Subject:
From: tchannel1@............
Date: Wed, 1 Oct 2008 22:38:06 -0600
I am exploring the subject of a torsion spring sensor again. I say =
again because I have tried this approach before with no success at all.
I took a long band saw blade cut it to form a long vertical torsion =
spring. Attached both ends and pulled it tight.
In the middle of this spring I attached a boom. On both ends of the boom =
I attached a mass of equal value.
This boom would move around the vertical axis with very little effort, =
twisting the spring and then reversing to the other direction, rocking =
back and forth for a very long time. I don't remember how long but I =
think it was one hour plus.
The period of oscillation was controlled by moving the masses further =
out on the boom. Very long periods 30 seconds plus. To make a long =
story short, it did not record any earthquakes.
I think I did two things wrong. 1. The booms of equal mass cancelled =
the movement of each other. And in this configuration the earthquake =
would need to spin the house to move the masses.
2. The torsion spring needed to be tipped, not vertical.
Here is my next attempt. 1. I removed the boom, which formed a (+) on =
the vertical torsion spring and replace it with a short pendulum boom, =
this time on one side only.=20
it looks like a T on its side ( l-)
2. I contained the vertical torsion spring in a strong box about =
12"x12"x36". This retains all the parts and I can add tension to the =
spring, and mount the magnet and coil
3. I placed three leveling legs on the base of the box. Now I can tip =
the vertical spring (Off Vertical). Similar to tipping a Lehman, =
pitching up or down.
The spring now at an angle, contains a pendulum which is now (Off =
Horizontal).
The pendulum I am using is only about 6" long, and I get a period of =
about 5 seconds. I could get 20 seconds with a 18" boom. But my box =
could only accommodate a 6" boom.
It is now running as a test......I will see if it will record =
earthquakes.
It is sensitive to me moving around the room, and to drafts and tilts.
I have seen something similar somewhere on the web, but I can't fine it. =
This is all I could find. If someone has tried this please email me. =
Thanks, Ted
Torsion Seismometer Wood Anderson
http://www.data.scec.org/Module/s3inset3.html
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<META http-equiv=3DContent-Type content=3D"text/html; =
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<DIV><FONT face=3DArial size=3D2>I am exploring the subject of a torsion =
spring=20
sensor again. I say again because I have tried this approach =
before with=20
no success at all.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I took a long band saw blade cut it to =
form a long=20
vertical torsion spring. Attached both ends and pulled it =
tight.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>In the middle of this spring I attached =
a boom. On=20
both ends of the boom I attached a mass of equal value.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>This boom would move around the =
vertical axis with=20
very little effort, twisting the spring and then reversing to the other=20
direction, rocking back and forth for a very long time. I don't =
remember=20
how long but I think it was one hour plus.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The period of oscillation was =
controlled by=20
moving the masses further out on the boom. Very long periods =
30=20
seconds plus. To make a long story short, it did not record any=20
earthquakes.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I think I did two things wrong. =
1. The booms=20
of equal mass cancelled the movement of each other. And in this=20
configuration the earthquake would need to spin the house to move =
the=20
masses.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>2. The torsion spring needed to be =
tipped, not=20
vertical.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Here is my next attempt. =
1. I=20
removed the boom, which formed a (+) on the vertical torsion spring and =
replace=20
it with a short pendulum boom, this time on one side only. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2>it looks like a T on its side ( =
l-)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>2. I contained the vertical =
torsion spring in=20
a strong box about 12"x12"x36". This retains all the parts and I =
can add=20
tension to the spring, and mount the magnet and coil</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>3. I placed three leveling legs =
on the base=20
of the box. Now I can tip the vertical spring (Off=20
Vertical). Similar to tipping a Lehman, pitching up or =
down.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The spring now at an angle, contains a =
pendulum=20
which is now (Off Horizontal).</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>The pendulum I am using is only about =
6" long, and=20
I get a period of about 5 seconds. I could get 20 seconds with a =
18"=20
boom. But my box could only accommodate a 6" boom.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2> It is now running as a =
test......I will see=20
if it will record earthquakes.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>It is sensitive to me moving around the =
room, and=20
to drafts and tilts.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I have seen something similar somewhere =
on the web,=20
but I can't fine it. This is all I could find. =
If=20
someone has tried this please email me. Thanks, =
Ted</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Torsion Seismometer Wood =
Anderson</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2><A=20
href=3D"http://www.data.scec.org/Module/s3inset3.html">http://www.data.sc=
ec.org/Module/s3inset3.html</A></FONT></DIV></BODY></HTML>
Subject: Re:
From: "meredith lamb" paleoartifact@.........
Date: Thu, 2 Oct 2008 15:29:20 -0600
Hi Ted,
Sorry...I couldn't find anything along the specific line you mention
either..especially the flat ribbon spring variety. If I read you email
right;
the very height you're using makes it a "giant" representation; and that
likely makes it much more responsive as you're seeing, and
to be fair the stresses involved will likely show all kinds of
metal/structure creep over time which you'll have to adjust for.
A lot of the web sites I've seen, go out of their way to describe such as
antiquated, obsolete, old etc; which is true in the sense
of what is predominately used now. On the other hand, the torsion aspect
really "does away" with a few of the normal pesky pivot problems
that are found in other seismometers/tiltmeters; and that alone is a good
adjustment and/or labor saving positive.
Yes indeed...explore away.....there is likely a world of different flat
ribbon or round wire sizes material one could try.
Take care, Meredith
On Wed, Oct 1, 2008 at 10:38 PM, <tchannel1@............> wrote:
> I am exploring the subject of a torsion spring sensor again. I say again
> because I have tried this approach before with no success at all.
> I took a long band saw blade cut it to form a long vertical torsion spring.
> Attached both ends and pulled it tight.
> In the middle of this spring I attached a boom. On both ends of the boom I
> attached a mass of equal value.
> This boom would move around the vertical axis with very little effort,
> twisting the spring and then reversing to the other direction, rocking back
> and forth for a very long time. I don't remember how long but I think it
> was one hour plus.
> The period of oscillation was controlled by moving the masses further out
> on the boom. Very long periods 30 seconds plus. To make a long story
> short, it did not record any earthquakes.
>
> I think I did two things wrong. 1. The booms of equal mass cancelled the
> movement of each other. And in this configuration the earthquake would need
> to spin the house to move the masses.
> 2. The torsion spring needed to be tipped, not vertical.
>
> Here is my next attempt. 1. I removed the boom, which formed a (+) on
> the vertical torsion spring and replace it with a short pendulum boom, this
> time on one side only.
> it looks like a T on its side ( l-)
> 2. I contained the vertical torsion spring in a strong box about
> 12"x12"x36". This retains all the parts and I can add tension to the
> spring, and mount the magnet and coil
> 3. I placed three leveling legs on the base of the box. Now I can tip the
> vertical spring (Off Vertical). Similar to tipping a Lehman, pitching up
> or down.
> The spring now at an angle, contains a pendulum which is now (Off
> Horizontal).
>
> The pendulum I am using is only about 6" long, and I get a period of about
> 5 seconds. I could get 20 seconds with a 18" boom. But my box could only
> accommodate a 6" boom.
>
> It is now running as a test......I will see if it will record earthquakes.
> It is sensitive to me moving around the room, and to drafts and tilts.
>
> I have seen something similar somewhere on the web, but I can't fine it.
> This is all I could find. If someone has tried this please email me.
> Thanks, Ted
>
> Torsion Seismometer Wood Anderson
>
>
> http://www.data.scec.org/Module/s3inset3.html
>
<div dir="ltr">Hi Ted,<br><br>Sorry...I couldn't find anything along the specific line you mention either..especially the flat ribbon spring variety. If I read you email right;<br>the very height you're using makes it a "giant" representation; and that likely makes it much more responsive as you're seeing, and<br>
to be fair the stresses involved will likely show all kinds of metal/structure creep over time which you'll have to adjust for.<br><br>A lot of the web sites I've seen, go out of their way to describe such as antiquated, obsolete, old etc; which is true in the sense<br>
of what is predominately used now. On the other hand, the torsion aspect really "does away" with a few of the normal pesky pivot problems<br>that are found in other seismometers/tiltmeters; and that alone is a good adjustment and/or labor saving positive.<br>
<br>Yes indeed...explore away.....there is likely a world of different flat ribbon or round wire sizes material one could try.<br><br>Take care, Meredith<br> <br><div class="gmail_quote">On Wed, Oct 1, 2008 at 10:38 PM, <span dir="ltr"><<a href="mailto:tchannel1@............">tchannel1@............</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div bgcolor="#ffffff">
<div><font face="Arial" size="2">I am exploring the subject of a torsion spring
sensor again. I say again because I have tried this approach before with
no success at all.</font></div>
<div><font face="Arial" size="2">I took a long band saw blade cut it to form a long
vertical torsion spring. Attached both ends and pulled it tight.</font></div>
<div><font face="Arial" size="2">In the middle of this spring I attached a boom. On
both ends of the boom I attached a mass of equal value.</font></div>
<div><font face="Arial" size="2">This boom would move around the vertical axis with
very little effort, twisting the spring and then reversing to the other
direction, rocking back and forth for a very long time. I don't remember
how long but I think it was one hour plus.</font></div>
<div><font face="Arial" size="2">The period of oscillation was controlled by
moving the masses further out on the boom. Very long periods 30
seconds plus. To make a long story short, it did not record any
earthquakes.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">I think I did two things wrong. 1. The booms
of equal mass cancelled the movement of each other. And in this
configuration the earthquake would need to spin the house to move the
masses.</font></div>
<div><font face="Arial" size="2">2. The torsion spring needed to be tipped, not
vertical.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">Here is my next attempt. 1. I
removed the boom, which formed a (+) on the vertical torsion spring and replace
it with a short pendulum boom, this time on one side only. </font></div>
<div><font face="Arial" size="2">it looks like a T on its side ( l-)</font></div>
<div><font face="Arial" size="2">2. I contained the vertical torsion spring in
a strong box about 12"x12"x36". This retains all the parts and I can add
tension to the spring, and mount the magnet and coil</font></div>
<div><font face="Arial" size="2">3. I placed three leveling legs on the base
of the box. Now I can tip the vertical spring (Off
Vertical). Similar to tipping a Lehman, pitching up or
down.</font></div>
<div><font face="Arial" size="2">The spring now at an angle, contains a pendulum
which is now (Off Horizontal).</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">The pendulum I am using is only about 6" long, and
I get a period of about 5 seconds. I could get 20 seconds with a 18"
boom. But my box could only accommodate a 6" boom.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2"> It is now running as a test......I will see
if it will record earthquakes.</font></div>
<div><font face="Arial" size="2">It is sensitive to me moving around the room, and
to drafts and tilts.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">I have seen something similar somewhere on the web,
but I can't fine it. This is all I could find. If
someone has tried this please email me. Thanks, Ted</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">Torsion Seismometer Wood Anderson</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2"><a href="http://www.data.scec.org/Module/s3inset3.html" target="_blank">http://www.data.scec.org/Module/s3inset3.html</a></font></div></div>
</blockquote></div><br></div>
Subject: Re: Re:
From: tchannel1@............
Date: Thu, 2 Oct 2008 17:11:16 -0600
Meredith, Thank you for your reply and encouragement. The first =
sensor I spoke of was about 8 foot tall and the boom was about 4 foot, =
two feet on each side of the ribbon.
I did not keep my notes on this unit but remember the period was =
massive, just moving the masses further out on the boom.
This present unit is only about 36" tall and the boom, one side of the =
ribbon only is about 6". I used a SS thin wire instead of the band saw =
blade ribbon. At this point I think it will respond similar to a =
Lehman with a 5 second period. So far it behaves, just like my Lehman.
I will let you know, if it works and send or post the .psn. =
It looks promising, very simple and if it works I will rebuild it =
targeting a 20 second period.
Cheers, Ted ps..............On some web site I saw the concept of a =
Torsion Spring Long Period, illustrated as a box with a vertical torsion =
spring in the center of the box, and a boom............but the entire =
box was tipped, to illustrate the vertical wire/spring needed to be off =
vertical, not unlike the Lehman
----- Original Message -----=20
From: meredith lamb=20
To: psn-l@.................
Sent: Thursday, October 02, 2008 3:29 PM
Subject: Re:
Hi Ted,
Sorry...I couldn't find anything along the specific line you mention =
either..especially the flat ribbon spring variety. If I read you email =
right;
the very height you're using makes it a "giant" representation; and =
that likely makes it much more responsive as you're seeing, and
to be fair the stresses involved will likely show all kinds of =
metal/structure creep over time which you'll have to adjust for.
A lot of the web sites I've seen, go out of their way to describe such =
as antiquated, obsolete, old etc; which is true in the sense
of what is predominately used now. On the other hand, the torsion =
aspect really "does away" with a few of the normal pesky pivot problems
that are found in other seismometers/tiltmeters; and that alone is a =
good adjustment and/or labor saving positive.
Yes indeed...explore away.....there is likely a world of different =
flat ribbon or round wire sizes material one could try.
Take care, Meredith
=20
On Wed, Oct 1, 2008 at 10:38 PM, <tchannel1@............> wrote:
I am exploring the subject of a torsion spring sensor again. I say =
again because I have tried this approach before with no success at all.
I took a long band saw blade cut it to form a long vertical torsion =
spring. Attached both ends and pulled it tight.
In the middle of this spring I attached a boom. On both ends of the =
boom I attached a mass of equal value.
This boom would move around the vertical axis with very little =
effort, twisting the spring and then reversing to the other direction, =
rocking back and forth for a very long time. I don't remember how long =
but I think it was one hour plus.
The period of oscillation was controlled by moving the masses =
further out on the boom. Very long periods 30 seconds plus. To make a =
long story short, it did not record any earthquakes.
I think I did two things wrong. 1. The booms of equal mass =
cancelled the movement of each other. And in this configuration the =
earthquake would need to spin the house to move the masses.
2. The torsion spring needed to be tipped, not vertical.
Here is my next attempt. 1. I removed the boom, which formed a =
(+) on the vertical torsion spring and replace it with a short pendulum =
boom, this time on one side only.=20
it looks like a T on its side ( l-)
2. I contained the vertical torsion spring in a strong box about =
12"x12"x36". This retains all the parts and I can add tension to the =
spring, and mount the magnet and coil
3. I placed three leveling legs on the base of the box. Now I can =
tip the vertical spring (Off Vertical). Similar to tipping a Lehman, =
pitching up or down.
The spring now at an angle, contains a pendulum which is now (Off =
Horizontal).
The pendulum I am using is only about 6" long, and I get a period of =
about 5 seconds. I could get 20 seconds with a 18" boom. But my box =
could only accommodate a 6" boom.
It is now running as a test......I will see if it will record =
earthquakes.
It is sensitive to me moving around the room, and to drafts and =
tilts.
I have seen something similar somewhere on the web, but I can't fine =
it. This is all I could find. If someone has tried this please email =
me. Thanks, Ted
Torsion Seismometer Wood Anderson
http://www.data.scec.org/Module/s3inset3.html
<!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 6.00.6001.18099" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Meredith, Thank you for your =
reply and=20
encouragement. The first sensor I spoke of was about 8 foot =
tall and=20
the boom was about 4 foot, two feet on each side of the =
ribbon.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I did not keep my notes on this unit =
but remember=20
the period was massive, just moving the masses further out on the=20
boom.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>This present unit is only about 36" =
tall and the=20
boom, one side of the ribbon only is about 6". I used a SS =
thin wire=20
instead of the band saw blade ribbon. At this point I think =
it will=20
respond similar to a Lehman with a 5 second period. So far it =
behaves,=20
just like my Lehman.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I will let you know, if it works and =
send or post=20
the=20
..psn. &n=
bsp; It=20
looks promising, very simple and if it works I will rebuild it targeting =
a 20=20
second period.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Cheers, Ted =
ps..............On=20
some web site I saw the concept of a Torsion Spring Long Period, =
illustrated as=20
a box with a vertical torsion spring in the center of the box, and a=20
boom............but the entire box was tipped, to illustrate the =
vertical=20
wire/spring needed to be off vertical, not unlike the =
Lehman</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=3Dpaleoartifact@............
href=3D"mailto:paleoartifact@.........">meredith lamb</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, October 02, =
2008 3:29=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re:</DIV>
<DIV><BR></DIV>
<DIV dir=3Dltr>Hi Ted,<BR><BR>Sorry...I couldn't find anything along =
the=20
specific line you mention either..especially the flat ribbon spring=20
variety. If I read you email right;<BR>the very height you're =
using=20
makes it a "giant" representation; and that likely makes it much more=20
responsive as you're seeing, and<BR>to be fair the stresses involved =
will=20
likely show all kinds of metal/structure creep over time which you'll =
have to=20
adjust for.<BR><BR>A lot of the web sites I've seen, go out of their =
way to=20
describe such as antiquated, obsolete, old etc; which is true in the=20
sense<BR>of what is predominately used now. On the other hand, =
the=20
torsion aspect really "does away" with a few of the normal pesky pivot =
problems<BR>that are found in other seismometers/tiltmeters; and that =
alone is=20
a good adjustment and/or labor saving positive.<BR><BR>Yes =
indeed...explore=20
away.....there is likely a world of different flat ribbon or round =
wire sizes=20
material one could try.<BR><BR>Take care, Meredith<BR> =
<BR>
<DIV class=3Dgmail_quote>On Wed, Oct 1, 2008 at 10:38 PM, <SPAN =
dir=3Dltr><<A=20
=
href=3D"mailto:tchannel1@............">tchannel1@............</A>></SP=
AN>=20
wrote:<BR>
<BLOCKQUOTE class=3Dgmail_quote=20
style=3D"PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: =
rgb(204,204,204) 1px solid">
<DIV bgcolor=3D"#ffffff">
<DIV><FONT face=3DArial size=3D2>I am exploring the subject of a =
torsion spring=20
sensor again. I say again because I have tried this approach =
before=20
with no success at all.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I took a long band saw blade cut it =
to form a=20
long vertical torsion spring. Attached both ends and pulled it=20
tight.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>In the middle of this spring I =
attached a boom.=20
On both ends of the boom I attached a mass of equal =
value.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>This boom would move around the =
vertical axis=20
with very little effort, twisting the spring and then reversing to =
the other=20
direction, rocking back and forth for a very long time. I =
don't=20
remember how long but I think it was one hour plus.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The period of oscillation was =
controlled=20
by moving the masses further out on the boom. Very long =
periods=20
30 seconds plus. To make a long story short, it did not record =
any=20
earthquakes.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I think I did two things =
wrong. 1. The=20
booms of equal mass cancelled the movement of each other. And =
in this=20
configuration the earthquake would need to spin the house to =
move the=20
masses.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>2. The torsion spring needed to be =
tipped, not=20
vertical.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Here is my next =
attempt. 1. I=20
removed the boom, which formed a (+) on the vertical torsion spring =
and=20
replace it with a short pendulum boom, this time on one side only.=20
</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>it looks like a T on its side (=20
l-)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>2. I contained the vertical =
torsion=20
spring in a strong box about 12"x12"x36". This retains all the =
parts=20
and I can add tension to the spring, and mount the magnet and=20
coil</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>3. I placed three leveling =
legs on the=20
base of the box. Now I can tip the vertical spring (Off=20
Vertical). Similar to tipping a Lehman, pitching =
up or=20
down.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The spring now at an angle, =
contains a pendulum=20
which is now (Off Horizontal).</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>The pendulum I am using is only =
about 6" long,=20
and I get a period of about 5 seconds. I could get 20 seconds =
with a=20
18" boom. But my box could only accommodate a 6" =
boom.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2> It is now running as a =
test......I will=20
see if it will record earthquakes.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>It is sensitive to me moving around =
the room,=20
and to drafts and tilts.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I have seen something similar =
somewhere on the=20
web, but I can't fine it. This is all I could =
find. =20
If someone has tried this please email me. Thanks,=20
Ted</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Torsion Seismometer Wood =
Anderson</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2><A=20
href=3D"http://www.data.scec.org/Module/s3inset3.html"=20
=
target=3D_blank>http://www.data.scec.org/Module/s3inset3.html</A></FONT><=
/DIV></DIV></BLOCKQUOTE></DIV><BR></DIV></BLOCKQUOTE></BODY></HTML>
Subject: Re: Torsion Seismometer
From: ChrisAtUpw@.......
Date: Thu, 2 Oct 2008 19:33:44 EDT
In a message dated 2008/10/02, tchannel1@............ writes:
> I have seen something similar somewhere on the web, but I can't find it.
> This is all I could find. If someone has tried this please email me.
> Thanks, Ted
> Torsion Seismometer Wood Anderson
> http://www.data.scec.org/Module/s3inset3.html
Hi Ted,
The Wood-Anderson was a horizontal system with a torsion suspension,
magnetic damping, optical + photographic recording and a period of about a se
cond. There is no reason why you could not fit a dual Si photocell readout
system.
To increase the period you can reduce the wire diameter / increase the
wire length / mount the mass on an extended side boom to increase the
inertia.
Check out
http://doga.ogs.trieste.it/doga/risk/woodanderson/index.html
http://www.eas.slu.edu/Earthquake_Center/Instruments/
Randall Peters has a vertical torsion device on this website.
http://physics.mercer.edu/hpage/peters.html
Regards,
Chris Chapman
<HTML><FONT FACE=3Darial,helvetica><HTML><FONT SIZE=3D2 PTSIZE=3D10>In a me=
ssage dated 2008/10/02, tchannel1@............ writes:<BR>
<BR>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">I have seen something similar s=
omewhere on the web, but I can't find it. This is all I could fi=
nd. If someone has tried this please email me. Thank=
s, Ted</FONT><FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-C=
OLOR: #ffffff" SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=
=3D"0"><BR>
</FONT><FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR:=
#ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0=
">Torsion Seismometer Wood Anderson</FONT><FONT COLOR=3D"#000000" BACK=3D"#=
ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D3 PTSIZE=3D12 FAMILY=3D"S=
ANSSERIF" FACE=3D"Arial" LANG=3D"0"><BR>
</FONT><FONT COLOR=3D"#0000ff" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR:=
#ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0=
"><A HREF=3D"http://www.data.scec.org/Module/s3inset3.html">http://www.data.=
scec.org/Module/s3inset3.html</A></FONT><FONT COLOR=3D"#000000" BACK=3D"#ff=
ffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SAN=
SSERIF" FACE=3D"Arial" LANG=3D"0"></BLOCKQUOTE><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 Ted,<BR>
<BR>
The Wood-Anderson was a horizontal syst=
em with a torsion suspension, magnetic damping, optical + photographic recor=
ding and a period of about a second. There is no reason why you could not fi=
t a dual Si photocell readout system. <BR>
<BR>
To increase the period you can reduce t=
he wire diameter / increase the wire length / mount the mass on an extended=20=
side boom to increase the inertia.<BR>
<BR>
Check out<BR>
http://doga.ogs.trieste.it/doga/risk/wo=
odanderson/index.html<BR>
http://www.eas.slu.edu/Earthquake_Cente=
r/Instruments/<BR>
<BR>
Randall Peters has a vertical torsion d=
evice on this website.<BR>
http://physics.mercer.edu/hpage/peters.=
html<BR>
<BR>
Regards,<BR>
<BR>
Chris Chapman</FONT> </HTML>
Subject: Re: Re:
From: "meredith lamb" paleoartifact@.........
Date: Thu, 2 Oct 2008 18:47:05 -0600
Hi Ted,
The "concept" or diagram you mention is possibly this:
http://physics.mercer.edu/petepag/tilt.gif
which is a part of:
http://physics.mercer.edu/petepag/tiltm.html
and the title of the above is "Tiltmeters and Angle Measuring Equipment" by
Randall Peters
but....I suppose you've already found such from Chris's reference.
Take care, Meredith
On Thu, Oct 2, 2008 at 5:11 PM, <tchannel1@............> wrote:
> Meredith, Thank you for your reply and encouragement. The first sensor
> I spoke of was about 8 foot tall and the boom was about 4 foot, two feet on
> each side of the ribbon.
> I did not keep my notes on this unit but remember the period was massive,
> just moving the masses further out on the boom.
>
> This present unit is only about 36" tall and the boom, one side of the
> ribbon only is about 6". I used a SS thin wire instead of the band saw
> blade ribbon. At this point I think it will respond similar to a Lehman
> with a 5 second period. So far it behaves, just like my Lehman.
>
> I will let you know, if it works and send or post the .psn. It
> looks promising, very simple and if it works I will rebuild it targeting a
> 20 second period.
>
> Cheers, Ted ps..............On some web site I saw the concept of a
> Torsion Spring Long Period, illustrated as a box with a vertical torsion
> spring in the center of the box, and a boom............but the entire box
> was tipped, to illustrate the vertical wire/spring needed to be off
> vertical, not unlike the Lehman
>
> ----- Original Message -----
> *From:* meredith lamb <paleoartifact@.........>
> *To:* psn-l@..............
> *Sent:* Thursday, October 02, 2008 3:29 PM
> *Subject:* Re:
>
> Hi Ted,
>
> Sorry...I couldn't find anything along the specific line you mention
> either..especially the flat ribbon spring variety. If I read you email
> right;
> the very height you're using makes it a "giant" representation; and that
> likely makes it much more responsive as you're seeing, and
> to be fair the stresses involved will likely show all kinds of
> metal/structure creep over time which you'll have to adjust for.
>
> A lot of the web sites I've seen, go out of their way to describe such as
> antiquated, obsolete, old etc; which is true in the sense
> of what is predominately used now. On the other hand, the torsion aspect
> really "does away" with a few of the normal pesky pivot problems
> that are found in other seismometers/tiltmeters; and that alone is a good
> adjustment and/or labor saving positive.
>
> Yes indeed...explore away.....there is likely a world of different flat
> ribbon or round wire sizes material one could try.
>
> Take care, Meredith
>
> On Wed, Oct 1, 2008 at 10:38 PM, <tchannel1@............> wrote:
>
>> I am exploring the subject of a torsion spring sensor again. I say
>> again because I have tried this approach before with no success at all.
>> I took a long band saw blade cut it to form a long vertical torsion
>> spring. Attached both ends and pulled it tight.
>> In the middle of this spring I attached a boom. On both ends of the boom I
>> attached a mass of equal value.
>> This boom would move around the vertical axis with very little effort,
>> twisting the spring and then reversing to the other direction, rocking back
>> and forth for a very long time. I don't remember how long but I think it
>> was one hour plus.
>> The period of oscillation was controlled by moving the masses further out
>> on the boom. Very long periods 30 seconds plus. To make a long story
>> short, it did not record any earthquakes.
>>
>> I think I did two things wrong. 1. The booms of equal mass cancelled the
>> movement of each other. And in this configuration the earthquake would need
>> to spin the house to move the masses.
>> 2. The torsion spring needed to be tipped, not vertical.
>>
>> Here is my next attempt. 1. I removed the boom, which formed a (+) on
>> the vertical torsion spring and replace it with a short pendulum boom, this
>> time on one side only.
>> it looks like a T on its side ( l-)
>> 2. I contained the vertical torsion spring in a strong box about
>> 12"x12"x36". This retains all the parts and I can add tension to the
>> spring, and mount the magnet and coil
>> 3. I placed three leveling legs on the base of the box. Now I can tip
>> the vertical spring (Off Vertical). Similar to tipping a Lehman, pitching
>> up or down.
>> The spring now at an angle, contains a pendulum which is now (Off
>> Horizontal).
>>
>> The pendulum I am using is only about 6" long, and I get a period of about
>> 5 seconds. I could get 20 seconds with a 18" boom. But my box could only
>> accommodate a 6" boom.
>>
>> It is now running as a test......I will see if it will record
>> earthquakes.
>> It is sensitive to me moving around the room, and to drafts and tilts.
>>
>> I have seen something similar somewhere on the web, but I can't fine it.
>> This is all I could find. If someone has tried this please email me.
>> Thanks, Ted
>>
>> Torsion Seismometer Wood Anderson
>>
>>
>> http://www.data.scec.org/Module/s3inset3.html
>>
>
>
<div dir="ltr"><div>Hi Ted,</div>
<div> </div>
<div>The "concept" or diagram you mention is possibly this:</div>
<div> </div>
<div><a href="http://physics.mercer.edu/petepag/tilt.gif">http://physics.mercer.edu/petepag/tilt.gif</a></div>
<div> </div>
<div>which is a part of:</div>
<div> </div>
<div><a href="http://physics.mercer.edu/petepag/tiltm.html">http://physics.mercer.edu/petepag/tiltm.html</a></div>
<div> </div>
<div>and the title of the above is "Tiltmeters and Angle Measuring Equipment" by Randall Peters</div>
<div> </div>
<div>but....I suppose you've already found such from Chris's reference.</div>
<div> </div>
<div>Take care, Meredith</div>
<div><br><br> </div>
<div class="gmail_quote">On Thu, Oct 2, 2008 at 5:11 PM, <span dir="ltr"><<a href="mailto:tchannel1@............">tchannel1@............</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div bgcolor="#ffffff">
<div><font face="Arial" size="2">Meredith, Thank you for your reply and encouragement. The first sensor I spoke of was about 8 foot tall and the boom was about 4 foot, two feet on each side of the ribbon.</font></div>
<div><font face="Arial" size="2">I did not keep my notes on this unit but remember the period was massive, just moving the masses further out on the boom.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">This present unit is only about 36" tall and the boom, one side of the ribbon only is about 6". I used a SS thin wire instead of the band saw blade ribbon. At this point I think it will respond similar to a Lehman with a 5 second period. So far it behaves, just like my Lehman.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">I will let you know, if it works and send or post the .psn. It looks promising, very simple and if it works I will rebuild it targeting a 20 second period.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">Cheers, Ted ps..............On some web site I saw the concept of a Torsion Spring Long Period, illustrated as a box with a vertical torsion spring in the center of the box, and a boom............but the entire box was tipped, to illustrate the vertical wire/spring needed to be off vertical, not unlike the Lehman</font></div>
<div>
<div></div>
<div class="Wj3C7c">
<blockquote dir="ltr" style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<div style="FONT: 10pt arial">----- Original Message ----- </div>
<div style="BACKGROUND: #e4e4e4; FONT: 10pt arial"><b>From:</b> <a title="paleoartifact@........." href="mailto:paleoartifact@........." target="_blank">meredith lamb</a> </div>
<div style="FONT: 10pt arial"><b>To:</b> <a title="psn-l@.............." href="mailto:psn-l@.............." target="_blank">psn-l@..............</a> </div>
<div style="FONT: 10pt arial"><b>Sent:</b> Thursday, October 02, 2008 3:29 PM</div>
<div style="FONT: 10pt arial"><b>Subject:</b> Re:</div>
<div><br></div>
<div dir="ltr">Hi Ted,<br><br>Sorry...I couldn't find anything along the specific line you mention either..especially the flat ribbon spring variety. If I read you email right;<br>the very height you're using makes it a "giant" representation; and that likely makes it much more responsive as you're seeing, and<br>
to be fair the stresses involved will likely show all kinds of metal/structure creep over time which you'll have to adjust for.<br><br>A lot of the web sites I've seen, go out of their way to describe such as antiquated, obsolete, old etc; which is true in the sense<br>
of what is predominately used now. On the other hand, the torsion aspect really "does away" with a few of the normal pesky pivot problems<br>that are found in other seismometers/tiltmeters; and that alone is a good adjustment and/or labor saving positive.<br>
<br>Yes indeed...explore away.....there is likely a world of different flat ribbon or round wire sizes material one could try.<br><br>Take care, Meredith<br> <br>
<div class="gmail_quote">On Wed, Oct 1, 2008 at 10:38 PM, <span dir="ltr"><<a href="mailto:tchannel1@............" target="_blank">tchannel1@............</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">
<div bgcolor="#ffffff">
<div><font face="Arial" size="2">I am exploring the subject of a torsion spring sensor again. I say again because I have tried this approach before with no success at all.</font></div>
<div><font face="Arial" size="2">I took a long band saw blade cut it to form a long vertical torsion spring. Attached both ends and pulled it tight.</font></div>
<div><font face="Arial" size="2">In the middle of this spring I attached a boom. On both ends of the boom I attached a mass of equal value.</font></div>
<div><font face="Arial" size="2">This boom would move around the vertical axis with very little effort, twisting the spring and then reversing to the other direction, rocking back and forth for a very long time. I don't remember how long but I think it was one hour plus.</font></div>
<div><font face="Arial" size="2">The period of oscillation was controlled by moving the masses further out on the boom. Very long periods 30 seconds plus. To make a long story short, it did not record any earthquakes.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">I think I did two things wrong. 1. The booms of equal mass cancelled the movement of each other. And in this configuration the earthquake would need to spin the house to move the masses.</font></div>
<div><font face="Arial" size="2">2. The torsion spring needed to be tipped, not vertical.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">Here is my next attempt. 1. I removed the boom, which formed a (+) on the vertical torsion spring and replace it with a short pendulum boom, this time on one side only. </font></div>
<div><font face="Arial" size="2">it looks like a T on its side ( l-)</font></div>
<div><font face="Arial" size="2">2. I contained the vertical torsion spring in a strong box about 12"x12"x36". This retains all the parts and I can add tension to the spring, and mount the magnet and coil</font></div>
<div><font face="Arial" size="2">3. I placed three leveling legs on the base of the box. Now I can tip the vertical spring (Off Vertical). Similar to tipping a Lehman, pitching up or down.</font></div>
<div><font face="Arial" size="2">The spring now at an angle, contains a pendulum which is now (Off Horizontal).</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">The pendulum I am using is only about 6" long, and I get a period of about 5 seconds. I could get 20 seconds with a 18" boom. But my box could only accommodate a 6" boom.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2"> It is now running as a test......I will see if it will record earthquakes.</font></div>
<div><font face="Arial" size="2">It is sensitive to me moving around the room, and to drafts and tilts.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">I have seen something similar somewhere on the web, but I can't fine it. This is all I could find. If someone has tried this please email me. Thanks, Ted</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">Torsion Seismometer Wood Anderson</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2"><a href="http://www.data.scec.org/Module/s3inset3.html" target="_blank">http://www.data.scec.org/Module/s3inset3.html</a></font></div></div></blockquote></div><br></div></blockquote></div>
</div></div></blockquote></div><br></div>
Subject: Re: Re:
From: tchannel1@............
Date: Thu, 2 Oct 2008 21:13:22 -0600
Thanks, Folks, Yes this was the image I had seen before. Thanks also =
for the various references.
Ted
----- Original Message -----=20
From: meredith lamb=20
To: psn-l@.................
Sent: Thursday, October 02, 2008 6:47 PM
Subject: Re: Re:
Hi Ted,
The "concept" or diagram you mention is possibly this:
http://physics.mercer.edu/petepag/tilt.gif
which is a part of:
http://physics.mercer.edu/petepag/tiltm.html
and the title of the above is "Tiltmeters and Angle Measuring =
Equipment" by Randall Peters
but....I suppose you've already found such from Chris's reference.
Take care, Meredith
=20
On Thu, Oct 2, 2008 at 5:11 PM, <tchannel1@............> wrote:
Meredith, Thank you for your reply and encouragement. The first =
sensor I spoke of was about 8 foot tall and the boom was about 4 foot, =
two feet on each side of the ribbon.
I did not keep my notes on this unit but remember the period was =
massive, just moving the masses further out on the boom.
This present unit is only about 36" tall and the boom, one side of =
the ribbon only is about 6". I used a SS thin wire instead of the band =
saw blade ribbon. At this point I think it will respond similar to a =
Lehman with a 5 second period. So far it behaves, just like my Lehman.
I will let you know, if it works and send or post the .psn. =
It looks promising, very simple and if it works I will rebuild it =
targeting a 20 second period.
Cheers, Ted ps..............On some web site I saw the concept of =
a Torsion Spring Long Period, illustrated as a box with a vertical =
torsion spring in the center of the box, and a boom............but the =
entire box was tipped, to illustrate the vertical wire/spring needed to =
be off vertical, not unlike the Lehman
----- Original Message -----=20
From: meredith lamb=20
To: psn-l@.................
Sent: Thursday, October 02, 2008 3:29 PM
Subject: Re:
Hi Ted,
Sorry...I couldn't find anything along the specific line you =
mention either..especially the flat ribbon spring variety. If I read =
you email right;
the very height you're using makes it a "giant" representation; =
and that likely makes it much more responsive as you're seeing, and
to be fair the stresses involved will likely show all kinds of =
metal/structure creep over time which you'll have to adjust for.
A lot of the web sites I've seen, go out of their way to describe =
such as antiquated, obsolete, old etc; which is true in the sense
of what is predominately used now. On the other hand, the torsion =
aspect really "does away" with a few of the normal pesky pivot problems
that are found in other seismometers/tiltmeters; and that alone is =
a good adjustment and/or labor saving positive.
Yes indeed...explore away.....there is likely a world of different =
flat ribbon or round wire sizes material one could try.
Take care, Meredith
=20
On Wed, Oct 1, 2008 at 10:38 PM, <tchannel1@............> wrote:
I am exploring the subject of a torsion spring sensor again. I =
say again because I have tried this approach before with no success at =
all.
I took a long band saw blade cut it to form a long vertical =
torsion spring. Attached both ends and pulled it tight.
In the middle of this spring I attached a boom. On both ends of =
the boom I attached a mass of equal value.
This boom would move around the vertical axis with very little =
effort, twisting the spring and then reversing to the other direction, =
rocking back and forth for a very long time. I don't remember how long =
but I think it was one hour plus.
The period of oscillation was controlled by moving the masses =
further out on the boom. Very long periods 30 seconds plus. To make a =
long story short, it did not record any earthquakes.
I think I did two things wrong. 1. The booms of equal mass =
cancelled the movement of each other. And in this configuration the =
earthquake would need to spin the house to move the masses.
2. The torsion spring needed to be tipped, not vertical.
Here is my next attempt. 1. I removed the boom, which formed =
a (+) on the vertical torsion spring and replace it with a short =
pendulum boom, this time on one side only.=20
it looks like a T on its side ( l-)
2. I contained the vertical torsion spring in a strong box =
about 12"x12"x36". This retains all the parts and I can add tension to =
the spring, and mount the magnet and coil
3. I placed three leveling legs on the base of the box. Now I =
can tip the vertical spring (Off Vertical). Similar to tipping a =
Lehman, pitching up or down.
The spring now at an angle, contains a pendulum which is now =
(Off Horizontal).
The pendulum I am using is only about 6" long, and I get a =
period of about 5 seconds. I could get 20 seconds with a 18" boom. But =
my box could only accommodate a 6" boom.
It is now running as a test......I will see if it will record =
earthquakes.
It is sensitive to me moving around the room, and to drafts and =
tilts.
I have seen something similar somewhere on the web, but I can't =
fine it. This is all I could find. If someone has tried this please =
email me. Thanks, Ted
Torsion Seismometer Wood Anderson
http://www.data.scec.org/Module/s3inset3.html
<!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 6.00.6001.18099" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Thanks, Folks, Yes this was the image I =
had seen=20
before. Thanks also for the various references.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Ted</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=3Dpaleoartifact@............
href=3D"mailto:paleoartifact@.........">meredith lamb</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, October 02, =
2008 6:47=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: Re:</DIV>
<DIV><BR></DIV>
<DIV dir=3Dltr>
<DIV>Hi Ted,</DIV>
<DIV> </DIV>
<DIV>The "concept" or diagram you mention is possibly this:</DIV>
<DIV> </DIV>
<DIV><A=20
=
href=3D"http://physics.mercer.edu/petepag/tilt.gif">http://physics.mercer=
..edu/petepag/tilt.gif</A></DIV>
<DIV> </DIV>
<DIV>which is a part of:</DIV>
<DIV> </DIV>
<DIV><A=20
=
href=3D"http://physics.mercer.edu/petepag/tiltm.html">http://physics.merc=
er.edu/petepag/tiltm.html</A></DIV>
<DIV> </DIV>
<DIV>and the title of the above is "Tiltmeters and Angle Measuring =
Equipment"=20
by Randall Peters</DIV>
<DIV> </DIV>
<DIV>but....I suppose you've already found such from Chris's =
reference.</DIV>
<DIV> </DIV>
<DIV>Take care, Meredith</DIV>
<DIV><BR><BR> </DIV>
<DIV class=3Dgmail_quote>On Thu, Oct 2, 2008 at 5:11 PM, <SPAN =
dir=3Dltr><<A=20
=
href=3D"mailto:tchannel1@............">tchannel1@............</A>></SP=
AN>=20
wrote:<BR>
<BLOCKQUOTE class=3Dgmail_quote=20
style=3D"PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: =
#ccc 1px solid">
<DIV bgcolor=3D"#ffffff">
<DIV><FONT face=3DArial size=3D2>Meredith, Thank you for your =
reply and=20
encouragement. The first sensor I spoke of was about 8 =
foot tall=20
and the boom was about 4 foot, two feet on each side of the=20
ribbon.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I did not keep my notes on this =
unit but=20
remember the period was massive, just moving the masses further out =
on the=20
boom.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>This present unit is only about 36" =
tall and=20
the boom, one side of the ribbon only is about 6". I =
used a SS=20
thin wire instead of the band saw blade ribbon. At this =
point I=20
think it will respond similar to a Lehman with a 5 second =
period. So=20
far it behaves, just like my Lehman.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I will let you know, if it works =
and send or=20
post the=20
=
..psn. &n=
bsp;=20
It looks promising, very simple and if it works I will rebuild it =
targeting=20
a 20 second period.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Cheers, Ted =20
ps..............On some web site I saw the concept of a Torsion =
Spring Long=20
Period, illustrated as a box with a vertical torsion spring in the =
center of=20
the box, and a boom............but the entire box was tipped, to =
illustrate=20
the vertical wire/spring needed to be off vertical, not unlike the=20
Lehman</FONT></DIV>
<DIV>
<DIV></DIV>
<DIV class=3DWj3C7c>
<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 style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial"><B>From:</B> =
<A=20
title=3Dpaleoartifact@......... =
href=3D"mailto:paleoartifact@........."=20
target=3D_blank>meredith lamb</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dpsn-l@.................
href=3D"mailto:psn-l@.............." =
target=3D_blank>psn-l@..............</A>=20
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Thursday, October 02, =
2008 3:29=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re:</DIV>
<DIV><BR></DIV>
<DIV dir=3Dltr>Hi Ted,<BR><BR>Sorry...I couldn't find anything =
along the=20
specific line you mention either..especially the flat ribbon =
spring=20
variety. If I read you email right;<BR>the very height =
you're using=20
makes it a "giant" representation; and that likely makes it much =
more=20
responsive as you're seeing, and<BR>to be fair the stresses =
involved will=20
likely show all kinds of metal/structure creep over time which =
you'll have=20
to adjust for.<BR><BR>A lot of the web sites I've seen, go out of =
their=20
way to describe such as antiquated, obsolete, old etc; which is =
true in=20
the sense<BR>of what is predominately used now. On the other =
hand,=20
the torsion aspect really "does away" with a few of the normal =
pesky pivot=20
problems<BR>that are found in other seismometers/tiltmeters; and =
that=20
alone is a good adjustment and/or labor saving =
positive.<BR><BR>Yes=20
indeed...explore away.....there is likely a world of different =
flat ribbon=20
or round wire sizes material one could try.<BR><BR>Take care,=20
Meredith<BR> <BR>
<DIV class=3Dgmail_quote>On Wed, Oct 1, 2008 at 10:38 PM, <SPAN=20
dir=3Dltr><<A href=3D"mailto:tchannel1@............"=20
target=3D_blank>tchannel1@............</A>></SPAN> wrote:<BR>
<BLOCKQUOTE class=3Dgmail_quote=20
style=3D"PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; =
BORDER-LEFT: rgb(204,204,204) 1px solid">
<DIV bgcolor=3D"#ffffff">
<DIV><FONT face=3DArial size=3D2>I am exploring the subject of a =
torsion=20
spring sensor again. I say again because I have tried this =
approach before with no success at all.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I took a long band saw blade =
cut it to form=20
a long vertical torsion spring. Attached both ends and pulled it =
tight.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>In the middle of this spring I =
attached a=20
boom. On both ends of the boom I attached a mass of equal=20
value.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>This boom would move around the =
vertical=20
axis with very little effort, twisting the spring and then =
reversing to=20
the other direction, rocking back and forth for a very long =
time. =20
I don't remember how long but I think it was one hour =
plus.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The period of oscillation =
was=20
controlled by moving the masses further out on the =
boom. =20
Very long periods 30 seconds plus. To make a long story =
short, it=20
did not record any earthquakes.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I think I did two things =
wrong. 1.=20
The booms of equal mass cancelled the movement of each =
other. And=20
in this configuration the earthquake would need to spin =
the house=20
to move the masses.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>2. The torsion spring needed to =
be tipped,=20
not vertical.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Here is my next =
attempt. =20
1. I removed the boom, which formed a (+) on the vertical =
torsion=20
spring and replace it with a short pendulum boom, this time on =
one side=20
only. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2>it looks like a T on its side ( =
l-)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>2. I contained the =
vertical torsion=20
spring in a strong box about 12"x12"x36". This retains all =
the=20
parts and I can add tension to the spring, and mount the magnet =
and=20
coil</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>3. I placed three =
leveling legs on=20
the base of the box. Now I can tip the vertical =
spring (Off=20
Vertical). Similar to tipping a Lehman, =
pitching up or=20
down.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The spring now at an angle, =
contains a=20
pendulum which is now (Off Horizontal).</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>The pendulum I am using is only =
about 6"=20
long, and I get a period of about 5 seconds. I could get 20 =
seconds=20
with a 18" boom. But my box could only accommodate a 6"=20
boom.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2> It is now running as a =
test......I=20
will see if it will record earthquakes.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>It is sensitive to me moving =
around the=20
room, and to drafts and tilts.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I have seen something similar =
somewhere on=20
the web, but I can't fine it. This is all I could=20
find. If someone has tried this please email =
me. =20
Thanks, Ted</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Torsion Seismometer Wood=20
Anderson</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2><A=20
href=3D"http://www.data.scec.org/Module/s3inset3.html"=20
=
target=3D_blank>http://www.data.scec.org/Module/s3inset3.html</A></FONT><=
/DIV></DIV></BLOCKQUOTE></DIV><BR></DIV></BLOCKQUOTE></DIV></DIV></DIV></=
BLOCKQUOTE></DIV><BR></DIV></BLOCKQUOTE></BODY></HTML>
Subject: Damping
From: tchannel1@............
Date: Fri, 3 Oct 2008 12:21:45 -0600
Hi Folks,
I understand the necessity of using a Damper to keep the arm or boom =
from oscillate or belling after a signal begins. I would guess, after =
an earthquake signal arrives, an undamper arm would continue to =
oscillate for many minutes, overwriting most of the incoming signature.
I also understand the importance of minimizing the friction of the =
sensor's hinges. The signals are very small and they must overcome the =
friction before any movement of the arm can take place.
My question is: Does a Damper, oil or magnetic, not act the same as =
hinge friction?, in that, the signal must, first, overcome the =
resistance of the Damper?
Is an undamper sensor more sensitive than a dampered sensor? I have =
never tried this. Again, I know the signature would be of little =
value, but I am curious about the friction of the dampers.
Thanks, Ted
<!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 6.00.6001.18099" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Hi Folks,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I understand the necessity of using a =
Damper to=20
keep the arm or boom from oscillate or belling after a signal=20
begins. I would guess, after an earthquake signal =
arrives, an=20
undamper arm would continue to oscillate for many minutes, overwriting =
most of=20
the incoming signature.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I also understand the importance of =
minimizing the=20
friction of the sensor's hinges. The signals are very small =
and they=20
must overcome the friction before any movement of the arm can take=20
place.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>My question is: Does a Damper, =
oil or=20
magnetic, not act the same as hinge friction?, in that, the signal must, =
first,=20
overcome the resistance of the Damper?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Is an undamper sensor more =
sensitive=20
than a dampered sensor? I have never tried =
this. =20
Again, I know the signature would be of little value, but I am curious =
about the=20
friction of the dampers.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Thanks, Ted</FONT></DIV></BODY></HTML>
Subject: Radio Signals and Seismic Events
From: "Jerry Payton" gpayton880@.......
Date: Fri, 3 Oct 2008 14:09:41 -0500
Hi Ted,
If everything else wasn't already confusing, check this site out when you
have time:
http://www.vlf.it/romero/seismic_rdf.htm
Regards,
Jerry
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Dwindows-1252">
<META content=3D"MSHTML 6.00.6000.16705" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial>Hi Ted,</FONT></DIV>
<DIV><FONT face=3DArial></FONT> </DIV>
<DIV><FONT face=3DArial>If everything else wasn't already confusing, =
check this=20
site out when you have time:</FONT></DIV>
<DIV><FONT face=3DArial></FONT> </DIV>
<DIV><FONT face=3DArial><A=20
href=3D"http://www.vlf.it/romero/seismic_rdf.htm">http://www.vlf.it/romer=
o/seismic_rdf.htm</A></FONT></DIV>
<DIV><FONT face=3DArial></FONT> </DIV>
<DIV><FONT face=3DArial>Regards,</FONT></DIV>
<DIV><FONT face=3DArial>Jerry</FONT></DIV></BODY></HTML>
Subject: Re: Damping
From: ChrisAtUpw@.......
Date: Fri, 3 Oct 2008 19:04:52 EDT
In a message dated 2008/10/03, tchannel1@............ writes:
> My question is: Does a Damper, oil or magnetic, not act the same as hinge
> friction?, in that, the signal must, first, overcome the resistance of the
> Damper?
Hi Ted,
Forget oil damping. Magnetic damping is easy to use, not expensive and
clean.
To stop the arm oscillating, you want to generate a retarding force
accurately proportional to the velocity. You DON'T want ANY static friction
> Is an undamper sensor more sensitive than a dampered sensor?
>
An undamped arm will oscillate at it's natural frequency and be very
sensitive, but the amplitude will form a wavy line over time as signals
continue to roll in. However, you want a response which is FLAT with frequency, say
at all periods from 20 seconds to 5 Hz and changes as the incoming signal level
changes, NOT a response which just has a peak at 20 seconds.
It is possible to use an underdamped sensor, but you need to do some
complicated maths analysis on it to extract the original ground motion from the
quake. There is no problem getting a high enough sensitivity from
semiconductor amplifiers. What limits your detection level is the ambient noise in the
ground from road traffic, wind noise from trees, wave noise from the oceans,
noise from weather systems......
Regards,
Chris Chapman
<HTML><FONT FACE=3Darial,helvetica><HTML><FONT SIZE=3D2 PTSIZE=3D10>In a me=
ssage dated 2008/10/03, tchannel1@............ writes:<BR>
<BR>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">My question is: Does a Da=
mper, oil or magnetic, not act the same as hinge friction?, in that, the sig=
nal must, first, overcome the resistance of the Damper?</FONT><FONT COLOR=
=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 P=
TSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"></BLOCKQUOTE><BR>
</FONT><FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR:=20=
#ffffff" SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SANSSERIF" 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"=
>Hi Ted,<BR>
<BR>
Forget oil damping. Magnetic damping is=
easy to use, not expensive and clean.<BR>
<BR>
To stop the arm oscillating, you want t=
o generate a retarding force accurately proportional to the velocity. You DO=
N'T want ANY static friction</FONT><FONT COLOR=3D"#000000" BACK=3D"#ffffff"=
style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SANSSERI=
F" FACE=3D"Arial" LANG=3D"0"><BR>
</FONT><FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR:=20=
#ffffff" SIZE=3D3 PTSIZE=3D12 FAMILY=3D"SANSSERIF" 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"=
><BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEF=
T: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Is an undamper sensor mo=
re sensitive than a dampered sensor? </FONT><FONT COLOR=3D"#000000" BACK=
=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D3 PTSIZE=3D12 FAMILY=
=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"><BR>
</BLOCKQUOTE><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"=
> An undamped arm will oscillate at it's=
natural frequency and be very sensitive, but the amplitude will form a wavy=
line over time as signals continue to roll in. However, you want a response=
which is FLAT with frequency, say at all periods from 20 seconds to 5 Hz an=
d changes as the incoming signal level changes, NOT a response which just ha=
s a peak at 20 seconds.<BR>
<BR>
It is possible to use an underdamped se=
nsor, but you need to do some complicated maths analysis on it to extract th=
e original ground motion from the quake. There is no problem getting a high=20=
enough sensitivity from semiconductor amplifiers. What limits your detection=
level is the ambient noise in the ground from road traffic, wind noise from=
trees, wave noise from the oceans, noise from weather systems......<BR>
<BR>
Regards,<BR>
<BR>
Chris Chapman<BR>
</FONT> </HTML>
Subject: Re: Radio Signals and Seismic Events
From: Brad Douglas rez@..................
Date: Fri, 03 Oct 2008 19:55:09 -0700
On Fri, 2008-10-03 at 14:09 -0500, Jerry Payton wrote:
> If everything else wasn't already confusing, check this site out when
> you have time:
>
> http://www.vlf.it/romero/seismic_rdf.htm
This is actually not so unusual for someone with an amateur radio
background (which this individual obviously has, judging by some of the
terminology). There are a couple people out there with nice ELF/VLF
setups. The government has some really cool stuff up in AK, but
slightly out of our price range. ;-)
I've done some work with these people, too (prototype tracking and
recovery):
http://quakefinder.com/
QuakeSat operates on the same principles.
--
73, de Brad KB8UYR/6 <rez touchofmadness com>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Damping
From: Brett Nordgren brett3nt@.............
Date: Fri, 03 Oct 2008 23:23:30 -0400
Ted,
The kind of damping you need will generate a retarding force which is
approximately proportional to velocity. For very slow motions, it
generates almost no damping force. Most types of sliding friction are
large until the joint 'breaks away' and starts moving, and then are
relatively constant with velocity. This is definitely not what you want
for seismo damping. Chris' magnets are a very good way of getting what you
need--no static 'break away' and zero damping force at DC, but having the
damping force linearly increasing with frequency.
As far as hinges go, flexures are pretty good, and some rolling designs are
also. Both have essentially no static, break away, friction.
An undamped sensor is actually more sensitive than a damped one. It's just
that an undamped sensor's output won't look at all like the actual earth
motion you are trying to record. With damping, you trade sensitivity for
accuracy.
Regards,
Brett
At 12:21 PM 10/3/2008 -0600, you wrote:
>Hi Folks,
>
>I understand the necessity of using a Damper to keep the arm or boom from
>oscillate or belling after a signal begins. I would guess, after an
>earthquake signal arrives, an undamper arm would continue to oscillate for
>many minutes, overwriting most of the incoming signature.
>
>I also understand the importance of minimizing the friction of the
>sensor's hinges. The signals are very small and they must overcome the
>friction before any movement of the arm can take place.
>
>My question is: Does a Damper, oil or magnetic, not act the same as hinge
>friction?, in that, the signal must, first, overcome the resistance of the
>Damper?
>
>Is an undamper sensor more sensitive than a dampered sensor? I have
>never tried this. Again, I know the signature would be of little value,
>but I am curious about the friction of the dampers.
>
>Thanks, Ted
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Damping
From: tchannel1@............
Date: Sat, 4 Oct 2008 07:25:14 -0600
Hi Folks, As usually many good answers to my questions. I am still trying
different configurations on the Torsion Spring machine. In my shop I made a
24", a 36" and a 60".
I could get 12 seconds on the 24", and 21 seconds on the 60" and an
oscillation of 75 mins. These were crude setups, so I still need to build
one with a better and proper three legged adj. base.
For these I just wanted to gather ideas for the next version.
I have one version finished and waiting for an earthquake, it has a
magnetic damper. When or if it records its first earthquake, I will remove
the Damper and try it again. As others pointed out the background noises
will most likely be so large, the sensor will be in motion almost
constantly. Having no damper, and being sensitive, it might just rock and
roll responding to the noises, 24/7.
I might leave it undampered for a few days, in hopes that if we have a
quiet night, it might respond to a small event. Presently I can just make
out a 4.1m in California, on most of my sensors. I will see if undampered,
if would pickup a 4.0
Again thanks for explaining how the properties of a Damper is different than
the friction of the hinges.
Ted
----- Original Message -----
From: "Brett Nordgren" <brett3nt@.............>
To: <psn-l@..............>
Sent: Friday, October 03, 2008 9:23 PM
Subject: Re: Damping
> Ted,
>
> The kind of damping you need will generate a retarding force which is
> approximately proportional to velocity. For very slow motions, it
> generates almost no damping force. Most types of sliding friction are
> large until the joint 'breaks away' and starts moving, and then are
> relatively constant with velocity. This is definitely not what you want
> for seismo damping. Chris' magnets are a very good way of getting what
> you need--no static 'break away' and zero damping force at DC, but having
> the damping force linearly increasing with frequency.
>
> As far as hinges go, flexures are pretty good, and some rolling designs
> are also. Both have essentially no static, break away, friction.
>
> An undamped sensor is actually more sensitive than a damped one. It's
> just that an undamped sensor's output won't look at all like the actual
> earth motion you are trying to record. With damping, you trade
> sensitivity for accuracy.
>
> Regards,
> Brett
>
> At 12:21 PM 10/3/2008 -0600, you wrote:
>>Hi Folks,
>>
>>I understand the necessity of using a Damper to keep the arm or boom from
>>oscillate or belling after a signal begins. I would guess, after an
>>earthquake signal arrives, an undamper arm would continue to oscillate for
>>many minutes, overwriting most of the incoming signature.
>>
>>I also understand the importance of minimizing the friction of the
>>sensor's hinges. The signals are very small and they must overcome the
>>friction before any movement of the arm can take place.
>>
>>My question is: Does a Damper, oil or magnetic, not act the same as hinge
>>friction?, in that, the signal must, first, overcome the resistance of the
>>Damper?
>>
>>Is an undamper sensor more sensitive than a dampered sensor? I have
>>never tried this. Again, I know the signature would be of little value,
>>but I am curious about the friction of the dampers.
>>
>>Thanks, Ted
>
>
> __________________________________________________________
>
> 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: Background Noise Again
From: "Gary Lindgren" gel@.................
Date: Mon, 6 Oct 2008 22:48:31 -0700
I observed a strange phenomenon this weekend with my 23 sec. Lehman.
Normally the background noise level drops down at night and gets very quiet
after 11PM and until around 6AM. However on Saturday and Sunday night this
past weekend, the background noise did not subside. Also the noise seem to
peak with a FFT scan at around .06 Hz/sec. or a 16 second period. This all
changed at around 0100 UTC 10/7/08 and is now back the normal signature.
Does this make sense at all. Surely the earth is not ringing is it?
Gary
Gary Lindgren
585 Lincoln Ave
Palo Alto CA 94301
650-326-0655
<http://www.blue-eagle-technologies.com/> www.blue-eagle-technologies.com
Check out Lastest Seismometer Reading
<http://www.cymonsplace.blogspot.com/> cymonsplace.blogspot.com
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<div class=3DSection1>
<p class=3DMsoNormal>I observed a strange phenomenon this weekend with =
my 23 sec.
Lehman. Normally the background noise level drops down at night and gets =
very
quiet after 11PM and until around 6AM. However on Saturday and Sunday =
night
this past weekend, the background noise did not subside. Also the noise =
seem to
peak with a FFT scan at around .06 Hz/sec. or a 16 second period. This =
all
changed at around 0100 UTC 10/7/08 and is now back the normal signature. =
Does
this make sense at all. Surely the earth is not ringing is =
it?<o:p></o:p></p>
<p class=3DMsoNormal>Gary<o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>Gary Lindgren</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>585 Lincoln Ave</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>Palo Alto CA 94301</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>650-326-0655<=
/span><o:p></o:p></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href=3D"http://www.blue-eagle-technologies.com/"><span =
style=3D'color:blue'>www.blue-eagle-technologies.com</span></a>
<span style=3D'color:red'>Check out Lastest Seismometer =
Reading</span></span><o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href=3D"http://www.cymonsplace.blogspot.com/"><span =
style=3D'color:blue'>cymonsplace.blogspot.com</span></a> </span><o:p=
></o:p></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
</div>
</body>
</html>
Subject: Re: Background Noise Again
From: Steinar Midtskogen steinar@.............
Date: Tue, 07 Oct 2008 08:16:49 +0200
[Gary Lindgren]
> I observed a strange phenomenon this weekend with my 23 sec. Lehman. Normally
> the background noise level drops down at night and gets very quiet after 11PM
> and until around 6AM. However on Saturday and Sunday night this past weekend,
> the background noise did not subside. Also the noise seem to peak with a FFT
> scan at around .06 Hz/sec. or a 16 second period. This all changed at around
> 0100 UTC 10/7/08 and is now back the normal signature. Does this make sense at
> all. Surely the earth is not ringing is it?
I haven't checked the frequencies, but I sometimes see similar things
when there's a storm in the ocean within a few hundred km.
--
Steinar
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Background Noise Again
From: Thomas Dick dickthomas01@.............
Date: Tue, 07 Oct 2008 07:13:55 -0500
I also saw a peak in that area of my FFT for 1100 UT on Sunday morning
and I sent Chris an email about it.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Torsion Seismometer
From: tchannel1@............
Date: Tue, 7 Oct 2008 07:39:05 -0600
Hi Folks, I just recorded the first event using my Torsion wire/spring =
sensor. The sensor was made using some bits and pieces from other =
units. The construction was not carefully designed or executed, as I =
just wanted to see if the concept would work. I will post three =
examples on PSN, Ch 1=3Da simple pendulum with a 2 second period, Ch =
2=3DThe New Torsion Spring with a 5second period, Ch 3=3D a Lehman at 20 =
seconds.
All three sensor recorded the 5.8M ARCTIC OCEAN today.
I have another Torsion Spring Mock-up made of wood on my bench, not to =
used, but to test for general dimensions and period. Happy to send =
picts and discuss design with anyone who is interested in helping me =
build a proper unit. The mock up is only 18"? tall, has a torsion =
spring of about 14" and a boom of 12". The frame looks like a Lehman, =
and the wire is near the vertical support. Under these conditions I =
could get a period of 25 seconds, but unstable. It now is adjusted to =
15 seconds and seems stable. A longer or shorter period should be =
possible.
The Wire is not spring wire, although it has some spring to it. It is =
..016" ss fishing lure. Thanks to J.P. for sending me the wire. For =
my experiments I have used, a bandsaw blade, brass music wire, and SS =
fishing wire.
Anyhow the idea seems to work and and very easy to adjust. I am not =
sure what sensor period I should target. Deciding that will dictate =
many of the other dimensions and overall size.
Cheers, Ted
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<DIV><FONT face=3DArial size=3D2>Hi Folks, I just recorded the =
first event=20
using my Torsion wire/spring sensor. The sensor was made=20
using some bits and pieces from other units. The construction =
was not=20
carefully designed or executed, as I just wanted to see if the concept =
would=20
work. I will post three examples on PSN, Ch 1=3Da simple =
pendulum with=20
a 2 second period, Ch 2=3DThe New Torsion Spring with a 5second =
period, Ch=20
3=3D a Lehman at 20 seconds.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>All three sensor recorded the 5.8M =
ARCTIC OCEAN=20
today.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I have another Torsion Spring Mock-up =
made of wood=20
on my bench, not to used, but to test for general dimensions and=20
period. Happy to send picts and discuss design with anyone =
who is=20
interested in helping me build a proper unit. The mock up is =
only=20
18"? tall, has a torsion spring of about 14" and a boom of 12". =
The frame=20
looks like a Lehman, and the wire is near the vertical =
support. =20
Under these conditions I could get a period of 25 seconds, but =
unstable. =20
It now is adjusted to 15 seconds and seems stable. A longer or =
shorter=20
period should be possible.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>The Wire is not spring wire, although =
it has some=20
spring to it. It is .016" ss fishing lure. Thanks to =
J.P. for=20
sending me the wire. For my experiments I have used, a =
bandsaw=20
blade, brass music wire, and SS fishing wire.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Anyhow the idea seems to work and and =
very easy to=20
adjust. I am not sure what sensor period I should =
target. =20
Deciding that will dictate many of the other dimensions and overall=20
size.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Cheers, Ted</FONT></DIV></BODY></HTML>
Subject: Re: Background Noise Again
From: ChrisAtUpw@.......
Date: Tue, 7 Oct 2008 23:09:06 EDT
In a message dated 2008/10/07, gel@................. writes:
> I observed a strange phenomenon this weekend with my 23 sec.
Hi Gary,
Look for ocean / storm related noise and also noise assocoiated with
weather fronts.
Ocean microiseisms tend to be in the 4 to 8 second region, but you may
get wave noise nerare 10 to 12 seconds. Weather noise is often broadband.
Have you got the damping set correctly? This can also cause noise
peaks if it is too low.
Regards,
Chris Chapman
<HTML><FONT FACE=3Darial,helvetica><HTML><FONT SIZE=3D2 PTSIZE=3D10>In a me=
ssage dated 2008/10/07, gel@................. writes:<BR>
<BR>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">I observed a strange phenomenon=
this weekend with my 23 sec. </BLOCKQUOTE><BR>
<BR>
Hi Gary,<BR>
<BR>
Look for ocean / storm related noise an=
d also noise assocoiated with weather fronts.<BR>
Ocean microiseisms tend to be in the 4=20=
to 8 second region, but you may get wave noise nerare 10 to 12 seconds. Weat=
her noise is often broadband.<BR>
<BR>
Have you got the damping set correctly?=
This can also cause noise peaks if it is too low.<BR>
<BR>
Regards,<BR>
<BR>
Chris Chapman<BR>
</FONT> </HTML>
Subject: Re: Torsion Seismometer
From: "meredith lamb" paleoartifact@.........
Date: Wed, 8 Oct 2008 11:27:46 -0600
Hi Ted,
Nothing new, but; music (piano) wire is very hard to beat for its high
tensile strength, durability, low cost and a good variation of diameter size
availability at a variety of hardware and hobby shops. Think you'll
eventually gravitate over to this material, as the material you've tried
will
stretch sag and change the period and position of the boom/mass if theirs
much of any weight involved in mass/boom you have or will try in the future.
Was wondering if you're contemplating making your "T" connection or
boom/wire connection to where it uses up the majority length of the wire?
If you get to this arrangement I would think if would allow more mass
weight, and limit too much wire play; while still using the wire torsion
aspect.
Am speculating...but say if your wire is 14" length, and your "T" length is
~ 10"; you could still see a lot of reasonable good response. Clamping
down
on the wire to where the "T" doesn't gravity weight slide down over time
might be a real anticipated potential problem.
I'd think the frame for such, would have to be mechanically superior to
support the wire tension necessary; i.e., big bulky high strength. One may
have to even use stuff like iron plumbing pipes with its lousy temperature
variations to get the high strength. Aluminum would be temperature"nicer",
but
obtaining really strong thick aluminum might only be available via a metals
scrap yard; and then, you'd need tools to work it down to the desired
size/s.
Overcoming this frame strength necessity is a major obstacle for a long
lasting torsion wire seismometer especially for a higher mass weight
variety.
Musings....
Take care, Meredith
On Tue, Oct 7, 2008 at 7:39 AM, <tchannel1@............> wrote:
> Hi Folks, I just recorded the first event using my Torsion wire/spring
> sensor. The sensor was made using some bits and pieces from other units.
> The construction was not carefully designed or executed, as I just wanted to
> see if the concept would work. I will post three examples on PSN, Ch 1=a
> simple pendulum with a 2 second period, Ch 2=The New Torsion Spring with a
> 5second period, Ch 3= a Lehman at 20 seconds.
> All three sensor recorded the 5.8M ARCTIC OCEAN today.
>
> I have another Torsion Spring Mock-up made of wood on my bench, not to
> used, but to test for general dimensions and period. Happy to send picts
> and discuss design with anyone who is interested in helping me build a
> proper unit. The mock up is only 18"? tall, has a torsion spring of about
> 14" and a boom of 12". The frame looks like a Lehman, and the wire is near
> the vertical support. Under these conditions I could get a period of 25
> seconds, but unstable. It now is adjusted to 15 seconds and seems stable.
> A longer or shorter period should be possible.
>
> The Wire is not spring wire, although it has some spring to it. It is
> .016" ss fishing lure. Thanks to J.P. for sending me the wire. For my
> experiments I have used, a bandsaw blade, brass music wire, and SS fishing
> wire.
>
> Anyhow the idea seems to work and and very easy to adjust. I am not sure
> what sensor period I should target. Deciding that will dictate many of the
> other dimensions and overall size.
>
> Cheers, Ted
>
<div dir="ltr">Hi Ted,<br><br>Nothing new, but; music (piano) wire is very hard to beat for its high tensile strength, durability, low cost and a good variation of diameter size<br>availability at a variety of hardware and hobby shops. Think you'll eventually gravitate over to this material, as the material you've tried will<br>
stretch sag and change the period and position of the boom/mass if theirs much of any weight involved in mass/boom you have or will try in the future. <br><br>Was wondering if you're contemplating making your "T" connection or boom/wire connection to where it uses up the majority length of the wire?<br>
If you get to this arrangement I would think if would allow more mass weight, and limit too much wire play; while still using the wire torsion aspect.<br>Am speculating...but say if your wire is 14" length, and your "T" length is ~ 10"; you could still see a lot of reasonable good response. Clamping down<br>
on the wire to where the "T" doesn't gravity weight slide down over time might be a real anticipated potential problem.<br><br>I'd think the frame for such, would have to be mechanically superior to support the wire tension necessary; i.e., big bulky high strength. One may<br>
have to even use stuff like iron plumbing pipes with its lousy temperature variations to get the high strength. Aluminum would be temperature"nicer", but<br>obtaining really strong thick aluminum might only be available via a metals scrap yard; and then, you'd need tools to work it down to the desired size/s.<br>
Overcoming this frame strength necessity is a major obstacle for a long lasting torsion wire seismometer especially for a higher mass weight variety. <br><br>Musings....<br><br>Take care, Meredith<br> <br><br><br><br>
<div class="gmail_quote">On Tue, Oct 7, 2008 at 7:39 AM, <span dir="ltr"><<a href="mailto:tchannel1@............">tchannel1@............</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div bgcolor="#ffffff">
<div><font face="Arial" size="2">Hi Folks, I just recorded the first event
using my Torsion wire/spring sensor. The sensor was made
using some bits and pieces from other units. The construction was not
carefully designed or executed, as I just wanted to see if the concept would
work. I will post three examples on PSN, Ch 1=a simple pendulum with
a 2 second period, Ch 2=The New Torsion Spring with a 5second period, Ch
3= a Lehman at 20 seconds.</font></div>
<div><font face="Arial" size="2">All three sensor recorded the 5.8M ARCTIC OCEAN
today.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">I have another Torsion Spring Mock-up made of wood
on my bench, not to used, but to test for general dimensions and
period. Happy to send picts and discuss design with anyone who is
interested in helping me build a proper unit. The mock up is only
18"? tall, has a torsion spring of about 14" and a boom of 12". The frame
looks like a Lehman, and the wire is near the vertical support.
Under these conditions I could get a period of 25 seconds, but unstable.
It now is adjusted to 15 seconds and seems stable. A longer or shorter
period should be possible.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">The Wire is not spring wire, although it has some
spring to it. It is .016" ss fishing lure. Thanks to J.P. for
sending me the wire. For my experiments I have used, a bandsaw
blade, brass music wire, and SS fishing wire.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">Anyhow the idea seems to work and and very easy to
adjust. I am not sure what sensor period I should target.
Deciding that will dictate many of the other dimensions and overall
size.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">Cheers, Ted</font></div></div>
</blockquote></div><br></div>
Subject: LIGO X-Suspension Pendulum
From: "Chuck Burch" cjburch@...........
Date: Thu, 09 Oct 2008 05:04:58 -0600
All,
I'm confused by the recent messages that imply that a pendulum with a LIGO X-
suspension should be designed with the center of mass above the platform
suspended by the crossed flexures.
In this scheme one end of each of 4 flexures (wires or shim stock strips) are rigidly
supported. (These supports make a rectangle in the the horizontal plane.) The other
ends of the flexures are connected to, and support, a platform so that the flexures
make an X when viewed from the side. The supported platform is the top of the
moving part of the pendulum.
This scheme is well described in the paper written by Barton and Kuroda, Ultralow
Frequency Oscillator, Rev. Sci. Instrum. 65 (12), Dec. 1994. It explains that for a
particular suspension geometry there is a critical vertical position. If the CoM is
below the critical position the pendulum is stable - if the CoM is above it is unstable.
As the CoM approaches the critical position from below the pendulum period
becomes arbitrarily large. Under most practical circumstances the critical position is
below the suspended platform.
My limited experiments with a LIGO X-suspension are consistent with Barton and
Kuroda's description.
Chuck Burch
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: LIGO X-Suspension Pendulum
From: ChrisAtUpw@.......
Date: Wed, 8 Oct 2008 22:28:57 EDT
In a message dated 2008/10/09, cjburch@........... writes:
> I'm confused by the recent messages that imply that a pendulum with a LIGO
> X-
> suspension should be designed with the center of mass above the platform
> suspended by the crossed flexures.
Hi Chuck,
There are two possible types of long period crossed wire suspension
systems. One has the mass positioned below the suspended plate. The LIGO system
has the mass positioned above the suspended plate, just below the position
where wires cross. This is much more compact.
Regards,
Chris Chapman
<HTML><FONT FACE=3Darial,helvetica><HTML><FONT SIZE=3D2 PTSIZE=3D10>In a me=
ssage dated 2008/10/09, cjburch@........... writes:<BR>
<BR>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">I'm confused by the recent mess=
ages that imply that a pendulum with a LIGO X-<BR>
suspension should be designed with the center of mass above the platform <BR=
>
suspended by the crossed flexures. </BLOCKQUOTE><BR>
<BR>
Hi Chuck,<BR>
<BR>
There are two possible types of long pe=
riod crossed wire suspension systems. One has the mass positioned below the=20=
suspended plate. The LIGO system has the mass positioned above the suspended=
plate, just below the position where wires cross. This is much more compact=
..<BR>
<BR>
Regards,<BR>
<BR>
Chris Chapman</FONT> </HTML>
Subject: Paper on seismometer pivot systems
From: Charles Patton charles.r.patton@........
Date: Tue, 14 Oct 2008 23:33:36 -0700
To the PSN community,
Please check out
http://www.myeclectic.info/SeismoPivots/seismopivots.htm
for the results of a series of discussions between Chris Chapman, Brett
Nordgren and myself on the applicability of various pivot systems to
the construction of seismometers. Comments are welcome as I view this
as a work in progress.
The work on this paper got me contemplating the construction of a LIGO
X-Suspension using 3/4" PVC pipe with Metglas band bearings. Something
a bit different.
Regards,
Charles R Patton
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Paper on seismometer pivot systems
From: "meredith lamb" paleoartifact@.........
Date: Wed, 15 Oct 2008 11:02:29 -0600
Congratulations to Charles, Chris and Brett for this fine publication! I
can readily see many months of work behind it.
The variety of pivot approaches and the improvements noted therein, will
likely make this publication the
most interesting, useful and suggestive of important improvements of present
working seismometers than has been
PSN presented at any time in the past. The "world" of the variety of pivots
shown should greatly enhance
a lot of exciting interesting experimentation with them! It readily
deserves a "first reader" status, for those either in entry
or any latter stage of home seismometry building comtemplation.
Again, many thanks!!!
Take care, Meredith Lamb
On Wed, Oct 15, 2008 at 12:33 AM, Charles Patton
<charles.r.patton@........>wrote:
> To the PSN community,
> Please check out
> http://www.myeclectic.info/SeismoPivots/seismopivots.htm
> for the results of a series of discussions between Chris Chapman, Brett
> Nordgren and myself on the applicability of various pivot systems to the
> construction of seismometers. Comments are welcome as I view this as a work
> in progress.
> The work on this paper got me contemplating the construction of a LIGO
> X-Suspension using 3/4" PVC pipe with Metglas band bearings. Something a
> bit different.
> Regards,
> Charles R Patton
>
>
>
>
<div dir="ltr"><div>Congratulations to Charles, Chris and Brett for this fine publication! I can readily see many months of work behind it.</div>
<div> </div>
<div>The variety of pivot approaches and the improvements noted therein, will likely make this publication the</div>
<div>most interesting, useful and suggestive of important improvements of present working seismometers than has been</div>
<div>PSN presented at any time in the past. The "world" of the variety of pivots shown should greatly enhance</div>
<div>a lot of exciting interesting experimentation with them! It readily deserves a "first reader" status, for those either in entry</div>
<div>or any latter stage of home seismometry building comtemplation.</div>
<div> </div>
<div>Again, many thanks!!!</div>
<div> </div>
<div>Take care, Meredith Lamb<br><br></div>
<div class="gmail_quote">On Wed, Oct 15, 2008 at 12:33 AM, Charles Patton <span dir="ltr"><<a href="mailto:charles.r.patton@........">charles.r.patton@........</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">To the PSN community,<br>Please check out<br><a href="http://www.myeclectic.info/SeismoPivots/seismopivots.htm" target="_blank">http://www.myeclectic.info/SeismoPivots/seismopivots.htm</a><br>
for the results of a series of discussions between Chris Chapman, Brett Nordgren and myself on the applicability of various pivot systems to the construction of seismometers. Comments are welcome as I view this as a work in progress. <br>
The work on this paper got me contemplating the construction of a LIGO X-Suspension using 3/4" PVC pipe with Metglas band bearings. Something a bit different. <br>Regards,<br>Charles R Patton<br><br><br><br></blockquote>
</div></div>
Subject: 3 wire "X" suspension ?
From: "meredith lamb" paleoartifact@.........
Date: Wed, 15 Oct 2008 12:30:30 -0600
Hi all,
I took a few minutes to build a non-working horizontal response model of
what I think a 3 wire "x" suspension could look like. Am
trying to grasp such. I don't know if its even ~ practical actually. I
would think it could have unidirectional horizontal response.
Its seemingly more likely to instead have the mass underneath the bottom
"plate" for perhaps better period adjustment range. See:
http://seismometer.googlepages.com/3wirexsuspension
New and "strange" yes, but interesting. The trouble with this is that I
don't think anyone has actual experience...but if they
do; I'd like to hear about it.....or.....any comments....
Take care, Meredith
<div dir="ltr"><div> </div>
<div>Hi all,</div>
<div> </div>
<div>I took a few minutes to build a non-working horizontal response model of what I think a 3 wire "x" suspension could look like. Am</div>
<div>trying to grasp such. I don't know if its even ~ practical actually. I would think it could have unidirectional horizontal response. </div>
<div>Its seemingly more likely to instead have the mass underneath the bottom "plate" for perhaps better period adjustment range. See:</div>
<div> </div>
<div><a href="http://seismometer.googlepages.com/3wirexsuspension">http://seismometer.googlepages.com/3wirexsuspension</a></div>
<div> </div>
<div>New and "strange" yes, but interesting. The trouble with this is that I don't think anyone has actual experience...but if they</div>
<div>do; I'd like to hear about it.....or.....any comments....</div>
<div> </div>
<div>Take care, Meredith </div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<div> </div></div>
Subject: Re: Paper on seismometer pivot systems
From: "James Allen" jcallen1@...........
Date: Wed, 15 Oct 2008 21:08:21 -0700
I would like to join Meredith in his praise of the the work of Charles, =
Chris and Brett. Very thought provoking.
James Allen=20
----- Original Message -----=20
From: meredith lamb=20
To: psn-l@.................
Sent: Wednesday, October 15, 2008 10:02 AM
Subject: Re: Paper on seismometer pivot systems
Congratulations to Charles, Chris and Brett for this fine publication! =
I can readily see many months of work behind it.
The variety of pivot approaches and the improvements noted therein, =
will likely make this publication the
most interesting, useful and suggestive of important improvements of =
present working seismometers than has been
PSN presented at any time in the past. The "world" of the variety of =
pivots shown should greatly enhance
a lot of exciting interesting experimentation with them! It readily =
deserves a "first reader" status, for those either in entry
or any latter stage of home seismometry building comtemplation.
Again, many thanks!!!
Take care, Meredith Lamb
On Wed, Oct 15, 2008 at 12:33 AM, Charles Patton =
<charles.r.patton@........> wrote:
To the PSN community,
Please check out
http://www.myeclectic.info/SeismoPivots/seismopivots.htm
for the results of a series of discussions between Chris Chapman, =
Brett Nordgren and myself on the applicability of various pivot systems =
to the construction of seismometers. Comments are welcome as I view =
this as a work in progress.=20
The work on this paper got me contemplating the construction of a =
LIGO X-Suspension using 3/4" PVC pipe with Metglas band bearings. =
Something a bit different.=20
Regards,
Charles R Patton
<!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 6.00.6001.18148" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>I would like to join Meredith in his =
praise of the=20
the work of Charles, Chris and Brett. Very thought =
provoking.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>James Allen</FONT> </DIV>
<DIV>----- Original Message ----- </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=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Dpaleoartifact@............
href=3D"mailto:paleoartifact@.........">meredith lamb</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> Wednesday, October 15, =
2008 10:02=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: Paper on =
seismometer pivot=20
systems</DIV>
<DIV><BR></DIV>
<DIV dir=3Dltr>
<DIV>Congratulations to Charles, Chris and Brett for this fine=20
publication! I can readily see many months of work behind =
it.</DIV>
<DIV> </DIV>
<DIV>The variety of pivot approaches and the improvements noted =
therein, will=20
likely make this publication the</DIV>
<DIV>most interesting, useful and suggestive of important improvements =
of=20
present working seismometers than has been</DIV>
<DIV>PSN presented at any time in the past. The "world" of the =
variety=20
of pivots shown should greatly enhance</DIV>
<DIV>a lot of exciting interesting experimentation with them! It =
readily=20
deserves a "first reader" status, for those either in entry</DIV>
<DIV>or any latter stage of home seismometry building =
comtemplation.</DIV>
<DIV> </DIV>
<DIV>Again, many thanks!!!</DIV>
<DIV> </DIV>
<DIV>Take care, Meredith Lamb<BR><BR></DIV>
<DIV class=3Dgmail_quote>On Wed, Oct 15, 2008 at 12:33 AM, Charles =
Patton <SPAN=20
dir=3Dltr><<A=20
=
href=3D"mailto:charles.r.patton@........">charles.r.patton@........</A>&g=
t;</SPAN>=20
wrote:<BR>
<BLOCKQUOTE class=3Dgmail_quote=20
style=3D"PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: =
#ccc 1px solid">To=20
the PSN community,<BR>Please check out<BR><A=20
href=3D"http://www.myeclectic.info/SeismoPivots/seismopivots.htm"=20
=
target=3D_blank>http://www.myeclectic.info/SeismoPivots/seismopivots.htm<=
/A><BR>for=20
the results of a series of discussions between Chris Chapman, Brett =
Nordgren=20
and myself on the applicability of various pivot systems to =
the=20
construction of seismometers. Comments are welcome as I view =
this as a=20
work in progress. <BR>The work on this paper got me contemplating =
the=20
construction of a LIGO X-Suspension using 3/4" PVC pipe with Metglas =
band=20
bearings. Something a bit different. <BR>Regards,<BR>Charles R =
=
Patton<BR><BR><BR><BR></BLOCKQUOTE></DIV></DIV></BLOCKQUOTE></BODY></HTML=
>
Subject: Pivot paper error correction 1
From: Charles Patton charles.r.patton@........
Date: Wed, 15 Oct 2008 21:37:22 -0700
There was an error in the formula for the X-roll studies spreadsheet and
PDF It was pointed out by Randy Pratt. Thanks! The correct papers
were not used when I started putting the web site
http://www.myeclectic.info/SeismoPivots/seismopivots.htm
together, but now they're updated. The new files are
X-Roll study 2.xls
X-Roll study 2.pdf
Regards,
Charles R Patton
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Pivot paper error correction 1
From: "Robert Thomasson" rlthomasson@.........
Date: Thu, 16 Oct 2008 17:07:15 +0300
Thanks for taking the time and effort to share your study - it's very
interesting.
On Thu, Oct 16, 2008 at 7:37 AM, Charles Patton
<charles.r.patton@........>wrote:
>
> There was an error in the formula for the X-roll studies spreadsheet and
> PDF It was pointed out by Randy Pratt. Thanks! The correct papers were
> not used when I started putting the web site
> http://www.myeclectic.info/SeismoPivots/seismopivots.htm
> together, but now they're updated. The new files are
> X-Roll study 2.xls
> X-Roll study 2.pdf
> Regards,
> Charles R Patton
> __________________________________________________________
>
> 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.
>
<div dir="ltr">Thanks for taking the time and effort to share your study - it's very interesting.<br><br><div class="gmail_quote">On Thu, Oct 16, 2008 at 7:37 AM, Charles Patton <span dir="ltr"><<a href="mailto:charles.r.patton@........">charles.r.patton@........</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br>
There was an error in the formula for the X-roll studies spreadsheet and PDF It was pointed out by Randy Pratt. Thanks! The correct papers were not used when I started putting the web site<br>
<a href="http://www.myeclectic.info/SeismoPivots/seismopivots.htm" target="_blank">http://www.myeclectic.info/SeismoPivots/seismopivots.htm</a><br>
together, but now they're updated. The new files are<br>
X-Roll study 2.xls<br>
X-Roll study 2.pdf<br>
Regards,<br>
Charles R Patton<br>
__________________________________________________________<br>
<br>
Public Seismic Network Mailing List (PSN-L)<br>
<br>
To leave this list email <a href="mailto:PSN-L-REQUEST@.............." target="_blank">PSN-L-REQUEST@..............</a> with the body of the message (first line only): unsubscribe<br>
See <a href="http://www.seismicnet.com/maillist.html" target="_blank">http://www.seismicnet.com/maillist.html</a> for more information.<br>
</blockquote></div><br></div>
Subject: Re: 3 wire "X" suspension ?
From: ChrisAtUpw@.......
Date: Thu, 16 Oct 2008 19:54:10 EDT
In a message dated 2008/10/15, paleoartifact@......... writes:
> Its seemingly more likely to instead have the mass underneath the bottom
> "plate" for perhaps better period adjustment range. See:
> http://seismometer.googlepages.com/3wirexsuspension
> New and "strange" yes, but interesting.
Hi Meredith,
I would advise making the twin wires have a wider separation at the
top than the attachement to the bottom plate. This will tend to inhibit sideways
motions.
Regards,
Chris
**************
<HTML><FONT FACE=3Darial,helvetica><HTML><FONT SIZE=3D2 PTSIZE=3D10>In a me=
ssage dated 2008/10/15, paleoartifact@......... writes:<BR>
<BR>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Its seemingly more likely to in=
stead have the mass underneath the bottom "plate" for perhaps better period=20=
adjustment range. See:<BR>
<A HREF=3D"http://seismometer.googlepages.com/3wirexsuspension">http://seis=
mometer.googlepages.com/3wirexsuspension</A><BR>
New and "strange" yes, but interesting. </BLOCKQUOTE><BR>
<BR>
Hi Meredith,<BR>
<BR>
I would advise making the twin wires ha=
ve a wider separation at the top than the attachement to the bottom plate. T=
his will tend to inhibit sideways motions.<BR>
<BR>
Regards,<BR>
<BR>
Chris<BR>
</FONT><BR><BR><BR>**************=
<BR> </HTML>
Subject: Re: Seismometer Pivot Studies - email
From: Charles Patton charles.r.patton@........
Date: Thu, 16 Oct 2008 23:22:35 -0700
(Bob sent the following email and said it would be OK to share it and my
reply with the PSN list.)
Bobhelenmcclure@....... wrote:
************************************
You advise the following:
Do NOT use either a 'point in a cup' or a genuine metal knife edge on a
flat for a suspension system. Both apply stresses over or near the
maximum strength of the metal and even if they work initially, they will
not last long. If the edges do not either roll over or shatter, they
will dig into the counterface. These systems are a common cause of poor
performance in amateur seismometers.
I have violated this advice for years, and have never experienced any
problems. I use pivots and sapphire cups salvaged from milliammeters. My
horizontal pendulums weigh only 100 grams, but this is still a much
higher load than the original meter coil assemblies imposed. My
horizontal sensors are described at
http://bobmcclure90.googlepages.com/horiz
Please feel free to comment.
Cheers,
Bob
************************************
Hi Bob,
I hadn't seen your Lehman before. Nice. I certainly won't argue with
success, but I would make a couple of quick comments.
Certainly a great contributor to your success with jewel pivots was the
sparing use of weight, but I wonder if that doesn't make you a bit more
susceptible to drafts? Also there have been several questions to the PSN
list from beginners in the vein of, "..how many pounds should my bob
weigh?" So there is a compromise somewhere there -- and I honestly
don't know where it should be. There is a minimum mass number that is
set by thermal motion noise. See:
http://www.iris.washington.edu/stations/seisWorkshop04/PDF/Wielandt-Design3.pdf
and an excerpt of the paper by Erhard Wielandt, Institute of Geophysics,
Stuttgart University is as follows:
“Brownian (thermal) noise
The resolution of an inertial seismometer is ultimately limited by the
Brownian motion of its seismic mass. The energy of this motion can be
concentrated near the mechanical eigenfrequency by minimizing the
damping (maximizing the quality factor). Since this enhances at the same
time the response to ground motion near the eigenfrequency, a high-Q
suspension in fact has a reduced noise level at all frequencies when the
noise is expressed as an equivalent ground motion. Treating the
mechanical pendulum as a simple damped harmonic oscillator with mass M
[kg], period T[s] and quality factor Q, one finds that the coefficients
involved cancel approximately, and the condition for resolving minimum
ground noise in the free-mode band is simply MTQ > 1 kg s. So
theoretically, even a pendulum with a small mass or a small free period
could be used for very-long period recording when the quality factor is
high enough. However, this is not generally true. The
harmonic-oscillator model neglects the fact that the mechanical damping
(especially of thermally self compensated spring materials) is not
viscous. For a given pendulum with an adjustable period such as a
LaCoste suspension, the quality factor decreases more rapidly at long
eigenperiods than it should do for viscous damping. Therefore, the
Brownian noise of mechanical suspensions increases at long periods,
comparable to the 1/f-noise of semiconductors. Unfortunately, very few
data are available on this phenomenon.”
I was recently reading a patent(?) on the invention of the taut-band
panel meter movement for use in long term industrial service (such as
power stations, etc.) They knew that the meter life was limited by the
jewel movement, and were touting the lifetime of the taut-band removing
that limitation. Your use of jewels with heavier loading than the
original movement certainly brings into question operating life.
Additionally, what kind of damping do you experience without the
resistor loading and magnet assembly in place? This would equate back
to the pivot friction plus the air eddy loss. If there is intent to
use force feedback at some point, then the Q of the setup becomes of
interest (as does the thermal noise for that matter.)
Chris remarked, “…What stiction levels do you get? Static friction is
always greater than dynamic friction and it is always present in a
mechanical sliding system. I can remember having to change meters which
had 'sticky' suspensions.”
I can certainly identify with the copper magnetic properties. Some 50+
years ago I made a scale with soda straws and straight pin on razor
blade edges. I attached a coil on the end to make a meter and noticed
the attraction when I added the magnets. But with regard to your
implementation of the Lehman, you made the argument yourself for
increased bob weight in order to get around the diamagnetic, and
paramagnetic effects of your coil. This is useful information to argue
for the use of capacitance sensing with aluminum vanes? (Although even
there and with the use of varible reluctance, too, there are direct
attraction effects from the voltages (or magnetics) at the levels we're
interested in.
Chris remarked, “…Another point which Bob has not mentioned is that
perspex is diamagnetic. I am well aware of some copper wire having Fe
traces. I have had severe problems with aluminum vanes on Lehman
seismometers giving instability when the sensor has drifted off centre.
Pure Cu seems to be OK. You need to keep the outer magnet high field
edges inside the damping plate at all times.
But back to the original point of the paper. I don't pretend it's the
end all of the discussion, but rather a rough guide to help center the
builder's approach. There are always other ways to accomplish an end
goal, but some paths generally have more leeway while on the way to
success. We're just trying to give some rough rules-of-thumb that might
help guide the unwary. Remember the experiments of Robt. Baker in Sci
Am? He used glass slides, RTV and razor blade edges with optical (LED)
sensors. Fascinating approach. Never have heard about whether it had
long term stability problems, though, which would be my concern.
Chris had a bit stronger comment, “Vividly. A really rubbish
construction which was sensitive to everything and did not enable you to
separate out any single effect.”
If it is OK with you, I would really like to post this email to the PSN
list, I think it's beneficial that #1, people see other approaches are
possible, but #2 what I think some of the trade-offs are. I certainly
am not a Lehman authority, I just started this discussion/paper on
pivots because of that very fact. I wanted more insight into the
possibilities. Discussions with Brett and Chris certainly helped guide
me. The paper was a distillation of those discussions so the PSN
community can share in some of the conclusions -- and de-bunk them if
necessary.
Regards,
Charles R Patton
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: 3 wire "X" suspension ?
From: "meredith lamb" paleoartifact@.........
Date: Fri, 17 Oct 2008 19:07:35 -0600
Hi Chris,
Your suggestion is perplexing; perhaps you really mean rotational movement?
Being short of a actual working model, it would appear likely that the wires
will touch at the "x" junctions. One thought I have is that on
the bottom plate (or on put on the top plate), one might have 2 of the 3
wires slightly vertically elevated via a spacer to get away hopefully
from such contact. Of the two spacers, they may each need to be different
heights.
Take care, Meredith
On Thu, Oct 16, 2008 at 5:54 PM, <ChrisAtUpw@.......> wrote:
> In a message dated 2008/10/15, paleoartifact@......... writes:
>
> Its seemingly more likely to instead have the mass underneath the bottom
> "plate" for perhaps better period adjustment range. See:
> http://seismometer.googlepages.com/3wirexsuspension
> New and "strange" yes, but interesting.
>
>
>
> Hi Meredith,
>
> I would advise making the twin wires have a wider separation at the
> top than the attachement to the bottom plate. This will tend to inhibit
> sideways motions.
>
> Regards,
>
> Chris
>
>
>
> **************
>
<div dir="ltr"><div>Hi Chris,</div>
<div> </div>
<div>Your suggestion is perplexing; perhaps you really mean rotational movement?</div>
<div> </div>
<div>Being short of a actual working model, it would appear likely that the wires will touch at the "x" junctions. One thought I have is that on</div>
<div>the bottom plate (or on put on the top plate), one might have 2 of the 3 wires slightly vertically elevated via a spacer to get away hopefully</div>
<div>from such contact. Of the two spacers, they may each need to be different heights. </div>
<div> </div>
<div>Take care, Meredith<br></div>
<div class="gmail_quote">On Thu, Oct 16, 2008 at 5:54 PM, <span dir="ltr"><<a href="mailto:ChrisAtUpw@.......">ChrisAtUpw@.......</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"><font face="arial,helvetica"><font size="2">
<div class="Ih2E3d">In a message dated 2008/10/15, <a href="mailto:paleoartifact@........." target="_blank">paleoartifact@.........</a> writes:<br><br>
<blockquote style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px" type="CITE">Its seemingly more likely to instead have the mass underneath the bottom "plate" for perhaps better period adjustment range. See:<br>
<a href="http://seismometer.googlepages.com/3wirexsuspension" target="_blank">http://seismometer.googlepages.com/3wirexsuspension</a><br>New and "strange" yes, but interesting. </blockquote><br><br></div>Hi Meredith,<br>
<br> I would advise making the twin wires have a wider separation at the top than the attachement to the bottom plate. This will tend to inhibit sideways motions.<br><br> Regards,<br><br> Chris<br> </font><br>
<br><br>**************<br></font></blockquote></div><br></div>
Subject: earthquake listings by year and month
From: tchannel1@............
Date: Sat, 18 Oct 2008 20:56:58 -0600
Hi Folks, Do you know of a website where it shows earthquakes by year, =
by month and magnitudes?
Thanks, Ted
<!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 6.00.6001.18148" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Hi Folks, Do you know of a =
website where it=20
shows earthquakes by year, by month and magnitudes?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Thanks, Ted</FONT></DIV></BODY></HTML>
Subject: Re: earthquake listings by year and month
From: Canie canie@...........
Date: Sat, 18 Oct 2008 20:37:53 -0700
<html>
<body>
How about this:<br>
<a href="http://neic.usgs.gov/neis/eqlists/eqstats.html" eudora="autourl">
http://neic.usgs.gov/neis/eqlists/eqstats.html</a> - it's not by month -
<br><br>
Otherwise, maybe download a catalog and parse it..<br><br>
There's a guy named Donald Boon who has collected that info - if you want
I can ask that he send you the table, or I could send you his email
privately.<br><br>
Canie<br><br>
At 07:56 PM 10/18/2008, you wrote:<br>
<blockquote type=cite class=cite cite=""><font size=2>Hi Folks, Do
you know of a website where it shows earthquakes by year, by month and
magnitudes?<br>
</font> <br>
<font size=2>Thanks, Ted</font></blockquote></body>
</html>
Subject: Re: earthquake listings by year and month
From: Bob Hancock carpediem1@.........
Date: Sat, 18 Oct 2008 20:54:57 -0700
Ted -
The list your probably want is at the IRIS site under Wilber II. See
link:
http://www.iris.edu/dms/wilber.htm
This list goes back to January 1, 1990. Be advised it only shows the
larger events, and contains worldwide data. You can also download SAC
files of the events and then convert them to PSN events either through
WinQuakes, or Bob McClures conversion proram, available at the
following web site.
http://bobmcclure90.googlepages.com/sitemap
Enjoy
Bob Hancock
On Oct 18, 2008, at 7:56 PM, <tchannel1@............> <tchannel1@............
> wrote:
> Hi Folks, Do you know of a website where it shows earthquakes by
> year, by month and magnitudes?
>
> Thanks, Ted
<html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; ">Ted -<div><br></div><div>The =
list your probably want is at the IRIS site under Wilber II. See =
link:</div><div><br></div><div><span class=3D"Apple-tab-span" =
style=3D"white-space:pre"> </span><a =
href=3D"http://www.iris.edu/dms/wilber.htm">http://www.iris.edu/dms/wilber=
..htm</a></div><div><br></div><div>This list goes back to January 1, =
1990. Be advised it only shows the larger events, and contains =
worldwide data. You can also download SAC files of the events and =
then convert them to PSN events either through WinQuakes, or Bob =
McClures conversion proram, available at the following web =
site.</div><div><br></div><div><span class=3D"Apple-tab-span" =
style=3D"white-space:pre"> </span><a =
href=3D"http://bobmcclure90.googlepages.com/sitemap">http://bobmcclure90.g=
ooglepages.com/sitemap</a></div><div><br></div><div>Enjoy</div><div><br></=
div><div>Bob Hancock</div><div><br><div><div>On Oct 18, 2008, at 7:56 =
PM, <<a =
href=3D"mailto:tchannel1@............">tchannel1@............</a>> =
<<a href=3D"mailto:tchannel1@............">tchannel1@............</a>> =
wrote:</div><br class=3D"Apple-interchange-newline"><blockquote =
type=3D"cite"><span class=3D"Apple-style-span" style=3D"border-collapse: =
separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; =
font-style: normal; font-variant: normal; font-weight: normal; =
letter-spacing: normal; line-height: normal; orphans: 2; text-align: =
auto; text-indent: 0px; text-transform: none; white-space: normal; =
widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; =
-webkit-border-vertical-spacing: 0px; =
-webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: =
auto; -webkit-text-stroke-width: 0; "><div bgcolor=3D"#ffffff"><div><font =
face=3D"Arial" size=3D"2">Hi Folks, Do you know of a website where =
it shows earthquakes by year, by month and =
magnitudes?</font></div><div><font face=3D"Arial" =
size=3D"2"></font> </div><div><font face=3D"Arial" size=3D"2">Thanks,=
=
Ted</font></div></div></span></blockquote></div><br></div></body></html>=
Subject: Re: earthquake listings by year and month
From: Stephen & Kathy skmort@............
Date: Sat, 18 Oct 2008 22:36:39 -0700
Hi Ted,
Here are the two main lists that I use. At the first link, you can
select a location range, (global, rectangular circular), and from there
you select a database, time frame, magnitude, depth, etc.
http://neic.usgs.gov/neis/epic/
http://en.wikipedia.org/wiki/List_of_earthquakes
Stephen
PSN Station #55
tchannel1@............ wrote:
> Hi Folks, Do you know of a website where it shows earthquakes by
> year, by month and magnitudes?
>
> Thanks, Ted
<!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 size="+1"><tt>Hi Ted,<br>
Here are the two main lists that I use. At the first link, you can
select a </tt></font><font size="+1"><tt>location range, (global,
rectangular circular), and from there you select a </tt></font><font
size="+1"><tt>database, time frame, magnitude, depth, etc. <br>
<br>
<a class="moz-txt-link-freetext" href="http://neic.usgs.gov/neis/epic/">http://neic.usgs.gov/neis/epic/</a><br>
<a class="moz-txt-link-freetext" href="http://en.wikipedia.org/wiki/List_of_earthquakes">http://en.wikipedia.org/wiki/List_of_earthquakes</a><br>
<br>
Stephen<br>
PSN Station #55<br>
</tt></font><br>
<a class="moz-txt-link-abbreviated" href="mailto:tchannel1@............">tchannel1@............</a> wrote:
<blockquote cite="mid:A8B395698863498D8787C90AC9309F26@TedPC"
type="cite">
<meta http-equiv="Content-Type" content="text/html; ">
<meta content="MSHTML 6.00.6001.18148" name="GENERATOR">
<style></style>
<div><font face="Arial" size="2">Hi Folks, Do you know of a website
where it shows earthquakes by year, by month and magnitudes?</font></div>
<div> </div>
<div><font face="Arial" size="2">Thanks, Ted</font></div>
</blockquote>
</body>
</html>
Subject: 7.1 Tonga Quake
From: "Geoff" gmvoeth@...........
Date: Sat, 18 Oct 2008 23:01:22 -0700
Gee Whillikers Guys, my system is only designed to get
2Hz to 3 Second vertical (Z) waves but with this Tonga quake
a few minutes ago Im getting 20 second surface waves
they must be really large since my system is relatively
insensitive at these periods. Can someone give me an
idea of the actual peak ground deflection from this
7.1 Tonga Quake at 20 seconds period surface waves and 81 degrees away ?
I do not know how to do this myself.
regards
geoff
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: 7.1 Tonga Quake
From: Bob Hancock carpediem1@.........
Date: Sat, 18 Oct 2008 23:17:54 -0700
Hi Geoff -
Use the following link to a USGS program and add the appropriate
information:
http://neic.usgs.gov/neis/travel_times/compute_tt.html
The answer you are looking for will be near the top of the page, prior
to the listing of the arrival times of the phases.
Cheers
Bob Hancock
On Oct 18, 2008, at 11:01 PM, Geoff wrote:
> Gee Whillikers Guys, my system is only designed to get
> 2Hz to 3 Second vertical (Z) waves but with this Tonga quake
> a few minutes ago Im getting 20 second surface waves
> they must be really large since my system is relatively
> insensitive at these periods. Can someone give me an
> idea of the actual peak ground deflection from this
> 7.1 Tonga Quake at 20 seconds period surface waves and 81 degrees
> away ?
> I do not know how to do this myself.
> regards
> geoff
>
>
> __________________________________________________________
>
> 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: earthquake listings by year and month
From: tchannel1@............
Date: Sun, 19 Oct 2008 09:36:09 -0600
Thanks All for this information. I have bookmarked several. Ted
----- Original Message -----=20
From: Stephen & Kathy=20
To: psn-l@.................
Sent: Saturday, October 18, 2008 11:36 PM
Subject: Re: earthquake listings by year and month
Hi Ted,
Here are the two main lists that I use. At the first link, you can =
select a location range, (global, rectangular circular), and from there =
you select a database, time frame, magnitude, depth, etc.=20
http://neic.usgs.gov/neis/epic/
http://en.wikipedia.org/wiki/List_of_earthquakes
Stephen
PSN Station #55
tchannel1@............ wrote:=20
Hi Folks, Do you know of a website where it shows earthquakes by =
year, by month and magnitudes?
Thanks, Ted
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE></TITLE>
<META http-equiv=3DContent-Type =
content=3Dtext/html;charset=3DISO-8859-1>
<META content=3D"MSHTML 6.00.6001.18148" name=3DGENERATOR></HEAD>
<BODY text=3D#000000 bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Thanks All for this =
information. I have=20
bookmarked several. Ted</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=3Dskmort@............ =
href=3D"mailto:skmort@............">Stephen &=20
Kathy</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> Saturday, October 18, =
2008 11:36=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: earthquake =
listings by year=20
and month</DIV>
<DIV><BR></DIV><FONT size=3D+1><TT>Hi Ted,<BR>Here are the two main =
lists that I=20
use. At the first link, you can select a </TT></FONT><FONT=20
size=3D+1><TT>location range, (global, rectangular circular), and from =
there you=20
select a </TT></FONT><FONT size=3D+1><TT>database, time frame, =
magnitude, depth,=20
etc. <BR><BR><A class=3Dmoz-txt-link-freetext=20
=
href=3D"http://neic.usgs.gov/neis/epic/">http://neic.usgs.gov/neis/epic/<=
/A><BR><A=20
class=3Dmoz-txt-link-freetext=20
=
href=3D"http://en.wikipedia.org/wiki/List_of_earthquakes">http://en.wikip=
edia.org/wiki/List_of_earthquakes</A><BR><BR> =20
Stephen<BR> PSN Station #55<BR></TT></FONT><BR><A=20
class=3Dmoz-txt-link-abbreviated=20
href=3D"mailto:tchannel1@............">tchannel1@............</A> =
wrote:=20
<BLOCKQUOTE cite=3Dmid:A8B395698863498D8787C90AC9309F26@TedPC =
type=3D"cite">
<META content=3D"MSHTML 6.00.6001.18148" name=3DGENERATOR>
<STYLE></STYLE>
<DIV><FONT face=3DArial size=3D2>Hi Folks, Do you know of a =
website where=20
it shows earthquakes by year, by month and magnitudes?</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Thanks,=20
Ted</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
Subject: Re: earthquake listings by year and month
From: "Kay Wyatt" kwyatt@.............
Date: Sun, 19 Oct 2008 10:28:18 -0700
Ted,
I like to use a resource offered by Larry Braile. He maintains a =
Microsoft spreadsheet on the internet of earthquakes recorded by his =
AS-1 seismograph at Purdue University. It is at =
http://web.ics.purdue.edu/~braile/edumod/as1lessons/InterpSeis/EqList.xls=
.. The nice thing about this is that you can do all the typical =
spreadsheet functions like sorting, etc, once you download it. He =
only saves the major earthquakes and it goes back to the year 2000.
This is a part of Larry's internet resources for learning about =
earthquakes and seismology. If you look at Lesson #13 on the page at =
http://web.ics.purdue.edu/~braile/edumod/as1lessons/as1lessons.htm you =
will see the spreadsheet.
Now the REALLY nice thing about this spreadsheet is that he makes =
available on this same page his corresponding Z files (for those of you =
familiar with Alan Jones Amaseis software) so that you can see the data =
recorded on his seismograph.
Take care,
Kay Wyatt
----- Original Message -----=20
From: tchannel1@...............
To: psn=20
Sent: Saturday, October 18, 2008 7:56 PM
Subject: earthquake listings by year and month
Hi Folks, Do you know of a website where it shows earthquakes by =
year, by month and magnitudes?
Thanks, Ted
<!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 6.00.6000.16735" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Ted,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I like to use a resource offered by =
Larry=20
Braile. He maintains a Microsoft spreadsheet on the internet of=20
earthquakes recorded by his AS-1 seismograph at Purdue University. =
It is=20
at <A=20
href=3D"http://web.ics.purdue.edu/~braile/edumod/as1lessons/InterpSeis/Eq=
List.xls">http://web.ics.purdue.edu/~braile/edumod/as1lessons/InterpSeis/=
EqList.xls</A>. =20
The nice thing about this is that you can do all the typical spreadsheet =
functions like sorting, etc, once you download it. He =
only=20
saves the major earthquakes and it goes back to the year =
2000.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>This is a part of Larry's internet =
resources for=20
learning about earthquakes and seismology. If you look at Lesson =
#13 on=20
the page at <A=20
href=3D"http://web.ics.purdue.edu/~braile/edumod/as1lessons/as1lessons.ht=
m">http://web.ics.purdue.edu/~braile/edumod/as1lessons/as1lessons.htm</A>=
you=20
will see the spreadsheet.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Now the REALLY nice thing about this =
spreadsheet is=20
that he makes available on this same page his corresponding Z files (for =
those=20
of you familiar with Alan Jones Amaseis software) so that you can see =
the data=20
recorded on his seismograph.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Take care,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Kay Wyatt</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV> </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=3Dtchannel1@...............
href=3D"mailto:tchannel1@............">tchannel1@............</A> =
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dpsn-l@.................
href=3D"mailto:psn-l@..............">psn</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Saturday, October 18, =
2008 7:56=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> earthquake listings by =
year and=20
month</DIV>
<DIV><BR></DIV>
<DIV><FONT face=3DArial size=3D2>Hi Folks, Do you know of a =
website where it=20
shows earthquakes by year, by month and magnitudes?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Thanks, =
Ted</FONT></DIV></BLOCKQUOTE></BODY></HTML>
Subject: Re: 7.1 Tonga Quake
From: Wayne wandc@.......
Date: Sun, 19 Oct 2008 14:18:23 -0700
Another useful one giving arrival times at your station:
<http://neic.usgs.gov/neis/travel_times/artim.html>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: 7.1 Tonga Quake
From: "Geoff" gmvoeth@...........
Date: Mon, 20 Oct 2008 22:15:09 -0700
It looks like about 54 micrometers peak Im guessing.
No wonder i felt sea sick.
Sort of like sea amd anchor detail through the
straights of juan de fuca.
Regards,
geoff
----- Original Message -----
From: "Bob Hancock" <carpediem1@.........>
To: <psn-l@..............>
Sent: Saturday, October 18, 2008 11:17 PM
Subject: Re: 7.1 Tonga Quake
> Hi Geoff -
>
> Use the following link to a USGS program and add the appropriate
> information:
>
> http://neic.usgs.gov/neis/travel_times/compute_tt.html
>
> The answer you are looking for will be near the top of the page, prior
> to the listing of the arrival times of the phases.
>
> Cheers
>
> Bob Hancock
>
>
> On Oct 18, 2008, at 11:01 PM, Geoff wrote:
>
>> Gee Whillikers Guys, my system is only designed to get
>> 2Hz to 3 Second vertical (Z) waves but with this Tonga quake
>> a few minutes ago Im getting 20 second surface waves
>> they must be really large since my system is relatively
>> insensitive at these periods. Can someone give me an
>> idea of the actual peak ground deflection from this
>> 7.1 Tonga Quake at 20 seconds period surface waves and 81 degrees
>> away ?
>> I do not know how to do this myself.
>> regards
>> geoff
>>
>>
>> __________________________________________________________
>>
>> 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: Pivot paper discussion
From: Charles Patton charles.r.patton@........
Date: Tue, 21 Oct 2008 19:59:26 -0700
Randy Pratt asked:
> Ball on plate:
>
> Columns A to C use lolocus and lolocrad in formulas. Where are these
> defined?
“lolocus” is cell C38 holding an input value.(highlight –select- a cell
and if they have a text name associated it will show on the left in the
toolbar where a cell location is normally shown.) The name change
happened because I was trying to clean up the visual aspect of the sheet
and didn’t go through and fix the formulas, too.
“lolocrad” is cell C34 and doesn’t follow what I just said as it has two
names defined. Ah well the hazards of editing. But double-clicking on
a formula shows all the cells making up the formula, so you can see
which cells are named what.
> Is this analysis for a single pivot or for a Lehman with 2 pivots as
drawn
> on the main page?
It actually applies to both the upper and lower pivots, even though it
might not seem so at first glance. Realize that if we have an arm
attached to the ball, the arm could extend up and to the left. I.e.,
start at P and continue through C and call the new end PP. C to PP
would be the upper suspension and can have the same locus center point
and as found for the ball on plate as illustrated (with the same locus
errors.) One can also enter negative values for P and get the results
for a particular beam length in the upper pivot case.
> I see references to twist in the revision history so is
> this twist resulting from upper and lower pivot travel in opposite
> direction? If so would not the support structure height play a role
as well
> as angle of the support wire to the boom?
That revision was early in the discussion with Brett and Chris. I had
taken a simplistic approach to the path based on the contact point.
Latter I agreed with Brett on the approach to finding the locus center
as is embodied in the current XLS calculations. That If a locus center
point exists that makes the locus a circular arc, then the twist doesn’t
exist. But even if twist exists, you choose your bob center-of-gravity
roughly half way in the Z axis between the upper and lower pivot points,
and its effect should drop out of the considerations. Either way, I
stopped considering it.
> Why was the locus chosen as a point behind the plate rather than the
contact
> point? Reason - In a Lehman, translation of a rolling pivot will
result in
> unsymetric forces on the boom. The compression in the boom and the
tension
> in the support wire will move out of the vertical plane. A horizontal
> friction force must be present to prevent slippage of the ball and this
> force is also a moment around the mass. These forces would have to be
> analysed from the contact point. Larger angles and larger balls would
> increase this effect.
Please see my answer to Bob McClure on 10/16, posted to the PSN list.
The “center point” is chosen to give the “ best fit” to the calculated
locus. It is not chosen for any other purpose than to answer
mathematically whether there is a close fit circular arc to the locus
that has been calculated. If there is, then it can be said that the bob
with regards to the vertical beam travels a circular arc therefore a
pendulum fit can be realized. You may be right about secondary effects
of the offset mass. I’ll have to think about that further, but I’ll
have to do that later. I’ll post this to PSN, and maybe Chris or Brett
can tackle that aspect.
>
> An upper pivot does not travel a semicircle around the circumference in
> relation to a near horizontal swing. The semicircle is tilted by the
support
> wire angle in relation to the near vertical swing axis. Do you agree?
No, because a ball always has circular cross section and tilt only
matters to the extent that it changes the length of CP. So the
hypothetical center of the arc may not be where the the physical contact
point is, but as you adjust the period of the swing, you will actually
be adjusting these centers in space to be almost in a vertical line,
with the upper just a bit forward to give the bob a pendulum arc that is
lowest in the center of the swing.
This was the whole point of doing all this analysis – trying to
understand just what the weight/bob was experiencing and what
arrangements of pivots had the best circular fit. Additionally what
shows up is the ball on plate inferior to plate on ball with regard to
the side slipping you touch on.
> Construction could change this I guess with rigid upper boom structure.
>
> Randy
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Digest from 10/21/2008 00:00:18
From: "Randy Pratt" rpratt@.............
Date: Wed, 22 Oct 2008 09:44:18 -0500
Charles, Chris, Brett,
But even if twist exists, you choose your bob center-of-gravity roughly half
way in the Z axis between the upper and lower pivot points,
and its effect should drop out of the considerations.
--This point seems to be a large deviation from the traditional horizontal
boom with double support wires and or underslung mass to prevent rocking on
the axis. It may be the improvement point we need to consider and
construct.
Randy
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Pivot paper discussion
From: ChrisAtUpw@.......
Date: Wed, 22 Oct 2008 18:13:41 EDT
In a message dated 2008/10/22, charles.r.patton@........ writes:
> Randy Pratt asked:
> > I see references to twist in the revision history so is
> > this twist resulting from upper and lower pivot travel in opposite
> > direction? If so would not the support structure height play a role=20
> as well
> > as angle of the support wire to the boom?
Hi Randy,
It does. The axis tilts as the spheres roll sideways, or the plane=20
rolls on the sphere. If the mass is lower than the centre of the rolling axi=
s,=20
this adds to the stability. If it is above this, it can detract from the=20
stability.
> That revision was early in the discussion with Brett and Chris. I had=20
> taken a simplistic approach to the path based on the contact point.=20
> Latter I agreed with Brett on the approach to finding the locus center=20
> as is embodied in the current XLS calculations. That If a locus center=20
> point exists that makes the locus a circular arc, then the twist doesn=E2=
=80=99t=20
> exist. But even if twist exists, you choose your bob center-of-gravity=20
> roughly half way in the Z axis between the upper and lower pivot points,=20
> and its effect should drop out of the considerations. Either way, I=20
> stopped considering it.
>=20
> > Why was the locus chosen as a point behind the plate rather than the=20
> contact
> > point? Reason - In a Lehman, translation of a rolling pivot will=20
> result in unsymetric forces on the boom. =20
Sorry but I don't understand what you are trying to say?
The compression in the boom and the > tension
> > in the support wire will move out of the vertical plane. A horizontal
> > friction force must be present to prevent slippage of the ball and this
> > force is also a moment around the mass. These forces would have to be
> > analysed from the contact point. Larger angles and larger balls would
> > increase this effect.
> Please see my answer to Bob McClure on 10/16, posted to the PSN list.=20
> The =E2=80=9Ccenter point=E2=80=9D is chosen to give the =E2=80=9C best fi=
t=E2=80=9D to the calculated=20
> locus. It is not chosen for any other purpose than to answer=20
> mathematically whether there is a close fit circular arc to the locus=20
> that has been calculated. If there is, then it can be said that the bob=20
> with regards to the vertical beam travels a circular arc therefore a=20
> pendulum fit can be realized. You may be right about secondary effects=20
> of the offset mass.=20
> >
> > An upper pivot does not travel a semicircle around the circumference in
> > relation to a near horizontal swing. The semicircle is tilted by the=20
> support
> > wire angle in relation to the near vertical swing axis. Do you agree?
Yes, but it is the swing axis itself which rotates.
> No, because a ball always has circular cross section and tilt only=20
> matters to the extent that it changes the length of CP. =20
I don't agree.
So the > hypothetical center of the arc may not be where the physical contac=
t=20
>=20
> point is, but as you adjust the period of the swing, you will actually=20
> be adjusting these centers in space to be almost in a vertical line,=20
> with the upper just a bit forward to give the bob a pendulum arc that is=20
> lowest in the center of the swing.
> This was the whole point of doing all this analysis =E2=80=93 trying to=20
> understand just what the weight/bob was experiencing and what=20
> arrangements of pivots had the best circular fit. Additionally what=20
> shows up is the ball on plate inferior to plate on ball with regard to=20
> the side slipping you touch on.
>=20
> > Construction could change this I guess with rigid upper boom structure.
> But even if twist exists, you choose your bob center-of-gravity roughly=20
> half
> way in the Z axis between the upper and lower pivot points, and its effect=
=20
> should drop out of the considerations.
It doesn't, since the swing axis is rotating about it's centre in the=
=20
near vertical plane. The gradient is still non linear.
> --This point seems to be a large deviation from the traditional horizontal
> boom with double support wires and or underslung mass to prevent rocking o=
n
> the axis. It may be the improvement point we need to consider and construc=
t.
You still need to prevent the boom from rotating about it's long axis=
..=20
A V wire upper support is most desirable. The problem is that the damping=20
force is not usually precisely on the line joining the centre of mass to the=
=20
lower point of rotation. This is a common cause of unwanted resonances, sinc=
e such=20
motions may be inadequately damped.
Regards,
Chris Chapman
<HTML><FONT FACE=3Darial,helvetica><HTML><FONT SIZE=3D2 PTSIZE=3D10>In a me=
ssage dated 2008/10/22, charles.r.patton@........ writes:<BR>
<BR>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Randy Pratt asked:<BR>
> I see references to twist in the revision history so is<BR>
> this twist resulting from upper and lower pivot travel in opposite<BR>
> direction? If so would not the support structure height play a ro=
le <BR>
as well<BR>
> as angle of the support wire to the boom?</FONT><FONT COLOR=3D"#000000=
" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10=20=
FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"></BLOCKQUOTE><BR>
<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"=
>Hi Randy,<BR>
<BR>
It does. The axis tilts as the spheres=20=
roll sideways, or the plane rolls on the sphere. If the mass is lower than t=
he centre of the rolling axis, this adds to the stability. If it is above th=
is, it can detract from the stability.</FONT><FONT COLOR=3D"#000000" BACK=
=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=
=3D"SANSSERIF" 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>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">That revision was early in the=20=
discussion with Brett and Chris. I had <BR>
taken a simplistic approach to the path based on the contact point. <BR>
Latter I agreed with Brett on the approach to finding the locus center <BR>
as is embodied in the current XLS calculations. That If a locus center=
<BR>
point exists that makes the locus a circular arc, then the twist doesn=E2=
=80=99t <BR>
exist. But even if twist exists, you choose your bob center-of-gravity=
<BR>
roughly half way in the Z axis between the upper and lower pivot points, <BR=
>
and its effect should drop out of the considerations. Either way=
, I <BR>
stopped considering it.<BR>
<BR>
> Why was the locus chosen as a point behind the plate rather than the <B=
R>
contact<BR>
> point? Reason - In a Lehman, translation of a rolling pivot will <BR>
result in unsymetric forces on the boom. </FONT><FONT COLOR=3D"#00000=
0" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10=
FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"></BLOCKQUOTE><BR>
<BR>
Sorry but I don't understand what you are trying to say?<=
BR>
<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"=
> The compression in the boom and the <B=
LOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT:=20=
5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">tension<BR>
> in the support wire will move out of the vertical plane. A horizo=
ntal<BR>
> friction force must be present to prevent slippage of the ball and this=
<BR>
> force is also a moment around the mass. These forces would have t=
o be<BR>
> analysed from the contact point. Larger angles and larger balls would<B=
R>
> increase this effect.<BR>
Please see my answer to Bob McClure on 10/16, posted to the PSN list. <BR>
The =E2=80=9Ccenter point=E2=80=9D is chosen to give the =E2=80=9C best fit=
=E2=80=9D to the calculated <BR>
locus. It is not chosen for any other purpose than to answer <BR>
mathematically whether there is a close fit circular arc to the locus <BR>
that has been calculated. If there is, then it can be said that the bo=
b <BR>
with regards to the vertical beam travels a circular arc therefore a <BR>
pendulum fit can be realized. You may be right about secondary effects=
<BR>
of the offset mass. <BR>
><BR>
> An upper pivot does not travel a semicircle around the circumference in=
<BR>
> relation to a near horizontal swing. The semicircle is tilted by the su=
pport<BR>
> wire angle in relation to the near vertical swing axis. Do you ag=
ree?</FONT><FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COL=
OR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=
=3D"0"></BLOCKQUOTE><BR>
<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"=
> Yes, but it is the swing axis itself w=
hich rotates.</FONT><FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKG=
ROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Aria=
l" 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>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">No, because a ball always has c=
ircular cross section and tilt only <BR>
matters to the extent that it changes the length of CP. </FONT><FONT =20=
COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=
=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"></BLOCKQUOTE=
><BR>
<BR>
I don't agree.<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>
So the <BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARG=
IN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">hypothetical center of t=
he arc may not be where the physical contact <BR>
point is, but as you adjust the period of the swing, you will actually <BR>
be adjusting these centers in space to be almost in a vertical line, <BR>
with the upper just a bit forward to give the bob a pendulum arc that is <BR=
>
lowest in the center of the swing.<BR>
This was the whole point of doing all this analysis =E2=80=93 trying to <BR>
understand just what the weight/bob was experiencing and what <BR>
arrangements of pivots had the best circular fit. Additionally what <B=
R>
shows up is the ball on plate inferior to plate on ball with regard to <BR>
the side slipping you touch on.<BR>
<BR>
> Construction could change this I guess with rigid upper boom structure.=
</BLOCKQUOTE><BR>
<BR>
<BR>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">But even if twist exists, you c=
hoose your bob center-of-gravity roughly half<BR>
way in the Z axis between the upper and lower pivot points, and its effect s=
hould drop out of the considerations.</FONT><FONT COLOR=3D"#000000" BACK=
=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=
=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"></BLOCKQUOTE><BR>
<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"=
> It doesn't, since the swing axis is ro=
tating about it's centre in the near vertical plane. The gradient is still n=
on linear.</FONT><FONT COLOR=3D"#000000" BACK=3D"#ffffff" style=3D"BACKGROU=
ND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial"=20=
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>
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">--This point seems to be a larg=
e deviation from the traditional horizontal<BR>
boom with double support wires and or underslung mass to prevent rocking on<=
BR>
the axis. It may be the improvement point we need to consider and construct.=
</BLOCKQUOTE><BR>
<BR>
You still need to prevent the boom from=
rotating about it's long axis. A V wire upper support is most desirable. Th=
e problem is that the damping force is not usually precisely on the line joi=
ning the centre of mass to the lower point of rotation. This is a common cau=
se of unwanted resonances, since such motions may be inadequately damped.<BR=
>
<BR>
Regards,<BR>
<BR>
Chris Chapman</FONT></HTML>
Subject: Re: Pivot paper discussion
From: Charles Patton charles.r.patton@........
Date: Wed, 22 Oct 2008 22:45:27 -0700
ChrisAtUpw@....... wrote:
> In a message dated 2008/10/22, charles.r.patton@........ writes:
>
>> Randy Pratt asked:
>> > I see references to twist in the revision history so is
>> > this twist resulting from upper and lower pivot travel in opposite
>> > direction? If so would not the support structure height play a role
>> as well
>> > as angle of the support wire to the boom?
>
>
> Hi Randy,
>
> It does. The axis tilts as the spheres roll sideways, or the
> plane rolls on the sphere. If the mass is lower than the centre of the
> rolling axis, this adds to the stability. If it is above this, it can
> detract from the stability.
CRP - I argue that if the angle of the flat plates of the pivots are
parallel to the real axis of swing (based on the center of locus points
being found in our XLS pgms, then there is essentially no twist because
then the pivot is "rotating" about the center of the locus with
essentially no circular arc curvature error therefore there is no
effective change of length of the suspension or boom and therefore the
bob is describing a circular arc whose plane is set by the tilt of the
vertical support and thereby the period of the pendulum.
>
>> That revision was early in the discussion with Brett and Chris. I had
>> taken a simplistic approach to the path based on the contact point.
>> Latter I agreed with Brett on the approach to finding the locus center
>> as is embodied in the current XLS calculations. That If a locus center
>> point exists that makes the locus a circular arc, then the twist doesn’t
>> exist. But even if twist exists, you choose your bob center-of-gravity
>> roughly half way in the Z axis between the upper and lower pivot points,
>> and its effect should drop out of the considerations. Either way, I
>> stopped considering it.
>>
>> > Why was the locus chosen as a point behind the plate rather than the
>> contact
>> > point? Reason - In a Lehman, translation of a rolling pivot will
>> result in unsymetric forces on the boom.
>
>
> Sorry but I don't understand what you are trying to say?
CRP-I didn't understand this question either.l
>
> The compression in the boom and the
>> tension
>> > in the support wire will move out of the vertical plane. A horizontal
>> > friction force must be present to prevent slippage of the ball and this
>> > force is also a moment around the mass. These forces would have to be
>> > analysed from the contact point. Larger angles and larger balls would
>> > increase this effect.
>> Please see my answer to Bob McClure on 10/16, posted to the PSN list.
>> The “center point†is chosen to give the “ best fit†to the calculated
>> locus. It is not chosen for any other purpose than to answer
>> mathematically whether there is a close fit circular arc to the locus
>> that has been calculated. If there is, then it can be said that the bob
>> with regards to the vertical beam travels a circular arc therefore a
>> pendulum fit can be realized. You may be right about secondary effects
>> of the offset mass.
>> >
>> > An upper pivot does not travel a semicircle around the circumference in
>> > relation to a near horizontal swing. The semicircle is tilted by the
>> support
>> > wire angle in relation to the near vertical swing axis. Do you agree?
>
>
> Yes, but it is the swing axis itself which rotates.
>
>> No, because a ball always has circular cross section and tilt only
>> matters to the extent that it changes the length of CP.
>
>
> I don't agree.
>
> So the
>> hypothetical center of the arc may not be where the physical contact
>> point is, but as you adjust the period of the swing, you will actually
>> be adjusting these centers in space to be almost in a vertical line,
>> with the upper just a bit forward to give the bob a pendulum arc that is
>> lowest in the center of the swing.
>> This was the whole point of doing all this analysis – trying to
>> understand just what the weight/bob was experiencing and what
>> arrangements of pivots had the best circular fit. Additionally what
>> shows up is the ball on plate inferior to plate on ball with regard to
>> the side slipping you touch on.
>>
>> > Construction could change this I guess with rigid upper boom structure.
>
>
>
>> But even if twist exists, you choose your bob center-of-gravity
>> roughly half
>> way in the Z axis between the upper and lower pivot points, and its
>> effect should drop out of the considerations.
>
>
> It doesn't, since the swing axis is rotating about it's centre in
> the near vertical plane. The gradient is still non linear.
CRP- as I argued above, the pivots are indeed swinging about a point
This is a critical statement. You will recall I initially argued in
agreement with Randy – that the rotation of ball on plate or plate on
ball caused the boom/suspension to move in opposite directions, leading
to twist in addition to errors in length causing the bob to be raised or
lowered in addition to the swing arc. You (Chris and Brett) convinced
me of the error of my ways, by introducing the concept of fitting a
center to the locus and observing that one is available for all the
pivots we’ve studied so far. My contribution was gathering together
exact locus calculations and encoding the error calculation of the
center of locus fit. So if the center of the locus is essentially a
point at the low swing angles we’re dealing with (and typically it is
within a few ppm, then twist is not possible. (The LIGO suspension is a
different case and does have twist, but it is also a different geometry.)
>
>> --This point seems to be a large deviation from the traditional horizontal
>> boom with double support wires and or underslung mass to prevent
>> rocking on
>> the axis. It may be the improvement point we need to consider and
>> construct.
>
>
> You still need to prevent the boom from rotating about it's long
> axis. A V wire upper support is most desirable. The problem is that the
> damping force is not usually precisely on the line joining the centre of
> mass to the lower point of rotation. This is a common cause of unwanted
> resonances, since such motions may be inadequately damped.
CRP-I agree.
>
> Regards,
>
> Chris Chapman
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Pivot paper
From: "Randy Pratt" rpratt@.............
Date: Thu, 23 Oct 2008 09:15:09 -0500
Hi All,
It does. The axis tilts as the spheres roll sideways, or the
> plane rolls on the sphere. If the mass is lower than the centre of the
> rolling axis, this adds to the stability. If it is above this, it can
> detract from the stability.
CRP - I argue that if the angle of the flat plates of the pivots are
parallel to the real axis of swing (based on the center of locus points
being found in our XLS pgms, then there is essentially no twist because then
the pivot is "rotating" about the center of the locus with essentially no
circular arc curvature error therefore there is no effective change of
length of the suspension or boom and therefore the bob is describing a
circular arc whose plane is set by the tilt of the vertical support and
thereby the period of the pendulum.
RP - Let's take a pendulum with axis north south. Tilt the axis to make a
Lehman i.e. vertical axis and north south boom. Rotate the axis 90 degrees
and you now have an east west pendulum. I would have to agree with Chris.
Randy
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: tutorial on pendulum theory
From: Randall Peters PETERS_RD@..........
Date: Thu, 23 Oct 2008 15:55:24 -0400
I've written a paper titled "A tutorial on gravitational pendulum theory
applied to seismic sensing of translation and rotation" for a special
edition of the Bull. Seism. Soc. Amer. concerned with rotation,
technical editor Willie Lee. I don't know if it is too technical for
the majority of folks but figured I would let you know about it anyway.
The paper has been posted to my webpage at
http://physics.mercer.edu/hpage/BSSA-tutorial/pend-theory.pdf
The request for me to generate this paper originated with John Lahr's
mentioning my research to Willie, with whom John worked for a long time
(before he retired from the USGS). Without John's passionate
involvement with amateur seismology and science education (reason I came
to know him) none of this would have happened.
Subject: calibration questions
From: Thomas Dick dickthomas01@.............
Date: Thu, 30 Oct 2008 12:25:12 -0500
On the east central Pacific Rise of 15:15:43 on this the 10/30, USGS
indicates the quake was Ms .5.7
Using WinSDR and Winquake; I calculated the P as 5.2 seconds on a AS-1
configuration.
The Mb calculated out as 4.1 The magnitude correction I had chosen was
-1.8. Is my next step to chose a positive number less than one.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: unusual frequency
From: Thomas Dick dickthomas01@.............
Date: Fri, 31 Oct 2008 09:54:55 -0500
Quiet weather all over U.S. right now. Starting about 18:30 on 10/30 I
began seeing a large amplitude signal coming in. It peaks at ~.2 Hz or 5
sec period It is twice as strong as the earthquake in Texas (~5 on Oct
31) here in southern Indiana. Is anyone else seeing this?
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: unusual frequency
From: "Geoff" gmvoeth@...........
Date: Fri, 31 Oct 2008 09:02:43 -0700
Affirmative from GVA
and you can see somethiong on the TUC station too.
Not sure but CAP ROCK station see,s close to it.
----- Original Message -----
From: "Thomas Dick" <dickthomas01@.............>
To: <psn-l@..............>
Sent: Friday, October 31, 2008 7:54 AM
Subject: unusual frequency
> Quiet weather all over U.S. right now. Starting about 18:30 on 10/30 I
> began seeing a large amplitude signal coming in. It peaks at ~.2 Hz or 5
> sec period It is twice as strong as the earthquake in Texas (~5 on Oct
> 31) here in southern Indiana. Is anyone else seeing this?
> __________________________________________________________
>
> 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: unusual frequency
From: "Geoff" gmvoeth@...........
Date: Fri, 31 Oct 2008 09:06:16 -0700
Correction.
Not talking about microseisims today but a
quake yjat seems yet unreported maybe
s-p time of two minutes.
----- Original Message -----
From: "Thomas Dick" <dickthomas01@.............>
To: <psn-l@..............>
Sent: Friday, October 31, 2008 7:54 AM
Subject: unusual frequency
> Quiet weather all over U.S. right now. Starting about 18:30 on 10/30 I
> began seeing a large amplitude signal coming in. It peaks at ~.2 Hz or 5
> sec period It is twice as strong as the earthquake in Texas (~5 on Oct
> 31) here in southern Indiana. Is anyone else seeing this?
> __________________________________________________________
>
> 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: unusual frequency
From: Thomas Dick dickthomas01@.............
Date: Fri, 31 Oct 2008 14:11:17 -0500
Geoff wrote:
> Correction.
> Not talking about microseisims today but a
> quake yjat seems yet unreported maybe
> s-p time of two minutes.
where are you located ....I copied a little one in Tennessee about 16:38
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: unusual frequency
From: "Geoff" gmvoeth@...........
Date: Sat, 1 Nov 2008 14:53:34 -0700
Hello Mr. Thomas Dick;
My Sensor located very close to 33.42138N -111.57477W about 507Meters above mean sea level.
I saw that TUC near Tucson also saw this signal about 1336 to 1338 on 31OCT2008 UTC.
I have not analyzed it to get an accurate and precise time simply because I can not
tell for sure it is in fact an Earthquake. If no one else is reporting it I do not trust
what I am looking at. In order for me to properly read a signal it takes extra effort
which translates to opportunity costs ( such as Battlefield 2142 time ) so I will not
pursue more knowledge in detail if I can not verify the source beforehand.
The distance seems 600 miles to 700 miles from here maybe magnitude 4
but nothing seems to match that as of my last look.
Regards;
geoff
----- Original Message -----
From: "Thomas Dick" <dickthomas01@.............>
To: <psn-l@..............>
Sent: Friday, October 31, 2008 12:11 PM
Subject: Re: unusual frequency
> Geoff wrote:
>> Correction.
>> Not talking about microseisims today but a
>> quake yjat seems yet unreported maybe
>> s-p time of two minutes.
> where are you located ....I copied a little one in Tennessee about 16:38
> __________________________________________________________
>
> 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: unusual frequency
From: Bob Hancock carpediem1@.........
Date: Sat, 1 Nov 2008 20:16:55 -0700
This event appears to be consistent with other low magnitude events
that have occurred to the Southwest of Tucson, AZ. I have seen other
events that are similar, and no information was ever posted on them.
I noticed the event was visible across the lower 48 states, and
southern Alaska. It is most likely less than M 4.0 as that is the
USGS minimum cutoff for display of information on international events.
Bob Hancock
On Nov 1, 2008, at 2:53 PM, Geoff wrote:
> Hello Mr. Thomas Dick;
> My Sensor located very close to 33.42138N -111.57477W about
> 507Meters above mean sea level.
> I saw that TUC near Tucson also saw this signal about 1336 to 1338
> on 31OCT2008 UTC.
> I have not analyzed it to get an accurate and precise time simply
> because I can not
> tell for sure it is in fact an Earthquake. If no one else is
> reporting it I do not trust
> what I am looking at. In order for me to properly read a signal it
> takes extra effort
> which translates to opportunity costs ( such as Battlefield 2142
> time ) so I will not
> pursue more knowledge in detail if I can not verify the source
> beforehand.
> The distance seems 600 miles to 700 miles from here maybe magnitude 4
> but nothing seems to match that as of my last look.
> Regards;
> geoff
>
> -
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: unusual frequency
From: "Geoff" gmvoeth@...........
Date: Sun, 2 Nov 2008 02:11:17 -0700
Hello Bob;
me Not being a physics major or math person.
Thats Interesting since I had a s-p or s-L time
of 2 minutes and that translates to
600 + miles maybe 700. This event set off
my automatic recording which usually does
not happen unless the quake is about 4.0
at 400 miles. For some reason more energy then
expected has arrived at this station sort of like
what bubbleheads ( submarine sailors )
might call a convergence zone
which happens in the ocean with sound waves.
Maybe quake waves in the earth behave like
sound waves in the ocean and are lazy which
will focus the energy at discreet distances
from the event. By lazy I mean they seem
to bend ( refract ) to the slowest velocity hitting the surface
with concentrated focused energy
in concentric rings around the event out to
some distance. Such behavior requires enough
depth of the strata to allow for this bending to happen.
Does this mean possibly deep crust or from the mantel ?
I should imagine the moho would keep a CZ zone
from the crust because it would reflect at that point
and divide the energy instead of refracting it.
What do you think might be going on that
would concentrate the energy from a less than
usual quake to set off my recording alarm ?
I understand wave velocity changes is the best way
to guess how waves are effected as they propagate.
Any sudden change is like a mirror and a gradual
change is like a lens.
I understand a transmitted ( radio wave ) signal can be bent
by having a series of antennas with a phasing
slightly later from antenna to antenna so that
the delaying of the phases of a single wave
will make the antenna behave as a massive
variable lens thus the phased array kind of antenna
or wullenwebber array.
Since we can not do what mother nature has
not already done in one way or another I can
imagine the earth itself is somehow making
areas of more and less energy as energy spreads
away from the focal point. I must have been
in an increased energy point if the quake
was less than 4.0 and 600 miles away.
Regards;
geoff
----- Original Message -----
From: "Bob Hancock" <carpediem1@.........>
To: <psn-l@..............>
Sent: Saturday, November 01, 2008 8:16 PM
Subject: Re: unusual frequency
> This event appears to be consistent with other low magnitude events
> that have occurred to the Southwest of Tucson, AZ. I have seen other
> events that are similar, and no information was ever posted on them.
> I noticed the event was visible across the lower 48 states, and
> southern Alaska. It is most likely less than M 4.0 as that is the
> USGS minimum cutoff for display of information on international events.
>
> Bob Hancock
>
>
> On Nov 1, 2008, at 2:53 PM, Geoff wrote:
>
>> Hello Mr. Thomas Dick;
>> My Sensor located very close to 33.42138N -111.57477W about
>> 507Meters above mean sea level.
>> I saw that TUC near Tucson also saw this signal about 1336 to 1338
>> on 31OCT2008 UTC.
>> I have not analyzed it to get an accurate and precise time simply
>> because I can not
>> tell for sure it is in fact an Earthquake. If no one else is
>> reporting it I do not trust
>> what I am looking at. In order for me to properly read a signal it
>> takes extra effort
>> which translates to opportunity costs ( such as Battlefield 2142
>> time ) so I will not
>> pursue more knowledge in detail if I can not verify the source
>> beforehand.
>> The distance seems 600 miles to 700 miles from here maybe magnitude 4
>> but nothing seems to match that as of my last look.
>> Regards;
>> geoff
>>
>> -
> __________________________________________________________
>
> 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: unusual frequency
From: "Geoff" gmvoeth@...........
Date: Sun, 2 Nov 2008 02:14:28 -0700
In my previous answer I made a mistake as follows.
"I had a s-p or s-L time"
Should have read as follows.
"I had a s-p or L-p time"
OOOPS !
geoff
----- Original Message -----
From: "Bob Hancock" <carpediem1@.........>
To: <psn-l@..............>
Sent: Saturday, November 01, 2008 8:16 PM
Subject: Re: unusual frequency
> This event appears to be consistent with other low magnitude events
> that have occurred to the Southwest of Tucson, AZ. I have seen other
> events that are similar, and no information was ever posted on them.
> I noticed the event was visible across the lower 48 states, and
> southern Alaska. It is most likely less than M 4.0 as that is the
> USGS minimum cutoff for display of information on international events.
>
> Bob Hancock
>
>
> On Nov 1, 2008, at 2:53 PM, Geoff wrote:
>
>> Hello Mr. Thomas Dick;
>> My Sensor located very close to 33.42138N -111.57477W about
>> 507Meters above mean sea level.
>> I saw that TUC near Tucson also saw this signal about 1336 to 1338
>> on 31OCT2008 UTC.
>> I have not analyzed it to get an accurate and precise time simply
>> because I can not
>> tell for sure it is in fact an Earthquake. If no one else is
>> reporting it I do not trust
>> what I am looking at. In order for me to properly read a signal it
>> takes extra effort
>> which translates to opportunity costs ( such as Battlefield 2142
>> time ) so I will not
>> pursue more knowledge in detail if I can not verify the source
>> beforehand.
>> The distance seems 600 miles to 700 miles from here maybe magnitude 4
>> but nothing seems to match that as of my last look.
>> Regards;
>> geoff
>>
>> -
> __________________________________________________________
>
> 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: NEIC EVENTS
From: "James Allen" jcallen1@...........
Date: Sun, 02 Nov 2008 15:15:24 -0800
Lately when I attempt to access NEIC events through the event report in
WinQuake I am invariable unsuccessful with the status box continuously
reflecting "connecting to host". Anyone having a similar problem or a fix
for this?
James Allen
----- Original Message -----
From: "Geoff" <gmvoeth@...........>
To: <psn-l@..............>
Sent: Sunday, November 02, 2008 1:14 AM
Subject: Re: unusual frequency
> In my previous answer I made a mistake as follows.
> "I had a s-p or s-L time"
> Should have read as follows.
> "I had a s-p or L-p time"
> OOOPS !
> geoff
>
>
> ----- Original Message -----
> From: "Bob Hancock" <carpediem1@.........>
> To: <psn-l@..............>
> Sent: Saturday, November 01, 2008 8:16 PM
> Subject: Re: unusual frequency
>
>
>> This event appears to be consistent with other low magnitude events that
>> have occurred to the Southwest of Tucson, AZ. I have seen other events
>> that are similar, and no information was ever posted on them. I noticed
>> the event was visible across the lower 48 states, and southern Alaska.
>> It is most likely less than M 4.0 as that is the USGS minimum cutoff for
>> display of information on international events.
>>
>> Bob Hancock
>>
>>
>> On Nov 1, 2008, at 2:53 PM, Geoff wrote:
>>
>>> Hello Mr. Thomas Dick;
>>> My Sensor located very close to 33.42138N -111.57477W about 507Meters
>>> above mean sea level.
>>> I saw that TUC near Tucson also saw this signal about 1336 to 1338 on
>>> 31OCT2008 UTC.
>>> I have not analyzed it to get an accurate and precise time simply
>>> because I can not
>>> tell for sure it is in fact an Earthquake. If no one else is reporting
>>> it I do not trust
>>> what I am looking at. In order for me to properly read a signal it
>>> takes extra effort
>>> which translates to opportunity costs ( such as Battlefield 2142 time )
>>> so I will not
>>> pursue more knowledge in detail if I can not verify the source
>>> beforehand.
>>> The distance seems 600 miles to 700 miles from here maybe magnitude 4
>>> but nothing seems to match that as of my last look.
>>> Regards;
>>> geoff
>>>
>>> -
>> __________________________________________________________
>>
>> 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: unusual frequency
From: Bob Hancock carpediem1@.........
Date: Sun, 2 Nov 2008 16:17:21 -0700
Without knowing the epicenter of the event, you cannot draw too many
conclusions. I downloaded the event using VASE, and look at it with
SAC. I used the unfiltered raw data from the IU/TUC station (STS-1)
and believe the P wave arrival time is 13:36:20 for that station. I
can pick out the Love & Rayleigh waves. However, the S wave is of
very low amplitude. I observed one very low amplitude oscillation
that could correspond to an S wave about 13:37:25, for a S-P time of
65 seconds or 4.47 degrees ( 496.75 km). In addition, the rayleigh
waves are much more pronounced on the vertical and north channels
which would be consistent with an event that is more southerly from
the receiving station than southwest. The Love waves first appear
about 13:37:45, and the Rayleigh waves appear about 13:38:25. Without
more information, it is not really possible to draw any conclusions on
why there was a diminished S wave. I have not looked at the event
with other than my station and Tucson. To me, it looks like a normal
regional event, but with a magnitude of less than 4.0, most likely
south of the border in Mexico.
Keep in mind one big problem in analyzing regional events is there is
insufficient time for good wave separation. They are all together and
that can complicate trying to pick out individual waves.
Bob Hancock
On Nov 2, 2008, at 2:11 AM, Geoff wrote:
> Hello Bob;
> me Not being a physics major or math person.
> Thats Interesting since I had a s-p or s-L time
> of 2 minutes and that translates to
> 600 + miles maybe 700. This event set off
> my automatic recording which usually does
> not happen unless the quake is about 4.0
> at 400 miles. For some reason more energy then
> expected has arrived at this station sort of like
> what bubbleheads ( submarine sailors )
> might call a convergence zone
> which happens in the ocean with sound waves.
> Maybe quake waves in the earth behave like
> sound waves in the ocean and are lazy which
> will focus the energy at discreet distances
> from the event. By lazy I mean they seem
> to bend ( refract ) to the slowest velocity hitting the surface
> with concentrated focused energy
> in concentric rings around the event out to
> some distance. Such behavior requires enough
> depth of the strata to allow for this bending to happen.
> Does this mean possibly deep crust or from the mantel ?
> I should imagine the moho would keep a CZ zone
> from the crust because it would reflect at that point
> and divide the energy instead of refracting it.
> What do you think might be going on that
> would concentrate the energy from a less than
> usual quake to set off my recording alarm ?
> I understand wave velocity changes is the best way
> to guess how waves are effected as they propagate.
> Any sudden change is like a mirror and a gradual
> change is like a lens.
> I understand a transmitted ( radio wave ) signal can be bent
> by having a series of antennas with a phasing
> slightly later from antenna to antenna so that
> the delaying of the phases of a single wave
> will make the antenna behave as a massive
> variable lens thus the phased array kind of antenna
> or wullenwebber array.
> Since we can not do what mother nature has
> not already done in one way or another I can
> imagine the earth itself is somehow making
> areas of more and less energy as energy spreads
> away from the focal point. I must have been
> in an increased energy point if the quake
> was less than 4.0 and 600 miles away.
>
> Regards;
> geoff
>
>
> ----- Original Message ----- From: "Bob Hancock"
> <carpediem1@.........>
> To: <psn-l@..............>
> Sent: Saturday, November 01, 2008 8:16 PM
> Subject: Re: unusual frequency
>
>
>> This event appears to be consistent with other low magnitude
>> events that have occurred to the Southwest of Tucson, AZ. I have
>> seen other events that are similar, and no information was ever
>> posted on them. I noticed the event was visible across the lower
>> 48 states, and southern Alaska. It is most likely less than M 4.0
>> as that is the USGS minimum cutoff for display of information on
>> international events.
>> Bob Hancock
>> On Nov 1, 2008, at 2:53 PM, Geoff wrote:
>>> Hello Mr. Thomas Dick;
>>> My Sensor located very close to 33.42138N -111.57477W about
>>> 507Meters above mean sea level.
>>> I saw that TUC near Tucson also saw this signal about 1336 to
>>> 1338 on 31OCT2008 UTC.
>>> I have not analyzed it to get an accurate and precise time simply
>>> because I can not
>>> tell for sure it is in fact an Earthquake. If no one else is
>>> reporting it I do not trust
>>> what I am looking at. In order for me to properly read a signal
>>> it takes extra effort
>>> which translates to opportunity costs ( such as Battlefield 2142
>>> time ) so I will not
>>> pursue more knowledge in detail if I can not verify the source
>>> beforehand.
>>> The distance seems 600 miles to 700 miles from here maybe
>>> magnitude 4
>>> but nothing seems to match that as of my last look.
>>> Regards;
>>> geoff
>>>
>>> -
>> __________________________________________________________
>> 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: NEIC EVENTS
From: Bob Hancock carpediem1@.........
Date: Sun, 2 Nov 2008 16:22:09 -0700
I have had no problems, I connected this morning and just tried it
again, with no problems..........the problem could possibly be related
to either your computer or method of connection, just a guess, but see
if you can troubleshoot and see if you have any other connectivity
problems.
Bob Hancock
On Nov 2, 2008, at 4:15 PM, James Allen wrote:
> Lately when I attempt to access NEIC events through the event
> report in WinQuake I am invariable unsuccessful with the status box
> continuously reflecting "connecting to host". Anyone having a
> similar problem or a fix for this?
> James Allen
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: NEIC EVENTS
From: "James Allen" jcallen1@...........
Date: Sun, 02 Nov 2008 17:35:09 -0800
Thanks for your response Bob. No problems connecting to the internet on
either of two computers being use. However, neither can access NEIC via
Winquake. I will try to look for some setting in Microsoft Explorer that
may be causing the problem.
Again, thanks Bob\
James Allen
----- Original Message -----
From: "Bob Hancock" <carpediem1@.........>
To: <psn-l@..............>
Sent: Sunday, November 02, 2008 3:22 PM
Subject: Re: NEIC EVENTS
>I have had no problems, I connected this morning and just tried it again,
>with no problems..........the problem could possibly be related to either
>your computer or method of connection, just a guess, but see if you can
>troubleshoot and see if you have any other connectivity problems.
>
> Bob Hancock
>
>
> On Nov 2, 2008, at 4:15 PM, James Allen wrote:
>
>> Lately when I attempt to access NEIC events through the event report in
>> WinQuake I am invariable unsuccessful with the status box continuously
>> reflecting "connecting to host". Anyone having a similar problem or a
>> fix for this?
>> James Allen
> __________________________________________________________
>
> 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: unusual frequency
From: Thomas Dick dickthomas01@.............
Date: Sun, 02 Nov 2008 19:40:17 -0600
May I add to your comments ---
1. first, there was a 3.1 in Oklahoma around 10:30 UTC, a 2 in Tenneesee
and a whole series of Texas quakes starting around 23 UTC --- these are
LISTED on regional networks .... BUT, there could be unlisted minor
events BUT shouldn't these events be in the .6 Hz/period of 1.5 for
regional events which is higher than what I was seeing
and what I was questioning....
2. "Quiet weather all over U.S. right now. Starting about 18:30 on 10/30
I began seeing a large amplitude signal coming in. It peaks at ~.2 Hz or
5 sec period It is twice as strong as the earthquake in Texas (~5 on Oct
31) here in southern Indiana. Is anyone else seeing this?"
and probably some form of weather phenonmena???
Bob Hancock wrote:
> Without knowing the epicenter of the event, you cannot draw too many
> conclusions. I downloaded the event using VASE, and look at it with
> SAC. I used the unfiltered raw data from the IU/TUC station (STS-1)
> and believe the P wave arrival time is 13:36:20 for that station. I
> can pick out the Love & Rayleigh waves. However, the S wave is of
> very low amplitude. I observed one very low amplitude oscillation
> that could correspond to an S wave about 13:37:25, for a S-P time of
> 65 seconds or 4.47 degrees ( 496.75 km). In addition, the rayleigh
> waves are much more pronounced on the vertical and north channels
> which would be consistent with an event that is more southerly from
> the receiving station than southwest. The Love waves first appear
> about 13:37:45, and the Rayleigh waves appear about 13:38:25. Without
> more information, it is not really possible to draw any conclusions on
> why there was a diminished S wave. I have not looked at the event
> with other than my station and Tucson. To me, it looks like a normal
> regional event, but with a magnitude of less than 4.0, most likely
> south of the border in Mexico.
>
> Keep in mind one big problem in analyzing regional events is there is
> insufficient time for good wave separation. They are all together and
> that can complicate trying to pick out individual waves.
>
> Bob Hancock
>
>
>
> On Nov 2, 2008, at 2:11 AM, Geoff wrote:
>
>> Hello Bob;
>> me Not being a physics major or math person.
>> Thats Interesting since I had a s-p or s-L time
>> of 2 minutes and that translates to
>> 600 + miles maybe 700. This event set off
>> my automatic recording which usually does
>> not happen unless the quake is about 4.0
>> at 400 miles. For some reason more energy then
>> expected has arrived at this station sort of like
>> what bubbleheads ( submarine sailors )
>> might call a convergence zone
>> which happens in the ocean with sound waves.
>> Maybe quake waves in the earth behave like
>> sound waves in the ocean and are lazy which
>> will focus the energy at discreet distances
>> from the event. By lazy I mean they seem
>> to bend ( refract ) to the slowest velocity hitting the surface
>> with concentrated focused energy
>> in concentric rings around the event out to
>> some distance. Such behavior requires enough
>> depth of the strata to allow for this bending to happen.
>> Does this mean possibly deep crust or from the mantel ?
>> I should imagine the moho would keep a CZ zone
>> from the crust because it would reflect at that point
>> and divide the energy instead of refracting it.
>> What do you think might be going on that
>> would concentrate the energy from a less than
>> usual quake to set off my recording alarm ?
>> I understand wave velocity changes is the best way
>> to guess how waves are effected as they propagate.
>> Any sudden change is like a mirror and a gradual
>> change is like a lens.
>> I understand a transmitted ( radio wave ) signal can be bent
>> by having a series of antennas with a phasing
>> slightly later from antenna to antenna so that
>> the delaying of the phases of a single wave
>> will make the antenna behave as a massive
>> variable lens thus the phased array kind of antenna
>> or wullenwebber array.
>> Since we can not do what mother nature has
>> not already done in one way or another I can
>> imagine the earth itself is somehow making
>> areas of more and less energy as energy spreads
>> away from the focal point. I must have been
>> in an increased energy point if the quake
>> was less than 4.0 and 600 miles away.
>>
>> Regards;
>> geoff
>>
>>
>> ----- Original Message ----- From: "Bob Hancock" <carpediem1@.........>
>> To: <psn-l@..............>
>> Sent: Saturday, November 01, 2008 8:16 PM
>> Subject: Re: unusual frequency
>>
>>
>>> This event appears to be consistent with other low magnitude events
>>> that have occurred to the Southwest of Tucson, AZ. I have seen
>>> other events that are similar, and no information was ever posted
>>> on them. I noticed the event was visible across the lower 48
>>> states, and southern Alaska. It is most likely less than M 4.0 as
>>> that is the USGS minimum cutoff for display of information on
>>> international events.
>>> Bob Hancock
>>> On Nov 1, 2008, at 2:53 PM, Geoff wrote:
>>>> Hello Mr. Thomas Dick;
>>>> My Sensor located very close to 33.42138N -111.57477W about
>>>> 507Meters above mean sea level.
>>>> I saw that TUC near Tucson also saw this signal about 1336 to 1338
>>>> on 31OCT2008 UTC.
>>>> I have not analyzed it to get an accurate and precise time simply
>>>> because I can not
>>>> tell for sure it is in fact an Earthquake. If no one else is
>>>> reporting it I do not trust
>>>> what I am looking at. In order for me to properly read a signal it
>>>> takes extra effort
>>>> which translates to opportunity costs ( such as Battlefield 2142
>>>> time ) so I will not
>>>> pursue more knowledge in detail if I can not verify the source
>>>> beforehand.
>>>> The distance seems 600 miles to 700 miles from here maybe magnitude 4
>>>> but nothing seems to match that as of my last look.
>>>> Regards;
>>>> geoff
>>>>
>>>> -
>>> __________________________________________________________
>>> 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)
>
> To leave this list email PSN-L-REQUEST@.............. withthe 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: NEIC EVENTS
From: "James Allen" jcallen1@...........
Date: Sun, 02 Nov 2008 17:46:12 -0800
Bob Hancock or other PSN members.
Is the appropriate web address in the WinQuake Event file for NEIC
ftp://ghtfp.cr:usgs.gov/pub/cnss.fing ?
James Allen
----- Original Message -----
From: "Bob Hancock" <carpediem1@.........>
To: <psn-l@..............>
Sent: Sunday, November 02, 2008 3:22 PM
Subject: Re: NEIC EVENTS
>I have had no problems, I connected this morning and just tried it again,
>with no problems..........the problem could possibly be related to either
>your computer or method of connection, just a guess, but see if you can
>troubleshoot and see if you have any other connectivity problems.
>
> Bob Hancock
>
>
> On Nov 2, 2008, at 4:15 PM, James Allen wrote:
>
>> Lately when I attempt to access NEIC events through the event report in
>> WinQuake I am invariable unsuccessful with the status box continuously
>> reflecting "connecting to host". Anyone having a similar problem or a
>> fix for this?
>> James Allen
> __________________________________________________________
>
> 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: NEIC EVENTS
From: Larry Cochrane lcochrane@..............
Date: Sun, 02 Nov 2008 18:18:42 -0800
Hi James,
The correct address is: ftp://hazards.cr.usgs.gov/cnss/cnss_14.fing
This file http://www.seismicnet.com/software/EventReportFiles.zip has updated
WinQuake event report data files. The two files in the zip file should be copied to
your WinQuake directory.
Regards,
Larry Cochrane
Redwood City, PSN
James Allen wrote:
> Bob Hancock or other PSN members.
> Is the appropriate web address in the WinQuake Event file for NEIC
> ftp://ghtfp.cr:usgs.gov/pub/cnss.fing ?
> James Allen
> ----- Original Message -----
> From: "Bob Hancock" <carpediem1@.........>
> To: <psn-l@..............>
> Sent: Sunday, November 02, 2008 3:22 PM
> Subject: Re: NEIC EVENTS
>
>
>>I have had no problems, I connected this morning and just tried it again,
>>with no problems..........the problem could possibly be related to either
>>your computer or method of connection, just a guess, but see if you can
>>troubleshoot and see if you have any other connectivity problems.
>>
>> Bob Hancock
>>
>>
>> On Nov 2, 2008, at 4:15 PM, James Allen wrote:
>>
>>> Lately when I attempt to access NEIC events through the event report in
>>> WinQuake I am invariable unsuccessful with the status box continuously
>>> reflecting "connecting to host". Anyone having a similar problem or a
>>> fix for this?
>>> James Allen
>> __________________________________________________________
>>
>> 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: NEIC EVENTS
From: "James Allen" jcallen1@...........
Date: Sun, 02 Nov 2008 18:40:18 -0800
Thanks Larry
James Allen
----- Original Message -----
From: "Larry Cochrane" <lcochrane@..............>
To: <psn-l@..............>
Sent: Sunday, November 02, 2008 6:18 PM
Subject: Re: NEIC EVENTS
> Hi James,
>
> The correct address is: ftp://hazards.cr.usgs.gov/cnss/cnss_14.fing
>
> This file http://www.seismicnet.com/software/EventReportFiles.zip has
> updated WinQuake event report data files. The two files in the zip file
> should be copied to your WinQuake directory.
>
> Regards,
> Larry Cochrane
> Redwood City, PSN
>
> James Allen wrote:
>> Bob Hancock or other PSN members.
>> Is the appropriate web address in the WinQuake Event file for NEIC
>> ftp://ghtfp.cr:usgs.gov/pub/cnss.fing ?
>> James Allen
>> ----- Original Message -----
>> From: "Bob Hancock" <carpediem1@.........>
>> To: <psn-l@..............>
>> Sent: Sunday, November 02, 2008 3:22 PM
>> Subject: Re: NEIC EVENTS
>>
>>
>>>I have had no problems, I connected this morning and just tried it
>>>again, with no problems..........the problem could possibly be related
>>>to either your computer or method of connection, just a guess, but see
>>>if you can troubleshoot and see if you have any other connectivity
>>>problems.
>>>
>>> Bob Hancock
>>>
>>>
>>> On Nov 2, 2008, at 4:15 PM, James Allen wrote:
>>>
>>>> Lately when I attempt to access NEIC events through the event report
>>>> in WinQuake I am invariable unsuccessful with the status box
>>>> continuously reflecting "connecting to host". Anyone having a similar
>>>> problem or a fix for this?
>>>> James Allen
>>> __________________________________________________________
>>>
>>> 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)
>
> 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: unusual frequency
From: "Geoff" gmvoeth@...........
Date: Mon, 3 Nov 2008 08:29:30 -0700
I have heard "somewhere on the internet" that 5 second period microseismic waves
are generated by waves in the oceans waters at certain resonant depth
and radiate for very long distances.
This has been determined through scientific observations.
Not to say other phenomena do not also create
5 second waves.
I often see such waves relating to weather fronts coming from
the pacific before it hits arizona.
And my system was designed only to see
3 second to 2Hz range so they must be
quite large in magnitude.
Its not weather over land but weather over ocean.
geoff
----- Original Message -----
From: "Thomas Dick" <dickthomas01@.............>
To: <psn-l@..............>
Sent: Sunday, November 02, 2008 6:40 PM
Subject: Re: unusual frequency
> May I add to your comments ---
> 1. first, there was a 3.1 in Oklahoma around 10:30 UTC, a 2 in Tenneesee
> and a whole series of Texas quakes starting around 23 UTC --- these are
> LISTED on regional networks .... BUT, there could be unlisted minor
> events BUT shouldn't these events be in the .6 Hz/period of 1.5 for
> regional events which is higher than what I was seeing
>
> and what I was questioning....
> 2. "Quiet weather all over U.S. right now. Starting about 18:30 on 10/30
> I began seeing a large amplitude signal coming in. It peaks at ~.2 Hz or
> 5 sec period It is twice as strong as the earthquake in Texas (~5 on Oct
> 31) here in southern Indiana. Is anyone else seeing this?"
> and probably some form of weather phenonmena???
>
>
> Bob Hancock wrote:
>> Without knowing the epicenter of the event, you cannot draw too many
>> conclusions. I downloaded the event using VASE, and look at it with
>> SAC. I used the unfiltered raw data from the IU/TUC station (STS-1)
>> and believe the P wave arrival time is 13:36:20 for that station. I
>> can pick out the Love & Rayleigh waves. However, the S wave is of
>> very low amplitude. I observed one very low amplitude oscillation
>> that could correspond to an S wave about 13:37:25, for a S-P time of
>> 65 seconds or 4.47 degrees ( 496.75 km). In addition, the rayleigh
>> waves are much more pronounced on the vertical and north channels
>> which would be consistent with an event that is more southerly from
>> the receiving station than southwest. The Love waves first appear
>> about 13:37:45, and the Rayleigh waves appear about 13:38:25. Without
>> more information, it is not really possible to draw any conclusions on
>> why there was a diminished S wave. I have not looked at the event
>> with other than my station and Tucson. To me, it looks like a normal
>> regional event, but with a magnitude of less than 4.0, most likely
>> south of the border in Mexico.
>>
>> Keep in mind one big problem in analyzing regional events is there is
>> insufficient time for good wave separation. They are all together and
>> that can complicate trying to pick out individual waves.
>>
>> Bob Hancock
>>
>>
>>
>> On Nov 2, 2008, at 2:11 AM, Geoff wrote:
>>
>>> Hello Bob;
>>> me Not being a physics major or math person.
>>> Thats Interesting since I had a s-p or s-L time
>>> of 2 minutes and that translates to
>>> 600 + miles maybe 700. This event set off
>>> my automatic recording which usually does
>>> not happen unless the quake is about 4.0
>>> at 400 miles. For some reason more energy then
>>> expected has arrived at this station sort of like
>>> what bubbleheads ( submarine sailors )
>>> might call a convergence zone
>>> which happens in the ocean with sound waves.
>>> Maybe quake waves in the earth behave like
>>> sound waves in the ocean and are lazy which
>>> will focus the energy at discreet distances
>>> from the event. By lazy I mean they seem
>>> to bend ( refract ) to the slowest velocity hitting the surface
>>> with concentrated focused energy
>>> in concentric rings around the event out to
>>> some distance. Such behavior requires enough
>>> depth of the strata to allow for this bending to happen.
>>> Does this mean possibly deep crust or from the mantel ?
>>> I should imagine the moho would keep a CZ zone
>>> from the crust because it would reflect at that point
>>> and divide the energy instead of refracting it.
>>> What do you think might be going on that
>>> would concentrate the energy from a less than
>>> usual quake to set off my recording alarm ?
>>> I understand wave velocity changes is the best way
>>> to guess how waves are effected as they propagate.
>>> Any sudden change is like a mirror and a gradual
>>> change is like a lens.
>>> I understand a transmitted ( radio wave ) signal can be bent
>>> by having a series of antennas with a phasing
>>> slightly later from antenna to antenna so that
>>> the delaying of the phases of a single wave
>>> will make the antenna behave as a massive
>>> variable lens thus the phased array kind of antenna
>>> or wullenwebber array.
>>> Since we can not do what mother nature has
>>> not already done in one way or another I can
>>> imagine the earth itself is somehow making
>>> areas of more and less energy as energy spreads
>>> away from the focal point. I must have been
>>> in an increased energy point if the quake
>>> was less than 4.0 and 600 miles away.
>>>
>>> Regards;
>>> geoff
>>>
>>>
>>> ----- Original Message ----- From: "Bob Hancock" <carpediem1@.........>
>>> To: <psn-l@..............>
>>> Sent: Saturday, November 01, 2008 8:16 PM
>>> Subject: Re: unusual frequency
>>>
>>>
>>>> This event appears to be consistent with other low magnitude events
>>>> that have occurred to the Southwest of Tucson, AZ. I have seen
>>>> other events that are similar, and no information was ever posted
>>>> on them. I noticed the event was visible across the lower 48
>>>> states, and southern Alaska. It is most likely less than M 4.0 as
>>>> that is the USGS minimum cutoff for display of information on
>>>> international events.
>>>> Bob Hancock
>>>> On Nov 1, 2008, at 2:53 PM, Geoff wrote:
>>>>> Hello Mr. Thomas Dick;
>>>>> My Sensor located very close to 33.42138N -111.57477W about
>>>>> 507Meters above mean sea level.
>>>>> I saw that TUC near Tucson also saw this signal about 1336 to 1338
>>>>> on 31OCT2008 UTC.
>>>>> I have not analyzed it to get an accurate and precise time simply
>>>>> because I can not
>>>>> tell for sure it is in fact an Earthquake. If no one else is
>>>>> reporting it I do not trust
>>>>> what I am looking at. In order for me to properly read a signal it
>>>>> takes extra effort
>>>>> which translates to opportunity costs ( such as Battlefield 2142
>>>>> time ) so I will not
>>>>> pursue more knowledge in detail if I can not verify the source
>>>>> beforehand.
>>>>> The distance seems 600 miles to 700 miles from here maybe magnitude 4
>>>>> but nothing seems to match that as of my last look.
>>>>> Regards;
>>>>> geoff
>>>>>
>>>>> -
>>>> __________________________________________________________
>>>> 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)
>>
>> To leave this list email PSN-L-REQUEST@.............. withthe 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: unusual frequency
From: Bob Hancock carpediem1@.........
Date: Mon, 3 Nov 2008 14:50:56 -0700
Geoff -
You are correct about the background noise. For more information,. I
would suggest that you download and read the following article from
the Albuquerque Seismological Laboratory:
OFR 93-322: Observations and Modeling of Seismic Background Noise
Use the following link:
http://earthquake.usgs.gov/regional/asl/pubs/files/ofr93-322.pdf
On page 14, the report states:
"...the most dominate features [Earth Noise] being the natural
microseisms in the period range from about 1 to 20 sec with peaks at 5
sec and 18 sec, and the Earth tides with peaks at semi-diurnal and
diurnal periods. The rounded low-noise peak in the long-period band
at a period of about 120 sec appears to be a real and significant
noise feature, it cause unknown...."
Cheers
Bob Hancock
On Nov 3, 2008, at 8:29 AM, Geoff wrote:
> I have heard "somewhere on the internet" that 5 second period
> microseismic waves
> are generated by waves in the oceans waters at certain resonant depth
> and radiate for very long distances.
> This has been determined through scientific observations.
> Not to say other phenomena do not also create
> 5 second waves.
> I often see such waves relating to weather fronts coming from
> the pacific before it hits arizona.
> And my system was designed only to see
> 3 second to 2Hz range so they must be
> quite large in magnitude.
> Its not weather over land but weather over ocean.
> geoff
>
>>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: unusual frequency
From: "Geoff" gmvoeth@...........
Date: Thu, 6 Nov 2008 12:03:28 -0700
Thanks Bob thats interesting;
The report i read about ocean waves being
the cause was much more recent than 1993
I think it was a study from sometime in the the 2000s.
I wish i could remember where I saw it
but i cant. It might have been in a Discover
magazine. and not an official government thing.
Lately Ive been spending most my time
playing games like BattleField2/2142. My computer is
quickly becoming obsolete so i want to get the
most from it before it can no longer play these types of games.
It will always be able to look at seismic stuff
but not so for these computer games.
Things are revolutionary instead of evolutionary
and I am unable to keep up with it all.
geoff
----- Original Message -----
From: "Bob Hancock" <carpediem1@.........>
To: <psn-l@..............>
Sent: Monday, November 03, 2008 2:50 PM
Subject: Re: unusual frequency
> Geoff -
>
> You are correct about the background noise. For more information,. I
> would suggest that you download and read the following article from
> the Albuquerque Seismological Laboratory:
>
> OFR 93-322: Observations and Modeling of Seismic Background Noise
> Use the following link:
>
> http://earthquake.usgs.gov/regional/asl/pubs/files/ofr93-322.pdf
>
> On page 14, the report states:
>
> "...the most dominate features [Earth Noise] being the natural
> microseisms in the period range from about 1 to 20 sec with peaks at 5
> sec and 18 sec, and the Earth tides with peaks at semi-diurnal and
> diurnal periods. The rounded low-noise peak in the long-period band
> at a period of about 120 sec appears to be a real and significant
> noise feature, it cause unknown...."
>
> Cheers
>
> Bob Hancock
>
>
>
> On Nov 3, 2008, at 8:29 AM, Geoff wrote:
>
>> I have heard "somewhere on the internet" that 5 second period
>> microseismic waves
>> are generated by waves in the oceans waters at certain resonant depth
>> and radiate for very long distances.
>> This has been determined through scientific observations.
>> Not to say other phenomena do not also create
>> 5 second waves.
>> I often see such waves relating to weather fronts coming from
>> the pacific before it hits arizona.
>> And my system was designed only to see
>> 3 second to 2Hz range so they must be
>> quite large in magnitude.
>> Its not weather over land but weather over ocean.
>> geoff
>>
>>>
> __________________________________________________________
>
> 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: Earthquakes and Animals
From: Angel sismos@..............
Date: Fri, 7 Nov 2008 10:29:08 +0000
Hi all,
I came across this in Google Books search and thought it might be of interest. My google search terms were
earthquake plant mimosa
http://books.google.com/books?id=-keARvIVkyIC&pg=PA14&lpg=PA14&dq=earthquake+plant+mimosa&source=web&ots=blaK6fQE6f&sig=IrNpFbiTPb2W3zHe2rUjW6Vs76g&hl=en&sa=X&oi=book_result&resnum=1&ct=result#PPA86,M1
The entire books seems to be on line, you can also buy it for about $90.
Angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re[2]: unusual frequency
From: Angel sismos@..............
Date: Fri, 7 Nov 2008 10:49:23 +0000
Hello Bob,
The diminished S wave might be a source mechanism thing. The P and S radiated energy is lobed, not circular and uniform. Some station might be in the azimuth between the radiation lobes of the S. Some directions see an S and other don't. Deep event also tend to have diminished S waves.
angel
Sunday, November 2, 2008, 11:17:21 PM, you wrote:
> Without knowing the epicenter of the event, you cannot draw too many
> conclusions. I downloaded the event using VASE, and look at it with
> SAC. I used the unfiltered raw data from the IU/TUC station (STS-1)
> and believe the P wave arrival time is 13:36:20 for that station. I
> can pick out the Love & Rayleigh waves. However, the S wave is of
> very low amplitude. I observed one very low amplitude oscillation
> that could correspond to an S wave about 13:37:25, for a S-P time of
> 65 seconds or 4.47 degrees ( 496.75 km). In addition, the rayleigh
> waves are much more pronounced on the vertical and north channels
> which would be consistent with an event that is more southerly from
> the receiving station than southwest. The Love waves first appear
> about 13:37:45, and the Rayleigh waves appear about 13:38:25. Without
> more information, it is not really possible to draw any conclusions on
> why there was a diminished S wave. I have not looked at the event
> with other than my station and Tucson. To me, it looks like a normal
> regional event, but with a magnitude of less than 4.0, most likely
> south of the border in Mexico.
> Keep in mind one big problem in analyzing regional events is there is
> insufficient time for good wave separation. They are all together and
> that can complicate trying to pick out individual waves.
> Bob Hancock
> On Nov 2, 2008, at 2:11 AM, Geoff wrote:
>> Hello Bob;
>> me Not being a physics major or math person.
>> Thats Interesting since I had a s-p or s-L time
>> of 2 minutes and that translates to
>> 600 + miles maybe 700. This event set off
>> my automatic recording which usually does
>> not happen unless the quake is about 4.0
>> at 400 miles. For some reason more energy then
>> expected has arrived at this station sort of like
>> what bubbleheads ( submarine sailors )
>> might call a convergence zone
>> which happens in the ocean with sound waves.
>> Maybe quake waves in the earth behave like
>> sound waves in the ocean and are lazy which
>> will focus the energy at discreet distances
>> from the event. By lazy I mean they seem
>> to bend ( refract ) to the slowest velocity hitting the surface
>> with concentrated focused energy
>> in concentric rings around the event out to
>> some distance. Such behavior requires enough
>> depth of the strata to allow for this bending to happen.
>> Does this mean possibly deep crust or from the mantel ?
>> I should imagine the moho would keep a CZ zone
>> from the crust because it would reflect at that point
>> and divide the energy instead of refracting it.
>> What do you think might be going on that
>> would concentrate the energy from a less than
>> usual quake to set off my recording alarm ?
>> I understand wave velocity changes is the best way
>> to guess how waves are effected as they propagate.
>> Any sudden change is like a mirror and a gradual
>> change is like a lens.
>> I understand a transmitted ( radio wave ) signal can be bent
>> by having a series of antennas with a phasing
>> slightly later from antenna to antenna so that
>> the delaying of the phases of a single wave
>> will make the antenna behave as a massive
>> variable lens thus the phased array kind of antenna
>> or wullenwebber array.
>> Since we can not do what mother nature has
>> not already done in one way or another I can
>> imagine the earth itself is somehow making
>> areas of more and less energy as energy spreads
>> away from the focal point. I must have been
>> in an increased energy point if the quake
>> was less than 4.0 and 600 miles away.
>> Regards;
>> geoff
>> ----- Original Message ----- From: "Bob Hancock"
>> <carpediem1@.........>
>> To: <psn-l@..............>
>> Sent: Saturday, November 01, 2008 8:16 PM
>> Subject: Re: unusual frequency
>>> This event appears to be consistent with other low magnitude
>>> events that have occurred to the Southwest of Tucson, AZ. I have
>>> seen other events that are similar, and no information was ever
>>> posted on them. I noticed the event was visible across the lower
>>> 48 states, and southern Alaska. It is most likely less than M 4.0
>>> as that is the USGS minimum cutoff for display of information on
>>> international events.
>>> Bob Hancock
>>> On Nov 1, 2008, at 2:53 PM, Geoff wrote:
>>>> Hello Mr. Thomas Dick;
>>>> My Sensor located very close to 33.42138N -111.57477W about
>>>> 507Meters above mean sea level.
>>>> I saw that TUC near Tucson also saw this signal about 1336 to
>>>> 1338 on 31OCT2008 UTC.
>>>> I have not analyzed it to get an accurate and precise time simply
>>>> because I can not
>>>> tell for sure it is in fact an Earthquake. If no one else is
>>>> reporting it I do not trust
>>>> what I am looking at. In order for me to properly read a signal
>>>> it takes extra effort
>>>> which translates to opportunity costs ( such as Battlefield 2142
>>>> time ) so I will not
>>>> pursue more knowledge in detail if I can not verify the source
>>>> beforehand.
>>>> The distance seems 600 miles to 700 miles from here maybe
>>>> magnitude 4
>>>> but nothing seems to match that as of my last look.
>>>> Regards;
>>>> geoff
>>>> -
>>> __________________________________________________________
>>> 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)
> 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.
--
Best regards,
Angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: A interesting home brew battery
From: "meredith lamb" paleoartifact@.........
Date: Wed, 12 Nov 2008 13:47:19 -0700
Hi all,
I suppose its a little bit off of a seismometer topic; unless...you're a
science experimenter or could
even consider it a back up battery source for your seismometer
amplifier....or just for pure fun
confirmation or basic personal curiosity.
http://seismometer.googlepages.com/makingahomebrewbattery
It uses carbon graphite plate/s, un-coated aluminum plates, water, a little
salt, and the key ingredient is...common
liquid bleach (!). The bleach more or less amplifies the current ~ 10-13x;
its a relatively strong oxidant. My big
shoebox size cell got up to ~ 1/8 ampere; which is considerably a lot more
than other small web sourced home
brew (1-2 mA ultra low current) batteries I've seen. It could probably be
more considered as a "reserve"
type battery; unless one can do ~ frequent 2-3 day maintenance. The web
site above is like a log of experiments
and comments over 4 days. Its probably not really new so to
speak....but....enjoy....
Take care, Meredith
Hi all,<br><br>I suppose its a little bit off of a seismometer topic; unless...you're a science experimenter or could <br>even consider it a back up battery source for your seismometer amplifier....or just for pure fun <br>
confirmation or basic personal curiosity.<br><br><a href="http://seismometer.googlepages.com/makingahomebrewbattery">http://seismometer.googlepages.com/makingahomebrewbattery</a><br><br>It uses carbon graphite plate/s, un-coated aluminum plates, water, a little salt, and the key ingredient is...common<br>
liquid bleach (!). The bleach more or less amplifies the current ~ 10-13x; its a relatively strong oxidant. My big<br>shoebox size cell got up to ~ 1/8 ampere; which is considerably a lot more than other small web sourced home<br>
brew (1-2 mA ultra low current) batteries I've seen. It could probably be more considered as a "reserve"<br>type battery; unless one can do ~ frequent 2-3 day maintenance. The web site above is like a log of experiments<br>
and comments over 4 days. Its probably not really new so to speak....but....enjoy....<br><br>Take care, Meredith<br><br><br>
Subject: Re: A interesting home brew battery
From: "Dale Hardy" photon1@...........
Date: Thu, 13 Nov 2008 09:07:24 +1100
Hi Meredith
your battery is an aluminium-hypochlorite battery, where the =
hypochlorite comes from the bleach. be aware you can get small amounts =
of chlorine from the carbon plates
for an overview of the electrochemistry see =
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=3DADD019917&Location=3DU2&doc=3DG=
etTRDoc.pdf
Dale
----- Original Message -----=20
From: meredith lamb=20
To: psn-l@.................
Sent: Thursday, November 13, 2008 7:47 AM
Subject: A interesting home brew battery
Hi all,
I suppose its a little bit off of a seismometer topic; unless...you're =
a science experimenter or could=20
even consider it a back up battery source for your seismometer =
amplifier....or just for pure fun=20
confirmation or basic personal curiosity.
http://seismometer.googlepages.com/makingahomebrewbattery
It uses carbon graphite plate/s, un-coated aluminum plates, water, a =
little salt, and the key ingredient is...common
liquid bleach (!). The bleach more or less amplifies the current ~ =
10-13x; its a relatively strong oxidant. My big
shoebox size cell got up to ~ 1/8 ampere; which is considerably a lot =
more than other small web sourced home
brew (1-2 mA ultra low current) batteries I've seen. It could =
probably be more considered as a "reserve"
type battery; unless one can do ~ frequent 2-3 day maintenance. The =
web site above is like a log of experiments
and comments over 4 days. Its probably not really new so to =
speak....but....enjoy....
Take care, Meredith
-------------------------------------------------------------------------=
-----
No virus found in this incoming message.
Checked by AVG - http://www.avg.com=20
Version: 8.0.175 / Virus Database: 270.9.2/1783 - Release Date: =
11/12/2008 10:01 AM
<!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 6.00.2900.3429" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Hi Meredith</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>your battery is an =
aluminium-hypochlorite battery,=20
where the hypochlorite comes from the bleach. be aware you can get small =
amounts=20
of chlorine from the carbon plates</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>for an overview of the electrochemistry =
see <A=20
href=3D"http://www.dtic.mil/cgi-bin/GetTRDoc?AD=3DADD019917&Location=3D=
U2&doc=3DGetTRDoc.pdf">http://www.dtic.mil/cgi-bin/GetTRDoc?AD=3DADD0=
19917&Location=3DU2&doc=3DGetTRDoc.pdf</A></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Dale</FONT></DIV>
<DIV> </DIV>
<BLOCKQUOTE=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=3Dpaleoartifact@............
href=3D"mailto:paleoartifact@.........">meredith lamb</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, November 13, =
2008 7:47=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> A interesting home =
brew=20
battery</DIV>
<DIV><BR></DIV>Hi all,<BR><BR>I suppose its a little bit off of a =
seismometer=20
topic; unless...you're a science experimenter or could <BR>even =
consider it a=20
back up battery source for your seismometer amplifier....or just for =
pure fun=20
<BR>confirmation or basic personal curiosity.<BR><BR><A=20
=
href=3D"http://seismometer.googlepages.com/makingahomebrewbattery">http:/=
/seismometer.googlepages.com/makingahomebrewbattery</A><BR><BR>It=20
uses carbon graphite plate/s, un-coated aluminum plates, water, a =
little salt,=20
and the key ingredient is...common<BR>liquid bleach (!). The =
bleach more=20
or less amplifies the current ~ 10-13x; its a relatively strong =
oxidant.=20
My big<BR>shoebox size cell got up to ~ 1/8 ampere; which is=20
considerably a lot more than other small web sourced home<BR>brew (1-2 =
mA=20
ultra low current) batteries I've seen. It could probably be =
more=20
considered as a "reserve"<BR>type battery; unless one can do ~ =
frequent 2-3=20
day maintenance. The web site above is like a log of =
experiments<BR>and=20
comments over 4 days. Its probably not really new so to=20
speak....but....enjoy....<BR><BR>Take care, Meredith<BR><BR><BR>
<P>
<HR>
<P></P><BR>No virus found in this incoming message.<BR>Checked by AVG =
-=20
http://www.avg.com <BR>Version: 8.0.175 / Virus Database: 270.9.2/1783 =
-=20
Release Date: 11/12/2008 10:01 AM<BR></BLOCKQUOTE></BODY></HTML>
Subject: Re: A interesting home brew battery
From: "meredith lamb" paleoartifact@.........
Date: Wed, 12 Nov 2008 20:52:25 -0700
Hi Dale,
Thanks for battery description...it also leads into a wide variety of other
interesting search engine results.
Take care, Meredith
On Wed, Nov 12, 2008 at 3:07 PM, Dale Hardy <photon1@...........> wrote:
> Hi Meredith
> your battery is an aluminium-hypochlorite battery, where the hypochlorite
> comes from the bleach. be aware you can get small amounts of chlorine from
> the carbon plates
> for an overview of the electrochemistry see
> http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADD019917&Location=U2&doc=GetTRDoc.pdf
> Dale
>
>
Hi Dale,<br><br>Thanks for battery description...it also leads into a wide variety of other interesting search engine results.<br><br>Take care, Meredith <br><br><div class="gmail_quote">On Wed, Nov 12, 2008 at 3:07 PM, Dale Hardy <span dir="ltr"><<a href="mailto:photon1@...........">photon1@...........</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div bgcolor="#ffffff">
<div><font face="Arial" size="2">Hi Meredith</font></div>
<div><font face="Arial" size="2">your battery is an aluminium-hypochlorite battery,
where the hypochlorite comes from the bleach. be aware you can get small amounts
of chlorine from the carbon plates</font></div>
<div><font face="Arial" size="2">for an overview of the electrochemistry see <a href="http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADD019917&Location=U2&doc=GetTRDoc.pdf" target="_blank">http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADD019917&Location=U2&doc=GetTRDoc.pdf</a></font></div>
<div><font face="Arial" size="2">Dale</font></div>
<div> </div>
</div></blockquote></div><br>
Subject: Old Lehman
From: "Edward Ianni" edwianni1@...........
Date: Sun, 16 Nov 2008 09:50:09 -0500
Years ago (as a interested, very amateur hobbyist) I built a Lehman =
Seismograph, but for a long time I have not had it in operation. I =
decided to turn my old seismograph on again to show some young friends =
that have an interest in seismology. I decided to update Amaseis also. I =
am surprised and confounded by the initial results of my "homemade =
Lehman" using it with the new version of AMASEIS. To get the trace "on =
screen" I had to set the zero level to approximately 28,000 instead of =
2048 and the trace is extremely volatile as I approach the seismograph =
with it's peak hitting a height of about 2 hours (above and below the 0 =
line, with a gain set at 20 [and no event happening]). I was wondering =
if there is anything that is glaringly wrong you might advise me on. =
Thanks a lot . Ed.=20
<!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 6.00.6000.16735" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>
<P>Years ago (as a interested, very amateur hobbyist) I built a Lehman=20
Seismograph, but for a long time I have not had it in operation. I =
decided to=20
turn my old seismograph on again to show some young friends that have an =
interest in seismology. I decided to update Amaseis also. I am surprised =
and=20
confounded by the initial results of my "homemade Lehman" using it with =
the new=20
version of AMASEIS. To get the trace "on screen" I had to set the =
<U>zero=20
level</U> to approximately 28,000 instead of 2048 and the trace is =
extremely=20
volatile as I approach the seismograph with it's peak hitting a height =
of about=20
2 hours (above and below the 0 line, with a gain set at 20 [and no event =
happening]). I was wondering if there is anything that is glaringly =
wrong you=20
might advise me on. Thanks a lot . Ed. </P></FONT></DIV></BODY></HTML>
Subject: quiet time records
From: Thomas Dick dickthomas01@.............
Date: Sun, 16 Nov 2008 10:13:12 -0600
Is there a way to get a set interval of minutes from a Wilber II site
that isn't an earthquake event?
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: quiet time records
From: Bob Hancock carpediem1@.........
Date: Sun, 16 Nov 2008 14:02:55 -0700
There is no way to download non-event data through Wilber II. The
closest you can come is by requesting 5 minutes of data before the
initial P wave on a specific event.
To download non-event data from a specific station, you need to use
VASE. Here is a link to the program:
http://www.iris.edu/dhi/vase_request.htm
WinQuake will read the SAC format data files. The VASE program lets
you set the amount of time you want to download from minutes to
hours. Downloads from VASE do not carry specific event information.
The program is fairly easy to use although there is a learning curve
with it. I would recommend that you download the manual for the
program. If you convert the SAC files to PSN format through WinQuake,
you can make three channel datasets with them.
Good Luck
Bob Hancock
On Nov 16, 2008, at 9:13 AM, Thomas Dick wrote:
> Is there a way to get a set interval of minutes from a Wilber II
> site that isn't an earthquake event?
> __________________________________________________________
>
> 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: Vertical Seismometer with Honey Support
From: "Gary Lindgren" gel@.................
Date: Sun, 16 Nov 2008 15:25:53 -0800
For the last few months I have been working on a vertical seismometer. =
Work
to date has been mostly with the measurement of N/A or newtons per amp
calibration factor for 3 different geometry versions. Results will be
reported in the next several days. Last week I started to cut metal and =
put
together the concept for my vertical. See
http://gelindgren.googlepages.com/gel_vert_11_16_08.jpg The jar of =
honey
supports the vertical spring. The most interesting part is the bearing
support. See
http://gelindgren.googlepages.com/gel_vert_bearings_11_16_08.jpg The =
black
ball bearings are made of silicon carbide and =BC=94 in diameter. The =
balls are
epoxied into a partially drilled hole in the aluminum cross bar. The =
balls
ride in two sets of two 1/8=94 diameter rods made from tungsten carbide =
and
will be polished to a mirror finish. As configured the resonant period =
is
very short, maybe =BD second. Is there an equation that defines a =
vertical
seismometer resonant period. I assume the spring constant is part of the
calculation. Is there a recommended source of compression springs with
various constants. Comments are most welcome. BTW, the jar of honey will =
be
replaced by a 4x4 lab jack.
=20
Gary
=20
=20
=20
=20
=20
=20
=20
Gary Lindgren
585 Lincoln Ave
Palo Alto CA 94301
=20
650-326-0655
=20
<http://www.blue-eagle-technologies.com/> =
www.blue-eagle-technologies.com
Check out Lastest Seismometer Reading
<http://www.cymonsplace.blogspot.com/> cymonsplace.blogspot.com=20
=20
=20
<html xmlns:v=3D"urn:schemas-microsoft-com:vml" =
xmlns:o=3D"urn:schemas-microsoft-com:office:office" =
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<body lang=3DEN-US link=3Dblue vlink=3Dpurple>
<div class=3DSection1>
<p class=3DMsoNormal>For the last few months I have been working on a =
vertical
seismometer. Work to date has been mostly with the measurement of N/A or
newtons per amp calibration factor for 3 different geometry versions. =
Results
will be reported in the next several days. Last week I started to cut =
metal and
put together the concept for my vertical. See <a
href=3D"http://gelindgren.googlepages.com/gel_vert_11_16_08.jpg">http://g=
elindgren.googlepages.com/gel_vert_11_16_08.jpg</a>=A0
The jar of honey supports the vertical spring. The most interesting part =
is the
bearing support. See <a
href=3D"http://gelindgren.googlepages.com/gel_vert_bearings_11_16_08.jpg"=
>http://gelindgren.googlepages.com/gel_vert_bearings_11_16_08.jpg</a>=A0
The black ball bearings are made of silicon carbide and =BC” in =
diameter. The
balls are epoxied into a partially drilled hole in the aluminum cross =
bar. The
balls ride in two sets of two=A0 1/8” diameter rods made from =
tungsten
carbide and will be polished to a mirror finish. As configured the =
resonant
period is very short, maybe =BD second. Is there an equation that =
defines a
vertical seismometer resonant period. I assume the spring constant is =
part of
the calculation. Is there a recommended source of compression springs =
with
various constants. Comments are most welcome. BTW, the jar of honey will =
be
replaced by a 4x4 lab jack.<o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal>Gary<o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>Gary Lindgren</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>585 Lincoln Ave</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>Palo Alto CA 94301</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>650-326-0655<=
/span><o:p></o:p></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href=3D"http://www.blue-eagle-technologies.com/"><span =
style=3D'color:blue'>www.blue-eagle-technologies.com</span></a>=A0=A0
<span style=3D'color:red'>Check out Lastest Seismometer =
Reading</span></span><o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href=3D"http://www.cymonsplace.blogspot.com/"><span =
style=3D'color:blue'>cymonsplace.blogspot.com</span></a> </span><o:p=
></o:p></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
</div>
</body>
</html>
Subject: Re: Vertical Seismometer with Honey Support
From: Brett Nordgren brett3nt@.............
Date: Sun, 16 Nov 2008 22:23:56 -0500
Gary,
Making a vertical seismometer using an ordinary coil spring is going to be=
=20
difficult. On the one hand it has to be strong enough to support the=20
seismic mass, but at the same time its lifting force should change very=20
little as the mass moves up and down if you want to get a long period. It=
=20
may be possible to do that with a very long (several meters) spring, but=20
it's not likely to be practical due to the spring's likely tendency to=20
vibrate from side to side. Normally, verticals tend to fall into two=20
types, the LaCoste 'zero length' coil spring design and the more modern=20
astatic leaf spring ones. They both have the property that the spring's=20
lifting force on the mass changes very little, or not at all, as the mass=20
moves up and down.
For sketches of how they work, check Professor Wielandt's papers.
http://www.geophys.uni-stuttgart.de/lehre/skripte/old_skripte/seismometry/hb=
k_html/node11.html
and
http://www.geophys.uni-stuttgart.de/lehre/skripte/old_skripte/seismometry/ma=
n_html/node15.html
It is worth the effort to browse around elsewhere in these documents.=20
Although they are similar, they are both filled with really good=20
stuff. Some of the math may be a bit advanced, but even without the math,=
=20
there is much there that should be useful.
As I recall, the period will be 2 Pi sqrt(M / K) Where M is the mass and K=
=20
is the spring constant, defined by K =3D (force change / length change).=
This=20
should all work if you get the units right. I'm doing this from memory, so=
=20
someone please let me know if I messed it up.
Regards,
Brett
At 03:25 PM 11/16/2008 -0800, you wrote:
>For the last few months I have been working on a vertical seismometer.=20
>Work to date has been mostly with the measurement of N/A or newtons per=20
>amp calibration factor for 3 different geometry versions. Results will be=
=20
>reported in the next several days. Last week I started to cut metal and=20
>put together the concept for my vertical. See=20
><http://gelindgren.googlepages.com/gel_vert_11_16_08.jpg>http://gelindgren.=
googlepages.com/gel_vert_11_16_08.jpg=20
>The jar of honey supports the vertical spring. The most interesting part=20
>is the bearing support. See=20
><http://gelindgren.googlepages.com/gel_vert_bearings_11_16_08.jpg>http://ge=
lindgren.googlepages.com/gel_vert_bearings_11_16_08.jpg=20
>The black ball bearings are made of silicon carbide and =BC in diameter.=
The=20
>balls are epoxied into a partially drilled hole in the aluminum cross bar.=
=20
>The balls ride in two sets of two 1/8 diameter rods made from tungsten=20
>carbide and will be polished to a mirror finish. As configured the=20
>resonant period is very short, maybe =BD second. Is there an equation that=
=20
>defines a vertical seismometer resonant period. I assume the spring=20
>constant is part of the calculation. Is there a recommended source of=20
>compression springs with various constants. Comments are most welcome.=20
>BTW, the jar of honey will be replaced by a 4x4 lab jack.
>
>
>
>Gary
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>Gary Lindgren
>
>585 Lincoln Ave
>
>Palo Alto CA 94301
>
>
>
>650-326-0655
>
>
>
><http://www.blue-eagle-technologies.com/>www.blue-eagle-technologies.com=20
>Check out Lastest Seismometer Reading
>
><http://www.cymonsplace.blogspot.com/>cymonsplace.blogspot.com
>
>
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Vertical Seismometer with Honey Support
From: "Robert McClure" bobmcclure90@.........
Date: Sun, 16 Nov 2008 22:53:11 -0500
Hi Gary,
I have a design calculator for spring-supported vertical seismometers. See
http://bobmcclure90.googlepages.com/springcalc
You wrote: As configured the resonant period is very short, maybe =BD
second. Is there an equation that defines a vertical seismometer resonant
period. I assume the spring constant is part of the calculation.
Bob
Hi Gary,<br><br> I have a design calculator for spring-supported verti=
cal seismometers. See<br><br> <a href=3D"http://bobmcclure90.googlepa=
ges.com/springcalc">http://bobmcclure90.googlepages.com/springcalc</a><br><=
br> You wrote: As configured the resonant period is very short, maybe=
=BD second. Is there an equation that defines a vertical seismometer reson=
ant period. I assume the spring constant is part of the calculation.<br>
<br>Bob<br>
Subject: Artic quake
From: Thomas Dick dickthomas01@.............
Date: Mon, 17 Nov 2008 08:57:05 -0600
Any one getting an unusual peak as I am after the SSS and before the LQ
on the vertical and N-S Lehman?
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Vertical Seismometer with Honey Support
From: ChrisAtUpw@.......
Date: Mon, 17 Nov 2008 11:03:47 EST
In a message dated 16/11/2008, gel@................. writes:
For the last few months I have been working on a vertical seismometer.
Hi Gary,
There is a reasonably good vertical design on John's website at
_http://jclahr.com/science/psn/hill/index.html_
(http://jclahr.com/science/psn/hill/index.html)
But I don't like either the suspension knife blade or the oil damping.
It is quite easy to use either a twin wire or foil suspension in tension or a
twin blade/foil suspension in compression. A bit of weak spring on the input
suspension doesn't matterin a vertical. Magnetic damping is vastly preferable
to oil. It is quite cheap, easy to adjust and clean.
See _http://jclahr.com/science/psn/chapman/as1%20damping/index.html_
(http://jclahr.com/science/psn/chapman/as1%20damping/index.html)
The longest period you can expect to get from a steel spring vertical is
about 6 seconds. The elastic properties of steel are strongly temperature
dependant and attempts at longer period suspensions simply collapse with small
changes in temperature. 6 seconds is fine if you want to study microseisms,
but it is not good for the surface waves from earthquakes.
However, you can make a 1.5 to 2 second vertical quite easily as shown
above and then extend the period to 15 to 20 seconds to cover the common Love
and Rayleigh surface waves at about 20 seconds, using an extra gain of x100.
If you do this digitally, you will need a 16 bit ADC to give you enough
signal resolution, with the normal sesimic background gain set at over 100
counts.
If you use an electronic period compensating amplifier, this needs to be
low noise, but you can use a 12 bit ADC with it (just!).
Sorry, but it is only fair to warn you that you WON'T get extended
periods with the vertical compression spring that you are trying to use. The
spring + the geometry are both wrong. See Bob's spring calculations?
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 6.00.6000.16735" 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 16/11/2008, gel@................. writes:</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>For the=20
last few months I have been working on a vertical=20
seismometer.</FONT></BLOCKQUOTE></DIV>
<DIV>Hi Gary,</DIV>
<DIV> </DIV>
<DIV> There is a reasonably good vertical design on=20
John's website at</DIV>
<DIV> <A=20
href=3D"http://jclahr.com/science/psn/hill/index.html">http://jclahr.com/sci=
ence/psn/hill/index.html</A></DIV>
<DIV> But I don't like either the suspension knife bl=
ade=20
or the oil damping. It is quite easy to use either a twin wire or foil=20
suspension in tension or a twin blade/foil suspension in compression. A bit=20=
of=20
weak spring on the input suspension doesn't matterin a vertical. Magnetic=20
damping is vastly preferable to oil. It is quite cheap, easy to adjust and=20
clean.</DIV>
<DIV> See <A=20
href=3D"http://jclahr.com/science/psn/chapman/as1%20damping/index.html">http=
://jclahr.com/science/psn/chapman/as1%20damping/index.html</A></DIV>
<DIV> The longest period you can expect to get f=
rom=20
a steel spring vertical is about 6 seconds. The elastic properties of steel=20=
are=20
strongly temperature dependant and attempts at longer period suspensions sim=
ply=20
collapse with small changes in temperature. 6 seconds is fine if you want to=
=20
study microseisms, but it is not good for the surface waves from=20
earthquakes.</DIV>
<DIV> However, you can make a 1.5 to 2 second vertica=
l=20
quite easily as shown above and then extend the period to 15 to 20 seco=
nds=20
to cover the common Love and Rayleigh surface waves at about 20 seconds, usi=
ng=20
an extra gain of x100. </DIV>
<DIV> If you do this digitally, you will need a 16 bi=
t=20
ADC to give you enough signal resolution, with the normal sesimic=20
background gain set at over 100 counts.</DIV>
<DIV> If you use an electronic period compensating=20
amplifier, this needs to be low noise, but you can use a 12 bit ADC with it=20
(just!).</DIV>
<DIV> Sorry, but it is only fair to warn you=20
that you WON'T get extended periods with the vertical compression sprin=
g=20
that you are trying to use. The spring + the geometry are both wrong. S=
ee=20
Bob's spring calculations?</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></DIV></FONT></BODY></HTML>
Subject: Re: Vertical Seismometer with Honey Support
From: Brett Nordgren brett3nt@.............
Date: Mon, 17 Nov 2008 11:03:11 -0500
Gary,
After looking at your design, I see that there was one thing I failed to
mention. The formula I gave for the period assumes that the distance from
the spring to the pivot is the same as the distance of the mass from the
pivot. If not, the period needs to be multiplied by (mass distance /
spring distance). In other words, the effective value of K gets reduced by
the square of that ratio.
Also, one set of units which will work has forces in Newtons, mass in
kilograms, distances in meters and time in seconds. If you convert your
units to those, the formula should give the proper results for the period.
Regards,
Brett
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Vertical Seismometer with Honey Support
From: "meredith lamb" paleoartifact@.........
Date: Mon, 17 Nov 2008 10:07:43 -0700
On Sun, Nov 16, 2008 at 4:25 PM, Gary Lindgren <gel@.................>wrote:
> For the last few months I have been working on a vertical seismometer.
>
Or................being as you're mechanically overall part way (~60%) there
already.....add more upright vertical support
and a horizontal extension (and a conventional extension spring) to the mast
and try out Randall Peters vertical setup.
His claims of; "at least 20s, etc." sure read enticing to verify.
http://physics.mercer.edu/hpage/new-z.html
Take care, Meredith
<br><br>
<div class="gmail_quote">On Sun, Nov 16, 2008 at 4:25 PM, Gary Lindgren <span dir="ltr"><<a href="mailto:gel@.................">gel@.................</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div lang="EN-US" vlink="purple" link="blue">
<div>
<p>For the last few months I have been working on a vertical seismometer. </p></div></div></blockquote>
<div>Or................being as you're mechanically overall part way (~60%) there already.....add more upright vertical support</div>
<div>and a horizontal extension (and a conventional extension spring) to the mast and try out Randall Peters vertical setup.</div>
<div>His claims of; "at least 20s, etc." sure read enticing to verify.</div>
<div> </div>
<div><a href="http://physics.mercer.edu/hpage/new-z.html">http://physics.mercer.edu/hpage/new-z.html</a></div>
<div> </div>
<div>Take care, Meredith</div>
<div> </div></div>
Subject: Re: quiet time records
From: Thomas Dick dickthomas01@.............
Date: Mon, 17 Nov 2008 12:40:48 -0600
Bob Hancock wrote:
> There is no way to download non-event data through Wilber II. The
> closest you can come is by requesting 5 minutes of data before the
> initial P wave on a specific event.
>
> To download non-event data from a specific station, you need to use
> VASE. Here is a link to the program:
>
> Thanks Bob, I had an earlier version of Vase and just hadn't used it
> because it kept taking over when I preferred Winquake. I tried it this
> morning and maybe it will give me what I want when I get up to speed
> with it.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Half Bridge Calibration signals
From: "Randy Pratt" rpratt@.............
Date: Mon, 17 Nov 2008 13:20:20 -0600
Hi All,
I have been reading about calibration using random signals input through =
a half bridge. Does anyone have a rule of thumb as to resistance values =
and any corrections to the signal that might be required? Specifically, =
I am looking at the CALEX5 program to obtain parameters for my systems.
Randy
<!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 6.00.2600.0" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Hi All,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I have been reading about calibration =
using random=20
signals input through a half bridge. Does anyone have a rule of =
thumb as=20
to resistance values and any corrections to the signal that might be=20
required? Specifically, I am looking at the CALEX5 program to =
obtain=20
parameters for my systems.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Randy</FONT></DIV></BODY></HTML>
Subject: Re: Artic quake
From: Bob Hancock carpediem1@.........
Date: Tue, 18 Nov 2008 00:29:35 -0700
Hi Tom -
I downloaded your event and looked at it.
Your recording show a strong amplitude wave on the north horizontal
channel and the vertical channel at the same time. This is consistent
with recording both vertical motion and transverse motion at the same
time. There are a few times when a love wave can be converted to a
rayleigh wave and then takes on the visual characteristics of a
rayleigh wave, but this does not appear to be within that category.
For reference look at my posting of the same event.
As for what wave you were seeing, The large amplitude wave that is
visible between the WinQuake projections for the SSS wave and LQ
(Love) wave indicators is infact the Love Wave.
The projected arrival times of body waves is usually accurate within 1
or 2 seconds. However, the arrival time of surface waves is
compounded by the type of crust they are traveling through and the
frequencies of the waves. The velocities of surface waves vary
significantly from Continental Crust and Oceanic Crust with wave
frequency contiributing significantly to this variation. I am unaware
of a single standing wave arrival time program that will cover these
variables.
Both Love and Rayleigh waves start out as low frequency waves and
change to higher frequency as the progress. Also there are changes in
the amplitude of the waves as they progress. However, the start of
love and rayleigh waves can be difficult to ascertain. Wave
identification of surface waves is tricky at best, and sometimes the
only way it can be confirmed is to rotate the data and look at the
particle motion on both the horizontal channels and vertical channel.
The program used by professional seismologists SAC (Seismic Analysis
Code), and another seismic wave timing program written by the
Seismologists at the University of South Carolina called TauP track
the arrival times of certain body waves. Neither program tracks the
arrival times of surface waves.
There is one USGS program that tracks the arrival times of surface
wave and it is available at the following link:
http://neic.usgs.gov/neis/travel_times/compute_tt.html
The USGS projected arrival times for the Love (LQ) and Rayleigh (LR)
waves at your station were LQ 13:16:53 and LR 13:19:15.
The projected arrival times for the Love and Rayleigh waves using
WinQuake at your station were LQ 13:22:17.9 and LR 13:26:10.5
Neither WinQuake or the USGS program give good arrival times on
surface waves consistently.
Looking visually at your posted seismogram, it appears that your love
wave starts at about 13:18:30.5. This is visible on both your north
and east channels. The Love wave is a transverse wave and will not
appear in the radial. While this event was mostly north of you, there
was also a small horizontal component in it also.
The actual start of the Rayleigh wave is harder to identify without
looking at particle motion. It appears to possibly start about
13:21:52.3 on the East and Vertical channels. I could be wrong on the
actual starting times, but that is the way they appear to me.
I hope this helps.
Bob Hancock
On Nov 17, 2008, at 7:57 AM, Thomas Dick wrote:
> Any one getting an unusual peak as I am after the SSS and before the
> LQ on the vertical and N-S Lehman?
> __________________________________________________________
>
> 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: Vertical Seismometer with Honey Support
From: "Gary Lindgren" gel@.................
Date: Tue, 18 Nov 2008 16:30:32 -0800
Hello Bob,
Thank you for your spring calculator. I would like to keep the mass at =
about
..5 Kg. so that I can eventually use a feedback system. I can see that =
I=92m
going to have a hard time getting a spring for this small mass size. =
From
what I can tell I need a spring with a constant of 3 Kg./m. This turns =
out
to be 0.17 lbs/in or a very small spring. The surprising thing is that I
don=92t need a long spring, just a small spring constant. BTW I tried =
the
parameters of the concept model. It turns out that the spring constant =
was
maybe 270 kg./m. I got 0.18 seconds for the period. That seems about
correct.
Thank you for the tool.
Gary
=20
From: psn-l-request@.............. [mailto:psn-l-request@............... =
On
Behalf Of Robert McClure
Sent: Sunday, November 16, 2008 7:53 PM
To: psn-l@..............
Subject: Re: Vertical Seismometer with Honey Support
=20
Hi Gary,
I have a design calculator for spring-supported vertical seismometers. =
See
http://bobmcclure90.googlepages.com/springcalc
You wrote: As configured the resonant period is very short, maybe =BD
second. Is there an equation that defines a vertical seismometer =
resonant
period. I assume the spring constant is part of the calculation.
Bob
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<div class=3DSection1>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Hello Bob,<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thank you for your spring calculator. I would like to =
keep the
mass at about .5 Kg. so that I can eventually use a feedback system. I =
can see
that I’m going to have a hard time getting a spring for this small =
mass
size. From what I can tell I need a spring with a constant of 3 Kg./m. =
This
turns out to be 0.17 lbs/in or a very small spring. The surprising thing =
is
that I don’t need a long spring, just a small spring constant. BTW =
I tried
the parameters of the concept model. It turns out that the spring =
constant was
maybe 270 kg./m. I got 0.18 seconds for the period. That seems about =
correct.<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thank you for the tool.<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Gary<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style=3D'border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt =
0in 0in 0in'>
<p class=3DMsoNormal><b><span =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span>=
</b><span
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
psn-l-request@.............. [mailto:psn-l-request@............... <b>On =
Behalf
Of </b>Robert McClure<br>
<b>Sent:</b> Sunday, November 16, 2008 7:53 PM<br>
<b>To:</b> psn-l@..............<br>
<b>Subject:</b> Re: Vertical Seismometer with Honey =
Support<o:p></o:p></span></p>
</div>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal>Hi Gary,<br>
<br>
I have a design calculator for spring-supported vertical =
seismometers.
See<br>
<br>
<a =
href=3D"http://bobmcclure90.googlepages.com/springcalc">http://bobmcclure=
90.googlepages.com/springcalc</a><br>
<br>
You wrote: As configured the resonant period is very short, maybe =
=BD
second. Is there an equation that defines a vertical seismometer =
resonant
period. I assume the spring constant is part of the calculation.<br>
<br>
Bob<o:p></o:p></p>
</div>
</body>
</html>
Subject: RE: Vertical Seismometer with Honey Support
From: "Gary Lindgren" gel@.................
Date: Tue, 18 Nov 2008 16:44:55 -0800
Meredith,
As I mentioned in my original Vertical message, this go around was a
concept. I consider the bearing system to be the most important part. =
Now I
need to add some height and a cross beam at the top to attach an =
extension
spring. By using Bob=92s calculation tool, it seems I could achieve a =
period
of about 1 =BD seconds with a spring with a very small constant. Then I =
would
use a feedback system to extend the period. Using Bob=92s period =
calculation
tool, I probably have a period of about 0.2 seconds for the vertical I
showed. Thank you very much for the feedback.
Gary
=20
=20
=20
=20
From: psn-l-request@.............. [mailto:psn-l-request@............... =
On
Behalf Of meredith lamb
Sent: Monday, November 17, 2008 9:08 AM
To: psn-l@..............
Subject: Re: Vertical Seismometer with Honey Support
=20
=20
On Sun, Nov 16, 2008 at 4:25 PM, Gary Lindgren <gel@.................>
wrote:
For the last few months I have been working on a vertical seismometer.=20
Or................being as you're mechanically overall part way (~60%) =
there
already.....add more upright vertical support
and a horizontal extension (and a conventional extension spring) to the =
mast
and try out Randall Peters vertical setup.
His claims of; "at least 20s, etc." sure read enticing to verify.
=20
http://physics.mercer.edu/hpage/new-z.html
=20
Take care, Meredith
=20
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<div class=3DSection1>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Meredith,<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>As I mentioned in my original Vertical message, this go =
around
was a <u>concept</u>. I consider the bearing system to be the most =
important
part. Now I need to add some height and a cross beam at the top to =
attach an
extension spring. By using Bob’s calculation tool, it seems I =
could
achieve a period of about 1 =BD seconds with a spring with a very small =
constant.
Then I would use a feedback system to extend the period. Using =
Bob’s
period calculation tool, I probably have a period of about 0.2 seconds =
for the vertical
I showed. Thank you very much for the feedback.<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Gary<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style=3D'border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt =
0in 0in 0in'>
<p class=3DMsoNormal><b><span =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span>=
</b><span
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
psn-l-request@.............. [mailto:psn-l-request@............... <b>On =
Behalf
Of </b>meredith lamb<br>
<b>Sent:</b> Monday, November 17, 2008 9:08 AM<br>
<b>To:</b> psn-l@..............<br>
<b>Subject:</b> Re: Vertical Seismometer with Honey =
Support<o:p></o:p></span></p>
</div>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal =
style=3D'margin-bottom:12.0pt'><o:p> </o:p></p>
<div>
<p class=3DMsoNormal>On Sun, Nov 16, 2008 at 4:25 PM, Gary Lindgren =
<<a
href=3D"mailto:gel@.................">gel@.................</a>> =
wrote:<o:p></o:p></p>
<div>
<div>
<p>For the last few months I have been working on a vertical =
seismometer. <o:p></o:p></p>
</div>
</div>
<div>
<p class=3DMsoNormal>Or................being as you're mechanically =
overall part
way (~60%) there already.....add more upright vertical =
support<o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal>and a horizontal extension (and a conventional
extension spring) to the mast and try out Randall Peters vertical =
setup.<o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal>His claims of; "at least 20s,
etc." sure read enticing =
to verify.<o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal><a =
href=3D"http://physics.mercer.edu/hpage/new-z.html">http://physics.mercer=
..edu/hpage/new-z.html</a><o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal>Take care, Meredith<o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal> <o:p></o:p></p>
</div>
</div>
</div>
</body>
</html>
Subject: Honey Jar Vertical spring
From: "Randy Pratt" rpratt@.............
Date: Wed, 19 Nov 2008 08:58:35 -0600
Gary,
Century Spring has an online catalog. Their Z-3 spring is .15 lb/inch =
and there may be something closer. Many hardware stores around here =
carry Century in display racks.
Randy
<!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">
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<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Gary,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Century Spring has an online =
catalog. Their=20
Z-3 spring is .15 lb/inch and there may be something closer. Many =
hardware=20
stores around here carry Century in display racks.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Randy</FONT></DIV></BODY></HTML>
Subject: RE: Honey Jar Vertical spring
From: "Gary Lindgren" gel@.................
Date: Wed, 19 Nov 2008 07:42:14 -0800
Hi Randy,
Yes, I have been looking at the Century Spring catalog. They seem to have
the most comprehensive supply.
Thank you,
Gary
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Randy Pratt
Sent: Wednesday, November 19, 2008 6:59 AM
To: psn-l@..............
Subject: Honey Jar Vertical spring
Gary,
Century Spring has an online catalog. Their Z-3 spring is .15 lb/inch and
there may be something closer. Many hardware stores around here carry
Century in display racks.
Randy
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<body bgcolor=3Dwhite lang=3DEN-US link=3Dblue vlink=3Dpurple>
<div class=3DSection1>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Hi Randy,<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Yes, I have been looking at the Century Spring catalog. =
They
seem to have the most comprehensive supply.<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thank you,<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Gary<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style=3D'border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt =
0in 0in 0in'>
<p class=3DMsoNormal><b><span =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span>=
</b><span
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
psn-l-request@.............. [mailto:psn-l-request@............... <b>On =
Behalf
Of </b>Randy Pratt<br>
<b>Sent:</b> Wednesday, November 19, 2008 6:59 AM<br>
<b>To:</b> psn-l@..............<br>
<b>Subject:</b> Honey Jar Vertical spring<o:p></o:p></span></p>
</div>
</div>
<p class=3DMsoNormal><o:p> </o:p></p>
<div>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>Gary,</span><=
o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>Century
Spring has an online catalog. Their Z-3 spring is .15 lb/inch and =
there
may be something closer. Many hardware stores around here carry =
Century
in display racks.</span><o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>Randy</span><=
o:p></o:p></p>
</div>
</div>
</body>
</html>
Subject: Re: tutorial on pendulum theory
From: "Robert Thomasson" rlthomasson@.........
Date: Wed, 19 Nov 2008 21:24:38 +0300
Randall,
Thanks for posting your paper and letting us know about it - I hope you
don't think your effort has gone unappreciated. I've downloaded and printed
it and I'm working my way through it as time allows and I'm sure I'm not
alone.
On Thu, Oct 23, 2008 at 10:55 PM, Randall Peters <PETERS_RD@..........>wrote:
> I've written a paper titled "A tutorial on gravitational pendulum theory
> applied to seismic sensing of translation and rotation" for a special
> edition of the Bull. Seism. Soc. Amer. concerned with rotation,
> technical editor Willie Lee. I don't know if it is too technical for
> the majority of folks but figured I would let you know about it anyway.
> The paper has been posted to my webpage at
> http://physics.mercer.edu/hpage/BSSA-tutorial/pend-theory.pdf
> The request for me to generate this paper originated with John Lahr's
> mentioning my research to Willie, with whom John worked for a long time
> (before he retired from the USGS). Without John's passionate
> involvement with amateur seismology and science education (reason I came
> to know him) none of this would have happened.
>
Randall,<br><br>Thanks for posting your paper and letting us know about it - I hope you don't think your effort has gone unappreciated. I've downloaded and printed it and I'm working my way through it as time allows and I'm sure I'm not alone.<br>
<br><div class="gmail_quote">On Thu, Oct 23, 2008 at 10:55 PM, Randall Peters <span dir="ltr"><<a href="mailto:PETERS_RD@..........">PETERS_RD@..........</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
I've written a paper titled "A tutorial on gravitational pendulum theory<br>
applied to seismic sensing of translation and rotation" for a special<br>
edition of the Bull. Seism. Soc. Amer. concerned with rotation,<br>
technical editor Willie Lee. I don't know if it is too technical for<br>
the majority of folks but figured I would let you know about it anyway.<br>
The paper has been posted to my webpage at<br>
<a href="http://physics.mercer.edu/hpage/BSSA-tutorial/pend-theory.pdf" target="_blank">http://physics.mercer.edu/hpage/BSSA-tutorial/pend-theory.pdf</a><br>
The request for me to generate this paper originated with John Lahr's<br>
mentioning my research to Willie, with whom John worked for a long time<br>
(before he retired from the USGS). Without John's passionate<br>
involvement with amateur seismology and science education (reason I came<br>
to know him) none of this would have happened.<br>
</blockquote></div><br>
Subject: RE: Honey Jar Vertical spring
From: "Gary Lindgren" gel@.................
Date: Wed, 19 Nov 2008 13:25:15 -0800
Randy,
I checked out my local hardware store and ran over to the spring display
where I picked up that compression spring. To my amazement, it is a Century
Spring display rack. I picked up a couple springs, but the K constant is too
low. I checked with the manager and he may be able to do a special buy for
me.
Thanks again,
Gary
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Randy Pratt
Sent: Wednesday, November 19, 2008 6:59 AM
To: psn-l@..............
Subject: Honey Jar Vertical spring
Gary,
Century Spring has an online catalog. Their Z-3 spring is .15 lb/inch and
there may be something closer. Many hardware stores around here carry
Century in display racks.
Randy
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<p class=3DMsoNormal><span =
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color:#1F497D'>Randy,<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I checked out my local hardware store and ran over to the =
spring
display where I picked up that compression spring. To my amazement, it =
is a <b><i>Century
Spring</i></b> display rack. I picked up a couple springs, but the K =
constant
is too low. I checked with the manager and he may be able to do a =
special buy
for me. <o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thanks again,<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Gary <o:p></o:p></span></p>
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color:#1F497D'><o:p> </o:p></span></p>
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color:#1F497D'><o:p> </o:p></span></p>
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<div>
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0in 0in 0in'>
<p class=3DMsoNormal><b><span =
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</b><span
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
psn-l-request@.............. [mailto:psn-l-request@............... <b>On =
Behalf
Of </b>Randy Pratt<br>
<b>Sent:</b> Wednesday, November 19, 2008 6:59 AM<br>
<b>To:</b> psn-l@..............<br>
<b>Subject:</b> Honey Jar Vertical spring<o:p></o:p></span></p>
</div>
</div>
<p class=3DMsoNormal><o:p> </o:p></p>
<div>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>Gary,</span><=
o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>Century
Spring has an online catalog. Their Z-3 spring is .15 lb/inch and =
there
may be something closer. Many hardware stores around here carry =
Century
in display racks.</span><o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>Randy</span><=
o:p></o:p></p>
</div>
</div>
</body>
</html>
Subject: Re: Vertical Seismometer with Honey Support
From: Angel sismos@..............
Date: Thu, 20 Nov 2008 10:15:29 +0000
Hello Gary,
Take a look at the spring on a Roger Sparks vertical from a while back
It is at the very bottom of the page.
http://mariottim.interfree.it/doc02v_e.htm
it also seem that Roger has a new configuration
http://www.fairpoint.net/~sparksite/CSpring%20Seismometer.html
Regards,
Angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Vertical Seismometer with Honey Support
From: "Gary Lindgren" gel@.................
Date: Thu, 20 Nov 2008 13:57:27 -0800
Angel,
Thank you for the vertical references. My original concept was to have
something like the Hacksaw suspension. However I was going to use a carbon
fiber material. The carbon fiber stuff didn't have a strong enough spring
constant so I switched to a compression spring. Now I going to an extension
spring. I will be trying an assortment of springs all closely matched to the
requirement, but with different Ks and lengths.
Gary
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Angel
Sent: Thursday, November 20, 2008 2:15 AM
To: Gary Lindgren
Subject: Re: Vertical Seismometer with Honey Support
Hello Gary,
Take a look at the spring on a Roger Sparks vertical from a while back
It is at the very bottom of the page.
http://mariottim.interfree.it/doc02v_e.htm
it also seem that Roger has a new configuration
http://www.fairpoint.net/~sparksite/CSpring%20Seismometer.html
Regards,
Angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re[2]: Vertical Seismometer with Honey Support
From: Angel sismos@..............
Date: Fri, 21 Nov 2008 01:08:44 +0000
Hello Gary,
Most of the carbon fiber that I have tried is a bit too strong. I have tried mainly unidirectional sheets and some twills. The unidirectional stuff is stiffer than hacksaw blades.
check out this site:
http://www.cstsales.com/carbon_Laminates_36.html
the 0.014 might be usefull
the 0.021 is probably too stiff.
the stuff is easy to crack to size, you just sort of snap it off in long strips.
Thursday, November 20, 2008, 9:57:27 PM, you wrote:
> Angel,
> Thank you for the vertical references. My original concept was to have
> something like the Hacksaw suspension. However I was going to use a carbon
> fiber material. The carbon fiber stuff didn't have a strong enough spring
> constant so I switched to a compression spring. Now I going to an extension
> spring. I will be trying an assortment of springs all closely matched to the
> requirement, but with different Ks and lengths.
> Gary
> -----Original Message-----
> From: psn-l-request@..............
> [mailto:psn-l-request@............... On
> Behalf Of Angel
> Sent: Thursday, November 20, 2008 2:15 AM
> To: Gary Lindgren
> Subject: Re: Vertical Seismometer with Honey Support
> Hello Gary,
> Take a look at the spring on a Roger Sparks vertical from a while back
> It is at the very bottom of the page.
> http://mariottim.interfree.it/doc02v_e.htm
> it also seem that Roger has a new configuration
> http://www.fairpoint.net/~sparksite/CSpring%20Seismometer.html
> Regards,
> Angel
> __________________________________________________________
> 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.
--
Best regards,
Angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Okhotsk quake
From: Steinar Midtskogen steinar@.............
Date: Mon, 24 Nov 2008 15:25:27 +0100
Today's 7.0 Okhotsk quake was recorded by my SEP seismometer. Not a
huge signal, but clear enough.
Sac-file: http://voksenlia.net/nytt/2008/jordskjelv-20081124.sac
PNG image: http://voksenlia.net/nytt/2008/jordskjelv-20081124.png
However, what's a bit surprising is that at the exact same time of the
arrival of the P wave my 4.5 Hz geophone recorded something pretty
strong as well for a few minutes. Mostly in the Z direction but
clearly in the other directions as well.
Sac-file Z: http://voksenlia.net/nytt/2008/jordskjelv_z-20081124.sac
PNG image Z: http://voksenlia.net/nytt/2008/jordskjelv_z-20081124.png
Sac-file N: http://voksenlia.net/nytt/2008/jordskjelv_n-20081124.sac
Sac-file E: http://voksenlia.net/nytt/2008/jordskjelv_e-20081124.sac
Will a quake nearly 7000 km away every show up on a 4.5 Hz geophone?
Or could a distant quake trigger a small local quake? Or are the
events unrelated?
Since this happened in daytime, and it's a bit windy outside today
also, there is quite a bit of noise, but the quakes are clear enough.
--
Steinar Midtskogen
http://voksenlia.net/met/
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Okhotsk quake
From: Bob Hancock carpediem1@.........
Date: Mon, 24 Nov 2008 07:57:14 -0700
Steinar -
This was a deep focus event (487.5 km) and the wave pattern is
different that what you see with shallow events. In this case some of
the body wave phases are more pronounced and the surface waves are
diminished. For comparison, I would suggest that you download this
event through the Wilber II option on the IRIS web site at:
http://www.iris.edu/dms/wilber.htm
There is a station near Oslo, Norway that has good data you could use
for comparative analysis. The station is part of the IU network
(Global Seismic Network). The station name is KONO, and its location
is Kongsberg, Norway at 59.65 N and 9.60 E. You can see a strong
signal for the P wave on all three channels.
Bob McClure has written a small program that converts SAC files to PSN
files which can be downloaded at:
http://bobmcclure90.googlepages.com/sitemap
Once you convert them to PSN format, you can edit the files to make
them the same size and with the same starting times, after which you
can put them into three file datasets. By opening a second window on
WinQuake, you can conduct detailed comparative analysis between you
recordings and those of station KONO..
Good Luck
Bob Hancock
Tucson, AZ
On Nov 24, 2008, at 7:25 AM, Steinar Midtskogen wrote:
> Today's 7.0 Okhotsk quake was recorded by my SEP seismometer. Not a
> huge signal, but clear enough.
>
> Sac-file: http://voksenlia.net/nytt/2008/jordskjelv-20081124.sac
> PNG image: http://voksenlia.net/nytt/2008/jordskjelv-20081124.png
>
> However, what's a bit surprising is that at the exact same time of the
> arrival of the P wave my 4.5 Hz geophone recorded something pretty
> strong as well for a few minutes. Mostly in the Z direction but
> clearly in the other directions as well.
>
> Sac-file Z: http://voksenlia.net/nytt/2008/jordskjelv_z-20081124.sac
> PNG image Z: http://voksenlia.net/nytt/2008/jordskjelv_z-20081124.png
> Sac-file N: http://voksenlia.net/nytt/2008/jordskjelv_n-20081124.sac
> Sac-file E: http://voksenlia.net/nytt/2008/jordskjelv_e-20081124.sac
>
> Will a quake nearly 7000 km away every show up on a 4.5 Hz geophone?
> Or could a distant quake trigger a small local quake? Or are the
> events unrelated?
>
> Since this happened in daytime, and it's a bit windy outside today
> also, there is quite a bit of noise, but the quakes are clear enough.
>
> --
> Steinar Midtskogen
> http://voksenlia.net/met/
> __________________________________________________________
>
> 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: Okhotsk quake
From: Steinar Midtskogen steinar@.............
Date: Mon, 24 Nov 2008 18:52:30 +0100
Bob,
> diminished. For comparison, I would suggest that you download this
> event through the Wilber II option on the IRIS web site at:
>
> http://www.iris.edu/dms/wilber.htm
A useful resource, thanks. I downloaded the SAC files from the
Kongsberg station, excellent data. They also had a very strong peak
at about 1.1 - 1.2 Hz for the first three minutes or so of the P wave,
like I saw on my geophone. I didn't expect that a geophone could
record quakes that distant.
>> Will a quake nearly 7000 km away every show up on a 4.5 Hz
>> geophone?
Typo, I meant "ever".
--
Steinar
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Okhotsk quake
From: Bob Hancock carpediem1@.........
Date: Mon, 24 Nov 2008 12:27:29 -0700
Steiner -
There is a USGS web site that computes phase arrival times. Beware
that the surface waves times may not be accurate, but the body waves
should be within a second or two. At the top in the header before the
list of phase arrival times, it lists the peak amplitude of 20 second
surface waves. You can compare that with what your instrument is
capable of recording. A geophone works in a higher frequency range
than surface waves. What you see primarily with a geophone is the
initial P waves and other higher frequency waves. See link to USGS
site:
http://neic.usgs.gov/neis/travel_times/compute_tt.html
The focal mechanism of an earthquakes, the ray path of the waves to
your station, and the sensitivity of your instrument will determine
what waves are visible at your station. Using this event, if you pick
a selection of other stations and look at the waves that are visible,
you will see significant variations. To read more about focal
mechanisms see the following link:
http://www.seismo.unr.edu/ftp/pub/louie/class/plate/seismology.html
There is no clear cut answer to your question about an earthquake that
is 7000 km showing up on a 4.5 Hz geophone. The answer is depend upon
several factors including the sensitivity of your geophone,
orientation of the instrument (unless it is 3 channel with proper
orientation), and the depth, magnitude, and focal mechanism of the
event. P wave recording should not be a problem assuming you're on
a lobe with peak amplitude. If you are in a null area you will not
record the event. Following is a link for focal mechanisms:
http://www.globalcmt.org/CMTsearch.html
Bob Hancock
On Nov 24, 2008, at 10:52 AM, Steinar Midtskogen wrote:
> Bob,
>
>> diminished. For comparison, I would suggest that you download this
>> event through the Wilber II option on the IRIS web site at:
>>
>> http://www.iris.edu/dms/wilber.htm
>
> A useful resource, thanks. I downloaded the SAC files from the
> Kongsberg station, excellent data. They also had a very strong peak
> at about 1.1 - 1.2 Hz for the first three minutes or so of the P wave,
> like I saw on my geophone. I didn't expect that a geophone could
> record quakes that distant.
>
>>> Will a quake nearly 7000 km away every show up on a 4.5 Hz
>>> geophone?
>
> Typo, I meant "ever".
>
> --
> Steinar
> __________________________________________________________
>
> 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: Okhotsk quake
From: jonfr@.........
Date: Tue, 25 Nov 2008 19:10:36 -0000 (UTC)
Hi
The signal from this earthquake did also appear on my sensor in Iceland.
Both on hvt sensor and hkb sensor far as I can tell. I will send in the
trace later on, when I have finish school.
Regards.
Jón Frímann.
> Today's 7.0 Okhotsk quake was recorded by my SEP seismometer. Not a
> huge signal, but clear enough.
>
> Sac-file: http://voksenlia.net/nytt/2008/jordskjelv-20081124.sac
> PNG image: http://voksenlia.net/nytt/2008/jordskjelv-20081124.png
>
> However, what's a bit surprising is that at the exact same time of the
> arrival of the P wave my 4.5 Hz geophone recorded something pretty
> strong as well for a few minutes. Mostly in the Z direction but
> clearly in the other directions as well.
>
> Sac-file Z: http://voksenlia.net/nytt/2008/jordskjelv_z-20081124.sac
> PNG image Z: http://voksenlia.net/nytt/2008/jordskjelv_z-20081124.png
> Sac-file N: http://voksenlia.net/nytt/2008/jordskjelv_n-20081124.sac
> Sac-file E: http://voksenlia.net/nytt/2008/jordskjelv_e-20081124.sac
>
> Will a quake nearly 7000 km away every show up on a 4.5 Hz geophone?
> Or could a distant quake trigger a small local quake? Or are the
> events unrelated?
>
> Since this happened in daytime, and it's a bit windy outside today
> also, there is quite a bit of noise, but the quakes are clear enough.
>
> --
> Steinar Midtskogen
> http://voksenlia.net/met/
> __________________________________________________________
>
> 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: Measuring Newtons/Amp
From: "Gary Lindgren" gel@.................
Date: Wed, 26 Nov 2008 16:05:44 -0800
I put together a web page that describes my process for measuring the
parameter, newtons/amp for 3 different coil and magnet assemblies. Check out
http://sites.google.com/site/seismicsensorinfo/meas-newtons-per-amp I will
be adding new information to the site as time permits. The goal is to use
one of these coils as part of a vertical seismometer with a feedback
mechanism. All comments are welcome. An aside note, Google no longer is
allowing additional googlepages web sites. However they now want people to
use http://sites.google.com/site/yoursitename as the free web tool. You
don't have as much freedom in this new environment, but you also have more
tools for adding content. The big difference is that Google does not want
you to add your own HTML code. So you may need some work-arounds for some
desired needs.
Gary
Gary Lindgren
585 Lincoln Ave
Palo Alto CA 94301
650-326-0655
<http://www.blue-eagle-technologies.com/> www.blue-eagle-technologies.com
Check out Lastest Seismometer Reading
<http://www.cymonsplace.blogspot.com/> cymonsplace.blogspot.com
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</head>
<body lang=3DEN-US link=3Dblue vlink=3Dpurple>
<div class=3DSection1>
<p class=3DMsoNormal>I put together a web page that describes my process =
for
measuring the parameter, newtons/amp for 3 different coil and magnet =
assemblies.
Check out <a
href=3D"http://sites.google.com/site/seismicsensorinfo/meas-newtons-per-a=
mp">http://sites.google.com/site/seismicsensorinfo/meas-newtons-per-amp</=
a>
I will be adding new information to the site as time permits. The goal =
is to
use one of these coils as part of a vertical seismometer with a feedback
mechanism. All comments are welcome. An aside note, Google no longer is
allowing additional googlepages web sites. However they now want people =
to use <a
href=3D"http://sites.google.com/site/yoursitename">http://sites.google.co=
m/site/yoursitename</a>
as the free web tool. You don’t have as much freedom in this new =
environment,
but you also have more tools for adding content. The big difference is =
that
Google does not want you to add your own HTML code. So you may need some =
work-arounds
for some desired needs. <o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal>Gary<o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>Gary Lindgren</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>585 Lincoln Ave</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>Palo Alto CA 94301</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>650-326-0655<=
/span><o:p></o:p></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href=3D"http://www.blue-eagle-technologies.com/"><span =
style=3D'color:blue'>www.blue-eagle-technologies.com</span></a> &nbs=
p;
<span style=3D'color:red'>Check out Lastest Seismometer =
Reading</span></span><o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href=3D"http://www.cymonsplace.blogspot.com/"><span =
style=3D'color:blue'>cymonsplace.blogspot.com</span></a> </span><o:p=
></o:p></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
</div>
</body>
</html>
Subject: Re: Measuring Newtons/Amp
From: ChrisAtUpw@.......
Date: Wed, 26 Nov 2008 19:49:04 EST
In a message dated 27/11/2008 00:06:02 GMT Standard Time,
gel@................. writes:
I put together a web page that describes my process for measuring the
parameter, newtons/amp for 3 different coil and magnet assemblies. Check out
_http://sites.google.com/site/seismicsensorinfo/meas-newtons-per-amp_
(http://sites.google.com/site/seismicsensorinfo/meas-newtons-per-amp)
Hi Gary,
I suggest that you use the smaller coil former, but substitute 36 gauge
wire to give maybe 1500 turns. You want to keep the DC coil resistance below
about 200 Ohms. This should give you about 35 N / Amp.
The relatively low figure that you got for the large coil is due to the
lower magnetic field of the quad 1/8" magnets. You could probably triple the
force with thicker magnets, but you are limited by the thickness of the iron
backing plates. They are already near saturation with the 1" square magnets.
I can't see a DVM in our photo? You need an accurate meter to measure
the current.
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 6.00.6000.16735" 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 27/11/2008 00:06:02 GMT Standard Time,=20
gel@................. 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 put=20
together a web page that describes my process for measuring the parameter,=
=20
newtons/amp for 3 different coil and magnet assemblies. Check out <A=20
title=3Dhttp://sites.google.com/site/seismicsensorinfo/meas-newtons-per-am=
p=20
href=3D"http://sites.google.com/site/seismicsensorinfo/meas-newtons-per-am=
p">http://sites.google.com/site/seismicsensorinfo/meas-newtons-per-amp</A>&n=
bsp;</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Gary,</DIV>
<DIV> </DIV>
<DIV> I suggest that you use the smaller coil former,=
but=20
substitute 36 gauge wire to give maybe 1500 turns. You want to keep the DC c=
oil=20
resistance below about 200 Ohms. This should give you about 35 N / Amp.</DIV=
>
<DIV> </DIV>
<DIV> The relatively low figure that you got for=
the=20
large coil is due to the lower magnetic field of the quad 1/8" magnets. You=20
could probably triple the force with thicker magnets, but you are limit=
ed=20
by the thickness of the iron backing plates. They are already near saturatio=
n=20
with the 1" square magnets.</DIV>
<DIV> </DIV>
<DIV> I can't see a DVM in our photo? You need an=20
accurate meter to measure the current.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Measuring Newtons/Amp
From: "Randy Pratt" rpratt@.............
Date: Thu, 27 Nov 2008 09:23:12 -0600
Hi Gary,
On the small neo magnet photo it appears the magnets are 90 degrees =
turned from what I would think to locate them. Did you try the other =
orientation?
I have used several speaker magnets. On most the 4 bolt holes do not go =
through the magnet ring itself. If you insert and tighten longer =
threaded bolts against the magnet, the pole ring will pop loose and then =
you can easily turn the gap wider to probably 1 cm or more on that =
magnet. Even if it won't come loose it is fairly easy to open the gap =
on a lathe but be careful of the turnings as they are very sharp and the =
magnetic field tends to align them into finger cutting angles. =
Extending the center pole into the coil with a short fat bolt after the =
gap is widened also seems to increase output. =20
Randy
<!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 6.00.2600.0" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Hi Gary,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>On the small neo magnet photo it =
appears the=20
magnets are 90 degrees turned from what I would think to locate =
them. Did=20
you try the other orientation?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I have used several speaker =
magnets. On most=20
the 4 bolt holes do not go through the magnet ring itself. If you =
insert=20
and tighten longer threaded bolts against the magnet, the pole=20
ring will pop loose and then you can easily turn the gap =
wider to=20
probably 1 cm or more on that magnet. Even if it won't come loose =
it is=20
fairly easy to open the gap on a lathe but be careful of the turnings as =
they=20
are very sharp and the magnetic field tends to align them into finger =
cutting=20
angles. Extending the center pole into the coil with a short fat =
bolt=20
after the gap is widened also seems to increase output. =
</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT><FONT face=3DArial =
size=3D2></FONT><FONT=20
face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Randy</FONT></DIV></BODY></HTML>
Subject: RE: Measuring Newtons/Amp
From: "Gary Lindgren" gel@.................
Date: Thu, 27 Nov 2008 11:57:42 -0800
Randy,
The configuration of the small and large coils and magnet assemblies is for
the coil to move in/out through the wide dimension. The idea is that this
would be used for a vertical seismometer. That's a good idea to modify the
voice coil magnet.
Gary
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Randy Pratt
Sent: Thursday, November 27, 2008 7:23 AM
To: psn-l@..............
Subject: Measuring Newtons/Amp
Hi Gary,
On the small neo magnet photo it appears the magnets are 90 degrees turned
from what I would think to locate them. Did you try the other orientation?
I have used several speaker magnets. On most the 4 bolt holes do not go
through the magnet ring itself. If you insert and tighten longer threaded
bolts against the magnet, the pole ring will pop loose and then you can
easily turn the gap wider to probably 1 cm or more on that magnet. Even if
it won't come loose it is fairly easy to open the gap on a lathe but be
careful of the turnings as they are very sharp and the magnetic field tends
to align them into finger cutting angles. Extending the center pole into
the coil with a short fat bolt after the gap is widened also seems to
increase output.
Randy
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<div class=3DSection1>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Randy,<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>The configuration of the small and large coils and magnet
assemblies is for the coil to move in/out through the wide dimension. =
The idea
is that this would be used for a vertical seismometer. =
That’s a
good idea to modify the voice coil magnet.<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Gary<o:p></o:p></span></p>
<p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style=3D'border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt =
0in 0in 0in'>
<p class=3DMsoNormal><b><span =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span>=
</b><span
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
psn-l-request@.............. [mailto:psn-l-request@............... <b>On =
Behalf
Of </b>Randy Pratt<br>
<b>Sent:</b> Thursday, November 27, 2008 7:23 AM<br>
<b>To:</b> psn-l@..............<br>
<b>Subject:</b> Measuring Newtons/Amp<o:p></o:p></span></p>
</div>
</div>
<p class=3DMsoNormal><o:p> </o:p></p>
<div>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>Hi
Gary,</span><o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>On
the small neo magnet photo it appears the magnets are 90 degrees turned =
from
what I would think to locate them. Did you try the other =
orientation?</span><o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>I
have used several speaker magnets. On most the 4 bolt holes do not =
go
through the magnet ring itself. If you insert and tighten longer =
threaded
bolts against the magnet, the pole =
ring will pop loose and
then you can easily turn the gap wider to probably 1 cm or more on that
magnet. Even if it won't come loose it is fairly easy to open the =
gap on
a lathe but be careful of the turnings as they are very sharp and the =
magnetic
field tends to align them into finger cutting angles. Extending =
the
center pole into the coil with a short fat bolt after the gap is widened =
also
seems to increase output. </span><o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>Randy</span><=
o:p></o:p></p>
</div>
</div>
</body>
</html>
Subject: Any Info on Time Constant for Undamped Vertical Sensor
From: "Gary Lindgren" gel@.................
Date: Fri, 28 Nov 2008 15:41:44 -0800
I'm just getting started with my first vertical seismometer. I will be using
an extension spring and supported at 90 degrees. Bearing concept is 2 sets
of tungsten carbide rods and a silicon carbide ball bearings. One of the
springs I have tested is a Century Spring No. 312. K factor is .28
pounds/inch and resonant period is 1.25 seconds. The tungsten rods are as
received and have not been polished yet. Undamped, I measured the damping
constant to be 372 seconds. I used the equation of Y=A*e-t/T. How does the
372 seconds compare to other vertical systems.
Gary
Gary Lindgren
585 Lincoln Ave
Palo Alto CA 94301
650-326-0655
<http://www.blue-eagle-technologies.com/> www.blue-eagle-technologies.com
Check out Lastest Seismometer Reading
<http://www.cymonsplace.blogspot.com/> cymonsplace.blogspot.com
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<body lang=3DEN-US link=3Dblue vlink=3Dpurple>
<div class=3DSection1>
<p class=3DMsoNormal>I’m just getting started with my first =
vertical
seismometer. I will be using an extension spring and supported at 90 =
degrees.
Bearing concept is 2 sets of tungsten carbide rods and a silicon carbide =
ball
bearings. One of the springs I have tested is a Century Spring No. 312. =
K
factor is .28 pounds/inch and resonant period is 1.25 seconds. The =
tungsten
rods are as received and have not been polished yet. Undamped, I =
measured the
damping constant to be 372 seconds. I used the equation of Y=3DA*e-t/T. =
How does
the 372 seconds compare to other vertical systems. <o:p></o:p></p>
<p class=3DMsoNormal>Gary<o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>Gary Lindgren</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>585 Lincoln Ave</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>Palo Alto CA 94301</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>650-326-0655<=
/span><o:p></o:p></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href=3D"http://www.blue-eagle-technologies.com/"><span =
style=3D'color:blue'>www.blue-eagle-technologies.com</span></a> &nbs=
p;
<span style=3D'color:red'>Check out Lastest Seismometer =
Reading</span></span><o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href=3D"http://www.cymonsplace.blogspot.com/"><span =
style=3D'color:blue'>cymonsplace.blogspot.com</span></a> </span><o:p=
></o:p></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
</div>
</body>
</html>
Subject: Re: Any Info on Time Constant for Undamped Vertical Sensor
From: ChrisAtUpw@.......
Date: Fri, 28 Nov 2008 21:55:03 EST
=20
In a message dated 28/11/2008 23:42:02 GMT Standard Time, =20
gel@................. writes:
I=E2=80=99m just getting started with my first vertical seismometer. I will=
be using=20
an extension spring and supported at 90 degrees. Bearing concept is 2 sets=20
of tungsten carbide rods and a silicon carbide ball bearings. One of the=20
springs I have tested is a Century Spring No. 312. K factor is .28 pounds/i=
nch and=20
resonant period is 1.25 seconds. The tungsten rods are as received and have=
=20
not been polished yet. Undamped, I measured the damping constant to be 372=20
seconds. I used the equation of Y=3DA*e-t/T. How does the 372 seconds compa=
re to=20
other vertical systems. =20
Hi Gary,
=20
If you can extend the top spring position beyond the vertical support=20
and also lower it a bit, you will get a longer period. The aim is to have t=
he=20
vertical above the hinge nearer the ''zero'' length of the spring.
=20
If you put a C shaped plate on the end of the horizontal beam, you coul=
d=20
use two short piano wire supports in tension. I have also used a pair of=20
razor blades extracted from single blade cheap plastic razors in compressio=
n. I=20
stick them between Al cross strips with acrylic adhesive with a gap of ~0.1=
".
=20
You should be able to improve on 1.25 seconds. Aim for a period of 1.5=20
to 2 seconds.=20
=20
Regards,
=20
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<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 28/11/2008 23:42:02 GMT Standard Time,=20
gel@................. 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 class=3DMsoNormal>I=E2=80=99m just getting started with my first vertic=
al=20
seismometer. I will be using an extension spring and supported at 90 degre=
es.=20
Bearing concept is 2 sets of tungsten carbide rods and a silicon carbide b=
all=20
bearings. One of the springs I have tested is a Century Spring No. 312. K=20
factor is .28 pounds/inch and resonant period is 1.25 seconds. The tungste=
n=20
rods are as received and have not been polished yet. Undamped, I measured=20=
the=20
damping constant to be 372 seconds. I used the equation of Y=3DA*e-t/T. Ho=
w does=20
the 372 seconds compare to other vertical systems.=20
<o:p></o:p></P></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Gary,</DIV>
<DIV> </DIV>
<DIV> If you can extend the top spring position beyon=
d=20
the vertical support and also lower it a bit, you will get a longer per=
iod.=20
The aim is to have the vertical above the hinge nearer the ''zero'' length o=
f=20
the spring.</DIV>
<DIV> </DIV>
<DIV> If you put a C shaped plate on the end of the=20
horizontal beam, you could use two short piano wire supports in tension=
.. I=20
have also used a pair of razor blades extracted from single blade cheap plas=
tic=20
razors in compression. I stick them between Al cross strips with=20
acrylic adhesive with a gap of ~0.1".</DIV>
<DIV> </DIV>
<DIV> You should be able to improve on 1.25=20
seconds. Aim for a period of 1.5 to 2 seconds. </DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: a possible seismometer?
From: Randall Peters PETERS_RD@..........
Date: Mon, 08 Dec 2008 16:50:11 -0500
I've been contemplating an instrument based on a piece of equipment we
use in the physics department to teach hydrostatics. It is a long tube
that is sealed on one end, and the open end is immersed in a larger tube
filled with water. The smaller tube achieves an equilibrium position
determined by its weight, overall length, and diameter of the internal
air column. If one lifts the inner tube and releases it, it oscillates
in simple harmonic motion with a period greater than one second. Also,
because of the water, the motion is dampened. The motion depends on the
compressibility of the trapped air.
I've done an idealized calculation in which the water would be
replaced with mineral oil and the plastic tube of the apparatus with a
thinwall metal tube of length in the neighborhood of one meter. It
appears that the damping would be close to optimal and the period just
under two seconds for the diameter of the inner tube being one
centimeter and that of the outer tube holding the mineral oil about two
cm's.
The inner tube should be constrained (perhaps with long triaxial
threads, so that the motion is strictly vertical.
I will be interested to know if any of you have considered such an
apparatus.
Randall
Subject: Re: a possible seismometer?
From: "Robert Thomasson" rlthomasson@.........
Date: Tue, 9 Dec 2008 01:10:42 +0300
Randall,
I haven't ever considered such a device and it sounds interesting. Without
attempting to mathematically model it (which for me generally results in a
learning process but very little usable results) I wonder what the effect
of the trapped and compressible air column is? What would be the difference
in response if the air was isolated from the water or mineral oil by a
sealed partition in the tube so that it would not compress? The tube would
be perforated below the partition to avoid trapping any additional air.
Also, I think it will be a challenge to restrain the tube so that it moves
vertically without adding friction or otherwise changing the response. What
about one of your capacitance sensors set up so that it will only respond to
vertical motion?
I'm still studying your pendulum paper that posted a link to here some time
ago.
Regards,
Bob
On Tue, Dec 9, 2008 at 12:50 AM, Randall Peters <PETERS_RD@..........>wrote:
> I've been contemplating an instrument based on a piece of equipment we
> use in the physics department to teach hydrostatics. It is a long tube
> that is sealed on one end, and the open end is immersed in a larger tube
> filled with water. The smaller tube achieves an equilibrium position
> determined by its weight, overall length, and diameter of the internal
> air column. If one lifts the inner tube and releases it, it oscillates
> in simple harmonic motion with a period greater than one second. Also,
> because of the water, the motion is dampened. The motion depends on the
> compressibility of the trapped air.
> I've done an idealized calculation in which the water would be
> replaced with mineral oil and the plastic tube of the apparatus with a
> thinwall metal tube of length in the neighborhood of one meter. It
> appears that the damping would be close to optimal and the period just
> under two seconds for the diameter of the inner tube being one
> centimeter and that of the outer tube holding the mineral oil about two
> cm's.
> The inner tube should be constrained (perhaps with long triaxial
> threads, so that the motion is strictly vertical.
> I will be interested to know if any of you have considered such an
> apparatus.
> Randall
>
Randall,<br><br>I haven't ever considered such a device and it sounds interesting. Without attempting to mathematically model it (which for me generally results in a learning process but very little usable results) I wonder what the effect of the trapped and compressible air column is? What would be the difference in response if the air was isolated from the water or mineral oil by a sealed partition in the tube so that it would not compress? The tube would be perforated below the partition to avoid trapping any additional air.<br>
<br>Also, I think it will be a challenge to restrain the tube so that it moves vertically without adding friction or otherwise changing the response. What about one of your capacitance sensors set up so that it will only respond to vertical motion?<br>
<br>I'm still studying your pendulum paper that posted a link to here some time ago.<br><br>Regards,<br><br>Bob<br><br><div class="gmail_quote">On Tue, Dec 9, 2008 at 12:50 AM, Randall Peters <span dir="ltr"><<a href="mailto:PETERS_RD@..........">PETERS_RD@..........</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">I've been contemplating an instrument based on a piece of equipment we<br>
use in the physics department to teach hydrostatics. It is a long tube<br>
that is sealed on one end, and the open end is immersed in a larger tube<br>
filled with water. The smaller tube achieves an equilibrium position<br>
determined by its weight, overall length, and diameter of the internal<br>
air column. If one lifts the inner tube and releases it, it oscillates<br>
in simple harmonic motion with a period greater than one second. Also,<br>
because of the water, the motion is dampened. The motion depends on the<br>
compressibility of the trapped air.<br>
I've done an idealized calculation in which the water would be<br>
replaced with mineral oil and the plastic tube of the apparatus with a<br>
thinwall metal tube of length in the neighborhood of one meter. It<br>
appears that the damping would be close to optimal and the period just<br>
under two seconds for the diameter of the inner tube being one<br>
centimeter and that of the outer tube holding the mineral oil about two<br>
cm's.<br>
The inner tube should be constrained (perhaps with long triaxial<br>
threads, so that the motion is strictly vertical.<br>
I will be interested to know if any of you have considered such an<br>
apparatus.<br>
<font color="#888888"> Randall<br>
</font></blockquote></div><br>
Subject: Re: a possible seismometer?
From: "Daryl P. Dacko" mycrump@........
Date: Mon, 08 Dec 2008 18:35:25 -0500
Randall,
In the old Scientific American "Amateur Scientist" column there is a
discussion or two about using these as seismometers and tiltmeters.
They talked about using capacitive detectors at the ends to measure the
displacement, if memory serves.
Some discussion on damping factors too, I believe.
You can get a compilation of all of the columns on CD for a very
reasonable charge on the web, highly recommended...
Now where did I put that CD... ;')
Daryl
Randall Peters wrote:
> I've been contemplating an instrument based on a piece of equipment we
> use in the physics department to teach hydrostatics. It is a long tube
> that is sealed on one end, and the open end is immersed in a larger tube
> filled with water. The smaller tube achieves an equilibrium position
> determined by its weight, overall length, and diameter of the internal
> air column. If one lifts the inner tube and releases it, it oscillates
> in simple harmonic motion with a period greater than one second. Also,
> because of the water, the motion is dampened. The motion depends on the
> compressibility of the trapped air.
> I've done an idealized calculation in which the water would be
> replaced with mineral oil and the plastic tube of the apparatus with a
> thinwall metal tube of length in the neighborhood of one meter. It
> appears that the damping would be close to optimal and the period just
> under two seconds for the diameter of the inner tube being one
> centimeter and that of the outer tube holding the mineral oil about two
> cm's.
> The inner tube should be constrained (perhaps with long triaxial
> threads, so that the motion is strictly vertical.
> I will be interested to know if any of you have considered such an
> apparatus.
> Randall
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: a possible seismometer?
From: ChrisAtUpw@.......
Date: Tue, 9 Dec 2008 01:00:08 EST
In a message dated 08/12/2008 21:50:51 GMT Standard Time,
PETERS_RD@.......... writes:
I've done an idealized calculation in which the water would be
replaced with mineral oil and the plastic tube of the apparatus with a
thinwall metal tube of length in the neighborhood of one meter.
Hi Randall,
The problem with oil is that the viscosity changes by x10 for every 20 C
Deg change in temperature. This is why oil damping is 'difficult' /
virtually useless for seismometers.
You could use a glass U tube and mercury? Since mercury is quite a good
electrical conductor, you could probably use magnetic damping? But you would
have to thermostat the gas pressure chamber, which could be tricky, otherwise
you are just making an expensive thermometer!
Another alternative would be to use a metal bellows at the bottom end of
the tube, maybe with an additional spring, to provide the pressure to
support a vertical liquid column.
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 6.00.6000.16735" 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 08/12/2008 21:50:51 GMT Standard Time,=20
PETERS_RD@.......... 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
I've done an idealized calculation in which the water would be<BR>replaced=
=20
with mineral oil and the plastic tube of the apparatus with a<BR>thinwall=20
metal tube of length in the neighborhood of one=20
meter. </FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Randall,</DIV>
<DIV> </DIV>
<DIV> The problem with oil is that the viscosity=20
changes by x10 for every 20 C Deg change in temperature. This is why oi=
l=20
damping is 'difficult' / virtually useless for seismometers.</DIV>
<DIV> </DIV>
<DIV> You could use a glass U tube and mercury? Since=
=20
mercury is quite a good electrical conductor, you could probably use magneti=
c=20
damping? But you would have to thermostat the gas pressure chamber, which co=
uld=20
be tricky, otherwise you are just making an expensive thermometer!</DIV>
<DIV> </DIV>
<DIV> Another alternative would be to use a metal bel=
lows=20
at the bottom end of the tube, maybe with an additional spring, to provide t=
he=20
pressure to support a vertical liquid column.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: a possible seismometer?
From: "Robert Thomasson" rlthomasson@.........
Date: Tue, 9 Dec 2008 09:58:52 +0300
Daryl,
I have that CD but dang if I can find the article with the built-in search
function. Do you happen to recall about what month and year it was?
Thanks,
Bob
On Tue, Dec 9, 2008 at 2:35 AM, Daryl P. Dacko <mycrump@........> wrote:
> Randall,
>
> In the old Scientific American "Amateur Scientist" column there is a
> discussion or two about using these as seismometers and tiltmeters.
> They talked about using capacitive detectors at the ends to measure the
> displacement, if memory serves.
> Some discussion on damping factors too, I believe.
>
> You can get a compilation of all of the columns on CD for a very reasonable
> charge on the web, highly recommended...
>
> Now where did I put that CD... ;')
>
> Daryl
>
>
> Randall Peters wrote:
>
>> I've been contemplating an instrument based on a piece of equipment we
>> use in the physics department to teach hydrostatics. It is a long tube
>> that is sealed on one end, and the open end is immersed in a larger tube
>> filled with water. The smaller tube achieves an equilibrium position
>> determined by its weight, overall length, and diameter of the internal
>> air column. If one lifts the inner tube and releases it, it oscillates
>> in simple harmonic motion with a period greater than one second. Also,
>> because of the water, the motion is dampened. The motion depends on the
>> compressibility of the trapped air.
>> I've done an idealized calculation in which the water would be
>> replaced with mineral oil and the plastic tube of the apparatus with a
>> thinwall metal tube of length in the neighborhood of one meter. It
>> appears that the damping would be close to optimal and the period just
>> under two seconds for the diameter of the inner tube being one
>> centimeter and that of the outer tube holding the mineral oil about two
>> cm's.
>> The inner tube should be constrained (perhaps with long triaxial
>> threads, so that the motion is strictly vertical.
>> I will be interested to know if any of you have considered such an
>> apparatus.
>> Randall
>>
>>
>
> __________________________________________________________
>
> 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.
>
Daryl,<br><br>I have that CD but dang if I can find the article with the built-in search function. Do you happen to recall about what month and year it was?<br><br>Thanks,<br><br>Bob<br><br><div class="gmail_quote">On Tue, Dec 9, 2008 at 2:35 AM, Daryl P. Dacko <span dir="ltr"><<a href="mailto:mycrump@........">mycrump@........</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Randall,<br>
<br>
In the old Scientific American "Amateur Scientist" column there is a discussion or two about using these as seismometers and tiltmeters.<br>
They talked about using capacitive detectors at the ends to measure the displacement, if memory serves.<br>
Some discussion on damping factors too, I believe.<br>
<br>
You can get a compilation of all of the columns on CD for a very reasonable charge on the web, highly recommended...<br>
<br>
Now where did I put that CD... ;')<br>
<br>
Daryl<div><div></div><div class="Wj3C7c"><br>
<br>
Randall Peters wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
I've been contemplating an instrument based on a piece of equipment we<br>
use in the physics department to teach hydrostatics. It is a long tube<br>
that is sealed on one end, and the open end is immersed in a larger tube<br>
filled with water. The smaller tube achieves an equilibrium position<br>
determined by its weight, overall length, and diameter of the internal<br>
air column. If one lifts the inner tube and releases it, it oscillates<br>
in simple harmonic motion with a period greater than one second. Also,<br>
because of the water, the motion is dampened. The motion depends on the<br>
compressibility of the trapped air.<br>
I've done an idealized calculation in which the water would be<br>
replaced with mineral oil and the plastic tube of the apparatus with a<br>
thinwall metal tube of length in the neighborhood of one meter. It<br>
appears that the damping would be close to optimal and the period just<br>
under two seconds for the diameter of the inner tube being one<br>
centimeter and that of the outer tube holding the mineral oil about two<br>
cm's.<br>
The inner tube should be constrained (perhaps with long triaxial<br>
threads, so that the motion is strictly vertical.<br>
I will be interested to know if any of you have considered such an<br>
apparatus.<br>
Randall<br>
<br>
</blockquote>
<br></div></div>
__________________________________________________________<br>
<br>
Public Seismic Network Mailing List (PSN-L)<br>
<br>
To leave this list email <a href="mailto:PSN-L-REQUEST@.............." target="_blank">PSN-L-REQUEST@..............</a> with the body of the message (first line only): unsubscribe<br>
See <a href="http://www.seismicnet.com/maillist.html" target="_blank">http://www.seismicnet.com/maillist.html</a> for more information.<br>
</blockquote></div><br>
Subject: Re: a possible seismometer?
From: ChrisAtUpw@.......
Date: Tue, 9 Dec 2008 07:21:56 EST
In a message dated 09/12/2008, rlthomasson@......... writes:
I have that CD but dang if I can find the article with the built-in search
function. Do you happen to recall about what month and year it was?
Hi Bob,
Try Stong, CL The Amateur Scientist, Sci. Am. mag., Nov. 1973 pp 124-129
"The mercury tiltmeter."
The detector electronics needs a re-design. George Bush has a good
updated circuit _ke6pxp@........ (mailto:ke6pxp@........
A large professional Hg seismometer designed by Benoit is described by
Gile, WW, Geophys. J. Roy. Astro. Soc. vol 36 1974 pp 153-165 "A Mercury
Pendulum Seismometer"
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 6.00.6000.16735" 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 09/12/2008, rlthomasson@......... 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
that CD but dang if I can find the article with the built-in search=20
function. Do you happen to recall about what month and year it=20
was?<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Bob,</DIV>
<DIV> </DIV>
<DIV> Try Stong, CL The Amateur Scientist, Sci. Am. m=
ag.,=20
Nov. 1973 pp 124-129 "<B>The mercury tiltmeter</B>."</DIV>
<DIV> The detector electronics needs a re-design. Geo=
rge=20
Bush has a good updated circuit <A title=3Dmailto:ke6pxp@..........
href=3D"mailto:ke6pxp@.......">ke6pxp@.......</A></DIV>
<DIV> </DIV>
<DIV> A large professional Hg seismometer designed by=
=20
Benoit is described by Gile, WW, Geophys. J. Roy. Astro. Soc. vol 36 1974 pp=
=20
153-165 "<B>A Mercury Pendulum Seismometer</B>"</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Power Supply, Amplifier, and AD
From: Dayana Andrea Schonwalder Angel dayanaangel82@.........
Date: Tue, 9 Dec 2008 09:47:04 -0800 (PST)
Hi every one
I would like to know if any body know, if there is a possibility ti buy thi=
s black box for a AS1 seismometer in any place in San Francisco in USA.
=C2=A0We are a mexicangropu of students and here in the city where we are w=
e can't find the pieces to bulid it.
So if any body can help us with this information, it will be great.
Thanks
Dayana Schonwalder
SisVOc
Postgrado en Geof=C3=ADsica
UNIVERSIDAD DE GUADALAJARA
Centro Universitario de la Costa
Av. Universidad 203 Del. Ixtapa,=20
Puerto Vallarta, JAL, M=C3=89XICO.
e-mail dayanaangel82@.........
=0A=0A=0A ____________________________________________________________=
________________________=0APremios MTV 2008=C2=A1En exclusiva! Fotos, nomin=
ados, videos, y mucho m=C3=A1s! Mira aqu=C3=AD http://mtvla.yahoo.com/
<table cellspacing=3D"0" cellpadding=3D"0" border=3D"0" ><tr><td valign=3D"=
top" style=3D"font: inherit;">Hi every one<br><br>I would like to know if a=
ny body know, if there is a possibility ti buy this black box for a AS1 sei=
smometer in any place in San Francisco in USA.<br> We are a mexicangro=
pu of students and here in the city where we are we can't find the pieces t=
o bulid it.<br><br>So if any body can help us with this information, it wil=
l be great.<br><br>Thanks<br><br><br>Dayana Schonwalder<br>
SisVOc<br>
Postgrado en Geof=C3=ADsica<br>
UNIVERSIDAD DE GUADALAJARA<br>
Centro Universitario de la Costa<br>
Av. Universidad 203 Del. Ixtapa, <br>
Puerto Vallarta, JAL, M=C3=89XICO.<br>
e-mail dayanaangel82@.........<br><br></td></tr></table><br>=0A=0A=0A=0A=0A=
=0A=0A <hr size=3D1><br><font face=3D"Verdana" size=3D"-2">=C2=A1Todo =
sobre Amor y Sexo!<br>La gu=C3=ADa completa para tu vida en Mujer de Hoy:<b=
r>=0Ahttp://mujerdehoy.telemundo.yahoo.com/</font>
Subject: Re: Power Supply, Amplifier, and AD
From: Angel sismos@..............
Date: Tue, 9 Dec 2008 18:10:35 +0000
Hello Dayana,
Don't buy the black box that you see with an AS1.
you can do much better and probably less expensive or close with Larry's boards.
http://psn.quake.net/serialatod.html
it would be 16 bits instead of 12 and you can use a GPS. WinSDR and Winquake are great.
Check it out.
Angel
Tuesday, December 9, 2008, 5:47:04 PM, you wrote:
> Hi every one
> I would like to know if any body know, if there is a possibility ti
> buy this black box for a AS1 seismometer in any place in San Francisco in USA.
> We are a mexicangropu of students and here in the city where we
> are we can't find the pieces to bulid it.
> So if any body can help us with this information, it will be great.
> Thanks
> Dayana Schonwalder
> SisVOc
> Postgrado en GeofÃsica
> UNIVERSIDAD DE GUADALAJARA
> Centro Universitario de la Costa
> Av. Universidad 203 Del. Ixtapa,
> Puerto Vallarta, JAL, MÉXICO.
> e-mail dayanaangel82@.........
>
> ____________________________________________________________________________________
> Premios MTV 2008¡En exclusiva! Fotos, nominados, videos, y mucho
> más! Mira aquà http://mtvla.yahoo.com/
--
Best regards,
Angel
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: a possible seismometer?
From: George Bush ke6pxp@.......
Date: Tue, 09 Dec 2008 10:15:15 -0800
Hi all-
Since Chris has mentioned me (or at least my email address), I thought I
would share some of my experiences with trying to build an updated
Mercury Tiltmeter. These instruments detect quakes, but my interest was
in Earth tides and other low freq phemomena. I constructred a tiltmeter
following the design in the Scientific American article but with a
capacitance sensor as suggested by Chris. Please see
http://ntweb.mcn.org/gbush/Tiltmeter/tiltmeter%20Main.html for
construction details. Sorry the site is not current and doesn't have the
new circuit on it as I consider it a work in progress. So far I have been
defeated by the thermal problems. I have the unit mounted in a solid foam
insulating chamber with a heated plate at the top to stratify the air
currents. But even with all of that it is just a VERRY expensive
(especially in time spent) thermometer!!!
There are successful instruments based on this principle around the
world, especially in Europe where one unit has cups separated by 100m of
tubing and is installed in an old mine tunnel. My plans are to completely
rebuild my unit with the cups separated to the ends of my gargage to
increase the sensitivity and install a motor-driven compensator, as
suggested in the Gile article, to balance out the thermal expansion of
the Hg.
I hope this helps- George
At 07:21 AM 12/9/2008 EST, you wrote:
>>>>
In a message dated 09/12/2008, rlthomasson@......... writes:
<excerpt>I have that CD but dang if I can find the article with the
built-in search function. Do you happen to recall about what month and
year it was?
Hi Bob,
Try Stong, CL The Amateur Scientist, Sci. Am. mag., Nov. 1973 pp
124-129 "<bold>The mercury tiltmeter</bold>."
The detector electronics needs a re-design. George Bush has a good
updated circuit <<mailto:ke6pxp@.......>ke6pxp@.......
A large professional Hg seismometer designed by Benoit is described
by Gile, WW, Geophys. J. Roy. Astro. Soc. vol 36 1974 pp 153-165 "<bold>A
Mercury Pendulum Seismometer</bold>"
Regards,
Chris Chapman
</excerpt><<<<<<<<
George
Subject: Re: Power Supply, Amplifier, and AD
From: Thomas Dick dickthomas01@.............
Date: Tue, 09 Dec 2008 12:17:04 -0600
Angel wrote:
> Hello Dayana,
>
> Don't buy the black box that you see with an AS1.
>
> you can do much better and probably less expensive or close with Larry's boards.
>
> http://psn.quake.net/serialatod.html
> I agree with Angel. I am using the setup Angel discribed from Larry. The GPS/timing aspect is a real plus.
>
>
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Power Supply, Amplifier, and AD
From: "Kay Wyatt" kwyatt@.............
Date: Tue, 9 Dec 2008 10:50:20 -0800
Dayana,
I agree that Larry's amplifier, etc, is a good choice. However, keep in
mind that the AS-1 is a vertical seismometer and its natural period is about
1.6 seconds. the one advantage of the original black box is that its
designer, Jeff Batton, added a period extending circuit to boost the very
low frequencies so that you can more easily record periods up to 20 seconds.
Most people who use Larry's board use it with horizontal seismometers which
have a longer natural period than the vertical AS-1.
I have several vertical seismometers here which I have built or am
evaluating. One has Larry's board attached. I've also two AS-1
seismometers. One with the original black box and one with a black box that
has been modified using suggestions from Chris Chapman.
If anybody has an add-on period extending circuit or Larry's board I would
be very interested!
Kay Wyatt
----- Original Message -----
From: "Thomas Dick" <dickthomas01@.............>
To: <psn-l@..............>
Sent: Tuesday, December 09, 2008 10:17 AM
Subject: Re: Power Supply, Amplifier, and AD
> Angel wrote:
>> Hello Dayana,
>>
>> Don't buy the black box that you see with an AS1.
>>
>> you can do much better and probably less expensive or close with Larry's
>> boards.
>>
>> http://psn.quake.net/serialatod.html
>> I agree with Angel. I am using the setup Angel discribed from Larry. The
>> GPS/timing aspect is a real plus.
>>
>>
>>
>
> __________________________________________________________
>
> 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: Power Supply, Amplifier, and AD
From: "Robert McClure" bobmcclure90@.........
Date: Tue, 9 Dec 2008 21:28:17 -0500
I have a digital inverse filter utility for PSN files. It is capable of
giving long-period response to the AS-1. See
http://bobmcclure90.googlepages.com/winsac
Bob
>If anybody has an add-on period extending circuit or Larry's board I would
be very interested!<
I have a digital inverse filter utility for PSN files. It is capable of giving long-period response to the AS-1. See<br><br><a href="http://bobmcclure90.googlepages.com/winsac">http://bobmcclure90.googlepages.com/winsac</a><br>
<br>Bob<br><br><br>>If anybody has an add-on period extending circuit or Larry's board I would <br>be very interested!<<br><br>
Subject: Re: Power Supply, Amplifier, and AD
From: ChrisAtUpw@.......
Date: Tue, 9 Dec 2008 21:30:14 EST
In a message dated 09/12/2008, sismos@.............. writes:
Hello Dayana,
Don't buy the black box that you see with an AS1.
you can do much better and probably less expensive or close with Larry's
boards.
Hi Dayana,
I believe that Jeff Batten _amateurseismo@..........
(mailto:amateurseismo@.......... will sell the electronics box and power supply separately.
Seismometers like the AS1 and EQ1 try to use oil + plunge plate damping.
The viscosity of oil changes by about x10 for every 20 C Deg / 36 F Deg
change in temperature. If you set up the damping to be correct at your room
temperature, you will only have an operating range of about +/-4 F Deg. This is
LESS than the normal daily variation. If the temperature falls much below this
range, the damping increases dramatically and the seismometer MAY stop
recording altogether. It's sensitivity will certainly decrease and the calibration
will NOT give the correct quake magnitude. I have designed a replacement
magnetic damper which is NOT effected by temperature and is both easy to set up
and CLEAN! No more oil creepage or spills!
See _http://jclahr.com/science/psn/chapman/as1%20damping/index.html_
(http://jclahr.com/science/psn/chapman/as1%20damping/index.html)
The AS1 uses a vertical swing arm with a natural period of about 1.5
seconds. So while the response is flat with velocity at periods shorter than
this (like a geophone), the sensitivity will fall off as f^2 below 0.75 Hz when
using a 'normal' seismic amplifier, like Larry's. The sensitivity to the 20
second period Rayleigh waves, will be down by a factor of about 180 - so you
normally won't see any!
A period extension circuit has been used in the AS1 'black box' to
extend the sensitivity ~flat from 1.5 to about 4.5 seconds. This boosts the low
frequency output. While it is OK for measuring microseisms, it is otherwise
rather limiting. A further period extension can be applied with the digital
compenation filter supplied with AmaSeis, but it only works well on moderately
strong signals.
I have extended the period to about 20 seconds by changing four
capacitors and three resistors. It now seems to work satisfactorily and covers most
of the normal seismic range.
On the EQ1 that we examined, the compensation covered about the same
compensation period range as an AS1, but the output seemed to be roughly
proportional to f. This did NOT give a flat output. Since the power laws are
different, I would not expect the digital frequency compensation built into AmaSeis
to work adequately with an EQ1 trace. The EQ1 electronics uses miniature
surface mount components, so I would NOT expect you to be able to modify EITHER
the compensation range OR the power law.
The relatively long springs expand and contract with temperature and may
well need adjustment with the seasons.
The AS1 is designed with the centre of gravity on the horizontal arm.
<!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 6.00.6000.16735" 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 09/12/2008, sismos@.............. 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>Hello=20
Dayana,<BR>Don't buy the black box that you see with an AS1.<BR>you can do=
=20
much better and probably less expensive or close with Larry's=20
boards.<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Dayana,</DIV>
<DIV> </DIV>
<DIV> I believe that Jeff Batten <A=20
href=3D"mailto:amateurseismo@.........">amateurseismo@.........</A> will sel=
l the=20
electronics box and power supply separately. </DIV>
<DIV> </DIV>
<DIV> Seismometers like the AS1 and EQ1 try to use oi=
l +=20
plunge plate damping. The viscosity of oil changes by about x10 for every 20=
C=20
Deg / 36 F Deg change in temperature. If you set up the damping to be correc=
t at=20
your room temperature, you will only have an operating range of about +/-4 F=
=20
Deg. This is LESS than the normal daily variation. If the temperature falls=20=
much=20
below this range, the damping increases dramatically and the seismometer MAY=
=20
stop recording altogether. It's sensitivity will certainly decrease and the=20
calibration will NOT give the correct quake magnitude. I have designed a=20
replacement magnetic damper which is NOT effected by temperature and is=20
both easy to set up and CLEAN! No more oil creepage or spills!</DIV>
<DIV> See <A=20
href=3D"http://jclahr.com/science/psn/chapman/as1%20damping/index.html">http=
://jclahr.com/science/psn/chapman/as1%20damping/index.html</A> </DIV>
<DIV> </DIV>
<DIV> The AS1 uses a vertical swing arm with a natura=
l=20
period of about 1.5 seconds. So while the response is flat with velocity at=20
periods shorter than this (like a geophone), the sensitivity will fall off a=
s=20
f^2 below 0.75 Hz when using a 'normal' seismic amplifier, like Larry's. The=
=20
sensitivity to the 20 second period Rayleigh waves, will be down by a factor=
of=20
about 180 - so you normally won't see any!</DIV>
<DIV> A period extension circuit has been used in the=
AS1=20
'black box' to extend the sensitivity ~flat from 1.5 to about 4.5 secon=
ds.=20
This boosts the low frequency output. While it is OK for measuring=20
microseisms, it is otherwise rather limiting. A further perio=
d=20
extension can be applied with the digital compenation filter supplied w=
ith=20
AmaSeis, but it only works well on moderately strong signals. </DIV>
<DIV> I have extended the period to about 20 seconds=20
by changing four capacitors and three resistors. It now seems=
to=20
work satisfactorily and covers most of the normal seismic range.</DIV>
<DIV> </DIV>
<DIV> On the EQ1 that we examined, the compensat=
ion=20
covered about the same compensation period range as an AS1, but the output=20
seemed to be roughly proportional to f. This did NOT give a flat output. Sin=
ce=20
the power laws are different, I would not expect the digital frequency=20
compensation built into AmaSeis to work adequately with an EQ1 trace. T=
he=20
EQ1 electronics uses miniature surface mount components, so I would NOT=20
expect you to be able to modify EITHER the compensation range OR t=
he=20
power law.</DIV>
<DIV> </DIV>
<DIV> The relatively long springs expand and contract=
=20
with temperature and may well need adjustment with the seasons.</DIV>
<DIV> </DIV>
<DIV> The AS1 is designed with the centre of gravity=20=
on=20
the horizontal arm. </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV></FONT></BODY></HTML>
Subject: Re: Power Supply, Amplifier, and AD
From: ChrisAtUpw@.......
Date: Tue, 9 Dec 2008 23:48:06 EST
In a message dated 09/12/2008 18:50:39 GMT Standard Time,
kwyatt@............. writes:
If anybody has an add-on period extending circuit or Larry's board I would
be very interested!
Hi Kay,
_http://jclahr.com/science/psn/roberts/index.html_
(http://jclahr.com/science/psn/roberts/index.html)
_http://jclahr.com/science/psn/cochrane/index.html_
(http://jclahr.com/science/psn/cochrane/index.html)
!!
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 6.00.6000.16762" 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 09/12/2008 18:50:39 GMT Standard Time,=20
kwyatt@............. 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>If=20
anybody has an add-on period extending circuit or Larry's board I would <B=
R>be=20
very interested!<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Kay,</DIV>
<DIV> </DIV>
<DIV> <A=20
href=3D"http://jclahr.com/science/psn/roberts/index.html">http://jclahr.com/=
science/psn/roberts/index.html</A></DIV>
<DIV> </DIV>
<DIV> <A=20
href=3D"http://jclahr.com/science/psn/cochrane/index.html">http://jclahr.com=
/science/psn/cochrane/index.html</A></DIV>
<DIV> </DIV>
<DIV> <FONT size=3D7>!!</FONT></DIV>
<DIV> </DIV>
<DIV> Chris</DIV></FONT></BODY></HTML>
Subject: Re: Power Supply, Amplifier, and AD
From: "Kareem, Heyjoojoo" system98765@.............
Date: Wed, 10 Dec 2008 11:43:13 -0800
Can anyone recommend something to help with a clogging pen. I have an
old PS2 recording system and the pen keeps clogging. I have contacted
the manufacturer and they want a large amount of $$ to send me new pens
and ink. I dont know if the ink is a problem or the paper. I'm actually
using good paper, the one that is manufactured by Kenemtrics. So, I don
think that the paper is what's causing the problem with the pen
clogging. Maybe the ink? Is there a certain type that is less prone to
clogging in pen stylus and capillary tube?
Kareem
ChrisAtUpw@....... wrote:
> In a message dated 09/12/2008 18:50:39 GMT Standard Time,
> kwyatt@............. writes:
>
> If anybody has an add-on period extending circuit or Larry's board
> I would
> be very interested!
>
> Hi Kay,
>
> http://jclahr.com/science/psn/roberts/index.html
>
> http://jclahr.com/science/psn/cochrane/index.html
>
> !!
>
> Chris
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com
> Version: 8.0.176 / Virus Database: 270.9.15/1839 - Release Date: 12/9/2008 9:59 AM
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Clogging pens
From: ChrisAtUpw@.......
Date: Wed, 10 Dec 2008 15:52:02 EST
In a message dated 10/12/2008, system98765@............. writes:
Can anyone recommend something to help with a clogging pen. I have an
old PS2 recording system and the pen keeps clogging. I have contacted
the manufacturer and they want a large amount of $$ to send me new pens
and ink.
Hi Kareem,
What ink are you using? Normal 'permanent' fountain pen inks will not
dissolve after they have dried out / aged.
I use UNO drawing pens made by Rotring. They sell a special cleaning
fluid for them, which works well. You may need to push a fine wire down the pen?
Rotring use a 'built-in' tungsten wire. Try a hard drawn Nichrome wire?
I have also looked at inks for chart recorder pens / inkjet printers and
you can buy specialist cleaning fluid for these. Check with your local
computer store / an on-line supplier? I can buy ink in ~50ml bottles and inject it
into commercial ink jet printer cartriges to re-fill them. Soaking the jet
plate with the cleaning fluid on a thin cover cloth does clean it. Maybe
overnight in a polythene bag?
Ask your manufacturer about a cleaning fluid for their pens? You don't
say what type / make of pen you are using! Ideally, you should clean capillary
tube pens out every few months, to prevent clogging problems. The special
needles used for injecting insulin used to come with a cleaning wire.
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 6.00.6000.16762" 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 10/12/2008, 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>Can=20
anyone recommend something to help with a clogging pen. I have an <BR>old=20=
PS2=20
recording system and the pen keeps clogging. I have contacted <BR>the=20
manufacturer and they want a large amount of $$ to send me new pens <BR>an=
d=20
ink.</FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Kareem,</DIV>
<DIV> </DIV>
<DIV> What ink are you using? Normal 'permanent' foun=
tain=20
pen inks will not dissolve after they have dried out / aged. </DIV>
<DIV> </DIV>
<DIV> I use UNO drawing pens made by Rotring. They se=
ll a=20
special cleaning fluid for them, which works well. You may need to push a fi=
ne=20
wire down the pen? Rotring use a 'built-in' tungsten wire. Try a hard drawn=20
Nichrome wire?</DIV>
<DIV> </DIV>
<DIV> I have also looked at inks for chart recorder p=
ens=20
/ inkjet printers and you can buy specialist cleaning fluid for these.=20
Check with your local computer store / an on-line supplier? I can buy ink in=
=20
~50ml bottles and inject it into commercial ink jet printer cartriges to re-=
fill=20
them. Soaking the jet plate with the cleaning fluid on a thin cove=
r=20
cloth does clean it. Maybe overnight in a polythene bag?</DIV>
<DIV> </DIV>
<DIV> Ask your manufacturer about a cleaning fluid fo=
r=20
their pens? You don't say what type / make of pen you are using!=20
Ideally, you should clean capillary tube pens out every few months, to preve=
nt=20
clogging problems. The special needles used for injecting insulin used to co=
me=20
with a cleaning wire.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Lehman sensor back online
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@.........
Date: Fri, 12 Dec 2008 21:27:56 +0000
Hello all
It has been some time since I have send a email to this postlist. But I
have been in school for past few months. Now the school is finished for
me.
I have finished the modifactions to the lehman I did get help with
building last spring. It appears to be working fine. The top of the
frequancy of the sensor is 2,5Hz (lower end somewhere around 0.5Hz or
lower) and I am not sure why that is. I hope it works with teleseismic
event. But only time is going to tell.
Here are the pictures of the sensor and the changes I did do to it.
http://www.jonfr.com/myndir/v/geology/seismometer/pc120001.jpg.html
Regards.
--=20
J=F3n Fr=EDmann
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Lehman sensor back online
From: Pete Rowe ptrowe@.........
Date: Fri, 12 Dec 2008 15:10:27 -0800 (PST)
Hi Jon
It is good to have you back again. I wondered what ever happened to you. Di=
d you graduate or are you on a winter break from school?
What are you studying?
Regards
Pete
--- On Fri, 12/12/08, J=F3n Fr=EDmann <jonfr@.........> wrote:
From: J=F3n Fr=EDmann <jonfr@.........>
Subject: Lehman sensor back online
To: "PSN-Postlist" <PSN-L@..............>
Date: Friday, December 12, 2008, 1:27 PM
Hello all
It has been some time since I have send a email to this postlist. But I
have been in school for past few months. Now the school is finished for
me.
I have finished the modifactions to the lehman I did get help with
building last spring. It appears to be working fine. The top of the
frequancy of the sensor is 2,5Hz (lower end somewhere around 0.5Hz or
lower) and I am not sure why that is. I hope it works with teleseismic
event. But only time is going to tell.
Here are the pictures of the sensor and the changes I did do to it.
http://www.jonfr.com/myndir/v/geology/seismometer/pc120001.jpg.html
Regards.
--=20
J=F3n Fr=EDmann
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
=0A=0A=0A
<table cellspacing=3D"0" cellpadding=3D"0" border=3D"0" ><tr><td valign=3D"=
top" style=3D"font: inherit;">Hi Jon<br>It is good to have you back again. =
I wondered what ever happened to you. Did you graduate or are you on a wint=
er break from school?<br>What are you studying?<br><br>Regards<br>Pete<br><=
br>--- On <b>Fri, 12/12/08, J=F3n Fr=EDmann <i><jonfr@.........></i><=
/b> wrote:<br><blockquote style=3D"border-left: 2px solid rgb(16, 16, 255);=
margin-left: 5px; padding-left: 5px;">From: J=F3n Fr=EDmann <jonfr@jonf=
r.com><br>Subject: Lehman sensor back online<br>To: "PSN-Postlist" <P=
SN-L@..............><br>Date: Friday, December 12, 2008, 1:27 PM<br><br>=
<pre>Hello all<br><br>It has been some time since I have send a email to th=
is postlist. But I<br>have been in school for past few months. Now the scho=
ol is finished for<br>me.<br><br>I have finished the modifactions to the le=
hman I did get help with<br>building last spring. It appears to be working =
fine. The
top of the<br>frequancy of the sensor is 2,5Hz (lower end somewhere around=
0.5Hz or<br>lower) and I am not sure why that is. I hope it works with tel=
eseismic<br>event. But only time is going to tell.<br><br>Here are the pict=
ures of the sensor and the changes I did do to it.<br>http://www.jonfr.com/=
myndir/v/geology/seismometer/pc120001.jpg.html<br><br>Regards.<br>-- <br>J=
=F3n Fr=EDmann<br><br>_____________________________________________________=
_____<br><br>Public Seismic Network Mailing List (PSN-L)<br><br>To leave th=
is list email PSN-L-REQUEST@.............. with<br>the body of the message =
(first line only): unsubscribe<br>See http://www.seismicnet.com/maillist.ht=
ml for more information.<br></pre></blockquote></td></tr></table><br>=0A=0A=
Subject: Re: Lehman sensor back online
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@.........
Date: Fri, 12 Dec 2008 23:24:37 +0000
Hi
I was just taking few classes that I wanted to learn. This time around
it was about car engenes and how to build stuff out of metal.
I also took a class in geology and social sience.
I don't have any plans to go back to school for now. What I have learned
for now is good enugh for me.
Regards.
J=F3n Fr=EDmann.
On f=F6s, 2008-12-12 at 15:10 -0800, Pete Rowe wrote:
> Hi Jon
> It is good to have you back again. I wondered what ever happened to
> you. Did you graduate or are you on a winter break from school?
> What are you studying?
>=20
> Regards
> Pete
>=20
> --- On Fri, 12/12/08, J=F3n Fr=EDmann <jonfr@.........> wrote:
> From: J=F3n Fr=EDmann <jonfr@.........>
> Subject: Lehman sensor back online
> To: "PSN-Postlist" <PSN-L@..............>
> Date: Friday, December 12, 2008, 1:27 PM
> =20
> Hello all
> =20
> It has been some time since I have send a email to this postlist.=
But I
> have been in school for past few months. Now the school is finish=
ed for
> me.
> =20
> I have finished the modifactions to the lehman I did get help wit=
h
> building last spring. It appears to be working fine. The
> top of the
> frequancy of the sensor is 2,5Hz (lower end somewhere around 0.5H=
z or
> lower) and I am not sure why that is. I hope it works with telese=
ismic
> event. But only time is going to tell.
> =20
> Here are the pictures of the sensor and the changes I did do to i=
t.
> http://www.jonfr.com/myndir/v/geology/seismometer/pc120001.jpg.ht=
ml
> =20
> Regards.
> --=20
> J=F3n Fr=EDmann
> =20
> __________________________________________________________
> =20
> Public Seismic Network Mailing List (PSN-L)
> =20
> 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: Spring Constant and Temperature
From: "Gary Lindgren" gel@.................
Date: Fri, 12 Dec 2008 17:44:54 -0800
As we know, the spring constant changes with temperature for the typical
materials used for springs. For instance, for carbon steel, the modulus of
elasticity is 29.5E6 psi at 70 degrees F and then changes to 28.8E6 psi at
200 degrees F. This means that the spring constant changes with temperature.
Is this a problem that I should be concerned about. My vertical seismometer
is located in the wine cellar and so the temperature does not vary during
the day, but the temperature may change 10 degrees F with the seasons. Does
anyone use a spring made with Ni-Span-C 902? This material is extremely
stable with temperature. The modulus of elasticity is 27.79E6 psi at 0, 100,
and 200 degrees F. The only problem is that this material is not used very
much and it's a made to order situation. Peck Springs in Connecticut (
860-747-5715) has made springs with material from time to time. They are
checking to see what the cost would be.
Any thoughts?
Gary
Gary Lindgren
585 Lincoln Ave
Palo Alto CA 94301
650-326-0655
<http://www.blue-eagle-technologies.com/> www.blue-eagle-technologies.com
Check out Lastest Seismometer Reading
<http://www.cymonsplace.blogspot.com/> cymonsplace.blogspot.com
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<div class=3DSection1>
<p class=3DMsoNormal>As we know, the spring constant changes with =
temperature for
the typical materials used for springs. For instance, for carbon steel, =
the modulus
of elasticity is 29.5E6 psi at 70 degrees F and then changes to 28.8E6 =
psi at
200 degrees F. This means that the spring constant changes with =
temperature. Is
this a problem that I should be concerned about. My vertical seismometer =
is
located in the wine cellar and so the temperature does not vary during =
the day,
but the temperature may change 10 degrees F with the seasons. Does =
anyone use a
spring made with Ni-Span-C 902? This material is extremely stable with
temperature. The modulus of elasticity is 27.79E6 psi at 0, 100, and 200
degrees F. The only problem is that this material is not used very much =
and it’s
a made to order situation. Peck Springs in Connecticut ( 860-747-5715) =
has made
springs with material from time to time. They are checking to see what =
the cost
would be. <o:p></o:p></p>
<p class=3DMsoNormal>Any thoughts?<o:p></o:p></p>
<p class=3DMsoNormal>Gary<o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>Gary Lindgren</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>585 Lincoln Ave</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal><b><span =
style=3D'font-size:12.0pt;font-family:"Arial","sans-serif";
color:#548DD4'>Palo Alto CA 94301</span></b><b><span =
style=3D'font-size:12.0pt;
color:#548DD4'><o:p></o:p></span></b></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'>650-326-0655<=
/span><o:p></o:p></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href=3D"http://www.blue-eagle-technologies.com/"><span =
style=3D'color:blue'>www.blue-eagle-technologies.com</span></a> &nbs=
p;
<span style=3D'color:red'>Check out Lastest Seismometer =
Reading</span></span><o:p></o:p></p>
<p class=3DMsoNormal><span =
style=3D'font-size:10.0pt;font-family:"Arial","sans-serif"'><a
href=3D"http://www.cymonsplace.blogspot.com/"><span =
style=3D'color:blue'>cymonsplace.blogspot.com</span></a> </span><o:p=
></o:p></p>
<p class=3DMsoNormal> <o:p></o:p></p>
<p class=3DMsoNormal><o:p> </o:p></p>
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Subject: Re: Spring Constant and Temperature
From: ChrisAtUpw@.......
Date: Fri, 12 Dec 2008 22:20:20 EST
In a message dated 13/12/2008, gel@................. writes:
The spring constant changes with temperature for the typical materials used
for springs. For instance, for carbon steel, the modulus of elasticity is
29.5E6 psi at 70 degrees F and then changes to 28.8E6 psi at 200 degrees F. This
means that the spring constant changes with temperature. Is this a problem
that I should be concerned about. My vertical seismometer is located in the
wine cellar and so the temperature does not vary during the day, but the
temperature may change 10 degrees F with the seasons.
Hi Gary,
This normally limits the maximum period that you can set a steel spring
vertical to about 6 seconds. The Tc of the modulus is about -2.4x10^-4 / C
Deg, which is large. If you try to make a vertical with a very long natural
period, it will collapse as the room temperature rises.
The 'work around' for a simple amateur system is to make a vertical
sensor with a 1.5 to 2 second period and then fit a 1/f^2 low frequency boost
amplifier to recover the long period signals. You can get at least a factor of
x10 this way before you run into noise problems, more if you use quad NdFeB
magnet + coil sensor. I run a sensor of this general type and it picks up the
Rayleigh waves very nicely.
You can get much greater period extensions if you use a position sensor
and force feedback - see the SG type pendulum seismometers on psn. You don't
have to use the RF oscillator + tuned sensor circuit. Large area Si
photodiodes, 10 to 20 sq mm, and a tungsten filament lamp will work OK. Small
photodiodes and photo transistors both have too high noise levels.
The professionals now tend to use N-SpanC springs and force feedback
systems to get periods to 360 seconds. The old Sprengnether verticals used an
Elinvar spring and got stable operation to 30 seconds.
Sean Morrissey developed a force feedback vertical with a steel leaf
spring which was OK for about +/-10 deg. It is all linked on psn, if you look!
Regards,
Chris Chapman
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<META http-equiv=3DContent-Type content=3D"text/html; charset=3DUS-ASCII">
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<DIV>
<DIV>In a message dated 13/12/2008, gel@................. 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
spring constant changes with temperature for the typical materials used fo=
r=20
springs. For instance, for carbon steel, the modulus of elasticity is 29.5=
E6=20
psi at 70 degrees F and then changes to 28.8E6 psi at 200 degrees F. This=20
means that the spring constant changes with temperature. Is this a problem=
=20
that I should be concerned about. My vertical seismometer is located in th=
e=20
wine cellar and so the temperature does not vary during the day, but the=20
temperature may change 10 degrees F with the seasons. </FONT></BLOCKQUOTE>=
</DIV>
<DIV></DIV>
<DIV>Hi Gary,</DIV>
<DIV> </DIV>
<DIV> This normally limits the maximum period that yo=
u=20
can set a steel spring vertical to about 6 seconds. The Tc of the modulus is=
=20
about -2.4x10^-4 / C Deg, which is large. If you try to make a vertica=
l=20
with a very long natural period, it will collapse as the room temperature=20
rises.</DIV>
<DIV> </DIV>
<DIV> The 'work around' for a simple amateur system i=
s to=20
make a vertical sensor with a 1.5 to 2 second period and then fit a=20
1/f^2 low frequency boost amplifier to recover the long period=20
signals. You can get at least a factor of x10 this way before you run into n=
oise=20
problems, more if you use quad NdFeB magnet + coil sensor. I run a sensor of=
=20
this general type and it picks up the Rayleigh waves very nicely. </DIV>
<DIV> </DIV>
<DIV> You can get much greater period extensions if y=
ou=20
use a position sensor and force feedback - see the SG type pendulum=20
seismometers on psn. You don't have to use the RF oscillator + tuned sensor=20
circuit. Large area Si photodiodes, 10 to 20 sq mm, and a tungsten filament=20=
lamp=20
will work OK. Small photodiodes and photo transistors both have too high noi=
se=20
levels. </DIV>
<DIV> </DIV>
<DIV> The professionals now tend to use N-SpanC=20
springs and force feedback systems to get periods to 360 seconds. The old=20
Sprengnether verticals used an Elinvar spring and got stable operation=20=
to=20
30 seconds. </DIV>
<DIV> </DIV>
<DIV> Sean Morrissey developed a force feedback verti=
cal=20
with a steel leaf spring which was OK for about +/-10 deg. It=
is=20
all linked on psn, if you look!</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: Spring Constant and Temperature
From: Brett Nordgren brett3nt@.............
Date: Fri, 12 Dec 2008 23:26:40 -0500
Hi Gary,
As Chris mentioned in his reply, feedback can help deal with support-spring
drift. What can be done is to roll off the instrument response at low
frequencies, in particular its response to forces/accelerations, and make
it fall toward zero at DC. The effect, then, is that the loop will tend to
cancel out any spring changes which are slow enough. You would probably
want to put the seismo in a can and surround it with thick insulation so
that ambient changes only get through to the seismo very slowly, and so can
be cancelled by the loop.
The integral feedback branch is the thing that does the job and if you have
a good integrator circuit it could probably do enough good to allow for
using a steel spring. It would be particularly effective with daily
variations, though for longer-term seasonal shifts, you'd probably need to
adjust the mechanical balance to re-null the loop. You don't want to be
running the instrument with the integrator continuously straining hard to
offset a large, permanent, spring change.
The main problem with Ni-Span-C, assuming that you can get some, is that
its performance is highly dependent on the way it is cold-worked and heat
treated.
See: http://bnordgren.org/seismo/ni-span-c_alloy_902.pdf
It is also only about 2/3 as strong as steel, and so will have 'lower'
performance as a spring, by some measures.
Regards,
Brett
At 05:44 PM 12/12/2008 -0800, you wrote:
>As we know, the spring constant changes with temperature for the typical
>materials used for springs. For instance, for carbon steel, the modulus of
>elasticity is 29.5E6 psi at 70 degrees F and then changes to 28.8E6 psi at
>200 degrees F. This means that the spring constant changes with
>temperature. Is this a problem that I should be concerned about. My
>vertical seismometer is located in the wine cellar and so the temperature
>does not vary during the day, but the temperature may change 10 degrees F
>with the seasons. Does anyone use a spring made with Ni-Span-C 902? This
>material is extremely stable with temperature. The modulus of elasticity
>is 27.79E6 psi at 0, 100, and 200 degrees F. The only problem is that this
>material is not used very much and it s a made to order situation. Peck
>Springs in Connecticut ( 860-747-5715) has made springs with material from
>time to time. They are checking to see what the cost would be.
>
>Any thoughts?
>
>Gary
>
>
>
>Gary Lindgren
>
>585 Lincoln Ave
>
>Palo Alto CA 94301
>
>
>
>650-326-0655
>
>
>
><http://www.blue-eagle-technologies.com/>www.blue-eagle-technologies.com
>Check out Lastest Seismometer Reading
>
><http://www.cymonsplace.blogspot.com/>cymonsplace.blogspot.com
>
>
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Lehman sensor back online
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@.........
Date: Sat, 13 Dec 2008 04:38:56 +0000
Hi all
The sensor is now back online on the internet, the plot can be seen on
the usual place.
http://www.simnet.is/jonfr500/earthquake/tremoren.htm
Regards.
--=20
J=F3n Fr=EDmann
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Spring Constant and Temperature
From: "Gary Lindgren" gel@.................
Date: Sat, 13 Dec 2008 10:36:11 -0800
Hi Brett,
I won't have a daily temperature issue because I have the seismo in the wine
cellar that is well insulated and in the basement. There are no daily
temperature variation, it's only the seasonal I need to worry about. Yes
indeed the Ni-Span-C 902 needs to be heat treated correctly. To achieve the
zero change with temperature the material needs to be heat treated at 1000
degrees F for 5 hours.
Gary
-----Original Message-----
From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of Brett Nordgren
Sent: Friday, December 12, 2008 8:27 PM
To: psn-l@..............
Subject: Re: Spring Constant and Temperature
Hi Gary,
As Chris mentioned in his reply, feedback can help deal with support-spring
drift. What can be done is to roll off the instrument response at low
frequencies, in particular its response to forces/accelerations, and make
it fall toward zero at DC. The effect, then, is that the loop will tend to
cancel out any spring changes which are slow enough. You would probably
want to put the seismo in a can and surround it with thick insulation so
that ambient changes only get through to the seismo very slowly, and so can
be cancelled by the loop.
The integral feedback branch is the thing that does the job and if you have
a good integrator circuit it could probably do enough good to allow for
using a steel spring. It would be particularly effective with daily
variations, though for longer-term seasonal shifts, you'd probably need to
adjust the mechanical balance to re-null the loop. You don't want to be
running the instrument with the integrator continuously straining hard to
offset a large, permanent, spring change.
The main problem with Ni-Span-C, assuming that you can get some, is that
its performance is highly dependent on the way it is cold-worked and heat
treated.
See: http://bnordgren.org/seismo/ni-span-c_alloy_902.pdf
It is also only about 2/3 as strong as steel, and so will have 'lower'
performance as a spring, by some measures.
Regards,
Brett
At 05:44 PM 12/12/2008 -0800, you wrote:
>As we know, the spring constant changes with temperature for the typical
>materials used for springs. For instance, for carbon steel, the modulus of
>elasticity is 29.5E6 psi at 70 degrees F and then changes to 28.8E6 psi at
>200 degrees F. This means that the spring constant changes with
>temperature. Is this a problem that I should be concerned about. My
>vertical seismometer is located in the wine cellar and so the temperature
>does not vary during the day, but the temperature may change 10 degrees F
>with the seasons. Does anyone use a spring made with Ni-Span-C 902? This
>material is extremely stable with temperature. The modulus of elasticity
>is 27.79E6 psi at 0, 100, and 200 degrees F. The only problem is that this
>material is not used very much and it s a made to order situation. Peck
>Springs in Connecticut ( 860-747-5715) has made springs with material from
>time to time. They are checking to see what the cost would be.
>
>Any thoughts?
>
>Gary
>
>
>
>Gary Lindgren
>
>585 Lincoln Ave
>
>Palo Alto CA 94301
>
>
>
>650-326-0655
>
>
>
><http://www.blue-eagle-technologies.com/>www.blue-eagle-technologies.com
>Check out Lastest Seismometer Reading
>
><http://www.cymonsplace.blogspot.com/>cymonsplace.blogspot.com
>
>
>
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: signal from my lehman sensor
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@.........
Date: Sun, 14 Dec 2008 01:27:39 +0000
Hi all
How does the signal from my lehman sensor look ? Bad or good ?
There has not been any big earthquake to check the sensor of it works or
not. So an opinion on the signal it currently gives is appreciated.
The signal can be found here.
http://www.simnet.is/jonfr500/earthquake/tremoren.htm
Regards.
--=20
J=F3n Fr=EDmann
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Interesting Article on Earthquakes
From: Bob Hancock carpediem1@.........
Date: Sat, 13 Dec 2008 22:09:08 -0700
http://www.newswise.com/articles/view/547288/?sc=dwhn
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: RE: Spring Constant and Temperature
From: Brett Nordgren brett3nt@.............
Date: Sun, 14 Dec 2008 13:18:05 -0500
Hi Gary,
There's also a slightly different approach you might want to consider,
which is what I now think they did in the STS-1 and probably others.
Heat treat the Ni-Span-C for maximum strength (~1300 deg F/5 hrs) which
gets the spec. yield strength up to 173 ksi. That ends up with a
relatively linear positive TCE of about +20ppm/degF. Then you can parallel
the Ni-Span spring with a relatively weaker steel spring which will
contribute a negative TCE. If the relative spring strengths are chosen
properly you could end up with a fairly constant net zero TCE.
I admit that's going pretty far for ultimate performance. That may be one
of reasons why those highly respected instruments cost so much. In
practice, there are going to be circuit issues which will add significantly
to the instrument temp. coeff. even if the spring is perfect.
Brett
At 10:36 AM 12/13/2008 -0800, Gary Lindgren wrote:
>Hi Brett,
>I won't have a daily temperature issue because I have the seismo in the wine
>cellar that is well insulated and in the basement. There are no daily
>temperature variation, it's only the seasonal I need to worry about. Yes
>indeed the Ni-Span-C 902 needs to be heat treated correctly. To achieve the
>zero change with temperature the material needs to be heat treated at 1000
>degrees F for 5 hours.
>Gary
>
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Spring Constant and Temperature
From: Barry Lotz barry_lotz@.............
Date: Tue, 16 Dec 2008 06:38:45 -0800 (PST)
Chris
I added a bymetal spiral spring from a dial thermometer to my Sean Morresse=
y vertical to help compensate for the temperature. It is mounted off to the=
side and rests on the boom in a fishing pole configuration. I move it up a=
nd down the boom until I get the proper compensation
Barry
--- On Fri, 12/12/08, ChrisAtUpw@....... <ChrisAtUpw@.......> wrote:
From: ChrisAtUpw@....... <ChrisAtUpw@.......>
Subject: Re: Spring Constant and Temperature
To: psn-l@..............
Date: Friday, December 12, 2008, 7:20 PM
=20
In a message dated 13/12/2008, gel@................. writes:
The=20
spring constant changes with temperature for the typical materials used f=
or=20
springs. For instance, for carbon steel, the modulus of elasticity is 29.=
5E6=20
psi at 70 degrees F and then changes to 28.8E6 psi at 200 degrees F. This=
=20
means that the spring constant changes with temperature. Is this a proble=
m=20
that I should be concerned about. My vertical seismometer is located in t=
he=20
wine cellar and so the temperature does not vary during the day, but the=
=20
temperature may change 10 degrees F with the seasons.=20
Hi Gary,
=A0
=A0=A0=A0=A0This normally limits the maximum period that you=20
can set a steel spring vertical to about 6 seconds. The Tc of the modulus i=
s=20
about =A0-2.4x10^-4 / C Deg, which is large. If you try to make a vertical=
=20
with a very long natural period, it will collapse as the room temperature=
=20
rises.
=A0
=A0=A0=A0=A0The 'work around' for a simple amateur system is to=20
make a vertical sensor with a 1.5 to 2 second period and then fit a=20
1/f^2=A0low frequency boost amplifier=A0to recover the long period=20
signals. You can get at least a factor of x10 this way before you run into =
noise=20
problems, more if you use quad NdFeB magnet + coil sensor. I run a sensor o=
f=20
this general type and it picks up the Rayleigh waves very nicely.=20
=A0
=A0=A0=A0=A0You can get much greater period extensions if you=20
use a position sensor and force feedback - see the SG type=A0pendulum=20
seismometers on psn. You don't have to use the RF oscillator + tuned sensor=
=20
circuit. Large area Si photodiodes, 10 to 20 sq mm, and a tungsten filament=
lamp=20
will work OK. Small photodiodes and photo transistors both have too high no=
ise=20
levels.=20
=A0
=A0=A0=A0=A0The professionals now=A0tend to use N-SpanC=20
springs and force feedback systems to get periods to 360 seconds. The old=
=20
Sprengnether verticals used an Elinvar spring and got=A0stable operation to=
=20
30 seconds.=A0
=A0
=A0=A0=A0=A0Sean Morrissey developed a force feedback vertical=20
with a steel leaf spring which was OK for=A0about=A0+/-10 deg.=A0It is=20
all linked on psn, if you look!
=A0
=A0=A0=A0=A0Regards,
=A0
=A0=A0=A0=A0Chris Chapman
<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">Chris<br>I added a bymetal spiral spring from a dial thermometer to my Sean Morressey vertical to help compensate for the temperature. It is mounted off to the side and rests on the boom in a fishing pole configuration. I move it up and down the boom until I get the proper compensation<br>Barry<br><br>--- On <b>Fri, 12/12/08, ChrisAtUpw@....... <i><ChrisAtUpw@.......></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;">From: ChrisAtUpw@....... <ChrisAtUpw@.......><br>Subject: Re: Spring Constant and Temperature<br>To: psn-l@..............<br>Date: Friday, December 12, 2008, 7:20 PM<br><br><div id="yiv2123364527">
<font id="role_document" size="2" color="#000000" face="Arial">
<div>
<div>In a message dated 13/12/2008, gel@................. writes:</div>
<blockquote style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font style="background-color: transparent;" size="2" color="#000000" face="Arial">The
spring constant changes with temperature for the typical materials used for
springs. For instance, for carbon steel, the modulus of elasticity is 29.5E6
psi at 70 degrees F and then changes to 28.8E6 psi at 200 degrees F. This
means that the spring constant changes with temperature. Is this a problem
that I should be concerned about. My vertical seismometer is located in the
wine cellar and so the temperature does not vary during the day, but the
temperature may change 10 degrees F with the seasons. </font></blockquote></div>
<div></div>
<div>Hi Gary,</div>
<div> </div>
<div> This normally limits the maximum period that you
can set a steel spring vertical to about 6 seconds. The Tc of the modulus is
about -2.4x10^-4 / C Deg, which is large. If you try to make a vertical
with a very long natural period, it will collapse as the room temperature
rises.</div>
<div> </div>
<div> The 'work around' for a simple amateur system is to
make a vertical sensor with a 1.5 to 2 second period and then fit a
1/f^2 low frequency boost amplifier to recover the long period
signals. You can get at least a factor of x10 this way before you run into noise
problems, more if you use quad NdFeB magnet + coil sensor. I run a sensor of
this general type and it picks up the Rayleigh waves very nicely. </div>
<div> </div>
<div> You can get much greater period extensions if you
use a position sensor and force feedback - see the SG type pendulum
seismometers on psn. You don't have to use the RF oscillator + tuned sensor
circuit. Large area Si photodiodes, 10 to 20 sq mm, and a tungsten filament lamp
will work OK. Small photodiodes and photo transistors both have too high noise
levels. </div>
<div> </div>
<div> The professionals now tend to use N-SpanC
springs and force feedback systems to get periods to 360 seconds. The old
Sprengnether verticals used an Elinvar spring and got stable operation to
30 seconds. </div>
<div> </div>
<div> Sean Morrissey developed a force feedback vertical
with a steel leaf spring which was OK for about +/-10 deg. It is
all linked on psn, if you look!</div>
<div> </div>
<div> Regards,</div>
<div> </div>
<div> Chris Chapman</div></font></div></blockquote></td></tr></table>
Subject: Low power monitor desired
From: Barry Lotz barry_lotz@.............
Date: Tue, 16 Dec 2008 06:50:53 -0800 (PST)
To all
I was trying to find a low power monitor for my acquisition system so I can=
run my system off solar. The best I could find was a 8" 12 vt DC LCD displ=
ay from Lilliput but it is not as inexpensive as the=A0 the larger AC LCD's=
commonly advertised. It wouldn't be on except to check sensor status. I fo=
und a low power computer ( 3-5 watts) that takes VGA input
Barry
=A0=20
<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">To all<br>I was trying to find a low power monitor for my acquisition system so I can run my system off solar. The best I could find was a 8" 12 vt DC LCD display from Lilliput but it is not as inexpensive as the the larger AC LCD's commonly advertised. It wouldn't be on except to check sensor status. I found a low power computer ( 3-5 watts) that takes VGA input<br><br>Barry<br> <br></td></tr></table>
Subject: Re: Low power monitor desired
From: Thomas Dick dickthomas01@.............
Date: Tue, 16 Dec 2008 09:10:30 -0600
Barry Lotz wrote:
> To all
> I was trying to find a low power monitor for my acquisition system so
> I can run my system off solar. The best I could find was a 8" 12 vt DC
> LCD display from Lilliput but it is not as inexpensive as the the
> larger AC LCD's commonly advertised. It wouldn't be on except to check
> sensor status. I found a low power computer ( 3-5 watts) that takes
> VGA input
>
> Barry
>
>
Maybe a dumb suggestion but ....
How about putting a wi-fi on the computer, shutting the monitor off when
not needed and monitoring the computer from a remote location. I already
do this. I don't connect the monitor to the backup power supply...I have
wi-fi in the house but still use solid cable to the network upstairs ..
waiting for the computer downstairs to "die".
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Low power monitor desired
From: Barry Lotz barry_lotz@.............
Date: Tue, 16 Dec 2008 17:36:13 -0800 (PST)
Tom
I agree. I sort of do that now. I have the seismic computer in the garage and run a networking cable into the house. I use a free software "Tight VNC" to see the sensor display in the house. The company I bought the computer from has an updated version with WiFi and a larger harddrive. I'm not familiar with WiFi capabilities. Will it go thru two walls and about 40'-50'? Do I use the same software I currently use, ie, is WiFi just a wireless network link?
Wireless would be nice.
Barry
--- On Tue, 12/16/08, Thomas Dick <dickthomas01@.............> wrote:
From: Thomas Dick <dickthomas01@.............>
Subject: Re: Low power monitor desired
To: psn-l@..............
Date: Tuesday, December 16, 2008, 7:10 AM
Barry Lotz wrote:
> To all
> I was trying to find a low power monitor for my acquisition system so
> I can run my system off solar. The best I could find was a 8" 12 vt
DC
> LCD display from Lilliput but it is not as inexpensive as the the
> larger AC LCD's commonly advertised. It wouldn't be on except to
check
> sensor status. I found a low power computer ( 3-5 watts) that takes
> VGA input
>
> Barry
>
>
Maybe a dumb suggestion but ....
How about putting a wi-fi on the computer, shutting the monitor off when
not needed and monitoring the computer from a remote location. I already
do this. I don't connect the monitor to the backup power supply...I have
wi-fi in the house but still use solid cable to the network upstairs ..
waiting for the computer downstairs to "die".
<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">Tom<br>I agree. I sort of do that now. I have the seismic computer in the garage and run a networking cable into the house. I use a free software "Tight VNC" to see the sensor display in the house. The company I bought the computer from has an updated version with WiFi and a larger harddrive. I'm not familiar with WiFi capabilities. Will it go thru two walls and about 40'-50'? Do I use the same software I currently use, ie, is WiFi just a wireless network link?<br>Wireless would be nice. <br>Barry<br><br><br>--- On <b>Tue, 12/16/08, Thomas Dick <i><dickthomas01@.............></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;">From: Thomas Dick <dickthomas01@.............><br>Subject: Re: Low power monitor desired<br>To: psn-l@..............<br>Date: Tuesday, December 16, 2008, 7:10
AM<br><br><pre>Barry Lotz wrote:<br>> To all<br>> I was trying to find a low power monitor for my acquisition system so <br>> I can run my system off solar. The best I could find was a 8" 12 vt<br>DC <br>> LCD display from Lilliput but it is not as inexpensive as the the <br>> larger AC LCD's commonly advertised. It wouldn't be on except to<br>check <br>> sensor status. I found a low power computer ( 3-5 watts) that takes <br>> VGA input<br>><br>> Barry<br>> <br>><br>Maybe a dumb suggestion but ....<br>How about putting a wi-fi on the computer, shutting the monitor off when <br>not needed and monitoring the computer from a remote location. I already <br>do this. I don't connect the monitor to the backup power supply...I have <br>wi-fi in the house but still use solid cable to the network upstairs .. <br>waiting for the computer downstairs to "die".<br><br></pre></blockquote></td></tr></table>
Subject: Dear (lcochrane@webtronics.com) December 87% OFF!
From: GUCCI lcochrane@..............
Date:
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Subject: Question of amplitude ?
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@.........
Date: Fri, 19 Dec 2008 16:09:06 +0000
Hi all
My lehman type sensor did not pickup the Mw5,9 earthquake south of
Iceland this morning. I am unsure why that did happen. I am wondering if
that is a question of amplitude or of there is something wrong with the
sensor it self.
There is a spike at 2,2Hz in the data from the sensor at SPS 100, but at
SPS 1 I get the spike at 0.22Hz.
Regards.
--=20
J=F3n Fr=EDmann
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Power Supply, Amplifier, and AD
From: "Robert Thomasson" rlthomasson@.........
Date: Sat, 20 Dec 2008 17:56:48 +0300
Chris,
Thinking about the damping, it seems like a basic coil and magnet sensor
like the AS-1 would be self damping due to the movement of the copper
winding in the magnetic field. Or is it a case of it being self damping but
still underdamped and needing additional damping?
Thanks,
Bob
On Wed, Dec 10, 2008 at 5:30 AM, <ChrisAtUpw@.......> wrote:
> In a message dated 09/12/2008, sismos@.............. writes:
>
> Hello Dayana,
> Don't buy the black box that you see with an AS1.
> you can do much better and probably less expensive or close with Larry's
> boards.
>
> Hi Dayana,
>
> I believe that Jeff Batten amateurseismo@......... will sell the
> electronics box and power supply separately.
>
> Seismometers like the AS1 and EQ1 try to use oil + plunge plate
> damping. The viscosity of oil changes by about x10 for every 20 C Deg / 36 F
> Deg change in temperature. If you set up the damping to be correct at your
> room temperature, you will only have an operating range of about +/-4 F Deg.
> This is LESS than the normal daily variation. If the temperature falls much
> below this range, the damping increases dramatically and the seismometer MAY
> stop recording altogether. It's sensitivity will certainly decrease and the
> calibration will NOT give the correct quake magnitude. I have designed a
> replacement magnetic damper which is NOT effected by temperature and is
> both easy to set up and CLEAN! No more oil creepage or spills!
> See http://jclahr.com/science/psn/chapman/as1%20damping/index.html
>
> The AS1 uses a vertical swing arm with a natural period of about 1.5
> seconds. So while the response is flat with velocity at periods shorter than
> this (like a geophone), the sensitivity will fall off as f^2 below 0.75 Hz
> when using a 'normal' seismic amplifier, like Larry's. The sensitivity to
> the 20 second period Rayleigh waves, will be down by a factor of about 180 -
> so you normally won't see any!
> A period extension circuit has been used in the AS1 'black box' to
> extend the sensitivity ~flat from 1.5 to about 4.5 seconds. This boosts the
> low frequency output. While it is OK for measuring microseisms, it is
> otherwise rather limiting. A further period extension can be applied with
> the digital compenation filter supplied with AmaSeis, but it only works well
> on moderately strong signals.
> I have extended the period to about 20 seconds by changing four
> capacitors and three resistors. It now seems to work satisfactorily and
> covers most of the normal seismic range.
>
> On the EQ1 that we examined, the compensation covered about the same
> compensation period range as an AS1, but the output seemed to be roughly
> proportional to f. This did NOT give a flat output. Since the power laws are
> different, I would not expect the digital frequency compensation built into
> AmaSeis to work adequately with an EQ1 trace. The EQ1 electronics uses
> miniature surface mount components, so I would NOT expect you to be able to
> modify EITHER the compensation range OR the power law.
>
> The relatively long springs expand and contract with temperature and
> may well need adjustment with the seasons.
>
> The AS1 is designed with the centre of gravity on the horizontal arm.
>
>
>
>
Chris,<br><br>Thinking about the damping, it seems like a basic coil and magnet sensor like the AS-1 would be self damping due to the movement of the copper winding in the magnetic field. Or is it a case of it being self damping but still underdamped and needing additional damping?<br>
<br>Thanks,<br><br>Bob<br><br><div class="gmail_quote">On Wed, Dec 10, 2008 at 5:30 AM, <span dir="ltr"><<a href="mailto:ChrisAtUpw@.......">ChrisAtUpw@.......</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div style="font-size: 10pt; color: rgb(0, 0, 0); font-family: Arial;"><font size="2" color="#000000" face="Arial">
<div>
<div>In a message dated 09/12/2008, <a href="mailto:sismos@.............." target="_blank">sismos@..............</a> writes:</div>
<blockquote style="border-left: 2px solid blue; padding-left: 5px; margin-left: 5px;"><font style="background-color: transparent;" size="2" color="#000000" face="Arial">Hello
Dayana,<br>Don't buy the black box that you see with an AS1.<br>you can do
much better and probably less expensive or close with Larry's
boards.<br></font></blockquote></div>
<div></div>
<div>Hi Dayana,</div>
<div> </div>
<div> I believe that Jeff Batten <a href="mailto:amateurseismo@........." target="_blank">amateurseismo@.........</a> will sell the
electronics box and power supply separately. </div>
<div> </div>
<div> Seismometers like the AS1 and EQ1 try to use oil +
plunge plate damping. The viscosity of oil changes by about x10 for every 20 C
Deg / 36 F Deg change in temperature. If you set up the damping to be correct at
your room temperature, you will only have an operating range of about +/-4 F
Deg. This is LESS than the normal daily variation. If the temperature falls much
below this range, the damping increases dramatically and the seismometer MAY
stop recording altogether. It's sensitivity will certainly decrease and the
calibration will NOT give the correct quake magnitude. I have designed a
replacement magnetic damper which is NOT effected by temperature and is
both easy to set up and CLEAN! No more oil creepage or spills!</div>
<div> See <a href="http://jclahr.com/science/psn/chapman/as1%20damping/index.html" target="_blank">http://jclahr.com/science/psn/chapman/as1%20damping/index.html</a> </div>
<div> </div>
<div> The AS1 uses a vertical swing arm with a natural
period of about 1.5 seconds. So while the response is flat with velocity at
periods shorter than this (like a geophone), the sensitivity will fall off as
f^2 below 0.75 Hz when using a 'normal' seismic amplifier, like Larry's. The
sensitivity to the 20 second period Rayleigh waves, will be down by a factor of
about 180 - so you normally won't see any!</div>
<div> A period extension circuit has been used in the AS1
'black box' to extend the sensitivity ~flat from 1.5 to about 4.5 seconds.
This boosts the low frequency output. While it is OK for measuring
microseisms, it is otherwise rather limiting. A further period
extension can be applied with the digital compenation filter supplied with
AmaSeis, but it only works well on moderately strong signals. </div>
<div> I have extended the period to about 20 seconds
by changing four capacitors and three resistors. It now seems to
work satisfactorily and covers most of the normal seismic range.</div>
<div> </div>
<div> On the EQ1 that we examined, the compensation
covered about the same compensation period range as an AS1, but the output
seemed to be roughly proportional to f. This did NOT give a flat output. Since
the power laws are different, I would not expect the digital frequency
compensation built into AmaSeis to work adequately with an EQ1 trace. The
EQ1 electronics uses miniature surface mount components, so I would NOT
expect you to be able to modify EITHER the compensation range OR the
power law.</div>
<div> </div>
<div> The relatively long springs expand and contract
with temperature and may well need adjustment with the seasons.</div>
<div> </div>
<div> The AS1 is designed with the centre of gravity on
the horizontal arm. </div>
<div> </div>
<div> </div>
<div> </div></font></div>
</blockquote></div><br>
Subject: Re: Power Supply, Amplifier, and AD
From: ChrisAtUpw@.......
Date: Sat, 20 Dec 2008 10:39:20 EST
In a message dated 20/12/2008, rlthomasson@......... writes:
Chris,
Thinking about the damping, it seems like a basic coil and magnet sensor
like the AS-1 would be self damping due to the movement of the copper winding in
the magnetic field. Or is it a case of it being self damping but still
underdamped and needing additional damping?
Bob
Hi Bob,
The coil + magnet supplied with the AS1 gives very roughly 0.1 damping,
when you actually need 0.7 damping, so a lot of additional damping is
required.
If you make you own system with a quad NdFeB magnet block and a
rectangular coil, like Bob McClure, you can put a variable resistor across the coil
and set the damping that way. This coil can give 20x the output you get from
an AS1.
If you connect the coil between Earth and the +ve input of an opamp, you
won't see any damping, since the input resistance is near infinite. If you
use an amplifier like Larry's, it already has a 10 k resistor across it, so
you could then get significant damping.
The AS1 uses a twin LF boost amplifier to recover longer period signals
out to about 5 seconds, but it is still poor at detecting 20 second signals.
John Lahr and I run modified AS1s which work out to 20 seconds
naturally. Thie involves changing 4 capacitors and three resistors on the AS1 board,
maybe $10 maximum
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 6.00.6000.16788" 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 20/12/2008, rlthomasson@......... 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>Chris,<BR>Thinking about the damping, it seems like a basic coil=20=
and=20
magnet sensor like the AS-1 would be self damping due to the movement of t=
he=20
copper winding in the magnetic field. Or is it a case of it being se=
lf=20
damping but still underdamped and needing additional=20
damping?<BR>Bob<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Bob,</DIV>
<DIV> </DIV>
<DIV> The coil + magnet supplied with the AS1 gives v=
ery=20
roughly 0.1 damping, when you actually need 0.7 damping, so a lot of additio=
nal=20
damping is required. </DIV>
<DIV> </DIV>
<DIV> If you make you own system with a quad NdF=
eB=20
magnet block and a rectangular coil, like Bob McClure, you can put a=20
variable resistor across the coil and set the damping that way. This coil ca=
n=20
give 20x the output you get from an AS1. </DIV>
<DIV> </DIV>
<DIV> If you connect the coil between Earth and the +=
ve=20
input of an opamp, you won't see any damping, since the input resistance is=20=
near=20
infinite. If you use an amplifier like Larry's, it already has a 10 k resist=
or=20
across it, so you could then get significant damping. </DIV>
<DIV> </DIV>
<DIV> The AS1 uses a twin LF boost amplifier to recov=
er=20
longer period signals out to about 5 seconds, but it is still poor at detect=
ing=20
20 second signals. </DIV>
<DIV> John Lahr and I run modified AS1s which work ou=
t to=20
20 seconds naturally. Thie involves changing 4 capacitors and three resistor=
s on=20
the AS1 board, maybe $10 maximum</DIV>
<DIV> </DIV>
<DIV> Regards,.</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: M6.5 7902km from Sea Ranch, CA USA, OFF EAST COAST OF HONSHU,
From: George Bush ke6pxp@.......
Date: Sat, 20 Dec 2008 11:42:32 -0800
The peacful day yesterday (no storm swells) allowed a quake to be
detected from almost 5000 miles away:
Region: OFF EAST COAST OF HONSHU, JAPAN
Geographic coordinates: 36.603N, 142.356E
Magnitude: 6.5 Mw
Depth: 10 km
Universal Time (UTC): 20 Dec 2008 10:29:22
Time near the Epicenter: 20 Dec 2008 19:29:22
Local standard time in your area: 20 Dec 2008 02:29:22
Location with respect to nearby cities:
139 km (87 miles) ESE (111 degrees) of Iwaki, Honshu, Japan
169 km (105 miles) E (81 degrees) of Mito, Honshu, Japan
209 km (130 miles) SE (126 degrees) of Fukushima, Honshu, Japan
256 km (159 miles) ENE (65 degrees) of TOKYO, Japan
This event has been reviewed by a seismologist at NEIC
For subsequent updates, maps, and technical information, see:
http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008avan.php
You can go to http://psn.quake.net/cgi-dos/event.exe and see my
recordings by clicking on "(GIF Image)" for the event files from Sea
Ranch.
Anyway, have a <color><param>0000,ffff,0000</param>Merry Xmas</color> and
a <color><param>ffff,0000,0000</param>Happy New Year</color>!
George
Subject: My apologies!
From: George Bush ke6pxp@.......
Date: Sat, 20 Dec 2008 11:47:34 -0800
Sorry to bother you, I just sent a detected quake notice to the PSN list
instead of to a small list of local people who are interested in the
quakes I detect!
But anyway, have a <color><param>0000,ffff,0000</param>Merry Xmas</color>
and a <color><param>ffff,0000,0000</param>Happy New Year</color>!
George Bush
Sea Ranch, CA, USA
38.73775N, 123.48882W
Subject: Re: Digest from 12/19/2008 00:00:43
From: JimT nyponen@.........
Date: Sun, 21 Dec 2008 17:38:49 -0800
We've had a swarm of small quakes in the neighborhood today, with
epicenters that appear to be close to the point where the Calaveras
fault joins the San Andreas fault. There were over 20 the last time I
counted. The biggest was 4.1.
http://quake.usgs.gov/recenteqs/Maps/121-36_eqs.htm
On 12/20/08, psn-l-digest-request@..............
<psn-l-digest-request@..............> wrote:
>
> .------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> | Message 1 |
> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> Subject: Question of amplitude ?
> From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= <jonfr@.........>
> Date: Fri, 19 Dec 2008 16:09:06 +0000
>
> Hi all
>
> My lehman type sensor did not pickup the Mw5,9 earthquake south of
> Iceland this morning. I am unsure why that did happen. I am wondering if
> that is a question of amplitude or of there is something wrong with the
> sensor it self.
>
> There is a spike at 2,2Hz in the data from the sensor at SPS 100, but at
> SPS 1 I get the spike at 0.22Hz.
>
> Regards.
> --=20
> J=F3n Fr=EDmann
>
>
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-DIGEST-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: Digest from 12/19/2008 00:00:43
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@.........
Date: Mon, 22 Dec 2008 01:48:49 +0000
Hi
Check for any sudden changes in that swarm, it might indicate a moderate
earthquake happening soon in that area or nearby.
Others earthquake on nearby fault lines also suggest this.
Regards
J=F3n Fr=EDmann.
On sun, 2008-12-21 at 17:38 -0800, JimT wrote:
> We've had a swarm of small quakes in the neighborhood today, with
> epicenters that appear to be close to the point where the Calaveras
> fault joins the San Andreas fault. There were over 20 the last time I
> counted. The biggest was 4.1.
>=20
> http://quake.usgs.gov/recenteqs/Maps/121-36_eqs.htm
>=20
> On 12/20/08, psn-l-digest-request@..............
> <psn-l-digest-request@..............> wrote:
> >
> > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> > | Message 1 |
> > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> > Subject: Question of amplitude ?
> > From: =3D?ISO-8859-1?Q?J=3DF3n_Fr=3DEDmann?=3D <jonfr@.........>
> > Date: Fri, 19 Dec 2008 16:09:06 +0000
> >
> > Hi all
> >
> > My lehman type sensor did not pickup the Mw5,9 earthquake south of
> > Iceland this morning. I am unsure why that did happen. I am wondering i=
f
> > that is a question of amplitude or of there is something wrong with the
> > sensor it self.
> >
> > There is a spike at 2,2Hz in the data from the sensor at SPS 100, but a=
t
> > SPS 1 I get the spike at 0.22Hz.
> >
> > Regards.
> > --=3D20
> > J=3DF3n Fr=3DEDmann
> >
> >
> >
> > __________________________________________________________
> >
> > Public Seismic Network Mailing List (PSN-L)
> >
> > To leave this list email PSN-L-DIGEST-REQUEST@.............. with
> > the body of the message (first line only): unsubscribe
> > See http://www.seismicnet.com/maillist.html for more information.
> >
> __________________________________________________________
>=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.
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Seismometer
From: "Edward Ianni" edwianni1@...........
Date: Mon, 22 Dec 2008 19:04:39 -0500
Has anyone noticed that WARD'S is selling a Seismometer.
http://wardsci.com/product.asp?pn=3DIG0018602&sid=3Dmercent&mr:referralID=
=3D5f903f77-d083-11dd-a8aa-000423bb4e95&bhcd2=3D1229989485
<!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 6.00.6000.16788" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Has anyone noticed that WARD'S is =
selling a=20
Seismometer.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2><A=20
href=3D"http://wardsci.com/product.asp?pn=3DIG0018602&sid=3Dmercent&a=
mp;mr:referralID=3D5f903f77-d083-11dd-a8aa-000423bb4e95&bhcd2=3D12299=
89485">http://wardsci.com/product.asp?pn=3DIG0018602&sid=3Dmercent&am=
p;mr:referralID=3D5f903f77-d083-11dd-a8aa-000423bb4e95&bhcd2=3D122998=
9485</A></FONT></DIV></BODY></HTML>
Subject: Vertical School Seismometer | WARD'S Natural Science
From: "Edward Ianni" edwianni1@...........
Date: Mon, 22 Dec 2008 19:17:14 -0500
This link may be more direct.
http://wardsci.com/product.asp_Q_pn_E_IG0018602
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Dwindows-1252">
<META content=3D"MSHTML 6.00.6000.16788" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>This link may be more =
direct.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV> </DIV><A=20
href=3D"http://wardsci.com/product.asp_Q_pn_E_IG0018602">http://wardsci.c=
om/product.asp_Q_pn_E_IG0018602</A></BODY></HTML>
Subject: Re: Seismometer
From: ChrisAtUpw@.......
Date: Mon, 22 Dec 2008 20:29:05 EST
In a message dated 23/12/2008, edwianni1@........... writes:
Has anyone noticed that WARD'S is selling a Seismometer.
Hi There,
Check out the school seismometer at
_http://www.bgs.ac.uk/schoolseismology/seismometer.html_ (http://www.bgs.ac.uk/schoolseismology/seismometer.html)
This one works well.
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 6.00.6000.16788" 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 23/12/2008, edwianni1@........... 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><FONT=20
face=3DArial size=3D2>Has anyone noticed that WARD'S is selling a=20
Seismometer.</FONT></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi There,</DIV>
<DIV> </DIV>
<DIV> Check out the school seismometer at <A=20
href=3D"http://www.bgs.ac.uk/schoolseismology/seismometer.html">http://www.b=
gs.ac.uk/schoolseismology/seismometer.html</A></DIV>
<DIV> </DIV>
<DIV> This one works well.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris</DIV></FONT></BODY></HTML>
Subject: Re: Vertical School Seismometer | WARD'S Natural Science
From: "Kay Wyatt" kwyatt@.............
Date: Tue, 23 Dec 2008 11:08:57 -0800
There is a little bit more information about the EQ-1 on this website:
http://www.nexgensci.com/store/pc/viewPrd.asp?idcategory=3D2&idproduct=3D=
1#details
If you choose to purchase the EQ-1, the Ward's website is cheaper. =
Also, sign up for the Ward's newsletter first. You will receive a =
"welcome" email from their newsletter that gives you a 10% discount on =
your next purchase from Ward's. This reduces the price further from =
$499 to $449. A cover is essential, but the one they offer is $100. =
You can find cheap glass aquariums at your local pet store for much =
less.
Their system still uses the older oil damping method. As Chris Chapman =
and so many others have pointed out, it is full of problems. Most =
notably, the damping changes with temperature. So you would need to =
change it to magnetic damping. See Chris Chapman's magnetic damping =
design at=20
http://jclahr.com/science/psn/chapman/as1%20damping/index.html
or John Lahr's version of Chris's design at=20
http://jclahr.com/science/psn/chapman/as1%20damping/lahr/index.html
----- Original Message -----=20
From: Edward Ianni=20
To: psn-l@.................
Sent: Monday, December 22, 2008 4:17 PM
Subject: Vertical School Seismometer | WARD'S Natural Science
This link may be more direct.
http://wardsci.com/product.asp_Q_pn_E_IG0018602
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Dwindows-1252">
<META content=3D"MSHTML 6.00.6000.16788" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial>There is a little bit more information about the =
EQ-1 on=20
this website:</FONT></DIV>
<DIV><FONT face=3DArial><A=20
href=3D"http://www.nexgensci.com/store/pc/viewPrd.asp?idcategory=3D2&=
idproduct=3D1#details">http://www.nexgensci.com/store/pc/viewPrd.asp?idca=
tegory=3D2&idproduct=3D1#details</A></FONT></DIV>
<DIV><FONT face=3DArial></FONT> </DIV>
<DIV><FONT face=3DArial>If you choose to purchase the EQ-1, the Ward's =
website is=20
cheaper. Also, sign up for the Ward's newsletter first. You =
will=20
receive a "welcome" email from their newsletter that gives you a 10% =
discount on=20
your next purchase from Ward's. This reduces the price further =
from $499=20
to $449. A cover is essential, but the one they offer is =
$100. You=20
can find cheap glass aquariums at your local pet store for much=20
less.</FONT></DIV>
<DIV><FONT face=3DArial></FONT> </DIV>
<DIV><FONT face=3DArial>Their system still uses the older oil damping=20
method. As Chris Chapman and so many others have pointed out, it =
is full=20
of problems. Most notably, the damping changes with =
temperature. So=20
you would need to change it to magnetic damping. See Chris =
Chapman's=20
magnetic damping design at </FONT></DIV>
<DIV><FONT face=3DArial><A=20
href=3D"http://jclahr.com/science/psn/chapman/as1%20damping/index.html">h=
ttp://jclahr.com/science/psn/chapman/as1%20damping/index.html</A></FONT><=
/DIV>
<DIV><FONT face=3DArial>or John Lahr's version of Chris's design at =
</FONT></DIV>
<DIV><FONT face=3DArial><A=20
href=3D"http://jclahr.com/science/psn/chapman/as1%20damping/lahr/index.ht=
ml">http://jclahr.com/science/psn/chapman/as1%20damping/lahr/index.html</=
A></FONT></DIV>
<DIV><FONT face=3DArial></FONT> </DIV>
<DIV><FONT face=3DArial></FONT> </DIV>
<BLOCKQUOTE=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=3Dedwianni1@........... =
href=3D"mailto:edwianni1@...........">Edward=20
Ianni</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> Monday, December 22, 2008 =
4:17=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Vertical School =
Seismometer |=20
WARD'S Natural Science</DIV>
<DIV><BR></DIV>
<DIV><FONT face=3DArial size=3D2>This link may be more =
direct.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV> </DIV><A=20
=
href=3D"http://wardsci.com/product.asp_Q_pn_E_IG0018602">http://wardsci.c=
om/product.asp_Q_pn_E_IG0018602</A>=20
</BLOCKQUOTE></BODY></HTML>
Subject: Morrissey Balance-beam Tiltmeter
From: Chuck/Judy Burch cjburch@...........
Date: Wed, 24 Dec 2008 17:56:37 -0700
Greetings all,
S-T Morrissey's website has an abstract for the fall 2000 AGU meeting
regarding a "Very Broadband Beam-Balance Tiltmeter." It also has
captions for a poster presentation on the same topic at the 2001 spring
SSA meeting. But no photos, drawings or diagrams seem to be available.
Does anyone know if the abstract and poster captions are all that is
available? I'd like to build such a device and any Morrissey diagrams
or photos would help me from reinventing the wheel (probably several
times). He mentions "a new low torque hinge flexure" and "a unique
vertical mass centering adjustment," both of which sound interesting.
Thanks,
Chuck Burch
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Morrissey Balance-beam Tiltmeter
From: ChrisAtUpw@.......
Date: Thu, 25 Dec 2008 22:40:21 EST
In a message dated 25/12/2008, cjburch@........... writes:
S-T Morrissey's website has an abstract for the fall 2000 AGU meeting
regarding a "Very Broadband Beam-Balance Tiltmeter." It also has captions for a
poster presentation on the same topic at the 2001 spring SSA meeting. But no
photos, drawings or diagrams seem to be available.
Hi Chuck,
Since the posters were displayed at the meetings, the preliminary
information is in the public domain. Accessing it may be a different matter. Sean
was going to patent the device, but I am uncertain as to what actually
happened, particularly with the long delays in processing American Patents. I did
try to follow up the poster and eventually managed to get a reference SSA / AGU
number. It is listed as C23 on
_http://www.seismosoc.org/meetings/ssa2001.html_ (http://www.seismosoc.org/meetings/ssa2001.html)
Sean presented a 30 page A4 poster with Brian J Mitchell of St Louis
University. He is now an Emeritus Professor _mitchbj@............
(mailto:mitchbj@............ in the Department of Earth and Atmospheric Sciences. A 70
page final NSF report was produced. I suggest that you ask him and the NSF?
It was funded by the NSF in October 1999, so there must be records of
this and of the report. The work was completed in October 2000. The NSF grant
reference is 9905328. The project funding was for $120,000.
See _http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=9905328_
(http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=9905328)
Does anyone know if the abstract and poster captions are all that is
available? I'd like to build such a device and any Morrissey diagrams or photos
would help me from reinventing the wheel (probably several times). He mentions
"a new low torque hinge flexure" and "a unique vertical mass centering
adjustment," both of which sound interesting.
After Sean's death the prototype level equipment was sent to the USGS
facility at Albuquerque, NM. I did contact Bob Hutt _bhutt@.........
(mailto:bhutt@......... about it, but he said that they had broken the suspension and that
it was no longer working. Ask him about it?
See also
_http://www.iris.washington.edu/stations/seisWorkshop04/abstracts/HuttAbstract.pdf_
(http://www.iris.washington.edu/stations/seisWorkshop04/abstracts/HuttAbstract.pdf) This seems to me to be a very high cost project
with limited prospects of success. The longest period was only about 10
seconds. An optimal design for a long period seismometer is likely to be different
to that of a tiltmeter.
You can get a fair indication of the main components from the page
headings. I do not know how he designed the suspension, or how he adjusted the C
of G. But I could make an educated guess of systems that you could try out. As
far as I am aware, there is no very long period high sensitivity tiltmeter
equipment available. One problem with measuring tilts is getting rid of near
surface environmental noise at a fixed point / location. Long period noise due
to the daily thermal cycle and from surface soil movement are also likely to
be observed / cause problems. It is fairly easy in principle to measure
tilts over say 1 km of open trough. There is a 43 m H2O tiltmeter in a salt mine
at Walferdange in Luxembourg. There is no substitute for a nice deep hole!
See
_http://www.geodesy.cwu.edu/index.html?page=http%3A//www.geodesy.cwu.edu/tilt/_
(http://www.geodesy.cwu.edu/index.html?page=http://www.geodesy.cwu.edu/tilt/) However, it may be possible to monitor the position sensor on some
long period seismometers.
Basically it was a high inertia horizontal beam with equal mass at both
ends. It was suspended at it's C of G. There were position sensors at both
ends and force feedback transducers. A very long integration period was used,
but no gravitational feedback. This could be an advantage, since it will not
be sensitive to very long period / permanent tilts, only to changes in tilt. I
presume that Sean used the same variable reluctance sensors that he used in
his seismometer. The measurement limit with an LVDT system is likely to be
over 0.1 nm, probably over 1 nm, due to Barkhausen magnetic domain 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 6.00.6000.16788" 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 25/12/2008, cjburch@........... 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>S-T M=
orrissey's=20
website has an abstract for the fall 2000 AGU meeting regarding a "Very=20
Broadband Beam-Balance Tiltmeter." It also has captions for a poster=
=20
presentation on the same topic at the 2001 spring SSA meeting. But n=
o=20
photos, drawings or diagrams seem to be available. </FONT></BLOCKQUO=
TE>
<DIV>Hi Chuck,</DIV>
<DIV> </DIV>
<DIV> Since the posters were displayed at the meeting=
s,=20
the preliminary information is in the public domain. Accessing it may be a=20
different matter. Sean was going to patent the device, but I am uncertain as=
to=20
what actually happened, particularly with the long delays in processing=
=20
American Patents. I did try to follow up the poster and eventually managed t=
o=20
get a reference SSA / AGU number. It is listed as C23 on <A=20
href=3D"http://www.seismosoc.org/meetings/ssa2001.html">http://www.seismosoc=
..org/meetings/ssa2001.html</A></DIV>
<DIV> </DIV>
<DIV> Sean presented a 30 page A4=20
poster with Brian J Mitchell of St Louis University. He is now an Emeri=
tus=20
Professor <A href=3D"mailto:mitchbj@...........">mitchbj@...........</A> in=20=
the=20
Department of Earth and Atmospheric Sciences. A 70 page final NSF report was=
=20
produced. I suggest that you ask him and the NSF? </DIV>
<DIV> </DIV>
<DIV> It was funded by the NSF in October 1999, so th=
ere=20
must be records of this and of the report. The work was completed in October=
=20
2000. The NSF grant reference is 9905328. The project funding was for=20
$120,000.</DIV>
<DIV>See <A=20
href=3D"http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=3D9905328">h=
ttp://www.nsf.gov/awardsearch/showAward.do?AwardNumber=3D9905328</A></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>Does=20=
anyone=20
know if the abstract and poster captions are all that is available? =20=
I'd=20
like to build such a device and any Morrissey diagrams or photos would hel=
p me=20
from reinventing the wheel (probably several times). He mentions "a=20=
new=20
low torque hinge flexure" and "a unique vertical mass centering adjustment=
,"=20
both of which sound interesting.<BR></FONT></BLOCKQUOTE>
<DIV></DIV>
<DIV> After Sean's death the prototype level equipmen=
t=20
was sent to the USGS facility at Albuquerque, NM. I did contact Bob Hutt <A=20
title=3Dmailto:bhutt@...........
href=3D"mailto:bhutt@........">bhutt@........</A> about it, but he said=
that=20
they had broken the suspension and that it was no longer working. Ask h=
im=20
about it?</DIV>
<DIV> See also <A=20
href=3D"http://www.iris.washington.edu/stations/seisWorkshop04/abstracts/Hut=
tAbstract.pdf">http://www.iris.washington.edu/stations/seisWorkshop04/abstra=
cts/HuttAbstract.pdf</A> =20
This seems to me to be a very high cost project with limited prospects of=20
success. The longest period was only about 10 seconds. An optimal design for=
a=20
long period seismometer is likely to be different to that of a tiltmeter. </=
DIV>
<DIV> </DIV>
<DIV> You can get a fair indication of the main=20
components from the page headings. I do not know how he designed the suspens=
ion,=20
or how he adjusted the C of G. But I could make an educated guess of systems=
=20
that you could try out. As far as I am aware, there is no very long period h=
igh=20
sensitivity tiltmeter equipment available. One problem with measuring tilts=20=
is=20
getting rid of near surface environmental noise at a fixed point /=20
location. Long period noise due to the daily thermal cycle and from surface=20=
soil=20
movement are also likely to be observed / cause problems. It is fairly=20
easy in principle to measure tilts over say 1 km of open trough. =20
There is a 43 m H2O tiltmeter in a salt mine at Walferdange in Luxembou=
rg.=20
There is no substitute for a nice deep hole! See <A=20
href=3D"http://www.geodesy.cwu.edu/index.html?page=3Dhttp%3A//www.geodesy.cw=
u.edu/tilt/">http://www.geodesy.cwu.edu/index.html?page=3Dhttp%3A//www.geode=
sy.cwu.edu/tilt/</A> =20
However, it may be possible to monitor the position sensor on some long peri=
od=20
seismometers.</DIV>
<DIV> </DIV>
<DIV> Basically it was a high inertia horizontal beam=
=20
with equal mass at both ends. It was suspended at it's C of G. There were=20
position sensors at both ends and force feedback transducers. A very long=20
integration period was used, but no gravitational feedback. This could be an=
=20
advantage, since it will not be sensitive to very long period / permane=
nt=20
tilts, only to changes in tilt. I presume that Sean used the same varia=
ble=20
reluctance sensors that he used in his seismometer. The measurement limit wi=
th=20
an LVDT system is likely to be over 0.1 nm, probably over 1 nm, due to=20
Barkhausen magnetic domain noise.</DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Earthquake trace of a fireball ?
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@.........
Date: Sun, 28 Dec 2008 05:04:52 +0000
Hi all.
Here is a news that is worth taking a notice in. Some of those located
in California might have recored this fireball on there seismometers
without noticeing.
CALIFORNIA FIREBALL: A remarkable fireball streaked over southern
Califonia on Dec. 27th around 1:50 am Pacific time. "It was as if
someone had set off a rescue flare that instantly bathed the countryside
in whitish blue-green light," reports Grant Bentley of Bishop, CA. "At
one point, the path of the meteor went behind a cirrus-stratus cloud
that it backlit in snowy green light. After a brilliant show of less
than three seconds, it was gone without a trace. This was easily the
most massive object I have ever seen burning up as it entered the
Earth's atmosphere." Readers, if you witnessed or photographed this
event, please submit a report.
http://www.spaceweather.com/
Regards.
--=20
J=F3n Fr=EDmann
__________________________________________________________
Public Seismic Network Mailing List (PSN-L)
Subject: Re: Earthquake trace of a fireball ?
From: Canie canie@...........
Date: Sat, 27 Dec 2008 22:26:20 -0800
That must have been the 4.5 reported, then=20
deleted in Utah this morning.. it's the right time:
>=3D=3D PRELIMINARY EARTHQUAKE REPORT =3D=3D
>
>
>
>Region: UTAH
>Geographic coordinates: 39.853N, 112.514W
>Magnitude: 4.5 Mcd
>Depth: 7 km
>Universal Time (UTC): 27 Dec 2008 09:18:25
>Time near the Epicenter: 27 Dec 2008 02:18:25
>Local standard time in your area: 27 Dec 2008 09:18:25
Canie
At 09:04 PM 12/27/2008, you wrote:
>Hi all.
>
>Here is a news that is worth taking a notice in. Some of those located
>in California might have recored this fireball on there seismometers
>without noticeing.
>
>CALIFORNIA FIREBALL: A remarkable fireball streaked over southern
>Califonia on Dec. 27th around 1:50 am Pacific time. "It was as if
>someone had set off a rescue flare that instantly bathed the countryside
>in whitish blue-green light," reports Grant Bentley of Bishop, CA. "At
>one point, the path of the meteor went behind a cirrus-stratus cloud
>that it backlit in snowy green light. After a brilliant show of less
>than three seconds, it was gone without a trace. This was easily the
>most massive object I have ever seen burning up as it entered the
>Earth's atmosphere." Readers, if you witnessed or photographed this
>event, please submit a report.
>
>http://www.spaceweather.com/
>
>Regards.
>--
>J=F3n Fr=EDmann
>
>__________________________________________________________
>
>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
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Subject: How much movement
From: Steinar Midtskogen steinar@.............
Date: Tue, 30 Dec 2008 21:34:41 +0100
I wonder, how big are the movements produced by distant quakes? Since
only the waves with very long periods are detectable, the shaking is
of course impossible to feel since even movements of several centimeters
would be difficult to feel if the period is around 20 seconds.
So, if my seismometer picks up a 6.0 quake 15.000 km away, what kind
of movement are we talking about?
--
Steinar Midtskogen
http://voksenlia.net/
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Subject: New fireball
From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@.........
Date: Tue, 30 Dec 2008 22:38:04 +0000
Hi all.
There was a new fireball, this time over New England. It did also
explode in the sky. Some of you close to this area might have recored
the fireball on the seismemtic sensors.
NEW ENGLAND FIREBALL: Last night, Dec. 29th at 9:30 p.m. EST, sky
watchers in Maine, New Hampshire, Massachusetts, New York and New Jersey
witnessed a magnitude -9 fireball that exploded colorfully in
mid-flight. No one knows if fragments of the meteoroid reached the
ground. Readers, if you saw or photographed this event, please submit a
report. Updated: Eye-witness accounts
http://www.spaceweather.com/
http://www.spaceweather.com/glossary/fireballreports_29dec08.htm?PHPSESSID=
=3D2vb1qaebkpbg5scj2s6tq23ra4
Regards.
--=20
J=F3n Fr=EDmann
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Subject: Re: How much movement
From: ChrisAtUpw@.......
Date: Tue, 30 Dec 2008 17:53:41 EST
In a message dated 30/12/2008 20:35:01 GMT Standard Time,
steinar@............. writes:
So, if my seismometer picks up a 6.0 quake 15.000 km away, what kind
of movement are we talking about?
Hi Steinar,
Check out the various pages and tables at
_http://jclahr.com/science/psn/magnitude.html_ (http://jclahr.com/science/psn/magnitude.html)
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 6.00.6000.16788" 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 30/12/2008 20:35:01 GMT Standard Time,=20
steinar@............. 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>So, if=20
my seismometer picks up a 6.0 quake 15.000 km away, what kind<BR>of moveme=
nt=20
are we talking about?<BR></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hi Steinar,</DIV>
<DIV> </DIV>
<DIV> Check out the various pages and tables at <A=20
href=3D"http://jclahr.com/science/psn/magnitude.html">http://jclahr.com/scie=
nce/psn/magnitude.html</A></DIV>
<DIV> </DIV>
<DIV> Regards,</DIV>
<DIV> </DIV>
<DIV> Chris Chapman</DIV></FONT></BODY></HTML>
Subject: Re: How much movement
From: Angel sismos@..............
Date: Tue, 30 Dec 2008 23:22:08 +0000
Hello Steinar,
Your question is central to seismometry and to be able to answer it you need to calibrate your seismometer. Once you do that you can convert volts or counts to real ground motion. The basic idea is simple, you move your sensor a known distance and see what you get in volts or counts at the end of your digitizer. If you do that at a bunch of frequencies you can then figure where you sensor is linear and where it is not. The you can derive the transfer function for your system and then you are set to answer your question.
Modern systems can resolve nano meters (billionth of a meter) the diameter of a molecule.
here are some values for ground motion in microns (millions of meter)
Dist(km) ML=0 ML=3 ML=6
100 0.000428 0.428486 428.4860279
200 0.000144 0.1441606 144.1606322
300 4.27E-05 0.0427143 42.71426138
400 1.8E-05 0.0180201 18.02007902
500 9.23E-06 0.0092263 9.226280458
600 5.34E-06 0.0053393 5.339282672
Happy New Year
Angel
Tuesday, December 30, 2008, 8:34:41 PM, you wrote:
> I wonder, how big are the movements produced by distant quakes? Since
> only the waves with very long periods are detectable, the shaking is
> of course impossible to feel since even movements of several centimeters
> would be difficult to feel if the period is around 20 seconds.
> So, if my seismometer picks up a 6.0 quake 15.000 km away, what kind
> of movement are we talking about?
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Subject: Re: How much movement
From: Bob Hancock carpediem1@.........
Date: Tue, 30 Dec 2008 23:12:41 -0700
Steiner -
One more comment on the subject of seismic wave amplitudes. The USGS
has a program that gives arrival times of both body and surface
waves. In the header is information on the expected 20 second period
surface wave amplitude, and expected 1 second period body wave
amplitude. The data is listed in both velocity and displacement
format. Here is the link to the program:
http://neic.usgs.gov/neis/travel_times/compute_tt.html
The same basic program is available for recent events within the past
14 days. Following is the link to that program:
http://neic.usgs.gov/neis/travel_times/artim.html
I hope this helps.
Bob Hancock
On Dec 30, 2008, at 1:34 PM, Steinar Midtskogen wrote:
> I wonder, how big are the movements produced by distant quakes? Since
> only the waves with very long periods are detectable, the shaking is
> of course impossible to feel since even movements of several
> centimeters
> would be difficult to feel if the period is around 20 seconds.
>
> So, if my seismometer picks up a 6.0 quake 15.000 km away, what kind
> of movement are we talking about?
>
>
> --
> Steinar Midtskogen
> http://voksenlia.net/
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-REQUEST@.............. with
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>
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Subject: Re: How much movement
From: Steinar Midtskogen steinar@.............
Date: Wed, 31 Dec 2008 14:15:45 +0100
[ChrisAtUpw@........
> Check out the various pages and tables at http://jclahr.com/science/psn/
> magnitude.html
Thanks for the link. It means that roughly 1 micron amplitude is
needed for my SEP seismometer to produce a clear signal. If I had a
better less noisy site for it, I guess I could make out movements of a
few 100 nanometers.
To detect a movement of 1 micron over 10 seconds sounds pretty
impressive. I'm a bit surprised that this is even possible in a noisy
city. In fact, the greatest noise problem is the ocean, which
sometimes masks out quakes expected to produce 10 micron movements
even if the storm is 500 km away.
--
Steinar Midtskogen
http://voksenlia.net/
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