn@...............
Date: Sun, 26 Mar 2006 08:44:02 +1000
dont ya just love typo's
As to Geoffery's questions,
another good rule is ALWAYS use love noise components....
should read .. ALWAYS use low noise components....
snip
Dave N
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Public Seismic Network Mailing List (PSN-L)
Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: ChrisAtUpw@.......
Date: Sat, 25 Mar 2006 18:45:16 EST
In a message dated 25/03/2006, davenn@............... writes:
Bi-FET Op-Amps .... eg the OPA 027 and similar
series, rather 741 etc type
Hi Dave,
Google can't find an OPA027 ! and neither can I !!
OPA27 are very low noise, but they are not Bi-FET The later types are
OPA227 LT1007 etc
In general, FET opamps have a much higher voltage noise than ordinary
transistor types. I would not use one by choice in a geophone or a coil sensor
circuit. Some of the less expensive / older types suffer from step noise -
transient level or pulsed shifts.
When you connect up a geophone, you need to wire the metal case to the
earth / shield line.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 25/03/2006, davenn@............... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2> =20
Bi-FET Op-Amps .... eg the OPA 027&nb=
sp;=20
and similar <BR>series, rather 741 etc=20
type<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Dave,</DIV>
<DIV> </DIV>
<DIV> Google can't find an OPA027 ! and neither can I=
=20
!!</DIV>
<DIV> OPA27 are very low noise, but they are not Bi-F=
ET=20
The later types are OPA227 LT1007 etc</DIV>
<DIV> In general, FET opamps have a much higher volta=
ge=20
noise than ordinary transistor types. I would not use one by choice in=20=
a=20
geophone or a coil sensor circuit. Some of the less expensive / older types=20
suffer from step noise - transient level or pulsed shifts. </DIV>
<DIV> </DIV>
<DIV> When you connect up a geophone, you need t=
o=20
wire the metal case to the earth / shield line.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: Dave Nelson davenn@...............
Date: Sun, 26 Mar 2006 15:03:46 +1000
yup Chris
jst some more typo's :)
cheers
Dave
At 06:45 PM 25/03/2006 -0500, you wrote:
>In a message dated 25/03/2006, davenn@............... writes:
> Bi-FET Op-Amps .... eg the OPA 027 and similar
>series, rather 741 etc type
>Hi Dave,
> Google can't find an OPA027 ! and neither can I !!
> OPA27 are very low noise, but they are not Bi-FET The later types are
> OPA227 LT1007 etc
> In general, FET opamps have a much higher voltage noise than ordinary
> transistor types. I would not use one by choice in a geophone or a coil
> sensor circuit. Some of the less expensive / older types suffer from step
> noise - transient level or pulsed shifts.
>
> When you connect up a geophone, you need to wire the metal case to
> the earth / shield line.
>
> Regards,
>
> Chris Chapman
>
>
>No virus found in this incoming message.
>Checked by AVG Anti-Virus.
>Version: 7.1.385 / Virus Database: 268.3.1/292 - Release Date: 24/03/2006
<html>
yup Chris<br><br>
jst some more typo's :)<br><br>
cheers<br>
Dave<br><br>
At 06:45 PM 25/03/2006 -0500, you wrote:<br><br>
<blockquote type=cite class=cite cite><font face="arial" size=2>In a
message dated 25/03/2006, davenn@............... writes:</font>
<dl>
<dd> Bi-FET Op-Amps .... eg
the OPA 027 and similar
<dd>series, rather 741 etc type
</dl>Hi Dave,<br>
Google can't find an OPA027 ! and neither can I
!!<br>
OPA27 are very low noise, but they are not Bi-FET The
later types are OPA227 LT1007 etc<br>
In general, FET opamps have a much higher voltage
noise than ordinary transistor types. I would not use one by choice in a
geophone or a coil sensor circuit. Some of the less expensive / older
types suffer from step noise - transient level or pulsed shifts. <br>
<br>
When you connect up a geophone, you need to wire the
metal case to the earth / shield line.<br>
<br>
Regards,<br>
<br>
Chris Chapman<br><br>
<br>
No virus found in this incoming message.<br>
Checked by AVG Anti-Virus.<br>
Version: 7.1.385 / Virus Database: 268.3.1/292 - Release Date:
24/03/2006</blockquote><br>
</html>
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Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: ian ian@...........
Date: Sun, 26 Mar 2006 07:56:02 +0100
sketches or pictures would be very useful for the suggested magnet
arrangements...
TIA
Ian
ChrisAtUpw@....... wrote:
> In a message dated 25/03/2006, gmvoeth@........... writes:
>
> Can someone out there run down a list of best ways to increase the
> signal to noise
> ratio of a seismic sensor?
>
> Hi Geoff,
>
> Wow, a BIG subject! Difficult to cover everything.
>
> Things like:
> 1. in a mass spring system use a larger mass
>
> Above about 35 gm, the intrinsic kT noise of the mass is less than
> natural noise. For 'safety', use maybe 5x to 10x this as minimum.
> For a spring / mass system the ends of the spring need to be
> straight wires effectively clamped. The same applies to suspension
> systems. Good clamp design is important.
> The mass should preferably be non magnetic.
> No horse shoe or open pole magnets should be mounted on the
> armature. This is just asking for trouble and you will get it! Mount
> the sensor and damping magnets on the baseplate and put the coils and
> damping plates on the arm. Note that carefully designed 'potcore'
> magnets are used as the mass in some seismometers. These do not have a
> high external magnetic field.
>
> 2. use a phased array
>
> This would allow you to cancel much of the local environmental
> noise if it is physically large, but it is a major undertaking.
>
> 3. use low resistance's in the circuitry
>
> Choose the amplifier noise impedance to roughly match the sensor
> resistance.
>
> 4. use a narrow bandwidth
>
> This can be fairly critical. However it varies with the local
> noise and the range of the signal that you want to detect. For local
> and near regional signals you need maybe 10 to 20 Hz. For teleseismic
> quakes you may only need 2 to 3 Hz, or less.
> In noisy situations you need properly matched fairly sharp cut-off
> multipole filters.
> You may also wish to provide a high pass filter to reduce VLF 1/f
> noise.
>
> 5. use a high Q
>
> Oscillators for driving sensor systems need to have very good
> frequency and amplitude stability.
>
> 6. shield everything against anything not a seismic signal.
>
> Agreed, but you do need a single effective earthing point, usually
> linked to the input of the first opamp where you have the minimum signal.
>
> 7. a high signal to noise ratio is not possible for the average
> amateur due to cost
> it might take a bunch of amateurs to pool their moneys and
> talents to
> create a decent seismic sensor, possibly such a thing is only
> possible
> at a university where both money and talent exists.
>
> I disagree entirely.
> Amateurs should be able to achieve instrument noise levels below
> their local ambient seismic levels without great difficulty.
> The more likely problems are interference, RF, magnetic or static
> electric, poor earthing, poor shielding, utility supply signals and
> noise and local environmental noise commonly due to wind, lightning
> and static electric discharge, human activity including ordinary
> movement, cars, lorries and other road traffic, trains, road and
> building work, quarrying, power plants, heavy machinery, mining....
> You need to try to identify the noise sources.
> It may be that you need to treat your site as though it were a
> heavy engineering factory and use isolating transformers and filters
> for supplying your system and the computer, sealed metal cases, common
> point earthing and braided screened connecting cables.
> It is no accident that most seismic sites are well away from human
> activity and fully encased borehole instruments are often used, buried
> maybe 100 m below ground level. This eliminates a great deal of the
> surface and weather related noise.
>
> However, the design of sensor and damping systems is very
> important. It is quite easy to increase the output of a system which
> used a coil and a horse shoe magnet, by using a NdFeB magnet array and
> a smaller coil.
>
> For a Lehman, I use two 1/4" thick mild steel plates, 3.5" long by
> 2" wide. The corners are drilled to take 1/4" mild steel set screws
> 2.5" long with mild steel washers and nuts. The two plates are held
> maybe 3/4" to 1" apart for a sensor, using three nuts on every bolt.
> A bolt is firmly secured to one plate using a nut. The second plate is
> mounted in between pairs of nuts on the free thread, to allow the
> separation of the plates to be adjusted. Four NdFeB magnets 1/8" thick
> by 1" square are mounted on the inside faces of the plates. A N+S
> pair on one face is opposed by a S+N pair on the other. The sensor
> coil is mounted in the high intensity magnetic field in the centre.
> This construction gives quite an effective magnetic and
> electrostatic screen around the coil. The external stray field is low.
> The sensitivity is high due to the high field and the response is
> reasonably linear. If you use rectangular instead of round coils, it
> can be made very highly linear over +/-1/2" movement.
> For induced current damping, I use four NdFeB bar magnets
> 1"x1/2"x1/4" thick in two opposing squares, with the same 1/4" steel
> plate mounting. I use a copper damping plate, 1/16" to 1/8" thick as
> appropriate, a bit over 2" wide and 2.5" free length. This allows the
> arm to swing +/-1/2" without the edge of the copper plate overlapping
> the edge of the 1" magnet square. The N+S join of the magnet pairs is
> set perpendicular to the direction of motion. The damping is adjusted
> by varying by the length of copper tongue overlapping the magnet
> square and also by varying the separation of the 1/4" mild steel
> plates and hence the magnet separations.
>
> Does any know of a system out there with the
> highest signal to noise ratio...if so can we see it ?
>
> More then likely it is in military hands and is secret ?
>
> More likely to be a commercial secret of the various seismometer
> manufacturers! It takes quite a bit of effort to get the instrument
> noise below the minimum earth noise levels. However, unless you are
> very fortunate with your site, you are very unlikely to see seismic
> noise levels even approaching that low.
>
> Try either wedging your sensor in a fixed position or substituting
> a resistor for it and running the whole system for 24 hrs on a
> weekday. This should demonstrate the amplitude and timing of many
> interfering signals. But it won't pick up sensor movement due to
> drafts, local magnetic field changes (including the earth, your
> refrigerators, car, bicycle or mowing machine), ground movement or
> tilt, insects or animals. Then you have the interesting task of
> identifying these sources and eliminating the effects. Compare the
> signals and timing with an active trace taken a seismically quiet day.
>
> Get onto the www and see how ham radio operators deal with
> earthing in your area, also the utility company. There are large areas
> of the US where the rocks and soils are dry and have very poor
> electrical conductivity. Your house or mobile home wiring may be
> sticking way up above the effective local 'earth' plane.
>
> For noise coming in through the utility wiring, you can provide a
> filter, but check that this has a good rejection from a few hundred Hz
> up and is not simply an RF filter. The next stage is to use a 1:1
> isolating transformer with a metal case and an electrostatic screen in
> between the windings. Consider providing a separate Earth for
> the screen, the case and the electronics. The more extreme alternative
> is to use two batteries, one to drive the equipment and a laptop
> computer while the other is charged on a separate power circuit. An
> alternative is to use a large ferrite core transformer, similar to
> that in a TV set, to provide a 15 kHz isolated charging circuit. You
> can also use optical or radio links to transfer data to and from the
> phone system.
>
> Hope that these comments / suggestions are of some help.
>
> Regards,
>
> Chris Chapman
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
sketches or pictures would be very useful for the suggested magnet
arrangements...<br>
<br>
TIA<br>
<br>
Ian<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:ChrisAtUpw@.......">ChrisAtUpw@.......</a> wrote:<br>
<blockquote cite="mid32e.cabb19.31571d1c@......." type="cite">
<meta http-equiv="Content-Type" content="text/html; ">
<meta content="MSHTML 6.00.2900.2802" name="GENERATOR">
<font id="role_document" color="#000000" face="Arial" size="2">
<div>In a message dated 25/03/2006, <a class="moz-txt-link-abbreviated" href="mailto:gmvoeth@...........">gmvoeth@...........</a> writes:</div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">Can someone out there run down a list of best ways to
increase the signal to noise<br>
ratio of a seismic sensor?</font></blockquote>
<div>Hi Geoff,</div>
<div> </div>
<div> Wow, a BIG subject! Difficult to cover everything.</div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">Things like:<br>
1. in a mass spring system use a larger mass</font></blockquote>
<div> Above about 35 gm, the intrinsic kT noise of the mass is
less than natural noise. For 'safety', use maybe 5x to 10x this as
minimum.</div>
<div> For a spring / mass system the ends of the spring need to be
straight wires effectively clamped. The same applies to suspension
systems. Good clamp design is important. </div>
<div> The mass should preferably be non magnetic.</div>
<div> No horse shoe or open pole magnets should be mounted on the
armature. <strong><em>This is just asking for trouble and you will get
it!</em></strong> Mount the sensor and damping magnets on the baseplate
and put the coils and damping plates on the arm. Note that carefully
designed 'potcore' magnets are used as the mass in some seismometers.
These do not have a high external magnetic field.</div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">2. use a phased array</font></blockquote>
<div> This would allow you to cancel much of the
local environmental noise if it is physically large, but it is a major
undertaking. </div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">3. use low resistance's in the circuitry</font></blockquote>
<div> Choose the amplifier noise impedance to roughly match the
sensor resistance. </div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">4. use a narrow bandwidth</font></blockquote>
<div> This can be fairly critical. However it varies with the
local noise and the range of the signal that you want to detect. For
local and near regional signals you need maybe 10 to 20 Hz. For
teleseismic quakes you may only need 2 to 3 Hz, or less.</div>
<div> In noisy situations you need properly matched fairly sharp
cut-off multipole filters. </div>
<div> You may also wish to provide a high pass filter to reduce
VLF 1/f noise.</div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">5. use a high Q</font></blockquote>
<div> Oscillators for driving sensor systems need to have very
good frequency and amplitude stability.</div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">6. shield everything against anything not a seismic signal.</font></blockquote>
<div> Agreed, but you do need a single effective earthing point,
usually linked to the input of the first opamp where you have the
minimum signal. </div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">7. a high signal to noise ratio is not possible for the
average amateur due to cost<br>
it might take a bunch of amateurs to pool their moneys and talents to<br>
create a decent seismic sensor, possibly such a thing is only
possible<br>
at a university where both money and talent exists.</font></blockquote>
<div> I disagree entirely. </div>
<div> Amateurs should be able to achieve instrument noise levels
below their local ambient seismic levels without great difficulty. </div>
<div> The more likely problems are interference, RF, magnetic or
static electric, poor earthing, poor shielding, utility supply signals
and noise and local environmental noise commonly due to wind, lightning
and static electric discharge, human activity including ordinary
movement, cars, lorries and other road traffic, trains, road and
building work, quarrying, power plants, heavy machinery, mining.... You
need to try to identify the noise sources.</div>
<div> It may be that you need to treat your site as though it were
a heavy engineering factory and use isolating transformers and filters
for supplying your system and the computer, sealed metal cases, common
point earthing and braided screened connecting cables.</div>
<div> It is no accident that most seismic sites are well away from
human activity and fully encased borehole instruments are often used,
buried maybe 100 m below ground level. This eliminates a great deal of
the surface and weather related noise. </div>
<div> </div>
<div> However, the design of sensor and damping systems is very
important. It is quite easy to increase the output of a system which
used a coil and a horse shoe magnet, by using a NdFeB magnet array and
a smaller coil. </div>
<div> </div>
<div> For a Lehman, I use two 1/4" thick mild steel plates, 3.5"
long by 2" wide. The corners are drilled to take 1/4" mild steel set
screws 2.5" long with mild steel washers and nuts. The two plates are
held maybe 3/4" to 1" apart for a sensor, using three nuts on every
bolt. A bolt is firmly secured to one plate using a nut. The second
plate is mounted in between pairs of nuts on the free thread, to allow
the separation of the plates to be adjusted. Four NdFeB magnets 1/8"
thick by 1" square are mounted on the inside faces of the plates. A N+S
pair on one face is opposed by a S+N pair on the other. The sensor coil
is mounted in the high intensity magnetic field in the centre. </div>
<div> This construction gives quite an effective magnetic and
electrostatic screen around the coil. The external stray field is low.
The sensitivity is high due to the high field and the response is
reasonably linear. If you use rectangular instead of round coils, it
can be made very highly linear over +/-1/2" movement.</div>
<div> For induced current damping, I use four NdFeB bar magnets
1"x1/2"x1/4" thick in two opposing squares, with the same 1/4" steel
plate mounting. I use a copper damping plate, 1/16" to 1/8" thick as
appropriate, a bit over 2" wide and 2.5" free length. This allows the
arm to swing +/-1/2" without the edge of the copper plate overlapping
the edge of the 1" magnet square. The N+S join of the magnet pairs is
set perpendicular to the direction of motion. The damping is adjusted
by varying by the length of copper tongue overlapping the magnet square
and also by varying the separation of the 1/4" mild steel plates and
hence the magnet separations.</div>
<blockquote
style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font
style="background-color: transparent;" color="#000000" face="Arial"
size="2">Does any know of a system out there with the<br>
highest signal to noise ratio...if so can we see it ?<br>
<br>
More then likely it is in military hands and is secret ?</font></blockquote>
<div> More likely to be a commercial secret of the various
seismometer manufacturers! It takes quite a bit of effort to get the
instrument noise below the minimum earth noise levels. However, unless
you are very fortunate with your site, you are very unlikely to see
seismic noise levels even approaching that low.</div>
<div> </div>
<div> Try either wedging your sensor in a fixed position or
substituting a resistor for it and running the whole system for 24 hrs
on a weekday. This should demonstrate the amplitude and timing of many
interfering signals. But it won't pick up sensor movement due to
drafts, local magnetic field changes (including the earth, your
refrigerators, car, bicycle or mowing machine), ground movement or
tilt, insects or animals. Then you have the interesting task of
identifying these sources and eliminating the effects. Compare the
signals and timing with an active trace taken a seismically quiet day.</div>
<div> </div>
<div> Get onto the www and see how ham radio operators deal with
earthing in your area, also the utility company. There are large areas
of the US where the rocks and soils are dry and have very poor
electrical conductivity. Your house or mobile home wiring may be
sticking way up above the effective local 'earth' plane. </div>
<div> </div>
<div> For noise coming in through the utility wiring, you can
provide a filter, but check that this has a good rejection from a few
hundred Hz up and is not simply an RF filter. The next stage is to use
a 1:1 isolating transformer <strong>with a metal case and
an electrostatic screen in between the windings</strong>. Consider
providing a separate Earth for the screen, the case and the
electronics. The more extreme alternative is to use two batteries, one
to drive the equipment and a laptop computer while the other is charged
on a separate power circuit. An alternative is to use a large ferrite
core transformer, similar to that in a TV set, to provide a 15 kHz
isolated charging circuit. You can also use optical or radio links to
transfer data to and from the phone system.</div>
<div> </div>
<div> Hope that these comments / suggestions are of some help.</div>
<div> </div>
<div> Regards,</div>
<div> </div>
<div> Chris Chapman</div>
</font></blockquote>
</body>
</html>
Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: ian ian@...........
Date: Sun, 26 Mar 2006 07:59:20 +0100
the magnets outside the coil are just acting as a convenient support
column for the ones that are inside. I'll start thinking about how to
get some into the other side of the coil...
Ian
Dave Nelson wrote:
>
> Agree with you John,
> Ian, as shown in your drawing 1/2 of your magnets are outside
> the coil area and only one side of the supporting bar. This severely
> reduces the amount of voltage generated in the coils.
>
> As to Geoffery's questions,
> another good rule is ALWAYS use love noise components....
>
> Bi-FET Op-Amps .... eg the OPA 027 and similar series,
> rather 741 etc type
>
> Metal Film resistors ... particularly are much lower noise
> producing than
> standard carbon resistors
>
> I have also always used coaxial cable for feedline between the
> sensor and the
> preamp board. and for the short period geophones ... Bury them !
> even 6 inches below ground level cuts out a lot of stray RF field
> pickup and other electrical noise.
>
> cheers
> Dave
>
>
>
> At 01:01 PM 25/03/2006 -0500, you wrote:
>
>> ian wrote:
>>
>>> just to clarify what I said about magnets, I've drawn a simple sketch:
>>> http://www.iasmith.com/pickup.gif
>>
>>
>> You might crank the signal up a bit more by splitting that stack of
>> magnets in half, and clamping or gluing them on opposite sides of an
>> iron slug, with the magnets repelling each other at the attachment to
>> the slug. The slug should sit in the center of the coil.
>>
>> The coil generates voltage in proportion to the flux that is passing
>> radially through the coil, and this arrangement crowds a lot more of
>> the flux in that direction. It also makes the total magnetic field
>> balanced, so that the Earth's magnetic field cannot push or pull on
>> the magnets as it changes. This reduces interference from things
>> like solar storms.
>>
>> Your present design wasts a lot of flux that passes out the hole in
>> the coil and generates no signal. Making the change I am suggesting
>> might double your signal while reducing some sources of interference
>> and not increasing resistive noise at all.
>
>
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Signal To Noise Ratio of a Seismic Sensor
From: "Geoffrey" gmvoeth@...........
Date: Sun, 26 Mar 2006 00:49:17 -0700
I am no expert at anything
but it is my understanding
you want the highest uniform magnetic
field possible and you want the
wires to move within that field
perpendicular. So to compliment
the field you will put two
horseshoe type magnets in
opposition with a gap then have
the coil in the middle with one
half cutting the N/S poles and the
other half cutting the S/N poles.
It seems best if the coil is smaller then the magnet
faces and is rectangular rather than circular.
If you could get several of those old military
magnetron magnets like they use in the
old days of electronics that are used for
Physics demonstrations today at the universities
you most probably would have the best magnet
you can get. But they look like they weigh
100 lbs each.
I cant imagine how you could safely create
a one inch gap with those monstrous magnets.
They would take off a finger or two if
you were not careful in keeping them apart.
No one talks about safety when playing
with springs and stuff so I guess no
amateurs have had any serious accidents
trying to build these seismometers.
sincerely;
gmvoeth
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re:Signal To Noise Ratio of a Seismic Sensor
From: Roger Sparks rsparks@..........
Date: Sun, 26 Mar 2006 09:27:47 -0800
Hello All,
For a good discussion of signal to noise ratio, we can begin by
separating seismic noise and instrument noise.
Seismic noise--Any motion of the ground or environment that generates a
signal on the motion detector that is not the desired quake:
1. Local movement causing ground vibrations
2. Wind or air density change, causing a change in the "float" depth of
a vertical sensing seismometer
3. Air movement around the seismometer
Instrument noise--Any condition of the sensor or electronics that
registers as data in the visual display:
1. Seismometer hinge--non-linearity or friction causes vibration
2. Electronic noise-- visible even when the seismometer is locked
3. Damper characteristics--Oil dampers will have internal fluid waves
4. Temperature changes
Some conditions affect the amount of signal captured but do not affect
the seismic signal or ground motion:
1. The size of the seismometer rest mass.
2. The period of the seismometer. Longer periods allow increased
ground motion before the seismic mass will move.
3. The damper. The damper absorbs seismic energy, and can also be
frequency sensitive or non-linear in response
After the signal is captured, the electronics can reduce or absorb the
signal:
1. Improperly set filters
2. Resistance
Each of these generally named sources of noise or signal loss can be
discussed in much greater detail.
The effects of the signal to noise ratio can be seen by looking at the
postings on the PSN website. The omnipresent microseims caused by
ocean wave action are detected by many instruments and create a waveform
which precludes recording a straight line trace. Small seismic
signals, whether generated locally or distant, should appear as higher
frequency deviations "riding" on the microseim trace. Only rarely
will the seismic signal frequency exactly match the microseim frequency
and therefore be masked as being a "greater microseism".
BW, Roger
psn-l-digest-request@.............. wrote:
> .------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> | Message 1 |
> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> Subject: Signal To Noise Ratio of a Seismic Sensor
> From: "Geoffrey" <gmvoeth@...........>
> Date: Sat, 25 Mar 2006 02:25:33 -0700
>
> Hello PSN:
>
> Can someone out there run down a list of
> best ways to increase the signal to noise
> ratio of a seismic sensor ?
>
> Things like:
> 1. in a mass spring system use a larger mass
> 2. use a phased array
> 3. use low resistance's in the circuitry
> 4. use a narrow bandwidth
> 5. use a high Q
> 6. shield everything against anything not a seismic signal.
> 7. a high signal to noise ratio is not possible for the average amateur due to cost
> it might take a bunch of amatures to pool their monies and talents to
> create a decent seismic sensor, possibly such a thing is only possible
> at a university where both money and talent exists.
>
> Does any know of a system out there with the
> highest signal to noise ratio...if so can we see it ?
>
> More then likely it is in military hands
> and is secret ?
>
> In all the discussions I have seen in this group
> none seem to concentrate on signal to noise ratio.
>
> Sincerely;
> gmvoeth
>
>
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Sensor and Damping magnets
From: ChrisAtUpw@.......
Date: Sun, 26 Mar 2006 21:52:22 EST
In a message dated 26/03/2006, gmvoeth@........... writes:
it is my understanding you want the highest uniform magnetic field possible
and you want the wires to move within that field perpendicular. So to
compliment the field you will put two horseshoe type magnets in opposition with a
gap then have
the coil in the middle with one half cutting the N/S poles and the other
half cutting the S/N poles.
It seems best if the coil is smaller then the magnet
faces and is rectangular rather than circular.
Hi Geoff, Ian,
If you could get several of those old military magnetron magnets like they
use in the old days of electronics that are used for Physics demonstrations
today at the universities you most probably would have the best magnet you can
get. But they look like they weigh 100 lbs each.
They can be used but they are very bulky and don't usually have the pole
shape that you want.
You are much better off with rectangular coils and rectangular magnets.
You need two adjacent areas of opposing high intensity field. NdFeB bar
magnets are not very expensive, but they are very powerful.
The 'I' is soft iron plate.
The 'B' are the support bolts with 3 off nuts locking the plates in
place.
The 'N' and 'S' are 1" square x 1/8" Neo magnets with poles on the
square face.
The 'CC-------CC' is a rectangular frame coil with an open centre and
maybe 3,000 to 5,000 turns, about 1" wide by 1,1/4" long. The coil overlaps the
ends of the magnets coming out of the paper. I used 4 paxolin rods and thin
sheet held together with epoxy glue to make the coil frame. Make a reinforced
hole in the centre so that you can mount the frame on a bolt in a hand drill
to wind on the wire.
Sensor. I have exaggerated the coil to magnet separation.
Magnets 1"squarex1/8" thick with poles on the square face
B B
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
B NNNNNNNNNNSSSSSSSSSS B
B B
B <- CC------------------CC -> B
B CC------------------CC B
B B
B SSSSSSSSSSNNNNNNNNNN B
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
B B
Damper. Cu is the wide copper damping plate, 1/16" to 1/8" thick
Magnets 1"x1/2"widex1/4" thick with poles on the 1"x1/2" face
View shows the 1/2"x1/4" magnet ends
B 3.5" long B Mild
Steel Plate
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 1/4" thick x 2" wide
B NNNNNSSSSS B
B <- CuCuCuCuCuCuCuCuCuCuCuCu -> B 1/4" mild steel bolts
B SSSSSNNNNN B full thread +
3 nuts
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
B B
For a Lehman, I use two 1/4" thick bright mild steel plates, 3.5" long by
2" wide. The corners are drilled to take 1/4" mild steel set screws 2.5"
long with mild steel washers and nuts. The two plates are held maybe 3/4" to 1"
apart for a sensor, using three nuts on every bolt. A bolt is firmly secured
to one plate using a nut. The second plate is mounted in between pairs of
nuts on the free thread, to allow the separation of the plates to be adjusted
and locked. Four NdFeB magnets 1/8" thick by 1" square are mounted on the
inside faces of the plates. A N+S pair on one face is opposed by a S+N pair on the
other. The sensor coil is mounted at the centre of the high intensity
magnetic field.
This construction gives quite an effective magnetic and electrostatic screen
around the coil. The external stray field is low. The sensitivity is high
due to the high field and the response is reasonably linear. If you use
rectangular instead of round coils, it can be made very highly linear over +/-1/2"
movement.
For induced current damping, I use four NdFeB bar magnets 1"x1/2"x1/4"
thick in two opposing squares, with the same 1/4" steel plate mounting, but
with a much smaller magnet separation. I use a copper damping plate, 1/16" to
1/8" thick as appropriate, a bit over 2" wide and 2.5" free length. This
allows the arm to swing +/-1/2" without the edge of the copper plate overlapping
the edge of the 1" magnet square. The N+S join of the magnet pairs is set
perpendicular to the direction of motion. The damping is adjusted by varying by
the length of copper tongue overlapping the magnet square and also by varying
the separation of the 1/4" mild steel plates and hence the magnet
separations. Most of the damping occurs close to the central N/S magnet join. This is a
very effective and easily adjusted design of damper.
I have also used soft Al damping plates, but Al is usually more strongly
paramagnetic than the copper is diamagnetic and it has a higher resistivity.
I use the damping plate to physically limit the sideways travel of the
seismometer arm. If the plate is made narrower and the arm drifts, you may get
'odd' force effects as the edge of the plate gets close to the outside edge of
the magnets. Al is usually mildly paramagnetic, but copper is usually
diamagnetic.
I can't imagine how you could safely create a one inch gap with those
monstrous magnets. They would take off a finger or two if you were not careful in
keeping them apart.
With some difficulty and great care! Neo magnets start to get dangerous
above about 1/4" thick, 1/2" square. I have a pair 2" square by 1/2" thick. I
can't put enough finger force on them to even slide them apart. I use wood
blocks and an A frame work bench. Two of these magnets will 'jump together'
if less than about a foot apart. Only ever handle ONE free magnet at a time!
No one talks about safety when playing with springs and stuff so I guess no
amateurs have had any serious accidents trying to build these seismometers.
Oh yes they do! Sean's EMails carried several warnings about dry wall
scraper spring systems.
Construction.
Cut and file the 2"x1/4" bright mild steel to length. Mark out the 3 or 4
bolt holes to choice on one plate, then clamp the two plates together and drill
all the clearance holes through both plates at the same time. Mark the plate
orientation with a centre punch. This ensures perfect bolt alignment.
Degrease, then coat the steel with acid anti rust liquid / paste, leave for ~10 min
and wipe off with a dry tissue. Let the plates dry. Mark the positions of
the magnets, nuts and washers and paint all other surfaces with Hammerite or a
similar anti rust paint.
Lightly grease the bolts, the clearance holes, exposed iron and the
nuts. Fully assemble one plate with bolts and finger tight nuts. Check that the
other plate fits on cleanly and fully tighten the nuts. Fit a second nut on
each bolt leaving about 3/4" thread between the nuts.
Lightly grease and wipe the magnet mounting spaces. Separate a magnet,
clean any dust or debris off it using gaffer sticky tape, apply it to the edge
of the steel plate and slide it into position. Check that a second magnet
has opposite top surface polarity and slide it into position. Check the
orientation of the free plate and assemble opposite polarity magnets on it - a N/S
magnet pair on one plate opposes S/N pair on the other.
Slide the free plate onto the mounting bolts, recheck the magnet
polarity, adjust the nuts to give the desired magnet gap separation and fit the lock
nuts. Wipe off any excess grease.
_http://www.amazingmagnets.com/_ (http://www.amazingmagnets.com/) and
_http://www.kjmagnetics.com/_ (http://www.kjmagnetics.com/) in the US stock
a wide range of NdFeB magnets amongst many other sources.
Geoff, you raised the question of how great a S/N ratio you can get. My
16 bit ADC gives me a 90 dB range. When I was developing my LVDT sensor, I
managed to get about 7 nano metre noise over a 6 mm linear movement with 10 Hz
bandwidth. This is not far short of 120 dB. However, my local ambient ground
noise is well over 10x this and it is strongly dependant on the weather, the
local traffic and the time of day. This is my practical concern and it is the
major limitation for a lot of 'amateur' systems. Many professional systems
use deep boreholes remote from human activity. I agree with Dave on the
desirability of burying geophones to reduce the pickup of surface noise.
With a low noise geophone / coil type amplifier, you should be able to
get quite a bit below 1 micro V input noise for 10 Hz bandwidth without using
'special' circuits. If you were prepared to build a chopper amplifier, you
would likely get below 100 nano V.
Roger Sparks commented on the presence of ocean microseisms masking
small quakes. It is possible to use a twin Tee variable width bandstop filter to
remove ~50 dB of this signal. The signals are usually quite narrow band,
although they do vary in period around the world and with time.
Regards,
Chris Chapman
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<DIV> You need two adjacent areas of opposing high=20
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<DIV> </DIV>
<DIV> The 'I' is soft iron plate. </DIV>
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<DIV><U>Sensor.</U> I have exaggerated the coil to magnet separation. </DIV>
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<DIV> B &nbs=
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<DIV> IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII=
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<DIV> B &nbs=
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<DIV> B &nbs=
p; =20
SSSSSSSSSSNNNNNNNNNN &n=
bsp; =20
B</DIV>
<DIV> IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII=
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII</DIV>
<DIV> B &nbs=
p; &n=
bsp; =
&nbs=
p; &n=
bsp; B</DIV>
<DIV> </DIV>
<DIV><U>Damper.</U> Cu is the wide copper damping plate, 1/16" to 1/8"=20
thick </DIV>
<DIV>Magnets 1"x1/2"widex1/4" thick with poles on the 1"x1/2" face</DIV>
<DIV>View shows the 1/2"x1/4" magnet ends</DIV>
<DIV> </DIV>
<DIV> B &nbs=
p; &n=
bsp; 3.5" long &nbs=
p; &n=
bsp; B =
;=20
Mild Steel Plate</DIV>
<DIV> IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII=
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII=20
1/4" thick x 2" wide</DIV>
<DIV> B &nbs=
p; &n=
bsp;NNNNNSSSSS &n=
bsp; =
B</DIV>
<DIV> B <-=20
CuCuCuCuCuCuCuCuCuCuCuCu -> B 1/4" mild ste=
el=20
bolts</DIV>
<DIV> B &nbs=
p; =20
SSSSSNNNNN =
&nbs=
p; =20
B full thread + 3 nuts</DIV>
<DIV> IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII=
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII</DIV>
<DIV> B &nbs=
p; &n=
bsp; =
&nbs=
p; &n=
bsp; =20
B</DIV>
<DIV> </DIV>
<DIV> For a Lehman, I use two 1/4" thick bright mild steel=20
plates, 3.5" long by 2" wide. The corners are drilled to take 1/4" mild stee=
l=20
set screws 2.5" long with mild steel washers and nuts. The two plates a=
re=20
held maybe 3/4" to 1" apart for a sensor, using three nuts on every bolt.=20
A bolt is firmly secured to one plate using a nut. The second plate is=20
mounted in between pairs of nuts on the free thread, to allow the separation=
of=20
the plates to be adjusted and locked. Four NdFeB magnets 1/8" thick by 1" sq=
uare=20
are mounted on the inside faces of the plates. A N+S pair on one face i=
s=20
opposed by a S+N pair on the other. The sensor coil is mounted at the centre=
of=20
the high intensity magnetic field. </DIV>
<DIV>
<DIV> This construction gives quite an effective magn=
etic=20
and electrostatic screen around the coil. The external stray field is low. T=
he=20
sensitivity is high due to the high field and the response is reasonably lin=
ear.=20
If you use rectangular instead of round coils, it can be made very highly li=
near=20
over +/-1/2" movement.</DIV>
<DIV> </DIV>
<DIV> For induced current damping, I=20
use four NdFeB bar magnets 1"x1/2"x1/4" thick in two opposing squa=
res,=20
with the same 1/4" steel plate mounting, but with a much smaller magnet=20
separation. I use a copper damping plate, 1/16" to 1/8" thick as=20
appropriate, a bit over 2" wide and 2.5" free length. This allows=20=
the=20
arm to swing +/-1/2" without the edge of the copper plate overlapping the ed=
ge=20
of the 1" magnet square. The N+S join of the magnet pairs is set perpendicul=
ar=20
to the direction of motion. The damping is adjusted by varying by the length=
of=20
copper tongue overlapping the magnet square and also by varying the separati=
on=20
of the 1/4" mild steel plates and hence the magnet separations. Most of the=20
damping occurs close to the central N/S magnet join. This is a very effectiv=
e=20
and easily adjusted design of damper. </DIV>
<DIV> I have also used soft Al damping plates, but Al=
is=20
usually more strongly paramagnetic than the copper is diamagnetic and it has=
a=20
higher resistivity. I use the damping plate to physically limit the sideways=
=20
travel of the seismometer arm. If the plate is made narrower and the arm dri=
fts,=20
you may get 'odd' force effects as the edge of the plate gets close to=20=
the=20
outside edge of the magnets. Al is usually mildly paramagnetic, but copper i=
s=20
usually diamagnetic.</DIV></DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>I can't=20
imagine how you could safely create a one inch gap with those monstrous=20
magnets. They would take off a finger or two if you were not careful in=20
keeping them apart.</FONT></BLOCKQUOTE>
<DIV> <STRONG><EM>With some difficulty and great care=
!=20
Neo magnets start to get dangerous above about 1/4" thick, 1/2"=20
square.</EM></STRONG> I have a pair 2" square by 1/2" thick. I can't put eno=
ugh=20
finger force on them to even slide them apart. I use wood blocks=20
and an A frame work bench. Two of these magnets will 'jump=20
together' if less than about a foot apart. <STRONG><EM>Only ever=20
handle ONE free magnet at a time!</EM></STRONG></DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>No one=20
talks about safety when playing with springs and stuff so I guess no amate=
urs=20
have had any serious accidents trying to build these=20
seismometers.</FONT></BLOCKQUOTE>
<DIV> Oh yes they do! Sean's EMails carried several=20
warnings about dry wall scraper spring systems.</DIV>
<DIV> </DIV>
<DIV> <U>Construction.</U><FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20
size=3D2><BR></DIV></FONT>
<DIV></DIV>
<DIV> Cut and file the 2"x1/4" bright mild steel to=20
length. Mark out the 3 or 4 bolt holes to choice on one plate, the=
n=20
clamp the two plates together and drill all the clearance holes through=
=20
both plates at the same time. Mark the plate orientation with a centre=20
punch. This ensures perfect bolt alignment. Degrease, then coat the ste=
el=20
with acid anti rust liquid / paste, leave for ~10 min and wipe off with=
a=20
dry tissue. Let the plates dry. Mark the positions of the magnets,=20
nuts and washers and paint all <U>other</U> surfaces with Hammerit=
e or=20
a similar anti rust paint.</DIV>
<DIV> Lightly grease the bolts, the clearance holes,=20
exposed iron and the nuts. Fully assemble one plate with bolts and fing=
er=20
tight nuts. Check that the other plate fits on cleanly and fully tighten the=
=20
nuts. Fit a second nut on each bolt leaving about 3/4" thread between the nu=
ts.=20
</DIV>
<DIV> Lightly grease and wipe the magnet mounting spa=
ces.=20
Separate a magnet, clean any dust or debris off it using gaffer sticky tape,=
=20
apply it to the edge of the steel plate and slide it into position. Check th=
at a=20
second magnet has opposite top surface polarity and slide it into position.=20
Check the orientation of the free plate and assemble opposite polarity magne=
ts=20
on it - a N/S magnet pair on one plate opposes S/N pair on the other. </DIV>
<DIV> Slide the free plate onto the mounting bolts,=20
recheck the magnet polarity, adjust the nuts to give the desired magnet gap=20
separation and fit the lock nuts. Wipe off any excess grease.</DIV=
>
<DIV> </DIV>
<DIV> <A=20
href=3D"http://www.amazingmagnets.com/">http://www.amazingmagnets.com/</A>&n=
bsp;=20
and <A=20
href=3D"http://www.kjmagnetics.com/">http://www.kjmagnetics.com/</A> in=
the=20
US stock a wide range of NdFeB magnets amongst many other sources.</DIV=
>
<DIV> </DIV>
<DIV> Geoff, you raised the question of how great a S=
/N=20
ratio you can get. My 16 bit ADC gives me a 90 dB range. When I was=20
developing my LVDT sensor, I managed to get about 7 nano metre noise ov=
er a=20
6 mm linear movement with 10 Hz bandwidth. This is not far short of 120=
dB.=20
However, my local ambient ground noise is well over 10x this and it is stron=
gly=20
dependant on the weather, the local traffic and the time of day. T=
his=20
is my practical concern and it is the major limitation for a lot of 'amateur=
'=20
systems. Many professional systems use deep boreholes remote from human=20
activity. I agree with Dave on the desirability of burying geophones to=
=20
reduce the pickup of surface noise.</DIV>
<DIV> With a low noise geophone / coil type amplifier=
,=20
you should be able to get quite a bit below 1 micro V input noise for 10 Hz=20
bandwidth without using 'special' circuits. If you were prepared to build a=20
chopper amplifier, you would likely get below 100 nano V.</DIV>
<DIV> Roger Sparks commented on the presence of ocean=
=20
microseisms masking small quakes. It is possible to use a twin Tee variable=20
width bandstop filter to remove ~50 dB of this signal. The signals are=20
usually quite narrow band, although they do vary in period around the world=20=
and=20
with time. </DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></DIV></FONT></BODY></HTML>
Subject: Re: Sensor and Damping magnets
From: "James Hannon" jmhannon@.........
Date: Mon, 27 Mar 2006 07:41:13 -0600
Here is another good place to buy magnets.
http://www.forcefieldmagnets.com/catalog/
Jim Hannon
--
Jim Hannon
http://www.fmtcs.com/web/jmhannon/
42,11.90N,91,39.26W
WB0TXL
--
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Sensor and Damping magnets
From: ChrisAtUpw@.......
Date: Mon, 27 Mar 2006 11:46:53 EST
In a message dated 27/03/2006, jmhannon@......... writes:
Here is another good place to buy magnets.
http://www.forcefieldmagnets.com/catalog/
Hi Jim,
They used to be quite good and inexpensive. However, they now only stock
the 0033 1"x1/2"x1/4" magnet size, not the 1" square x1/8". For these they
want $3+pp each and they only have 39 in stock.
Looking at their copper wire they want $18 for a 1lb reel of 36 awg and
they only have 4 reels in stock. This is 13,219 ft at 423 Ohm /1000 ft. They
have 6 of the 34awg reels @ $17, 8,310 ft at 266 ohms / 1000 ft. You might
need a bit over 1,500 ft for a coil.
_http://www.kjmagnetics.com/_ (http://www.kjmagnetics.com/) have to
1"x1/2"x1/4" BX084 magnets 4off @ $7.95 and the 1"square x1/8" BX0X02 magnets
4off @ $12.45
When I make suggestions for suppliers, I do try to check that they have
the products available and at a 'market' price.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 27/03/2006, jmhannon@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Here is=20
another good place to buy=20
magnets.<BR>http://www.forcefieldmagnets.com/catalog/<BR></FONT></BLOCKQUO=
TE></DIV>
<DIV></DIV>
<DIV>Hi Jim,</DIV>
<DIV> </DIV>
<DIV> They used to be quite good and inexpensive.=20
However, they now only stock the 0033 1"x1/2"x1/4" magnet size, not the 1"=20
square x1/8". For these they want $3+pp each and they only have 39 in stock.=
=20
</DIV>
<DIV> Looking at their copper wire they want $18 for=20=
a=20
1lb reel of 36 awg and they only have 4 reels in stock. This is 13,219=20=
ft=20
at 423 Ohm /1000 ft. They have 6 of the 34awg reels @ $17, 8,310 ft at=
266=20
ohms / 1000 ft. You might need a bit over 1,500 ft for a coil.</DIV>
<DIV> </DIV>
<DIV> <A=20
href=3D"http://www.kjmagnetics.com/">http://www.kjmagnetics.com/</A> ha=
ve to=20
1"x1/2"x1/4" BX084 magnets 4off @ $7.95 and the 1"square x1/8" BX0X02 magnet=
s=20
4off @ $12.45 </DIV>
<DIV> When I make suggestions for suppliers, I do try=
to=20
check that they have the products available and at a 'market' price.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Sensor and Damping magnets
From: "James Hannon" jmhannon@.........
Date: Mon, 27 Mar 2006 10:54:51 -0600
Things must have changed. I haven't done any comparisons lately but when I did I thought they had good prices on the magnets.
Sorry,
Jim Hannon
---------- Original Message ----------------------------------
From: ChrisAtUpw@.......
Reply-To: psn-l@..............
Date: Mon, 27 Mar 2006 11:46:53 EST
>
>In a message dated 27/03/2006, jmhannon@......... writes:
>
>Here is another good place to buy magnets.
>http://www.forcefieldmagnets.com/catalog/
>
>
>
>Hi Jim,
>
> They used to be quite good and inexpensive. However, they now only stock
>the 0033 1"x1/2"x1/4" magnet size, not the 1" square x1/8". For these they
>want $3+pp each and they only have 39 in stock.
> Looking at their copper wire they want $18 for a 1lb reel of 36 awg and
>they only have 4 reels in stock. This is 13,219 ft at 423 Ohm /1000 ft. They
>have 6 of the 34awg reels @ $17, 8,310 ft at 266 ohms / 1000 ft. You might
>need a bit over 1,500 ft for a coil.
>
> _http://www.kjmagnetics.com/_ (http://www.kjmagnetics.com/) have to
>1"x1/2"x1/4" BX084 magnets 4off @ $7.95 and the 1"square x1/8" BX0X02 magnets
>4off @ $12.45
> When I make suggestions for suppliers, I do try to check that they have
>the products available and at a 'market' price.
>
> Regards,
>
> Chris Chapman
>
>
--
Jim Hannon
http://www.fmtcs.com/web/jmhannon/
42,11.90N,91,39.26W
WB0TXL
--
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Sensor and Damping magnets
From: ian ian@...........
Date: Mon, 27 Mar 2006 18:10:07 +0100
I got mine from ebay... Real cheap too!
Ian
James Hannon wrote:
>Things must have changed. I haven't done any comparisons lately but when I did I thought they had good prices on the magnets.
>
>Sorry,
>Jim Hannon
>
>
>---------- Original Message ----------------------------------
>From: ChrisAtUpw@.......
>Reply-To: psn-l@..............
>Date: Mon, 27 Mar 2006 11:46:53 EST
>
>
>
>>In a message dated 27/03/2006, jmhannon@......... writes:
>>
>>Here is another good place to buy magnets.
>>http://www.forcefieldmagnets.com/catalog/
>>
>>
>>
>>Hi Jim,
>>
>> They used to be quite good and inexpensive. However, they now only stock
>>the 0033 1"x1/2"x1/4" magnet size, not the 1" square x1/8". For these they
>>want $3+pp each and they only have 39 in stock.
>> Looking at their copper wire they want $18 for a 1lb reel of 36 awg and
>>they only have 4 reels in stock. This is 13,219 ft at 423 Ohm /1000 ft. They
>>have 6 of the 34awg reels @ $17, 8,310 ft at 266 ohms / 1000 ft. You might
>>need a bit over 1,500 ft for a coil.
>>
>> _http://www.kjmagnetics.com/_ (http://www.kjmagnetics.com/) have to
>>1"x1/2"x1/4" BX084 magnets 4off @ $7.95 and the 1"square x1/8" BX0X02 magnets
>>4off @ $12.45
>> When I make suggestions for suppliers, I do try to check that they have
>>the products available and at a 'market' price.
>>
>> Regards,
>>
>> Chris Chapman
>>
>>
>>
>>
>
>--
>Jim Hannon
>http://www.fmtcs.com/web/jmhannon/
>42,11.90N,91,39.26W
>WB0TXL
>--
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with
>the body of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
>
>
>
>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
I got mine from ebay... Real cheap too!<br>
<br>
Ian<br>
<br>
James Hannon wrote:<br>
<blockquote cite="mid200603271054.AA13697360@........." type="cite">
<pre wrap="">Things must have changed. I haven't done any comparisons lately but when I did I thought they had good prices on the magnets.
Sorry,
Jim Hannon
---------- Original Message ----------------------------------
From: <a class="moz-txt-link-abbreviated" href="mailto:ChrisAtUpw@.......">ChrisAtUpw@.......</a>
Reply-To: <a class="moz-txt-link-abbreviated" href="mailto:psn-l@..............">psn-l@..............</a>
Date: Mon, 27 Mar 2006 11:46:53 EST
</pre>
<blockquote type="cite">
<pre wrap="">In a message dated 27/03/2006, <a class="moz-txt-link-abbreviated" href="mailto:jmhannon@.........">jmhannon@.........</a> writes:
Here is another good place to buy magnets.
<a class="moz-txt-link-freetext" href="http://www.forcefieldmagnets.com/catalog/">http://www.forcefieldmagnets.com/catalog/</a>
Hi Jim,
They used to be quite good and inexpensive. However, they now only stock
the 0033 1"x1/2"x1/4" magnet size, not the 1" square x1/8". For these they
want $3+pp each and they only have 39 in stock.
Looking at their copper wire they want $18 for a 1lb reel of 36 awg and
they only have 4 reels in stock. This is 13,219 ft at 423 Ohm /1000 ft. They
have 6 of the 34awg reels @ $17, 8,310 ft at 266 ohms / 1000 ft. You might
need a bit over 1,500 ft for a coil.
_<a class="moz-txt-link-freetext" href="http://www.kjmagnetics.com/_">http://www.kjmagnetics.com/_</a> (<a class="moz-txt-link-freetext" href="http://www.kjmagnetics.com/">http://www.kjmagnetics.com/</a>) have to
1"x1/2"x1/4" BX084 magnets 4off @ $7.95 and the 1"square x1/8" BX0X02 magnets
4off @ $12.45
When I make suggestions for suppliers, I do try to check that they have
the products available and at a 'market' price.
Regards,
Chris Chapman
</pre>
</blockquote>
<pre wrap=""><!---->
--
Jim Hannon
<a class="moz-txt-link-freetext" href="http://www.fmtcs.com/web/jmhannon/">http://www.fmtcs.com/web/jmhannon/</a>
42,11.90N,91,39.26W
WB0TXL
--
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
To leave this list email <a class="moz-txt-link-abbreviated" href="mailto:PSN-L-REQUEST@..............">PSN-L-REQUEST@..............</a> with
the body of the message (first line only): unsubscribe
See <a class="moz-txt-link-freetext" href="http://www.seismicnet.com/maillist.html">http://www.seismicnet.com/maillist.html</a> for more information.
</pre>
</blockquote>
</body>
</html>
Subject: Re: Sensor and Damping magnets
From: Bobhelenmcclure@.......
Date: Mon, 27 Mar 2006 14:54:12 EST
I highly recommend the following magnets:
_http://www.gaussboys.com_ (http://www.gaussboys.com)
Block #18
Shape: Block
Size: 50mm x 18mm x 6mm
Plating: Nickel
Surface Gauss: 2900
Material Grade: N38
Strength: 70 lbs
Price: $5.00 each
Place pairs on quarter-inch or thicker steel plates and hold the plates
apart with stove bolts. Assemble very carefully, using a thick shim to hold the
gap, and then jack the gap open with the bolts to release the shim. Wear heavy
gloves! For a gap of 0.250 inches, you get a field of 8000 gauss. A
rectangular coil of 1100 turns yields 85v-s/m output. You won't need separate damping
magnets. A shunt resistor will provide the damping.
Bob
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV> I highly recommend the following magnets:</DIV>
<DIV> </DIV>
<DIV><A href=3D"http://www.gaussboys.com">http://www.gaussboys.com</A><BR>Bl=
ock=20
#18 <BR>Shape: Block <BR>Size: 50mm x 18mm x 6mm <BR>Plating: Nickel <BR>Sur=
face=20
Gauss: 2900 <BR>Material Grade: N38 <BR>Strength: 70 lbs <BR>Price: $5.00=20
each</DIV>
<DIV> </DIV>
<DIV>Place pairs on quarter-inch or thicker steel plates and hold the plates=
=20
apart with stove bolts. Assemble very carefully, using a thick shim to hold=20=
the=20
gap, and then jack the gap open with the bolts to release the shim. Wear hea=
vy=20
gloves! For a gap of 0.250 inches, you get a field of 8000 gauss. A rectangu=
lar=20
coil of 1100 turns yields 85v-s/m output. You won't need separate damping=20
magnets. A shunt resistor will provide the damping.</DIV>
<DIV> </DIV>
<DIV>Bob</DIV></FONT></BODY></HTML>
Subject: Weeks or month system ?
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Mon, 27 Mar 2006 22:32:15 +0000
Hi all
I am wondering if it is better for me to put the files with the
earthquakes that i record in week long system or a month long type of
system like i have now.
I am wondering about this becose i will get more then a 100 files (z,n,e
channels) in one folder if i have it in a month type system. I am also
unsure how well winquake is going to handle huge number of files. Becose
one day i will see a massive earthquake swarm and record large number of
earthquakes.
I also wonder what system other pepole here have on earthquake
recordings time and dates.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Sensor and Damping magnets
From: ChrisAtUpw@.......
Date: Mon, 27 Mar 2006 22:47:04 EST
In a message dated 27/03/2006, Bobhelenmcclure@....... writes:
Place pairs on quarter-inch or thicker steel plates and hold the plates
apart with stove bolts. Assemble very carefully, using a thick shim to hold the
gap, and then jack the gap open with the bolts to release the shim. Wear heavy
gloves! For a gap of 0.250 inches, you get a field of 8000 gauss. A
rectangular coil of 1100 turns yields 85v-s/m output. You won't need separate damping
magnets. A shunt resistor will provide the damping.
Hi Bob,
What are 'stove bolts' please?
You may need rather thicker plate than 1/4" with two side by side 18 mm
x 6 mm thick magnets. The 5 mm plate that I used at first was only just thick
enough to take the flux of the 1/2" x 1/4" thick magnets.
Are you using a pair of magnets on one plate and then putting a bare
iron plate over the top, or do you use four magnets on two plates? I have found
using four magnets gives a more constant central field. It also allows a bit
more thread to fit the two central nuts.
The reason why I do not use this sort of damping is that I want the
damping and the sensitivity to be independent. The damping that you need is a
function of the period. Setting up a system where the sensitivity and the
damping are both a function of the period is a bit more difficult the second time.
I use the wide copper damping plate as a mechanical stop. The plate edge
can never move into the high field region at the edge of the magnets. If
your coil drifted off the magnet, the damping would go to zero. I have also had
some variable force effects when the copper wire is close to the edge of a
magnet. Not all copper wire seems to have the same diamagnetic properties.
Is the 85V/m/sec figure correct? It does not sound very high.
Regards,
Chris Chapman
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<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
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face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 27/03/2006, Bobhelenmcclure@....... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>
<DIV></DIV>
<DIV>Place pairs on quarter-inch or thicker steel plates and hold the plat=
es=20
apart with stove bolts. Assemble very carefully, using a thick shim to hol=
d=20
the gap, and then jack the gap open with the bolts to release the shim. We=
ar=20
heavy gloves! For a gap of 0.250 inches, you get a field of 8000 gauss. A=20
rectangular coil of 1100 turns yields 85v-s/m output. You won't need separ=
ate=20
damping magnets. A shunt resistor will provide the=20
damping.</DIV></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Bob,</DIV>
<DIV> </DIV>
<DIV> What are 'stove bolts' please?</DIV>
<DIV> </DIV>
<DIV> You may need rather thicker plate than 1/4" wit=
h=20
two side by side 18 mm x 6 mm thick magnets. The 5 mm plate that I used=
at=20
first was only just thick enough to take the flux of the 1/2" x 1/4" thick=20
magnets.</DIV>
<DIV> </DIV>
<DIV> Are you using a pair of magnets on one plate an=
d=20
then putting a bare iron plate over the top, or do you use four magnets=
on=20
two plates? I have found using four magnets gives a more constant central fi=
eld.=20
It also allows a bit more thread to fit the two central nuts.</DIV>
<DIV> </DIV>
<DIV> The reason why I do not use this sort of dampin=
g is=20
that I want the damping and the sensitivity to be independent. The damping t=
hat=20
you need is a function of the period. Setting up a system where the sensitiv=
ity=20
and the damping are both a function of the period is a bit more difficult th=
e=20
second time.</DIV>
<DIV> </DIV>
<DIV> I use the wide copper damping plate as a mechan=
ical=20
stop. The plate edge can never move into the high field region at the e=
dge=20
of the magnets. If your coil drifted off the magnet, the damping would=20=
go=20
to zero. I have also had some variable force effects when the copper wire is=
=20
close to the edge of a magnet. Not all copper wire seems to have the sa=
me=20
diamagnetic properties.</DIV>
<DIV> </DIV>
<DIV> Is the 85V/m/sec figure correct? It does not so=
und=20
very high. </DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: RE: Sensor and Damping magnets
From: "Jack Ivey" ivey@..........
Date: Tue, 28 Mar 2006 09:51:45 -0500
Chris,
=20
>The 5 mm plate that I used at first was only just thick enough to take
the flux of the 1/2" x 1/4" thick magnets.
Did you calculate this or measure it somehow?
=20
Thanks,
Jack
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<div class=3DSection1>
<div>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Chris,<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dblack face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:black'> <o:p></o:p></span></font></p>=
</div>
<div>
<p class=3DMsoNormal><font size=3D2 color=3Dblack face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:black'> </span></font><font size=3D2
color=3Dnavy face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:navy'>></span></font><font size=3D2 color=3Dblack =
face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial;color:black'>The 5 mm plate =
that I
used at first was only just thick enough to take the flux of the =
1/2" x
1/4" thick magnets.<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D3 color=3Dnavy face=3D"Times New =
Roman"><span
style=3D'font-size:12.0pt;color:navy'>Did you calculate this or measure =
it
somehow?<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Thanks,<o:p></o:p></span></font></p>=
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Jack<o:p></o:p></span></font></p>
</div>
</div>
</body>
</html>
Subject: Re: Sensor and Damping magnets
From: Bobhelenmcclure@.......
Date: Tue, 28 Mar 2006 16:54:23 EST
Hi Chris,
Take a look at
_http://www.jclahr.com/science/psn/mcclure/horiz.html_
(http://www.jclahr.com/science/psn/mcclure/horiz.html)
for my magnet design. This page shows different sized magnets, but 2" by 3"
by 1/4" steel plates for the Gaussboys blk18 magnets work ok, with only slight
saturation.
I have no problems with sensitivity vs damping. My coil resistance is 340
ohms, and critical damping is achieved with ~25,000 ohms shunt resistance.
Regarding output sensitivity, the formula is V=BLnv, where B is magnetic
field in Teslas, L is the effective length of wire per turn (in meters)
cutting the magnetic field lines, n is the number of turns, and v is the velocity,
in meters per second.
The L per turn is twice the length of the Gaussboys magnets , so L=0.1m.
Let n=1100, B=0.8T, and v=1.0 m/s. This gives a sensitivity of 88v-s/m.
The biggest problem I have with this design is the diamagnetism of the
copper wire. Having a core of acrylic plastic for the coil and an outer plate of
acrylic plastic helps to reduce net diamagnetic force on the coil assembly,
since the plastic is also diamagnetic.
Bob
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e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>Hi Chris,</DIV>
<DIV> </DIV>
<DIV> Take a look at </DIV>
<DIV> </DIV>
<DIV><A=20
href=3D"http://www.jclahr.com/science/psn/mcclure/horiz.html">http://www.jcl=
ahr.com/science/psn/mcclure/horiz.html</A></DIV>
<DIV> </DIV>
<DIV>for my magnet design. This page shows different sized magnets, but 2" b=
y 3"=20
by 1/4" steel plates for the Gaussboys blk18 magnets work ok, with only slig=
ht=20
saturation.</DIV>
<DIV> </DIV>
<DIV> I have no problems with sensitivity vs damping. My coil resistan=
ce=20
is 340 ohms, and critical damping is achieved with ~25,000 ohms shunt=20
resistance.</DIV>
<DIV> </DIV>
<DIV> Regarding output sensitivity, the formula is V=3DBLnv, where B i=
s=20
magnetic field in Teslas, L is the effective length of wire per turn (in met=
ers)=20
cutting the magnetic field lines, n is the number of turns, and v is the=20
velocity, in meters per second.</DIV>
<DIV> </DIV>
<DIV> The L per turn is twice the length of the Gaussboys magnets , so=
=20
L=3D0.1m. Let n=3D1100, B=3D0.8T, and v=3D1.0 m/s. This gives a sensitivity=20=
of=20
88v-s/m.</DIV>
<DIV> </DIV>
<DIV> The biggest problem I have with this design is the diamagnetism=20=
of=20
the copper wire. Having a core of acrylic plastic for the coil and an outer=20
plate of acrylic plastic helps to reduce net diamagnetic force on the coil=20
assembly, since the plastic is also diamagnetic.</DIV>
<DIV> </DIV>
<DIV>Bob</DIV></FONT></BODY></HTML>
Subject: Re: Sensor and Damping magnets
From: ChrisAtUpw@.......
Date: Tue, 28 Mar 2006 17:30:42 EST
In a message dated 28/03/2006, Bobhelenmcclure@....... writes:
The biggest problem I have with this design is the diamagnetism of the
copper wire. Having a core of acrylic plastic for the coil and an outer plate of
acrylic plastic helps to reduce net diamagnetic force on the coil assembly,
since the plastic is also diamagnetic.
Hi Bob,
Not all Copper wire is diamagnetic! It was because I had noticed force
effects when windings were near or over the edges of the magnets that I used
the 1" square magnets and the narrower coils.
Regards,
Chris
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<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
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e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 28/03/2006, Bobhelenmcclure@....... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>The=20
biggest problem I have with this design is the diamagnetism of the copper=20
wire. Having a core of acrylic plastic for the coil and an outer plate of=20
acrylic plastic helps to reduce net diamagnetic force on the coil assembly=
,=20
since the plastic is also diamagnetic.</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Bob,</DIV>
<DIV> </DIV>
<DIV> Not all Copper wire is diamagnetic! It was beca=
use=20
I had noticed force effects when windings were near or over the edges o=
f=20
the magnets that I used the 1" square magnets and the narrower coils.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris</DIV></FONT></BODY></HTML>
Subject: RE: Sensor and Damping magnets
From: "Jack Ivey" ivey@..........
Date: Tue, 28 Mar 2006 17:38:45 -0500
>The biggest problem I have with this design is the diamagnetism of the
copper wire.=20
=20
How does this manifest itself? Does the coil get pushed out of the
slot?
=20
>Having a core of acrylic plastic for the coil and an outer plate of
acrylic plastic helps to reduce net diamagnetic force on the=20
>coil assembly, since the plastic is also diamagnetic.
=20
How does this help?
=20
Thanks,
Jack
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<div class=3DSection1>
<div>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>></span></font><font size=3D2
color=3Dblack face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:black'>The biggest problem I have with this design is the =
diamagnetism of
the copper wire. </span></font><font size=3D2 color=3Dnavy =
face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial;color:navy'><o:p></o:p></span=
></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>How does this manifest =
itself? Does the
coil get pushed out of the slot?<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>></span></font><font size=3D2
color=3Dblack face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:black'>Having a core of acrylic plastic for the coil and an outer =
plate
of acrylic plastic helps to reduce net diamagnetic force on the =
</span></font><font
size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:navy'><o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>></span></font><font size=3D2
color=3Dblack face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:black'>coil assembly, since the plastic is also =
diamagnetic.</span></font><font
size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:navy'><o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>How does this =
help?<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Thanks,<o:p></o:p></span></font></p>=
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Jack<o:p></o:p></span></font></p>
</div>
</div>
</body>
</html>
Subject: RE: Sensor and Damping magnets
From: "Jack Ivey" ivey@..........
Date: Tue, 28 Mar 2006 17:38:45 -0500
>The biggest problem I have with this design is the diamagnetism of the
copper wire.=20
=20
How does this manifest itself? Does the coil get pushed out of the
slot?
=20
>Having a core of acrylic plastic for the coil and an outer plate of
acrylic plastic helps to reduce net diamagnetic force on the=20
>coil assembly, since the plastic is also diamagnetic.
=20
How does this help?
=20
Thanks,
Jack
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leftmargin=3D7 topmargin=3D7 rightMargin=3D7>
<div class=3DSection1>
<div>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>></span></font><font size=3D2
color=3Dblack face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:black'>The biggest problem I have with this design is the =
diamagnetism of
the copper wire. </span></font><font size=3D2 color=3Dnavy =
face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial;color:navy'><o:p></o:p></span=
></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>How does this manifest =
itself? Does the
coil get pushed out of the slot?<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>></span></font><font size=3D2
color=3Dblack face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:black'>Having a core of acrylic plastic for the coil and an outer =
plate
of acrylic plastic helps to reduce net diamagnetic force on the =
</span></font><font
size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:navy'><o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>></span></font><font size=3D2
color=3Dblack face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:black'>coil assembly, since the plastic is also =
diamagnetic.</span></font><font
size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial;
color:navy'><o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>How does this =
help?<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Thanks,<o:p></o:p></span></font></p>=
<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>Jack<o:p></o:p></span></font></p>
</div>
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</html>
Subject: Geophone and long time of vibrations
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Tue, 28 Mar 2006 23:49:32 +0000
Hi all
What does long period of vibrations from wind and ocen wave have on the
geophone type that i have. I am wondering about the effects becose there
is going to be hig wind for the next few days due to a storm that is
passing over Iceland. I don't plan to take the geophone offline.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Geophone and long time of vibrations
From: ChrisAtUpw@.......
Date: Tue, 28 Mar 2006 19:17:00 EST
In a message dated 29/03/2006, jonfr500@......... writes:
What does long period of vibrations from wind and ocean wave have on the
geophone type that i have. I am wondering about the effects because there
is going to be high wind for the next few days due to a storm that is
passing over Iceland. I don't plan to take the geophone offline.
Hi Jon,
Generally a large increase in the background noise. You may also see
particular frequencies excited due to buildings, cavities like corridors,
ventilation shafts, vertical poles.... increased sea waves.... You don't have trees
do you?
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 29/03/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>What=20
does long period of vibrations from wind and ocean wave have on=20
the<BR>geophone type that i have. I am wondering about the effects because=
=20
there<BR>is going to be high wind for the next few days due to a storm tha=
t=20
is<BR>passing over Iceland. I don't plan to take the geophone=20
offline.<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> Generally a large increase in the background no=
ise.=20
You may also see particular frequencies excited due to buildings, cavities l=
ike=20
corridors, ventilation shafts, vertical poles.... increased sea waves.... Yo=
u=20
don't have trees do you?</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Geophone and long time of vibrations
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Wed, 29 Mar 2006 00:26:51 +0000
Hi Chris
I did type this in wrong. What i ment what effect does long perid
vibration have on the geophone componment, the coil, springs and so on.
I know about the background noise, it is clearly visable on my online
graphs at the moment. But this is going to be long and hig frequancy
vibration becose of the wind and problay for some part of the ocen wave
hitting the beach.
There are not many trees near the house. There are few, but nothing that
sheilds the house from the wind.
>
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Geophone and long time of vibrations
From: ChrisAtUpw@.......
Date: Tue, 28 Mar 2006 20:51:12 EST
In a message dated 29/03/2006, jonfr500@......... writes:
What i meant what effect does long period
vibration have on the geophone component, the coil, springs and so on.
But this is going to be long and high frequency
vibration because of the wind and problem for some part of the ocean wave
hitting the beach.
Hi Jon,
It is very unlikely indeed to damage your geophones. Your house would
probably blow away first..!
There are not many trees near the house. There are few, but nothing that
shields the house from the wind.
It is not the shielding that matters, but the swaying coupled to the
ground via the roots.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>In a message dated 29/03/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>What i=20
meant what effect does long period<BR>vibration have on the geophone=20
component, the coil, springs and so on.<BR>But this is going to be long an=
d=20
high frequency<BR>vibration because of the wind and problem for some part=20=
of=20
the ocean wave<BR>hitting the beach.</FONT></BLOCKQUOTE>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> It is very unlikely indeed to damage your=20
geophones. Your house would probably blow away first..!</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>There=20
are not many trees near the house. There are few, but nothing that<BR>shie=
lds=20
the house from the wind.</FONT></BLOCKQUOTE>
<DIV> It is not the shielding that matters, but the=20
swaying coupled to the ground via the roots.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20
size=3D2><BR></FONT> </BLOCKQUOTE>
<DIV></DIV>
<DIV> </DIV></FONT></BODY></HTML>
Subject: Re: Sensor and Damping magnets
From: ChrisAtUpw@.......
Date: Tue, 28 Mar 2006 20:59:10 EST
In a message dated 28/03/2006, ivey@.......... writes:
Chris,
>The 5 mm plate that I used at first was only just thick enough to take the
flux of the 1/2" x 1/4" thick magnets.
Did you calculate this or measure it somehow?
Thanks,
Jack
Hi Jack,
I did both. You can look up the flux densities of the magnets and the Bm
saturation for mild steel. If you want to get very low leakage flux, all the
flux has to go sideways through the mild steel plate. In my design, I allow
a 1/2" border around the periphery of the magnets for the internal field to
spread out and also to catch stray flux. You get a flux concentration near the
magnet join and field from the edges of the magnets themselves.
I also mounted various arrangements of magnets on one side of a larger
mild steel plate and then used a transformer lamination strip suspended with
cellotape on the other side to check if there was any field penetration. With
the 5 mm plate and 20x10x5 mm magnet pairs, there was no effect. With 20x20x5
mm magnets there was a small joint area which attracted the strip. Going to
1"x1/2"x1/4" magnet pairs, I could just detect some attraction. Doubling it
up to 1"x1"x1/4" magnet pairs produced a fairly strong attraction area. In
contrast, the 1"squarex1/8" sensor magnet pairs seemed OK.
I chose 1/4" mild steel (6.35 mm) with the 1"x1/2"x1/4" magnet pairs. I
may be being 'a bit fussy', but I don't want any stray field about and I do
want the maximum field in the magnet gap. Using mild steel bolts to secure the
plates was of considerable help - no two magnets have an identical flux and
I am using 4 off ! I was satisfied the this was 'good enough'.
The maximum damping effect is near the central join. To get maximum
damping the copper plate needs to overlap both ends of the 1" magnet square by
about 1/2".
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML xmlns:o =3D "urn:schemas-microsoft-com:office:office"><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 28/03/2006, ivey@.......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>
<DIV class=3DSection1>
<DIV>
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Chris,</SPAN></=
FONT><FONT=20
face=3DArial color=3Dblack size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial"> <o:p></o=
:p></SPAN></FONT></P></DIV>
<DIV>
<P class=3DMsoNormal><FONT face=3DArial color=3Dblack size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial"> </SPAN><=
/FONT><FONT=20
face=3DArial color=3Dnavy size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">></SPAN></FO=
NT><FONT=20
face=3DArial color=3Dblack size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial">The 5 mm plate=
that=20
I used at first was only just thick enough to take the flux of the 1/2" x=20=
1/4"=20
thick magnets.<o:p></o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3D"Times New Roman" color=3Dnavy size=3D3>=
<SPAN=20
style=3D"FONT-SIZE: 12pt; COLOR: navy">Did you calculate this or measure i=
t=20
somehow?<o:p></o:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:=
p></SPAN></FONT><FONT=20
face=3DArial color=3Dnavy size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Thanks,<o:p></o=
:p></SPAN></FONT></P>
<P class=3DMsoNormal><FONT face=3DArial color=3Dnavy size=3D2><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Jack</SPAN></FO=
NT></P></DIV></DIV></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>
<DIV>Hi Jack, </DIV>
<DIV> </DIV>
<DIV> I did both. You can look up the flux densities=20=
of=20
the magnets and the Bm saturation for mild steel. If you want to get very lo=
w=20
leakage flux, all the flux has to go sideways through the mild steel plate.=20=
In=20
my design, I allow a 1/2" border around the periphery of the magnets fo=
r=20
the internal field to spread out and also to catch stray flux. You=
get=20
a flux concentration near the magnet join and field from the edges of the=20
magnets themselves.</DIV>
<DIV> I also mounted various arrangements of mag=
nets=20
on one side of a larger mild steel plate and then used a transform=
er=20
lamination strip suspended with cellotape on the other side to check if=
=20
there was any field penetration. With the 5 mm plate and 20x10x5 mm magnet=20
pairs, there was no effect. With 20x20x5 mm magnets there was a small joint=20=
area=20
which attracted the strip. Going to 1"x1/2"x1/4" magnet pairs, I could just=20
detect some attraction. Doubling it up to 1"x1"x1/4" magnet pairs produced a=
=20
fairly strong attraction area. In contrast, the 1"squarex1/8" sensor ma=
gnet=20
pairs seemed OK. </DIV>
<DIV> I chose 1/4" mild steel (6.35 mm) with the=20
1"x1/2"x1/4" magnet pairs. I may be being 'a bit fussy', but I don't wa=
nt=20
any stray field about and I do want the maximum field in the magnet gap. Usi=
ng=20
mild steel bolts to secure the plates was of considerable help - no two magn=
ets=20
have an identical flux and I am using 4 off ! I was satisfied the this was '=
good=20
enough'.</DIV>
<DIV> The maximum damping effect is near the=20
central join. To get maximum damping the copper plate needs to overlap=20=
both=20
ends of the 1" magnet square by about 1/2". </DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></DIV></FONT></BODY></HTML>
Subject: Re: Sensor and Damping magnets
From: Bobhelenmcclure@.......
Date: Tue, 28 Mar 2006 23:58:31 EST
Chris--
=20
I purchased #38 wire (Low temperature (105=B0C, NEMA STD MW-1-c) enamel=20
coated magnet wire) on quarter-pound spools for $7.50 off from Alltronics.c=
om. It=20
is diamagnetic. I believe that if a wire is fabricated from OFHC copper, it=
=20
will be diamagnetic, but I do not know anything about this particular wire=20
except that it is cheap and has a very low temperature rating.
=20
In an attempt to answer Jack Ivey's question, a diamagnetic coil in my 4=20
pole magnet structure experiences a decentering force, which makes stable=20
adjustment of natural period very difficult. Imbedding the coil in a thick=20
diamagnetic sheet of plastic of transverse dimensions larger than the magne=
tic=20
field region reduces the diamagnetic pull exerted on the coil by the gradie=
nts of=20
the field reversal and the edge fields of the magnet.
=20
Bob
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DISO-8859-1">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2><FONT id=3Drole_document face=3DArial=20=
color=3D#000000=20
size=3D2><FONT id=3Drole_document face=3DArial color=3D#000000 size=3D2>
<DIV>Chris--</DIV>
<DIV> </DIV>
<DIV> I purchased #38 wire (<FONT face=3DHelvetica>Low temperatur=
e=20
(105=B0C, NEMA STD MW-1-c) enamel coated magnet wire)</FONT> on quarter-poun=
d=20
spools for $7.50 off from Alltronics.com. It is diamagnetic. I believe that=20=
if a=20
wire is fabricated from OFHC copper, it will be diamagnetic, but I do not kn=
ow=20
anything about this particular wire except that it is cheap and has a very l=
ow=20
temperature rating.</DIV>
<DIV> </DIV>
<DIV> In an attempt to answer Jack Ivey's question, a=20
diamagnetic coil in my 4 pole magnet structure experiences a decentering for=
ce,=20
which makes stable adjustment of natural period very difficult. Imbeddi=
ng=20
the coil in a thick diamagnetic sheet of plastic of transverse dimensions la=
rger=20
than the magnetic field region reduces the diamagnetic pull exerted on the c=
oil=20
by the gradients of the field reversal and the edge fields of the magnet.</D=
IV>
<DIV> </DIV>
<DIV>Bob</DIV></FONT></FONT></FONT></BODY></HTML>
Subject: 2006 SF Quake
From: Richard Webb dwebb002@.............
Date: Wed, 29 Mar 2006 17:31:11 -0500
Hi,
The SSA is having the 2006 meeting in SF the week of April 17. Are any
PSN types going to be there?
Dick
Raleigh, NC
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: l15b 4.5 Geophone, detecting teleseismic earthquake
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr500@.........
Date: Fri, 31 Mar 2006 02:18:48 +0000
Hi all
Is it impossible for l15b 4.5Hz geophone to detect teleseismic
earthquakes or just improbable. I am not sure of this yet, but i think
that i did detect the Iran earthquake that did happen today at 01:17, 31
Mars 2006, it was 5.7mb in size based on data from emsc-csem. It was
visable at Icelandic Met Office stations on 2Hz and somewhat above and
below frequancyes, according to tremor plots on there website.
Regards.
--
Jón Frímann Jónsson
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: L15B 4.5 Geophone, detecting teleseismic earthquake
From: ChrisAtUpw@.......
Date: Thu, 30 Mar 2006 21:57:46 EST
In a message dated 31/03/2006, jonfr500@......... writes:
Is it impossible for L15B 4.5Hz geophone to detect teleseismic
earthquakes or just improbable.
Hi Jon,
The sensitivity is down to ~1/5 at 2 Hz and it falls off increasingly
rapidly below this. At 1 Hz it is ~1/20. So what you can see depends on the P
wave frequency and on the magnitude of the quake. I would say that it may be
'difficult'.
It is possible to use a 'Roberts type' frequency compensating amplifier
to boost the output of a 4.5 Hz geophone fairly level down to ~0.5 Hz. This
enables you to use these geophones fairly well for teleseismic quakes.
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
<META content=3D"MSHTML 6.00.2900.2802" name=3DGENERATOR></HEAD>
<BODY id=3Drole_body style=3D"FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY:=20=
Arial"=20
bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7><FONT id=3Drol=
e_document=20
face=3DArial color=3D#000000 size=3D2>
<DIV>
<DIV>In a message dated 31/03/2006, jonfr500@......... writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Is it=20
impossible for L15B 4.5Hz geophone to detect teleseismic<BR>earthquakes or=
=20
just improbable. </FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Jon,</DIV>
<DIV> </DIV>
<DIV> The sensitivity is down to ~1/5 at 2 Hz and it=20
falls off increasingly rapidly below this. At 1 Hz it is ~1/20. So what you=20=
can=20
see depends on the P wave frequency and on the magnitude of the quake.=20=
I=20
would say that it may be 'difficult'. </DIV>
<DIV> It is possible to use a 'Roberts type' frequenc=
y=20
compensating amplifier to boost the output of a 4.5 Hz geophone fairly level=
=20
down to ~0.5 Hz. This enables you to use these geophones fairly well fo=
r=20
teleseismic quakes. </DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: 2006 SF Quake
From: John or Jan Lahr JohnJan@........
Date: Thu, 30 Mar 2006 20:25:36 -0800
I'll be attending the meeting. Maybe we should have an informal PSN
meeting one evening?
Tuesday or Wednesday would be the best for me. (April 18 or 19).
Cheers,
John
At 02:31 PM 3/29/2006, you wrote:
>Hi,
>
>The SSA is having the 2006 meeting in SF the week of April 17. Are
>any PSN types going to be there?
>
>Dick
>Raleigh, NC
>__________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email PSN-L-REQUEST@.............. with the body
>of the message (first line only): unsubscribe
>See http://www.seismicnet.com/maillist.html for more information.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: L15B 4.5 Geophone, detecting teleseismic earthquake
From: "Kareem at HeyJooJoo" system98765@.............
Date: Thu, 30 Mar 2006 20:45:16 -0800
Hi Chris (& everyone else),
Where can one get more information about the 'Roberts Amplifyer'?
Kareem
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of ChrisAtUpw@.......
Sent: Thursday, March 30, 2006 6:58 PM
To: psn-l@..............
Subject: Re: L15B 4.5 Geophone, detecting teleseismic earthquake
In a message dated 31/03/2006, jonfr500@......... writes:
Is it impossible for L15B 4.5Hz geophone to detect teleseismic
earthquakes or just improbable.
Hi Jon,
The sensitivity is down to ~1/5 at 2 Hz and it falls off increasingly
rapidly below this. At 1 Hz it is ~1/20. So what you can see depends on the
P wave frequency and on the magnitude of the quake. I would say that it may
be 'difficult'.
It is possible to use a 'Roberts type' frequency compensating amplifier
to boost the output of a 4.5 Hz geophone fairly level down to ~0.5 Hz. This
enables you to use these geophones fairly well for teleseismic quakes.
Regards,
Chris Chapman
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: speaking about bad luck
From: ian ian@...........
Date: Fri, 31 Mar 2006 06:07:30 +0100
it used to (and still does) happen to me all the time. So much so that
some people have asked me to warn them when my seismometer is off! I
missed the Boxing day quake in Indonesia for instance.
Ian
Jón Frímann wrote:
>Hi all
>
>I had a really bad luck today. As i told you in my email early today i
>had a psu failure in the computer that records earthquakes for me. But
>also today there was a earthquake that was 4.5Mb on the Reykjanes ridge,
>it was felt in Reykjavik. More info here,
>http://www.emsc-csem.org/index.php?page=current&sub=detail&id=HP408;2006
>
>But becose my earthquake computer is down i didn't record this
>earthquake. :(
>
>I really hate it when something like this happens.
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: speaking about bad luck
From: ian ian@...........
Date: Fri, 31 Mar 2006 06:07:30 +0100
it used to (and still does) happen to me all the time. So much so that
some people have asked me to warn them when my seismometer is off! I
missed the Boxing day quake in Indonesia for instance.
Ian
Jón Frímann wrote:
>Hi all
>
>I had a really bad luck today. As i told you in my email early today i
>had a psu failure in the computer that records earthquakes for me. But
>also today there was a earthquake that was 4.5Mb on the Reykjanes ridge,
>it was felt in Reykjavik. More info here,
>http://www.emsc-csem.org/index.php?page=current&sub=detail&id=HP408;2006
>
>But becose my earthquake computer is down i didn't record this
>earthquake. :(
>
>I really hate it when something like this happens.
>
>Regards.
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: 2006 SF Quake
From: Richard Webb dwebb002@.............
Date: Fri, 31 Mar 2006 08:59:29 -0500
John,
I think an informal get together on either day would be great.
Dick
John or Jan Lahr wrote:
> I'll be attending the meeting. Maybe we should have an informal PSN
> meeting one evening?
> Tuesday or Wednesday would be the best for me. (April 18 or 19).
>
> Cheers,
> John
>
> At 02:31 PM 3/29/2006, you wrote:
>> Hi,
>>
>> The SSA is having the 2006 meeting in SF the week of April 17. Are
>> any PSN types going to be there?
>>
>> Dick
>> Raleigh, NC
>> __________________________________________________________
>>
>> Public Seismic Network Mailing List (PSN-L)
>>
>> To leave this list email PSN-L-REQUEST@.............. with the body
>> of the message (first line only): unsubscribe
>> See http://www.seismicnet.com/maillist.html for more information.
>
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with the body of
> the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: L15B 4.5 Geophone, detecting teleseismic earthquake
From: ChrisAtUpw@.......
Date: Fri, 31 Mar 2006 10:26:37 EST
In a message dated 31/03/2006, system98765@............. writes:
Hi Chris (& everyone else),
Where can one get more information about the 'Roberts Amplifier'?
Kareem
Hi Kareem,
Go to _http://psn.quake.net/bibliography.html_
(http://psn.quake.net/bibliography.html)
Roberts, PM "A Versatile Equilization Circuit for Increasing Seismometer
Velocity Response Below the Natural Frequency." (for 4.5Hz geophones) BSSA,
vol 79, pp 1607-1617 Oct. 1989
Your local library should be able to get you a photocopy.
I made some simple circuit changes which reduced the very low frequency
noise, if anyone is interested. The modified circuit seems to work fine.
Lennartz use geophone compensators of this general type on their professional
range. You get about a factor of 10 reduction in the minimum frequency - e.g. a
4.5Hz geophone will reproduce ~flat down to 0.45Hz. This enables you to pick
up teleseismic quakes as well as local and regional ones.
Regards,
Chris Chapman
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<DIV>
<DIV>In a message dated 31/03/2006, system98765@............. writes:</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>Hi Chris=20
(& everyone else),<BR>Where can one get more information about the=20
'Roberts Amplifier'? <BR>Kareem<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Kareem,</DIV>
<DIV> </DIV>
<DIV> Go to <A=20
href=3D"http://psn.quake.net/bibliography.html">http://psn.quake.net/bibliog=
raphy.html</A> </DIV>
<DIV> </DIV>
<DIV> Roberts, PM "A Versatile Equilization Circuit f=
or=20
Increasing Seismometer Velocity Response Below the Natural Frequency." (for=20
4.5Hz geophones) BSSA, vol 79, pp 1607-1617 Oct. 1989</DIV>
<DIV> </DIV>
<DIV> Your local library should be able to get you a=20
photocopy.</DIV>
<DIV> </DIV>
<DIV> I made some simple circuit changes which reduce=
d=20
the very low frequency noise, if anyone is interested. The modified circuit=20
seems to work fine. Lennartz use geophone compensators of this general type=20=
on=20
their professional range. You get about a factor of 10 reduction in the mini=
mum=20
frequency - e.g. a 4.5Hz geophone will reproduce ~flat down to 0.45Hz. This=20
enables you to pick up teleseismic quakes as well as local and regional=20
ones.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV>
<DIV> </DIV></FONT></BODY></HTML>
Subject: RE: 2006 SF Quake
From: "Keith Payea" kpayea@...........
Date: Fri, 31 Mar 2006 09:01:03 -0800
All:
I'm up for it. Either day is fine. If everyone interested chimes in, we
can get an idea of how many to accommodate.
Keith Payea
Santa Rosa, CA
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Richard Webb
Sent: Friday, March 31, 2006 5:59 AM
To: psn-l@..............
Subject: Re: 2006 SF Quake
John,
I think an informal get together on either day would be great.
Dick
John or Jan Lahr wrote:
> I'll be attending the meeting. Maybe we should have an informal PSN
> meeting one evening?
> Tuesday or Wednesday would be the best for me. (April 18 or 19).
>
> Cheers,
> John
>
> At 02:31 PM 3/29/2006, you wrote:
>> Hi,
>>
>> The SSA is having the 2006 meeting in SF the week of April 17. Are
>> any PSN types going to be there?
>>
>> Dick
>> Raleigh, NC
>> __________________________________________________________
>>
>> Public Seismic Network Mailing List (PSN-L)
>>
>> To leave this list email PSN-L-REQUEST@.............. with the body
>> of the message (first line only): unsubscribe
>> See http://www.seismicnet.com/maillist.html for more information.
>
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with the body of
> the message (first line only): unsubscribe
> See http://www.seismicnet.com/maillist.html for more information.
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: L15B 4.5 Geophone, detecting teleseismic earthquake
From: Stephen & Kathy skmort@..........
Date: Fri, 31 Mar 2006 10:15:32 -0800
Count me in,,, I'd like to see your circuit!!!!
Stephen
PSN Station #55
ChrisAtUpw@....... wrote:
> In a message dated 31/03/2006, system98765@............. writes:
>
> Hi Chris (& everyone else),
> Where can one get more information about the 'Roberts Amplifier'?
> Kareem
>
> Hi Kareem,
>
> Go to http://psn.quake.net/bibliography.html
>
> Roberts, PM "A Versatile Equilization Circuit for Increasing
> Seismometer Velocity Response Below the Natural Frequency." (for 4.5Hz
> geophones) BSSA, vol 79, pp 1607-1617 Oct. 1989
>
> Your local library should be able to get you a photocopy.
>
> I made some simple circuit changes which reduced the very low
> frequency noise, if anyone is interested. The modified circuit seems to
> work fine. Lennartz use geophone compensators of this general type on
> their professional range. You get about a factor of 10 reduction in the
> minimum frequency - e.g. a 4.5Hz geophone will reproduce ~flat down to
> 0.45Hz. This enables you to pick up teleseismic quakes as well as local
> and regional ones.
>
> Regards,
>
> Chris Chapman
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)