Subject: Re: A little Friday coolness From: John Lahr johnjan@........ Date: Sat, 30 Jun 2007 12:02:23 -0700 Hi Paul, There was an instrument called a seismoscope that was an inverted pendulum that scratched a smoked glass plate to record the 2-dimensional motion of the pendulum. If swung in the absence of ground motion, a record like that of a Harmonograph would be generated. See: http://www.data.scec.org/Module/sec3pg07.html and There is a picture of the outside of a seismoscope posted here: http://www.geocities.com/meredithlamb/page022.html I can't find one right now that shows the inside. Does anyone have such a picture? With out any indication of time, these records were very hard to interpret. Cheers, John At 01:06 PM 6/29/2007, you wrote: >Folks, > >With all the talk about pendulums, it reminded me of a article I saw >in a magazine once. > >The article was about a Harmonograph. > >I won't even think about the math involved that would be Chris's department. > >It seems to me like a mechanical pendulum adding machine. >Where the length, decay, friction.. all play a roll in drawing not a >seismogram, but a ...? > >Early predecessor to the Spirograph toy?? Interesting, and not too >far off topic. > >PauLC >W1VLF > >http://physics.kenyon.edu/EarlyApparatus/Oscillations_and_Waves/Harmonographs/Harmonographs.html > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Seismic sensors From: ChrisAtUpw@....... Date: Sat, 30 Jun 2007 19:07:05 EDT In a message dated 2007/06/29, Tangazazen@....... writes: > Hi Chris, > Each of the photo detector quadrants generate about 0.7 microamp which > are fed into virtual earth charge sensitive amplifiers. > There are numerous noise sources but as you point out the shot noise > associated with the photo current is dominant. The quadrant detector is 8mm dia, in > fact a larger detector means a larger capacitance which in turn increases the > noise. Hi Martin, What sort of seismometer are you using this on? Is it in a feedback loop? 8 mm is rather small for use with a Lehman. These tend to have appreciable drifts, but +/-1/2" is usually adequate. You can get 10mm long Si photocells quite easily. You are driving the photo output into a zero impedance maintained at zero volts. What I don't follow is where any considerations of capacity arise? And why would increased capacity increase the noise? L and C components usually have no noise associated with them. However, this seems to be a very small photocurrent. What actually limits your resolution, if it isn't the shot noise of the photocurrent? It is the 'lock-in amplifier' approach that controls the noise level. For an integration > time of a few milliseconds the effective bandwidth at 10KHz is 100 - 200 or > so Hz. Lock-in systems can pull out a signal that is substantially less than > the noise level. Certainly lock-in amplifiers make you immune to 1/f noise and the output signal is integrated. I would hope for a bandwidth considerably less than 200 Hz. I appreciate that lock-in amplifiers can allow you to dig below ambient noise levels, but what does this do to the S/N ratio? What measured resolution are you getting? > The noise level of the LED has not been noticeable. The random conversion > to photons is offset by the use of a diffuse encapsulation, a bit like an > integrating sphere. The important requirement of the LED is uniformity of the > light spot and reasonable linearity when modulated. The feedback from the sum of > the quad elements is dynamic but there is a limit to how much the amplifier > loop can correct for nonlinearity. Which LED and photocell are you using? What is the optical setup? What sort of shutter are you using? Can you not use a LED with a flat window and a metal case - no integral lens? I would expect a diffuse response to give a reduced resolution? > LED temperature dependence under constant current conditions is non linear > but -0.7% over 20C to 80C is an approximate figure for a Gallium Arsenide > Phosphide at 670nm. The feedback loop as mentioned overcomes any temperature > dependence. Interestingly LED temperature coefficients seems to get smaller at > the shorter wavelength but the quantum yield of the LED and the response of > the Silicon diode decrease, it's a question of optimisation. This is still quite a serious temperature dependence. How are you driving the LED? Is it constant on current, variable time, or constant on time, variable current? Half sine, triangle or square wave? Maybe switch to GaAs photocells? > If I had to choose between full capacitive bridge and a quad photo > detector I would choose the latter, It's a much more elegant solution. Do you have a circuit diagram, please? Regards, Chris Chapman In a me= ssage dated 2007/06/29, Tangazazen@....... writes:

Hi Chris,
      Each of the photo detector quadrants generate= about 0.7 microamp which are fed into virtual earth charge sensitive amplif= iers.
There are numerous noise sources but as you point out the shot noise associa= ted with the photo current is dominant. The quadrant detector is 8mm dia, in= fact a larger detector means a larger capacitance which in turn increases t= he noise.


Hi Martin,

       What sort of seismometer are you using=20= this on? Is it in a feedback loop? 8 mm is rather small for use with a Lehma= n. These tend to have appreciable drifts, but +/-1/2" is usually adequate. Y= ou can get 10mm long Si photocells quite easily.

       You are driving the photo output into a= zero impedance maintained at zero volts. What I don't follow is where any c= onsiderations of capacity arise? And why would increased capacity increase t= he noise? L and C components usually have no noise associated with them.

       However, this seems to be a very small=20= photocurrent. What actually limits your resolution, if it isn't the shot noi= se of the photocurrent?

It is the 'lock-in amplifier' approach that controls the noise level. For an= integration
time of a few milliseconds the= effective bandwidth at 10KHz is 100 - 200 or so Hz. Lock-in systems can pul= l out a signal that is substantially less than the noise level.

       Certainly lock-in amplifiers make you=20= immune to 1/f noise and the output signal is integrated. I would hope for a=20= bandwidth considerably less than 200 Hz. I appreciate that lock-in amplifier= s can allow you to dig below ambient noise levels, but what does this do to=20= the S/N ratio?

       What measured resolution are you gettin= g?

The noise level of the LED has=20= not been noticeable. The random conversion to photons is offset by the use o= f a diffuse encapsulation, a bit like an integrating sphere. The important r= equirement of the LED is uniformity of the light spot and reasonable lineari= ty when modulated. The feedback from the sum of the quad elements is dynamic= but there is a limit to how much the amplifier loop can correct for nonline= arity.


       Which LED and photocell are you using?=
       What is the optical setup?
       What sort of shutter are you using?
       Can you not use a LED with a flat windo= w and a metal case - no integral lens?
       I would expect a diffuse response to gi= ve a reduced resolution?

LED temperature dependence und= er constant current conditions is non linear but -0.7% over 20C to 80C is an= approximate figure for a Gallium Arsenide Phosphide at 670nm. The feedback=20= loop as mentioned overcomes any temperature dependence. Interestingly LED te= mperature coefficients seems to get smaller at the shorter wavelength but th= e quantum yield of the LED and the response of the Silicon diode decrease, i= t's a question of optimisation. 

  
       This is still quite a serious temperatu= re dependence.
       How are you driving the LED? Is it cons= tant on current, variable time, or constant on time, variable current? Half=20= sine, triangle or square wave?
       Maybe switch to GaAs photocells?=

If I had to choose between ful= l capacitive bridge and a quad photo detector I would choose the latter, It'= s a much more elegant solution.


       Do you have a circuit diagram, please?<= BR>
       Regards,

       Chris Chapman Subject: Re: Seismic sensors From: Tangazazen@....... Date: Sun, 1 Jul 2007 06:19:04 EDT Hi Chris, The seismometer is not a Lehman but a single pendulum with a natural period of 1 second. It is supported by two pairs of leaf suspensions arranged in a gimble form and give the pendulum two degrees of freedom but no rotation about it's axis. The LED and projection optics are mounted on the lower end and projects a 4mm spot of light modulated at 10KHz onto the quadrant photo cell. The quadrant detector produces the X & Y components of motion which in turn, via phase-sensitive detectors and appropriate feedback to orthogonal force transducers, hold the pendulum in a fixed position. A two axis broadband in fact but with a period of 60 seconds. The two axis output signals are of course the restraining force in volts/meter/second. Unlike the vertical broadband, temperature correction is unnecessary and tilt errors are compensated by giving the integrator a large dynamic range. The capacitance does not directly generate noise but modifies the source impedance which in turn change the ratio of the noise voltage to noise current contributions to the total noise. The photo current of 0.7 micro amps is large compared with the FET gate leakage current and is the dominate noise source. Narrower bandwidths of lock-in systems will improve the S/N ratio but may compromise the transient response, it's a question of optimisation. The important characteristics of the LED are uniformity of the light spot and linearity. The LED control feedback is dynamic i.e. both amplitude and wave form are controlled, but there is a limit to how much the loop can correct non-linearity before the onset of instability. The theoretical analysis of Force Balance Feedback is covered in Thomas Forbriger and Erhard Wielandt papers, the former is in German but the more practical aspects are well documented by Sean-Thomas Morrissey and Allen Coleman. I should perhaps point out that large quadrant silicon photo detectors are a little expensive to say the least and I would not have use this approach if I had not been given a handful. Regards Martin
Hi Chris,
 
     The seismometer is not a Lehman but a single=20 pendulum with a natural period of 1 second. It is supported by two pairs of=20= leaf=20 suspensions arranged in a gimble form and give the pendulum two degrees of=20 freedom but no rotation about it's axis. The LED and projection optics=20= are=20 mounted on the lower end and projects a 4mm spot of light modulated at 10KHz= =20 onto the quadrant photo cell. The quadrant detector produces the X & Y=20 components of motion which in turn, via phase-sensitive detectors and=20 appropriate feedback to orthogonal force transducers, hold the pendulum in a= =20 fixed position. A two axis broadband in fact but with a period of 60=20 seconds. The two axis output signals are of course the restraining forc= e in=20 volts/meter/second. Unlike the vertical broadband, temperature correction is= =20 unnecessary and tilt errors are compensated by giving the integrator a large= =20 dynamic range. 
 
The capacitance does not directly generate noise but modifies the=20 source impedance which in turn change the ratio of the noise voltage to nois= e=20 current contributions to the total noise. The photo current of 0.7 micr= o=20 amps is large compared with the FET gate leakage current and is the dominate= =20 noise source.
 
Narrower bandwidths of lock-in systems will improve the S/N ratio but m= ay=20 compromise the transient response, it's a question of optimisation.
 
The important characteristics of the LED are uniformity of the light sp= ot=20 and linearity. The LED control feedback is dynamic i.e. both amplitude and w= ave=20 form are controlled, but there is a limit to how much the loop can=20 correct non-linearity before the onset of instability.
 
The theoretical analysis of Force Balance Feedback is covered in Thomas= =20 Forbriger and Erhard Wielandt papers, the former is in German but the more=20 practical aspects are well documented by Sean-Thomas Morrissey and Allen=20 Coleman.
 
 I should perhaps point out that large quadrant silicon photo=20 detectors are a little expensive to say the least and I would not have use t= his=20 approach if I had not been given a handful.
 
 
 
 Regards Martin
 Subject: Earthquake at 110km depth ?! From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 01 Jul 2007 13:06:57 +0000 Hi all The SIL network of the Icelandic met office has detected something intresting, the automatic system shows a earthquake at 110km depth, where the crust is only ~30 km thick. This might be a error, but my station shows a event at that same time. If this earthquake gets confirmed at depth of more then 30km there must be something intresting be under the crust in my area. I did check for gloabl earthquake and I didn't see any event big enugh to create a false local earthquake, but that requires a mag 8.0+ less then 7700 km away from Iceland to do that. Any suggestion on what this is are welcomed. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Earthquake at 110km depth ?! From: Mark Robinson mark.robinson@............... Date: Mon, 02 Jul 2007 02:09:21 +1200 Jón Frímann wrote: > Hi all > > The SIL network of the Icelandic met office has detected something > intresting, the automatic system shows a earthquake at 110km depth, > where the crust is only ~30 km thick. This might be a error, but my > station shows a event at that same time. If this earthquake gets > confirmed at depth of more then 30km there must be something intresting > be under the crust in my area. > > I did check for gloabl earthquake and I didn't see any event big enugh > to create a false local earthquake, but that requires a mag 8.0+ less > then 7700 km away from Iceland to do that. > > Any suggestion on what this is are welcomed. Hi Jón, You might be interested to look at this image: http://www.geonet.org.nz/images/earthquake/quakes/2757147gc.png It's a scattergram of earthquake locations mapped onto the earth's surface and a plot showing the depth of the quakes along a line perpendicular to the major fault. I'm sure you'll be able to find similar plots for Iceland. -- cheers Mark __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Earthquake at 110km depth ?! From: John Lahr johnjan@........ Date: Sun, 01 Jul 2007 08:04:25 -0700 J=F3n, You can explore in map view and cross section the=20 seismicity of any area with the free program=20 SeismicEruption. This is on Alan Jones' web site: http://www.geol.binghamton.edu/faculty/jones/ To visualize the paths of teleseismic arrivals, Alan's program SeismicWaves= is excellent (from the same site). Cheers, John At 07:09 AM 7/1/2007, you wrote: >J=F3n Fr=EDmann wrote: >>Hi all >> >>intresting, the automatic system shows a earthquake at 110km depth, > >Hi J=F3n, > >You might be interested to look at this image: > >I'm sure you'll be able to find similar plots for Iceland. >-- >cheers >Mark > >____________ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Earthquake at 110km depth ?! From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 01 Jul 2007 15:31:43 +0000 Hi all The only telesesmic earthquake that is close to this event is a mb5.5 earthquake in Japan at 04:12 UTC. http://www.emsc-csem.org/index.php?page=3Dcurrent&sub=3Ddetail&id=3D48436 But I do not think that this event is big enugh to create a viewable wave on the SIL network, but that is based on 1Hz stations and my 4.5Hz geophone, I have have had bigger events closer then this and not seen them. This is a mistery to me. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Earthquake at 110km depth ?! From: Tangazazen@....... Date: Sun, 1 Jul 2007 12:14:35 EDT Hi Jon, It might well be the M 5.5 earthquake from Japan at 04:12 UTC. While my recorder was not active the seismometer alarm did wake me unfortunately, just after that time. I have in the past picked up the M 5.4 from Luzon on 6-5-07 and a whole series from Ryukyo Islands on 20-4-07. The later consisted of 7 events ranging from 5.1 to 6.1 between 00:26:45 to 05:23:11 UTC. I wish some of these teleseismic events would occur during more civilised hours! Regards Martin
Hi Jon,
 
   It might well be the M 5.5 earthquake from Japan at 04:12=20= UTC.=20 While my recorder was not active the seismometer alarm did wake me= =20 unfortunately, just after that time. I have in the past picked up the&n= bsp;=20 M 5.4 from Luzon on 6-5-07 and a whole series from Ryukyo Islands on 20-4-07= ..=20 The later consisted of 7 events ranging from 5.1 to 6.1 between 00:26:45 to=20 05:23:11 UTC.  I wish some of these teleseismic events would occur= =20 during more civilised hours!
 
 
Regards Martin
 Subject: Re: Seismic sensors From: ChrisAtUpw@....... Date: Sun, 1 Jul 2007 13:47:39 EDT In a message dated 2007/07/01 11:19:30 GMT Daylight Time, Tangazazen@....... writes: > Subj:Re: Seismic sensors > Date:2007/07/01 11:19:30 GMT Daylight Time > From:Tangazazen@....... > Reply-to:psn-l@.............. > To:psn-l@.............. > Sent from the Internet > > > > Hi Chris, > > The seismometer is not a Lehman but a single pendulum with a natural > period of 1 second. It is supported by two pairs of leaf suspensions arranged > in a gimble form and give the pendulum two degrees of freedom but no rotation > about it's axis. The LED and projection optics are mounted on the lower end > and projects a 4mm spot of light modulated at 10KHz onto the quadrant photo > cell. The quadrant detector produces the X & Y components of motion which in > turn, via phase-sensitive detectors and appropriate feedback to orthogonal > force transducers, hold the pendulum in a fixed position. A two axis broadband in > fact but with a period of 60 seconds. The two axis output signals are of > course the restraining force in volts/meter/second. Unlike the vertical > broadband, temperature correction is unnecessary and tilt errors are compensated by > giving the integrator a large dynamic range. > > The capacitance does not directly generate noise but modifies the source > impedance which in turn change the ratio of the noise voltage to noise current > contributions to the total noise. The photo current of 0.7 micro amps is large > compared with the FET gate leakage current and is the dominate noise source. > > Narrower bandwidths of lock-in systems will improve the S/N ratio but may > compromise the transient response, it's a question of optimisation. > > The important characteristics of the LED are uniformity of the light spot > and linearity. The LED control feedback is dynamic i.e. both amplitude and wave > form are controlled, but there is a limit to how much the loop can correct > non-linearity before the onset of instability. > > The theoretical analysis of Force Balance Feedback is covered in Thomas > Forbriger and Erhard Wielandt papers, the former is in German but the more > practical aspects are well documented by Sean-Thomas Morrissey and Allen Coleman. > > I should perhaps point out that large quadrant silicon photo detectors are > a little expensive to say the least and I would not have use this approach if > I had not been given a handful. > > > > Regards Martin > In a me= ssage dated 2007/07/01 11:19:30 GMT Daylight Time, Tangazazen@....... writes= :


Subj:Re: Seismic sensors
Date:2007/07/01 11:19:30 GMT Daylight Time
From:Tangazazen@.......
Reply-to:psn-l@.............. To:psn-l@..............
Sent from the Internet



Hi Chris,

     The seismometer is not a Lehman but a single pendul= um with a natural period of 1 second. It is supported by two pairs of leaf s= uspensions arranged in a gimble form and give the pendulum two degrees of fr= eedom but no rotation about it's axis. The LED and projection optics are mou= nted on the lower end and projects a 4mm spot of light modulated at 10KHz on= to the quadrant photo cell. The quadrant detector produces the X & Y com= ponents of motion which in turn, via phase-sensitive detectors and appropria= te feedback to orthogonal force transducers, hold the pendulum in a fixed po= sition. A two axis broadband in fact but with a period of 60 seconds. The tw= o axis output signals are of course the restraining force in volts/meter/sec= ond. Unlike the vertical broadband, temperature correction is unnecessary an= d tilt errors are compensated by giving the integrator a large dynamic range= ..

The capacitance does not directly generate noise but modifies the source imp= edance which in turn change the ratio of the noise voltage to noise current=20= contributions to the total noise. The photo current of 0.7 micro amps is lar= ge compared with the FET gate leakage current and is the dominate noise sour= ce.

Narrower bandwidths of lock-in systems will improve the S/N ratio but may co= mpromise the transient response, it's a question of optimisation.

The important characteristics of the LED are uniformity of the light spot an= d linearity. The LED control feedback is dynamic i.e. both amplitude and wav= e form are controlled, but there is a limit to how much the loop can correct= non-linearity before the onset of instability.

The theoretical analysis of Force Balance Feedback is covered in Thomas Forb= riger and Erhard Wielandt papers, the former is in German but the more pract= ical aspects are well documented by Sean-Thomas Morrissey and Allen Coleman.=

I should perhaps point out that large quadrant silicon photo detectors are=20= a little expensive to say the least and I would not have use this approach i= f I had not been given a handful.



Regards Martin


 Subject: Re: Seismic sensors From: ChrisAtUpw@....... Date: Sun, 1 Jul 2007 13:53:19 EDT In a message dated 2007/07/01 11:19:30 GMT Daylight Time, Tangazazen@....... writes: > The important characteristics of the LED are uniformity of the light spot > and linearity. The LED control feedback is dynamic i.e. both amplitude and > wave form are controlled, but there is a limit to how much the loop can correct > non-linearity before the onset of instability. > > I should perhaps point out that large quadrant silicon photo detectors are > a little expensive to say the least. Hi Martin, Do you use a round or a square spot and do you use a mask to define it accurately? What are the type numbers of your driver LED and the photodetector, please? Regards, Chris Chapman In a me= ssage dated 2007/07/01 11:19:30 GMT Daylight Time, Tangazazen@....... writes= :


The important characteristics o= f the LED are uniformity of the light spot and linearity. The LED control fe= edback is dynamic i.e. both amplitude and wave form are controlled, but ther= e is a limit to how much the loop can correct non-linearity before the onset= of instability.

I should perhaps point out that large quadrant silicon photo detectors are=20= a little expensive to say the least.


Hi Martin,

       Do you use a round or a square spot and= do you use a mask to define it accurately?

       What are the type numbers of your drive= r LED and the photodetector, please?

       Regards,
      
       Chris Chapman Subject: 6 month to go From: tchannel1@............ Date: Mon, 2 Jul 2007 21:48:32 -0600 Hi All, Where are all the big ones? Or should I ask, Major ones? = Years 2000-2006 averaged 12, Earthquakes 7.0-7.9M, per year. With six months gone and six months to go, this site shows 2 thus far, = this year. At this rate we would only see two more, for a total of = four, vs. twelve. I would think, from this, we are either going to = have a very slow year for Major earthquakes, or its going to be busy the = next six month. We would need 1.666 Majors events each month, to the = end of the year just to maintain that six year average. (Was it )? John, please let us know it you unplug your machine again. Ted http://www.infoplease.com/ipa/A0197840.html
Hi All,  Where are all the big=20 ones?   Or should  I ask, Major ones?  Years = 2000-2006=20 averaged 12, Earthquakes  7.0-7.9M, per year.
With six months gone and six months to = go, this=20 site shows 2 thus far, this year.  At this rate we would only see = two more,=20 for a total of four, vs. twelve.     I would think, = from=20 this, we are either going to have a very slow year for Major = earthquakes, or its=20 going to be busy the next six month.  We would need 1.666 Majors = events=20 each month, to the end of the year just to maintain that six year=20 average.
 
(Was it )? John, please let us know it = you unplug=20 your machine again.
Ted
 
 
 
 
http://www.infopleas= e.com/ipa/A0197840.html
Subject: Re: Period From: "Geoffrey" gmvoeth@........... Date: Tue, 3 Jul 2007 02:17:31 -0700 Hello tchannel1, I think it might be interesting to sum all three axis possibly by some kind of vector math to obtain a single signal. I have never done this before but I know for a fact the main signal most probably is not in any of the three planes but some vector of all three together. Regards; geoff ----- Original Message ----- From: To: Sent: Saturday, June 30, 2007 06:07 Subject: Period Hi All, I just did a side by side comparison of an Earthquake recorded by a Vertical with a 2? second period and a Horz Pendulum with a 10? second period. The different on this 6.7M at 10000km was very pronounced, showing all the advantages of the Horz. However, using the Vertical, I record many more Earthquake, and smaller ones. If the event is large, both sensors are impressive (to me). In planning my next sensor, I need to pick a target period. I already see the advantage of each. What period might be the best target? Or is it just better to pick one end of the spectrum and not the center? Thanks, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Period From: "Geoffrey" gmvoeth@........... Date: Tue, 3 Jul 2007 03:44:57 -0700 Hello tchannel1; This is a response to your post and intended for everyone at PSN. A period range of 0.2 Hz to 2Hz is by far the best range for seeing P and S of most EQ signals If one lives in a noisy area with lots of vehicular traffic this is the best range to use. In this range you should be able to crank up the gain until you see both low and high frq noise about +/- two samples maybe four then you should be able to see a 4.0 regional quake at 6 degrees of distance as the guideline for a MDL (Minimum discernable level). The smaller the bandwidth the less the noise. If you are in a quiet area by all means open up the bandwidth to see the close quakes better. If you have like a 24 bit A/D converter you can make the gain adjustable simply be looking at 8 or 12 or 16 bits and scaling everything else then you can digitally set the gain from the keyboard. If you program a modulo recorder of 12 minutes or so there are almost no earthquakes of any size that you will miss with a computer oriented recorder and a seismic alarm that works something like a venus fly trap trigger hairs. Do you know if anyone has ever used a laser pointer in a seismic sensor ? Possibly using surfaced mirrors to provide mechanical amplification like a lever arm ? If you do not build your own electronics and program your own software then most probably forget these finer details. Like Always, I am no expert but i do have several broken years of practical experience. To me an Amateur can be a layman who simply watches the signals and cares nothing more about the science since an amateur receives No pay for his hobby. Laymen Professional Expert are different ideas. I think you can find all three in any amateur group. I am an Amateur layman with some formal technical education and experience but no degree\certificates that means anything. The range I tell you here is from personal experience over the past 13 years. I have found the 500LB geophone used all over the world by the USGS gives the best signal right down to 20 seconds even tho it is a 1sec free period device. It does not have the severe natural damping of the smaller geophones but does have a very powerful magnet. My thought is this; The sensor should be in a vacuum and have a very powerful magnet and in a faraday shield otherwise the sensor will typically be marginal at best. Everything needs to be shielded and bonded between the Computer including the sensor. AntiAlising filtration by whatever means prior to conversion/recording by the A/D converter. Do not use the sensor coil for damping because that reduces sensitivity but instead use a seperate magnet/Copper Plate arrangement. The preamplifier to be a differential type with both +/- of the opamp equalized for DC. Put as little load on the sensor as possible. It used to be easy to get copper in Arizona but not any more unless you pay lots of cash, copper has become outrageously expensive along with everything else. It seems to me they (My Country/USA) do not want people playing around with Science and Technology unless they are rich or Formally educated. I think they (My USA) are overly Religious and overly paranoid. The majority of people here are not well enough educated (including myself). It is humbling to note that after study of life that intelligence/education are not necessary for survival. Winquake is the best public seismic program I have seen for the layman. I will convert my data to text to use in winquake and find the data easier to analyze. But to be most precise and accurate I will read using my own program on a sample by sample bases. Winquake gives a sort of standard for PSN and lets people share their data. But I have found that if you are converting your own data into PSN form you must start the first sample relating to an exact start of minute or the times will not be right. In Winquake You must test your sample rate and make sure its right. Start all your data for winquake at HH:MM:00.0 the seconds always being zero for your very first sample. You need cal markes from WWV/CHU or something like that to see the top of second zero in each minute. Say Minute 59-60 second mark goes high at sample #1025 use sample #1024 as the very first sample and stop the samples at the N= The next cal mark high - one sample at the end. Winquake should agree that the times are all right so long as you got the sample rate right. Winquake does not give me good times if I do not follow this idea. I can not just start out in the middle of a minute and end just anywhere. Without Cal marks of some standard type the times for the layman are uncertain. Winquake needs a FFT waterfall display to see a movie like of shifting frequencies over time. Possibly in 1024 sample chunks advancing one sample for the next 1024. Nothing fancy, Black and white and shades of gray, totally suitable. Regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: 6 month to go From: "Michael Kimzey" mckimzey@........... Date: Tue, 03 Jul 2007 07:40:59 -0400 >With six months gone and six months to go, this site shows 2 thus far, this >year. At this rate we would only see two more, for a total of four, vs. >twelve. I would think, from this, we are either going to have a very >slow year for Major earthquakes, or its going to be busy the next six >month. We would need 1.666 Majors events each month, to the end of the >year just to maintain that six year average. > >(Was it )? John, please let us know it you unplug your machine again. >Ted > It was me...and all sensors are on-line again...and just to further confound everyone, I collecting parts for a copy of Sean's Vertical. When it's complete, I expect the cessation of all seismic activity across the world!! - Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Period From: ChrisAtUpw@....... Date: Tue, 3 Jul 2007 09:30:11 EDT In a message dated 2007/07/03, gmvoeth@........... writes: > Do you know if anyone has ever used a laser pointer > in a seismic sensor ? Possibly using surfaced mirrors > to provide mechanical amplification like a lever arm ? Hi Geoff, Laser pointers are very noisy and drift in intensity with temperature. You could maybe use a multiple reflection optical lever system with surface silvered mirrors, but getting satisfactory results may be difficult. The red light is too long a wavelength to use interference fringe counting at all easily. You have steps of ~300 nano metres between each fringe. Sensing to a fraction of a wavelength is possible using Moire fringes, but costly. Using large area differential Si or GaAs photocells and a stabilised voltage tungsten bulb work reasonably well. You can also use IR LEDs, but you need to stabilise the output - the photo output drifts quite strongly with temperature. IR and Superbright LEDs may be reasonably quiet, but ordinary LEDs can be quite noisy. The % noise decreases with increasing total photo current. The signal is proportional to the number of photons N in any sample, but the noise is proportional to Sqrt N. The size of the detector needs to be several thousand wavelengths minimum. You can also use IR LEDs in pulsed mode as the signal generator in a phase lock loop differential photo detector system, but the photo output needs to be stabilised. Photo detectors are well described at http://sales.hamamatsu.com/assets/applications/SSD/photodiode_technical_information.pdf Regards, Chris Chapman In a me= ssage dated 2007/07/03, gmvoeth@........... writes:

Do you know if anyone has ever=20= used a laser pointer
in a seismic sensor ? Possibly using surfaced mirrors
to provide mechanical amplification like a lever arm ?


Hi Geoff,

       Laser pointers are very noisy and drift= in intensity with temperature. You could maybe use a multiple reflection op= tical lever system with surface silvered mirrors, but getting satisfactory r= esults may be difficult.
       The red light is too long a wavelength=20= to use interference fringe counting at all easily. You have steps of ~300 na= no metres between each fringe. Sensing to a fraction of a wavelength is poss= ible using Moire fringes, but costly.

       Using large area differential Si or GaA= s photocells and a stabilised voltage tungsten bulb work reasonably well. Yo= u can also use IR LEDs, but you need to stabilise the output - the photo out= put drifts quite strongly with temperature. IR and Superbright LEDs may be r= easonably quiet, but ordinary LEDs can be quite noisy.
       The % noise decreases with increasing t= otal photo current. The signal is proportional to the number of photons N in= any sample, but the noise is proportional to Sqrt N. The size of the detect= or needs to be several thousand wavelengths minimum.

       You can also use IR LEDs in pulsed mode= as the signal generator in a phase lock loop differential photo detector sy= stem, but the photo output needs to be stabilised.

       Photo detectors are well described at h= ttp://sales.hamamatsu.com/assets/applications/SSD/photodiode_technical_infor= mation.pdf
      
       Regards,

       Chris Chapman

 Subject: Yes we felt it! 4.3M Central California From: tchannel1@............ Date: Tue, 3 Jul 2007 08:02:20 -0600 Hi All, Linda's Brother in Morgan Hill Ca. 16.5 miles North of the = 070702.195853.tcidzs.psn writes: =20 "Hi Linda and Ted, Yes, we did feel the earthquake at 12:58 this afternoon. I always look = at the clock when we have an earthquake so I knew your time was right = on. The dishes in my kitchen cupboards even rattled." We=20
Hi All,  Linda's Brother in Morgan = Hill=20 Ca.  16.5 miles North of the 070702.195853.tcidzs.psn writes:  =

"Hi Linda and = Ted,

Yes, we did = feel the=20 earthquake at 12:58 this afternoon. I always look at the clock when we = have an=20 earthquake so I knew your time was right on. The dishes in my kitchen = cupboards=20 even rattled."

We=20

Subject: RE: Period From: "Bob Hancock" carpediem1@......... Date: Tue, 3 Jul 2007 07:03:52 -0700 Hi Geoff - If you did sum all the channels, how would you compensate for the fact that the P & S body waves do not always have the same initial direction (compression or dilation,) of travel on all channels. In addition, how would you compensate for Love waves which only appear on the transverse channel, and Rayleigh wave only appears only on the vertical and radial channels? Finally, the fault dynamics (focal mechanism) adds it own twist to the amplitudes of waves and how visible they will be depending upon the event to station and station to event azimuths. It would take a very complex algorithm to accomplish this and while I am certain it could be done, I am not sure just what would be accomplished. Bob -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Geoffrey Sent: Tuesday, July 03, 2007 02:18 To: psn-l@.............. Subject: Re: Period Hello tchannel1, I think it might be interesting to sum all three axis possibly by some kind of vector math to obtain a single signal. I have never done this before but I know for a fact the main signal most probably is not in any of the three planes but some vector of all three together. Regards; geoff ----- Original Message ----- From: To: Sent: Saturday, June 30, 2007 06:07 Subject: Period Hi All, I just did a side by side comparison of an Earthquake recorded by a Vertical with a 2? second period and a Horz Pendulum with a 10? second period. The different on this 6.7M at 10000km was very pronounced, showing all the advantages of the Horz. However, using the Vertical, I record many more Earthquake, and smaller ones. If the event is large, both sensors are impressive (to me). In planning my next sensor, I need to pick a target period. I already see the advantage of each. What period might be the best target? Or is it just better to pick one end of the spectrum and not the center? Thanks, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: 6 month to go From: tchannel1@............ Date: Tue, 3 Jul 2007 08:11:48 -0600 Mike, Thanks, and we will be watching. Ted ----- Original Message ----- From: "Michael Kimzey" To: Sent: Tuesday, July 03, 2007 5:40 AM Subject: RE: 6 month to go > > >>With six months gone and six months to go, this site shows 2 thus far, >>this year. At this rate we would only see two more, for a total of four, >>vs. twelve. I would think, from this, we are either going to have a >>very slow year for Major earthquakes, or its going to be busy the next six >>month. We would need 1.666 Majors events each month, to the end of the >>year just to maintain that six year average. >> >>(Was it )? John, please let us know it you unplug your machine again. >>Ted >> > > It was me...and all sensors are on-line again...and just to further > confound everyone, I collecting parts for a copy of Sean's Vertical. When > it's complete, I expect the cessation of all seismic activity across the > world!! > > - Mike > > > __________________________________________________________ > > 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: Period From: tchannel1@............ Date: Tue, 3 Jul 2007 08:13:23 -0600 Hi Geoff, >Do you know if anyone has ever used a laser pointer in a seismic sensor ? Possibly using surfaced mirrors to provide mechanical amplification like a lever arm ? No I do not. Thanks for all this good information. Ted ----- Original Message ----- From: "Geoffrey" To: Sent: Tuesday, July 03, 2007 4:44 AM Subject: Re: Period > Hello tchannel1; > > This is a response to your post and intended > for everyone at PSN. > > A period range of 0.2 Hz to 2Hz is by far the best > range for seeing P and S of most EQ signals > If one lives in a noisy area with lots of vehicular > traffic this is the best range to use. In this range you > should be able to crank up the gain until you see > both low and high frq noise about +/- two samples > maybe four then you should be able to see a 4.0 > regional quake at 6 degrees of distance as the > guideline for a MDL (Minimum discernable level). > The smaller the bandwidth the less the noise. > If you are in a quiet area by all means open up the bandwidth > to see the close quakes better. > If you have like a 24 bit A/D converter you can make the gain > adjustable simply be looking at 8 or 12 or 16 bits and scaling > everything else then you can digitally set the gain from > the keyboard. > > If you program a modulo recorder of 12 minutes or so > there are almost no earthquakes of any size > that you will miss with a computer oriented recorder > and a seismic alarm that works something like a venus fly trap > trigger hairs. > > Do you know if anyone has ever used a laser pointer > in a seismic sensor ? Possibly using surfaced mirrors > to provide mechanical amplification like a lever arm ? > > If you do not build your own electronics and program your own > software then most probably forget these finer details. > Like Always, I am no expert but i do have several broken > years of practical experience. > > To me an Amateur can be a layman who simply watches the signals > and cares nothing more about the science since an amateur receives > No pay for his hobby. Laymen Professional Expert are different ideas. > I think you can find all three in any amateur group. I am an Amateur > layman > with some formal technical education and experience but no > degree\certificates > that means anything. > The range I tell you here is from personal experience over the past 13 > years. > I have found the 500LB geophone used all over the world by the USGS gives > the > best signal right down to 20 seconds even tho it is a 1sec free period > device. > It does not have the severe natural damping of the smaller geophones > but does have a very powerful magnet. > > My thought is this; > The sensor should be in a vacuum and have a very powerful magnet > and in a faraday shield otherwise the sensor will typically be marginal at > best. > Everything needs to be shielded and bonded between the Computer including > the sensor. > AntiAlising filtration by whatever means prior to conversion/recording by > the A/D converter. > Do not use the sensor coil for damping because that reduces sensitivity > but instead > use a seperate magnet/Copper Plate arrangement. The preamplifier to be a > differential type with both +/- of the opamp equalized for DC. > Put as little load on the sensor as possible. > It used to be easy to get copper in Arizona but not any more > unless you pay lots of cash, copper has become outrageously expensive > along with everything else. > It seems to me they (My Country/USA) do not want people playing > around with Science and Technology unless they are rich or > Formally educated. I think they (My USA) are overly Religious and overly > paranoid. > The majority of people here are not well enough educated (including > myself). > It is humbling to note that after study of life that > intelligence/education are not necessary for survival. > > Winquake is the best public seismic program I have seen for the layman. > I will convert my data to text to use in winquake and find the data > easier to analyze. But to be most precise and accurate I will read > using my own program on a sample by sample bases. > Winquake gives a sort of standard for PSN and lets people > share their data. But I have found that if you are converting > your own data into PSN form you must start the first sample > relating to an exact start of minute or the times will not be right. > In Winquake You must test your sample rate and make sure its right. > Start all your data for winquake at HH:MM:00.0 the seconds always > being zero for your very first sample. You need cal markes from > WWV/CHU or something like that to see the top of second zero > in each minute. > Say Minute 59-60 second mark goes high at sample #1025 > use sample #1024 as the very first sample and stop the samples > at the N= The next cal mark high - one sample at the end. Winquake > should agree that the times are all right so long as you got the > sample rate right. > Winquake does not give me good times if I do not follow this idea. > I can not just start out in the middle of a minute and end just anywhere. > Without Cal marks of some standard type the times for the layman are > uncertain. > > Winquake needs a FFT waterfall display to see a movie like of > shifting frequencies over time. > Possibly in 1024 sample chunks advancing one sample for the next 1024. > Nothing fancy, Black and white and shades of gray, totally suitable. > > 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: 6 month to go From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Tue, 03 Jul 2007 17:11:26 +0000 Hi all I have to repair my computer tomorrow. I am expecting stuff to happen. :-/ I have to replace the video card in my computer, the one I currently have is dieing and giving bad colors and dark screen. That is also the reason why I haven't send in new earthquakes for the past days. Besides that I have been away for two weeks now in vacation. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Period From: Bobhelenmcclure@....... Date: Tue, 3 Jul 2007 21:40:38 EDT On 3 Jul 2007 03:44:57 gmvoeth@....... wrote: Winquake needs a FFT waterfall display to see a movie like of shifting frequencies over time. Possibly in 1024 sample chunks advancing one sample for the next 1024. Nothing fancy, Black and white and shades of gray, totally suitable. Hi Geoff, WinQuake does not have a waterfall display, but it does have a useful procedure for viewing a scanning spectrogram. Here is how: (1) Set "X Scale" to the time interval window you want to use for an FFT. You will get a slider button on the bottom of the screen which will allow you to view any portion of the event record. (2) From the menu bar, select "Calculate", "FFT...", "View Only". An FFT plot will appear. (3) From the menu bar, select "Window", "Arrange". You can then simultaneously view the windowed event data and the FFT for the window. (4) Use the slider button to scan through the file. As the event data slides through the window, the FFT display will update almost continuously to display the spectrum for the data displayed in the window. (Unfortunately, the scale for the FFT may change as well.) Bob PSN Station REM Locust Valley, NY ************************************** See what's free at http://www.aol.com.
On 3 Jul 2007 03:44:57 gmvoeth@....... wrote:
Winquake needs a FFT=20 waterfall display to see a movie like of shifting frequencies over=20 time.
Possibly in 1024 sample chunks advancing one sample for the next=20 1024.
Nothing fancy, Black and white and shades of gray,  totally=20 suitable.
 
Hi Geoff,
 
  WinQuake does not have a waterfall display, but it does have a=20 useful procedure for viewing a scanning spectrogram. Here is how:
 
(1) Set "X Scale" to the time interval window you want to use for an FF= T.=20 You will get a slider button on the bottom of the screen which will allow yo= u to=20 view any portion of the event record.
 
(2) From the menu bar, select "Calculate", "FFT...", "View Only". An FF= T=20 plot will appear.
 
(3) From the menu bar, select "Window", "Arrange". You can then=20 simultaneously view the windowed event data and the FFT for the window.
 
(4) Use the slider button to scan through the file. As the event data=20 slides through the window, the FFT display will update almost continuously t= o=20 display the spectrum for the data displayed in the window. (Unfortunately, t= he=20 scale for the FFT may change as well.)
 
Bob
PSN Station REM
Locust Valley, NY



See what's free at AOL.com.
Subject: RE: Period From: "Paul Cianciolo" Paulc@........ Date: Thu, 5 Jul 2007 09:50:01 -0400 Bob, Geoff This was quite helpful as it was a question I had been wondering about as well. PauLC W1VLF -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of Bobhelenmcclure@....... Sent: Tuesday, July 03, 2007 9:41 PM To: psn-l@.............. Cc: gmvoeth@........... Subject: Re: Period On 3 Jul 2007 03:44:57 gmvoeth@....... wrote: Winquake needs a FFT waterfall display to see a movie like of shifting frequencies over time. Possibly in 1024 sample chunks advancing one sample for the next 1024. Nothing fancy, Black and white and shades of gray, totally suitable. Hi Geoff, WinQuake does not have a waterfall display, but it does have a useful procedure for viewing a scanning spectrogram. Here is how: (1) Set "X Scale" to the time interval window you want to use for an FFT. You will get a slider button on the bottom of the screen which will allow you to view any portion of the event record. (2) From the menu bar, select "Calculate", "FFT...", "View Only". An FFT plot will appear. (3) From the menu bar, select "Window", "Arrange". You can then simultaneously view the windowed event data and the FFT for the window. (4) Use the slider button to scan through the file. As the event data slides through the window, the FFT display will update almost continuously to display the spectrum for the data displayed in the window. (Unfortunately, the scale for the FFT may change as well.) Bob PSN Station REM Locust Valley, NY ---------------------------------------------------------------------------- -- See what's free at AOL.com.
Bob, Geoff
 
This was quite helpful as it was a = question=20 I had been wondering about as well.
 
 
 
PauLC
W1VLF
 
 
 
 -----Original=20 Message-----
From: psn-l-request@................. [mailto:psn-l-request@...............On Behalf Of=20 Bobhelenmcclure@.......
Sent: Tuesday, July 03, 2007 9:41=20 PM
To: psn-l@..............
Cc:=20 gmvoeth@...........
Subject: Re: Period

On 3 Jul 2007 03:44:57 gmvoeth@....... wrote:
Winquake needs a = FFT=20 waterfall display to see a movie like of shifting frequencies over=20 time.
Possibly in 1024 sample chunks advancing one sample for the = next=20 1024.
Nothing fancy, Black and white and shades of gray,  = totally=20 suitable.
 
Hi Geoff,
 
  WinQuake does not have a waterfall display, but it does = have a=20 useful procedure for viewing a scanning spectrogram. Here is = how:
 
(1) Set "X Scale" to the time interval window you want to use for = an FFT.=20 You will get a slider button on the bottom of the screen which will = allow you=20 to view any portion of the event record.
 
(2) From the menu bar, select "Calculate", "FFT...", "View Only". = An FFT=20 plot will appear.
 
(3) From the menu bar, select "Window", "Arrange". You can then=20 simultaneously view the windowed event data and the FFT for the = window.
 
(4) Use the slider button to scan through the file. As the event = data=20 slides through the window, the FFT display will update almost = continuously to=20 display the spectrum for the data displayed in the window. = (Unfortunately, the=20 scale for the FFT may change as well.)
 
Bob
PSN Station REM
Locust Valley, NY



See what's free at AOL.com.=20
Subject: Earthquake in Canada! From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 06 Jul 2007 02:07:26 +0000 Hi all A rare event just happend, a earthquake in Canada, http://www.emsc-csem.org/index.php?page=3Dcurrent&sub=3Ddetail&id=3D48916 Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Earthquake in Canada! From: "Michael Kimzey" mckimzey@........... Date: Thu, 05 Jul 2007 22:17:10 -0400 There was just one in Mexico, also. The one in Canada may also be in the signal I recorded. This will be a first for me, but I will get to work with 2 P and S' on the same signal. Nice. - Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Earthquake in Canada! From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Fri, 06 Jul 2007 04:04:49 +0000 Hi all I am looking at the raw date from emsc, is it possible that the earthquake in Canada is actually a false one ? USGS does not list it as current, the raw data from emsc can be seen here, http://www.emsc-csem.org/index.php?page=3Dcurrent&sub=3Dmsg Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Earthquake in Canada! From: "Michael Kimzey" mckimzey@........... Date: Fri, 06 Jul 2007 06:42:55 -0400 >I am looking at the raw date from emsc, is it possible that the >earthquake in Canada is actually a false one ? USGS does not list it as >current, the raw data from emsc can be seen here, >http://www.emsc-csem.org/index.php?page=current&sub=msg I suspect that it might be a false alarm. The main screen doesn't even list it. The linked page does have that disclaimer that it's raw data only... - Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Did I feel it??? From: tchannel1@............ Date: Fri, 6 Jul 2007 10:51:57 -0600 This is a new story: My wife Linda (IMMG Museum) came upstairs from = our basement last night and said she was sure she felt the earth move! = I was standing in front of the fridge, looking at the last two cupcakes, = "Should I eat the two cupcakes, or have some nice carrots? Let's see, = if I choose the cupcakes, I could eat just one, at 250 calories=3D30 = mins on the treadmill, or I could eat 20 carrots, and save that 30 = mins?" Just as I was pouring a glass of milk to go with the two = cupcakes, she grabbed my arm, nearly spilling my milk, and proclaimed, = "I just felt what I thought was an earthquake!" Here it is in her own words: But first, the timeline, and these are fairly accurate and true: 01:12:00 Linda felt the earth move. 01:12:15 Linda got up and walked up to the helicorder and noted the = time, but saw no earthquake signal. 01:14:00 Linda walked upstairs to tell me. 01:16:12 I put down my cupcakes and walked downstairs and saw the = earthquake begin; about 12 seconds of the signal were already traced on = the screen. 01:16:01 The P wave arrived in Boise Idaho. Linda writing: "I was sitting on the couch in the basement when I felt = ever so slightly lightheaded and the couch felt as if the ground swelled = a tiny bit underneath it about 5 or 6 times. The movement was nearly = undetectable (I'm sure if I had been standing or moving around, I would = not have felt it), and the ground swells passed at about the same rate = as a heartbeat. I am confident I really felt something because I = thought to myself, "Huh, how strange this sensation is . . . I wonder = whether that was an earthquake . . . weird, I thought there would be = more distance between waves . . . they are actually pretty close = together, exactly like ripples spreading out in a pond when a stone is = thrown in; it kind of feels like when we used to sit in our sailboat = when the wind was quiet and feel the water gently rock the boat."=20 Is there any kind of wave I would have felt before the P wave actually = arrived? Yes, I was awake, not dreaming! Linda and Ted
This is a new story:   My = wife Linda=20 (IMMG Museum) came upstairs from our basement last night and said she = was sure=20 she felt the earth move!  I was standing in front of the fridge, = looking at=20 the last two cupcakes,  "Should I eat the two cupcakes, or have = some nice=20 carrots?  Let's see, if I choose the cupcakes, I could eat just = one, at 250=20 calories=3D30 mins on the treadmill, or I could eat 20 carrots, and save = that 30=20 mins?"  Just as I was pouring a glass of milk to go with the = two=20 cupcakes, she grabbed my arm, nearly spilling my milk, and = proclaimed, "I=20 just felt what I thought was an earthquake!"
 
Here it is in her own = words:
 
But first, the timeline, and these are = fairly=20 accurate and true:
01:12:00 Linda felt the earth = move.
01:12:15 Linda got up and = walked up to the=20 helicorder and noted the time, but saw no earthquake = signal.
01:14:00 Linda walked upstairs to tell=20 me.
01:16:12 I put down my cupcakes and = walked=20 downstairs and saw the earthquake begin; about 12 seconds of the signal = were=20 already traced on the screen.
01:16:01 The P wave arrived = in Boise=20 Idaho.
 
Linda writing:  "I was sitting on = the couch in=20 the basement when I felt ever so slightly lightheaded and the = couch felt as=20 if the ground swelled a tiny bit underneath it about 5 or 6 = times. =20 The movement was nearly undetectable (I'm sure if I had been standing or = moving=20 around, I would not have felt it), and the ground swells passed at about = the=20 same rate as a heartbeat.  I am confident I really felt something = because I=20 thought to myself, "Huh, how strange this sensation is . . . I wonder = whether=20 that was an earthquake . . . weird, I thought there would be more = distance=20 between waves . . . they are actually pretty close together, = exactly like=20 ripples spreading out in a pond when a stone is thrown in; it kind of = feels like=20 when we used to sit in our sailboat when the wind was quiet and = feel the=20 water gently rock the boat." 
 
Is there any kind of wave I would have = felt before=20 the P wave actually arrived?  Yes, I was awake, not = dreaming!
 
Linda and = Ted
Subject: Re: Did I feel it??? From: Pete Rowe ptrowe@......... Date: Fri, 6 Jul 2007 11:23:19 -0700 (PDT) Ted Before we discuss this further we need the following information: Just how many cupcakes had Linda had? What was in the cupcakes? Perhaps the USGS could buy this recipe from her and finally predict earthquakes??? Enjoy life!!! Pete --- tchannel1@............ wrote: > This is a new story: My wife Linda (IMMG Museum) > came upstairs from our basement last night and said > she was sure she felt the earth move! I was > standing in front of the fridge, looking at the last > two cupcakes, "Should I eat the two cupcakes, or > have some nice carrots? Let's see, if I choose the > cupcakes, I could eat just one, at 250 calories=30 > mins on the treadmill, or I could eat 20 carrots, > and save that 30 mins?" Just as I was pouring a > glass of milk to go with the two cupcakes, she > grabbed my arm, nearly spilling my milk, and > proclaimed, "I just felt what I thought was an > earthquake!" > > Here it is in her own words: > > But first, the timeline, and these are fairly > accurate and true: > 01:12:00 Linda felt the earth move. > 01:12:15 Linda got up and walked up to the > helicorder and noted the time, but saw no earthquake > signal. > 01:14:00 Linda walked upstairs to tell me. > 01:16:12 I put down my cupcakes and walked > downstairs and saw the earthquake begin; about 12 > seconds of the signal were already traced on the > screen. > 01:16:01 The P wave arrived in Boise Idaho. > > Linda writing: "I was sitting on the couch in the > basement when I felt ever so slightly lightheaded > and the couch felt as if the ground swelled a tiny > bit underneath it about 5 or 6 times. The movement > was nearly undetectable (I'm sure if I had been > standing or moving around, I would not have felt > it), and the ground swells passed at about the same > rate as a heartbeat. I am confident I really felt > something because I thought to myself, "Huh, how > strange this sensation is . . . I wonder whether > that was an earthquake . . . weird, I thought there > would be more distance between waves . . . they are > actually pretty close together, exactly like ripples > spreading out in a pond when a stone is thrown in; > it kind of feels like when we used to sit in our > sailboat when the wind was quiet and feel the water > gently rock the boat." > > Is there any kind of wave I would have felt before > the P wave actually arrived? Yes, I was awake, not > dreaming! > > Linda and Ted ____________________________________________________________________________________ Looking for a deal? Find great prices on flights and hotels with Yahoo! FareChase. http://farechase.yahoo.com/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Did I feel it??? From: ChrisAtUpw@....... Date: Fri, 6 Jul 2007 14:44:20 EDT In a message dated 2007/07/06, tchannel1@............ writes: > Is there any kind of wave I would have felt before the P wave actually > arrived? Hi Ted, No, but she may well have experienced a local quake. What was recorded on the seismometer? Remember that you may also feel the effects of wind. Regards, Chris Chapman In a me= ssage dated 2007/07/06, tchannel1@............ writes:

Is there any kind of wave I wou= ld have felt before the P wave actually arrived? 


Hi Ted,

       No, but she may well have experienced a= local quake. What was recorded on the seismometer? Remember that you may al= so feel the effects of wind.

       Regards,

       Chris Chapman Subject: Re: Did I feel it??? From: Mark Robinson mark.robinson@............... Date: Sat, 07 Jul 2007 07:05:15 +1200 tchannel1@............ wrote: > > This is a new story: My wife Linda (IMMG Museum) came upstairs from > our basement last night and said she was sure she felt the earth move! > I was standing in front of the fridge, looking at the last two > cupcakes, "Should I eat the two cupcakes, or have some nice carrots? > Let's see, if I choose the cupcakes, I could eat just one, at 250 > calories=30 mins on the treadmill, or I could eat 20 carrots, and save > that 30 mins?" Just as I was pouring a glass of milk to go with the two > cupcakes, she grabbed my arm, nearly spilling my milk, and > proclaimed, "I just felt what I thought was an earthquake!" > > Here it is in her own words: > > But first, the timeline, and these are fairly accurate and true: > 01:12:00 Linda felt the earth move. > 01:12:15 Linda got up and walked up to the helicorder and noted the > time, but saw no earthquake signal. > 01:14:00 Linda walked upstairs to tell me. > 01:16:12 I put down my cupcakes and walked downstairs and saw the > earthquake begin; about 12 seconds of the signal were already traced on > the screen. > 01:16:01 The P wave arrived in Boise Idaho. > > Linda writing: "I was sitting on the couch in the basement when I felt > ever so slightly lightheaded and the couch felt as if the ground swelled > a tiny bit underneath it about 5 or 6 times. The movement was nearly > undetectable (I'm sure if I had been standing or moving around, I would > not have felt it), and the ground swells passed at about the same rate > as a heartbeat. I am confident I really felt something because I > thought to myself, "Huh, how strange this sensation is . . . I wonder > whether that was an earthquake . . . weird, I thought there would be > more distance between waves . . . they are actually pretty close > together, exactly like ripples spreading out in a pond when a stone is > thrown in; it kind of feels like when we used to sit in our sailboat > when the wind was quiet and feel the water gently rock the boat." > > Is there any kind of wave I would have felt before the P wave actually > arrived? Yes, I was awake, not dreaming! > > Linda and Ted This from the USGS: DELETED: Event UU 07040118 == EVENT DELETED NOTIFICATION == ***This event has been deleted after review by a seismologist.*** Geographic coordinates: 37.539N, 112.508W Magnitude: 1.7 Universal Time (UTC): 4 Jul 2007 01:17:19 Time near the Epicenter: 3 Jul 2007 19:17:19 Location with respect to nearby cities: 11 km (7 miles) NNW (348 degrees) of Alton, UT 14 km (9 miles) SSW (207 degrees) of Hatch, UT 24 km (15 miles) NNE (20 degrees) of Glendale, UT 162 km (100 miles) ENE (59 degrees) of Mesquite, NV 284 km (176 miles) ENE (57 degrees) of Las Vegas, NV Curiouser and curiouser. I've never felt even the smallest quake which didn't show up on the instrumentation and I wouldn't expect to feel a 1.7 unless it was very shallow and right here. -- regards Mark Robinson ------------- 06 Jul 1932 Kenneth Grahame, author of "The Wind in the Willows", died. 06 Jul 1936 Dave Allen born. 06 Jul 1946 Sylvester Stallone born. 06 Jul 1954 Elvis Presley recorded his first single, "That's all right mama" backed with "Blue Moon of Kentucky". It did not chart. 06 Jul 1957 Althea Gibson wins women's title at Wimbledon. 06 Jul 1973 Queen released their first sinlge "Keep yourself alive". 06 Jul 1987 Crowded House meet with Prime Minister David Lange for a chat about about the New Zealand recording industry. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Did I feel it??? From: "Geoffrey" gmvoeth@........... Date: Sat, 7 Jul 2007 04:05:09 -0700 I got news for you. The ladies have great imaginations and I have repeatedly been told that the two remaining females in my family (we are getting old) that they feel earthquakes when I record absolutely nothing. I have noticed in the past that boom like sounds will rattle windows and such and never record as any kind of EQ. I have a suspicion that females are more sensitive than males to vibrations and such and if they have no seismology training want to call just about anything that shake rattles or rolls an Earthquake. It is best to keep your hobby stuff within the realm of those interested in the science or you will be pestered by false alerts...especially when dealing with females. This is just as it seems to me and might not be a reality since it would take a research in Forensic Social-Psychology on this subject of false perceptions to be sure. Regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: The Magic From: tchannel1@............ Date: Sat, 7 Jul 2007 10:43:29 -0600 Hi All, Linda, would not tell me how many cupcakes she ate, and as you = might have guessed they are all gone now. She nor I, have felt anything = that could be considered an earthquake in the last few days. She is often at the computer, by the Sensor, when people visit the = museum. One question she gets, is "How does it work" She understands = how it is built and all the parts, but when the questions focuses on the = magnetic field and the coil, she can only discuss their interaction, = creates a current, like "Magic" I have seen a formula explaining the three factors, The Field, The Coil, = and The Velocity.......... Could someone tell me or direct me to an explanation of "The Magic" = which is really the basic for this type of sensor. Thanks, Ted
Hi All,  Linda, would not tell me = how many=20 cupcakes she ate, and as you might have guessed they are all gone=20 now.  She nor I, have felt anything that could be considered = an=20 earthquake in the last few days.
 
She is often at the computer, by the = Sensor, when=20 people visit the museum.  One question she gets, is "How does it=20 work"  She understands how it is built and all the parts, but when = the=20 questions focuses on the magnetic field and the coil, she can only = discuss their=20 interaction, creates a current, like "Magic"
 
I have seen a formula explaining the = three factors,=20 The Field, The Coil, and The Velocity..........
Could someone tell me or direct me to = an=20 explanation of "The Magic"  which is really the basic for this type = of=20 sensor.
 
Thanks, Ted
Subject: Re: The Magic From: ChrisAtUpw@....... Date: Sat, 7 Jul 2007 18:53:23 EDT In a message dated 2007/07/07, tchannel1@............ writes: > She is often at the computer, by the Sensor, when people visit the museum. > One question she gets, is "How does it work" She understands how it is > built and all the parts, but when the questions focuses on the magnetic field and > the coil, she can only discuss their interaction, creates a current, like > "Magic" Hi Ted, Movement of a coil in a magnetic changing field does not produce a current, but a voltage across the ends of the coil. This voltage is proportional to the number of turns, to the area of the coil and to the rate of change of the field. A current flowing in a conductor has a ring magnetic field assocciated with it. If you use a circular solenoid, the turns add up to give an axial agnetic field. I use a school demo system having quad NdFeB magnets on two parallel mild steel backplates. I use a relay coil on a handle connected to back to back red and green LEDs. You move the coil one way and the red LED lights, the other way and the green LED lights. If you move the coil more rapidly, the LEDs glow a lot brighter. Why not make up a similar model for the museum? > I have seen a formula explaining the three factors, The Field, The Coil, > and The Velocity.......... > Could someone tell me or direct me to an explanation of "The Magic" which > is really the basic for this type of sensor. Regards, Chris Chapman In a me= ssage dated 2007/07/07, tchannel1@............ writes:

She is often at the computer, b= y the Sensor, when people visit the museum.  One question she gets, is=20= "How does it work"  She understands how it is built and all the parts,=20= but when the questions focuses on the magnetic field and the coil, she can o= nly discuss their interaction, creates a current, like "Magic"

Hi Ted,
      
       Movement of a coil in a magnetic changi= ng field does not produce a current, but a voltage across the ends of the co= il. This voltage is proportional to the number of turns, to the area of the=20= coil and to the rate of change of the field.
       A current flowing in a conductor has a=20= ring magnetic field assocciated with it. If you use a circular solenoid, the= turns add up to give an axial agnetic field.

    I use a school demo system having quad NdFeB magnets=20= on two parallel mild steel backplates. I use a relay coil on a handle connec= ted to back to back red and green LEDs. You move the coil one way and the re= d LED lights, the other way and the green LED lights. If you move the coil m= ore rapidly, the LEDs glow a lot brighter. Why not make up a similar model f= or the museum?

I have seen a formula explain= ing the three factors, The Field, The Coil, and The Velocity..........
Could someone tell me or direct me to an explanation of "The Magic"  w= hich is really the basic for this type of sensor.


       Regards,

       Chris Chapman Subject: Re: The Magic From: tchannel1@............ Date: Sat, 7 Jul 2007 17:52:53 -0600 Hi Chris, That is a good idea..........The visitors to the Museum are = mostly tour groups of kids...They love to touch things, and maybe I = could work something like this up. I think that would explain the = Magic very well. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Saturday, July 07, 2007 4:53 PM Subject: Re: The Magic In a message dated 2007/07/07, tchannel1@............ writes: She is often at the computer, by the Sensor, when people visit the = museum. One question she gets, is "How does it work" She understands = how it is built and all the parts, but when the questions focuses on the = magnetic field and the coil, she can only discuss their interaction, = creates a current, like "Magic" Hi Ted,=20 =20 Movement of a coil in a magnetic changing field does not = produce a current, but a voltage across the ends of the coil. This = voltage is proportional to the number of turns, to the area of the coil = and to the rate of change of the field.=20 A current flowing in a conductor has a ring magnetic field = assocciated with it. If you use a circular solenoid, the turns add up to = give an axial agnetic field. I use a school demo system having quad NdFeB magnets on two = parallel mild steel backplates. I use a relay coil on a handle connected = to back to back red and green LEDs. You move the coil one way and the = red LED lights, the other way and the green LED lights. If you move the = coil more rapidly, the LEDs glow a lot brighter. Why not make up a = similar model for the museum? I have seen a formula explaining the three factors, The Field, The = Coil, and The Velocity.......... Could someone tell me or direct me to an explanation of "The Magic" = which is really the basic for this type of sensor. Regards, Chris Chapman
Hi Chris,  That is a good = idea..........The=20 visitors to the Museum are mostly tour groups of kids...They love to = touch=20 things, and maybe I could work something like this up.   I = think that=20 would explain the Magic very well.
Thanks, Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Saturday, July 07, 2007 = 4:53=20 PM
Subject: Re: The Magic

In a=20 message dated 2007/07/07, tchannel1@............=20 writes:

She is often at the computer, by the Sensor, when people = visit=20 the museum.  One question she gets, is "How does it work"  = She=20 understands how it is built and all the parts, but when the = questions=20 focuses on the magnetic field and the coil, she can only discuss = their=20 interaction, creates a current, like "Magic"


Hi Ted,=20
      =20
       Movement of a coil in a = magnetic=20 changing field does not produce a current, but a voltage across the = ends of=20 the coil. This voltage is proportional to the number of turns, to the = area of=20 the coil and to the rate of change of the field.=20
       A current flowing in a = conductor has=20 a ring magnetic field assocciated with it. If you use a circular = solenoid, the=20 turns add up to give an axial agnetic field.

    = I use a school demo system = having quad NdFeB=20 magnets on two parallel mild steel backplates. I use a relay coil on a = handle=20 connected to back to back red and green LEDs. You move the coil one = way and=20 the red LED lights, the other way and the green LED lights. If you = move the=20 coil more rapidly, the LEDs glow a lot brighter. Why not make up a = similar=20 model for the museum?

I have=20 seen a formula explaining the three factors, The Field, The Coil, = and The=20 Velocity..........
Could someone tell me or direct me to an = explanation of "The=20 Magic"  which is really the basic for this type of=20 sensor.

      =20 Regards,

       Chris = Chapman=20 Subject: Re: The Magic From: ChrisAtUpw@....... Date: Sun, 8 Jul 2007 00:55:45 EDT In a message dated 2007/07/08 , tchannel1@............ writes: > Hi Chris, That is a good idea..........The visitors to the Museum are > mostly tour groups of kids...They love to touch things, and maybe I could work > something like this up. I think that would explain the Magic very well. > Thanks, Ted Hi Ted, See the drawing at http://jclahr.com/science/psn/chapman/lehman/LehmanNdFeBSensor2.jpg for the basic idea. Regards, Chris In a me= ssage dated 2007/07/08 , tchannel1@............ writes:

Hi Chris,  That is a good=20= idea..........The visitors to the Museum are mostly tour groups of kids...Th= ey love to touch things, and maybe I could work something like this up. = ;  I think that would explain the Magic very well.
Thanks, Ted


Hi Ted,

       See the drawing at http://jclahr.com/sc= ience/psn/chapman/lehman/LehmanNdFeBSensor2.jpg for the basic idea.

       Regards,

       Chris Subject: Most Recent Discover Magazine pp66-67 WaterFall Display From: "Geoffrey" gmvoeth@........... Date: Sat, 7 Jul 2007 21:59:12 -0700 Hi All You PSN Fanatics (Im One Too); Here is a scientific example of a waterfall display that might be usful in one way or another to us Amateures. The only differences are that the time needs to be on the Y axis and Freq. on the X axis. In Science/Math time is always assigned to X axis but in reality you make it to suit your own tastes according to importance. This amounts to signature analysis where the data forms a picture. Over time you build a database of known events so that in the future you can simply look at the signature to tell pretty much what your looking at and give the event a classification. Black and White and shades of gray are better than this colorful stuff because not all people (especially males) have perfect color vision. There should be a range of signatures for events such as tornadoes and hurricanse and wave action and seismic events. You most probably do not need more than 1024 discrete frequencies and in an fft algorithim the number of samples you use in your conversion determins the frequency resolution. the FFT is an energy thing I think meaning the area under a curve. It can be of use to us if amateures are serious minded hobbiests. I lack the ability to program or I would do this myself. This is sort of a challange to all you amateures to develop a program that will take text or raw data in the form of bytes or words or text to make a water fall display in B/W 16 shades of gray with each time frame jumping only one sample at a time. Distrubute this analysis program freely to all seismic amateures and build a data base of known signatures that can be used by anyone in the PSN. Regards; Geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Most Recent Discover Magazine pp66-67 WaterFall Display From: ChrisAtUpw@....... Date: Sun, 8 Jul 2007 06:46:29 EDT In a message dated 2007/07/08, gmvoeth@........... writes: > Hi All You PSN Fanatics (Im One Too); > Here is a scientific example of a waterfall display > that might be usful in one way or another to us > Amateures. The only differences are that the > time needs to be on the Y axis and Freq. > on the X axis. In Science/Math time is always assigned to > X axis but in reality you make it to suit your own tastes > according to importance. Alternatively convert your files to a format which can be read by such a program? I seem to remember that this has been done? See http://www.radiosky.com/skypipeishere.html Why use B/W when color gives a better display? Regards, Chris Chapman In a me= ssage dated 2007/07/08, gmvoeth@........... writes:

Hi All You PSN Fanatics (Im One= Too);
Here is a scientific example of a waterfall display
that might be usful in one way or another to us
Amateures. The only differences are that the
time needs to be on the Y axis and Freq.
on the X axis. In Science/Math time is always assigned to
X axis but in reality you make it to suit your own tastes
according to importance.


       Alternatively convert your files to a f= ormat which can be read by such a program? I seem to remember that this has=20= been done?  See = http://www.radiosky.com/skypipeishere.html
       Why use B/W when color gives a better d= isplay?

       Regards,

       Chris Chapman Subject: Re: Most Recent Discover Magazine pp66-67 WaterFall Display From: "Geoffrey" gmvoeth@........... Date: Sun, 8 Jul 2007 07:01:56 -0700 This program seems to not use data files but wants you to build a custom A/D that will be read by the program itself. Not sure a sound card will take sample rates as low as 20Hz because most sound hardware has a capacitor input that rejects DC or freqs below the sense of hearing. It would be so nice to have this feature in Winquake to do an Analysis of file data in TXT/8/12/16/24 bit form or text form all you have to do is limit the frq between Dc and 5 Hz or so and make atleast 1024 samples per spectrum line. I have seen the routine in the library at ASU to FFT and there seems to be several ways. The best i like seems to result in the final results with the number of samples to be worked setting the resolution over the band. These people who write these books on FFT are oriented only to their own kind so if you do not know calculus or higher transforming their ideas into a computer program is very difficult. But I have in the past done this successfully myself. On a very small scale with a VIC20 machine running 10MHz. You need to take the first 1024 samples then make an imaginary set from the same ones then do a butterfly operation (some kind of fancy math) that results in a backward spectrum with each sample now representing a frequency band. Then you straighten out the results to get the low freq at the low sample number position. The final results is the freq range represented within the sample set chosen and that would be line one. Then you advance one sample in the data and do the same for the next contiguous 1024 samples. This is repeated until you have built a picture of your entire data file. The sample rate determins the freq limits I think. Why do not more people take an interest in the math and programming and hardware because seismology is just a fine specialty and I think more serious PROs should take an interest in fostering human interests in all lines of Science. You got to be an MD or equiv before you can get into forensic medicine ot Toxicology but this Seismology stuff is non license stuff and great way to learn many facets of science. Please someone with Math background make us a Basic Program like QBASIC or POWERBASIC to do one line of FFT and I will take it from there to make the whole program. I did this once myself but did not record the final program and would have to learn everything all over again to do this program again. A Burgler stole the VIC20 laptop with all my programs several years ago so those programs are lost. There is more to amateur stuff then just watching the waves and building things with your hands. It is a great chance to play general science and bring most everything together to see how it works with NO MYSTRIES. There seems to be effort to compartmentize information in the USA because of its capitalistic nature forcing one to become a college goon before you are able to do anything academic. The truth of the matter is to get a formal degree the system studies you as much as you study your subject so there is no real privacy or artisic freedom for the adventerous academic without government awareness. The Counter Intelligence peoples do not want Academic Freedom in the USA. Even tho we are playing with this harmless passive seismology stuff. I have come to realize that in some European Countries they have laws amounting to NEPLEONIC LAW which basically says everything is illegal except that which is specified by government. These kinds of forces are what we up against even in this relatively harmless area of seismology. If there is no common place to get knowledge we must make it ourselves even if it angers the powers that be. It is no accident we can not find a simple BASIC FFT source code with logic trees etc in laymen terms for our interest area. Everyone is trying to keep secrets or make money. For the sake of the evolution of science lets please gather together a collection of utility programs free for universal use in this PSN group. I am assuming PSN means Public like WORLD PUBLIC and not just California Public. One LAST thing for NOW. Black and White and shades of gray is by far the best for resolution and universal readability. If a person is lucky to get a totally black and white monitor or green you will see no sharper images than with such an analog electrostatic scanning device. The military used to preferr these over color since it used to be all male (for warships) and males have the highest incident of color blindness. Regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Most Recent Discover Magazine pp66-67 WaterFall Display From: ChrisAtUpw@....... Date: Sun, 8 Jul 2007 10:45:54 EDT In a message dated 2007/07/08, gmvoeth@........... writes: > This program seems to not use data files but wants you to build a custom > A/D that > will be read by the program itself. Hi Geoff, I am absolutely certain that I have seen seismic data on waterfall displays, but I can't remeber where. Certainly they were on line. That program will take binary data files, like amaseis? Have a look at www.vlf.it ? Regards, Chris Chapman In a me= ssage dated 2007/07/08, gmvoeth@........... writes:

This program seems to not use d= ata files but wants you to build a custom A/D that
will be read by the program itself.


Hi Geoff,

       I am absolutely certain that I have see= n seismic data on waterfall displays, but I can't remeber where. Certainly t= hey were on line. That program will take binary data files, like amaseis?
       Have a look at www.vlf.it ?

       Regards,

       Chris Chapman Subject: Re: Most Recent Discover Magazine pp66-67 WaterFall Display From: Mike Price mprice@........ Date: Sun, 08 Jul 2007 11:39:07 -0700 Geoff, The FFT algorithm is well documented and implementations abound. The FFT is widely used by anyone interested in exploring data in the frequency domain and it would be hard to find an algorithm better explained or more readily available. A Google search for "fft source code" generates 1.3M hits; indeed, the first one is www.fftw.org which has downloadable C source and links to many other sites containing source in several languages. You can find a basic implementation at: http://logosfoundation.org/fft/fft.html for example. The notion that access to FFT code is somehow restricted is misguided. Mike Geoffrey wrote: > This program seems to not use data files > but wants you to build a custom A/D that > will be read by the program itself. > Not sure a sound card will take sample rates > as low as 20Hz because most sound hardware > has a capacitor input that rejects DC or freqs > below the sense of hearing. > > It would be so nice to have this feature in Winquake to > do an Analysis of file data in TXT/8/12/16/24 bit form > or text form all you have to do is limit the frq > between Dc and 5 Hz or so and make atleast > 1024 samples per spectrum line. > > I have seen the routine in the library at ASU > to FFT and there seems to be several ways. > The best i like seems to result in the final > results with the number of samples to be worked > setting the resolution over the band. > > These people who write these books on FFT are oriented > only to their own kind so if you do not know calculus or higher > transforming their ideas into a computer program is very difficult. > > But I have in the past done this successfully myself. > On a very small scale with a VIC20 machine running 10MHz. > > You need to take the first 1024 samples then make an imaginary > set from the same ones then do a butterfly operation > (some kind of fancy math) that results in a backward > spectrum with each sample now representing a frequency band. > > Then you straighten out the results to get the low freq at the low > sample number position. > > The final results is the freq range represented within the sample set > chosen > and that would be line one. > > Then you advance one sample in the data and do the same for the > next contiguous 1024 samples. > > This is repeated until you have built a picture of your entire data file. > > The sample rate determins the freq limits I think. > > Why do not more people take an interest > in the math and programming and hardware > because seismology is just a fine specialty > and I think more serious PROs should take an > interest in fostering human interests in all lines of Science. > > You got to be an MD or equiv before you can > get into forensic medicine ot Toxicology but this > Seismology stuff is non license stuff and great way to > learn many facets of science. > > Please someone with Math background make us a > Basic Program like QBASIC or POWERBASIC > to do one line of FFT and I will take it from there > to make the whole program. > > I did this once myself but did not record the final > program and would have to learn everything all over > again to do this program again. > A Burgler stole the VIC20 laptop with all my programs > several years ago so those programs are lost. > > There is more to amateur stuff then just watching the waves > and building things with your hands. It is a great chance > to play general science and bring most everything together > to see how it works with NO MYSTRIES. > > There seems to be effort to compartmentize information > in the USA because of its capitalistic nature forcing one > to become a college goon before you are able to > do anything academic. The truth of the matter > is to get a formal degree the system studies you as much > as you study your subject so there is no real privacy > or artisic freedom for the adventerous academic without > government awareness. The Counter Intelligence peoples > do not want Academic Freedom in the USA. > Even tho we are playing with this harmless passive seismology stuff. > > I have come to realize that in some European Countries > they have laws amounting to NEPLEONIC LAW which basically > says everything is illegal except that which is specified by government. > > These kinds of forces are what we up against even in this > relatively harmless area of seismology. > > If there is no common place to get knowledge we must make it ourselves > even if it angers the powers that be. > > It is no accident we can not find a simple BASIC FFT source code > with logic trees etc in laymen terms for our interest area. > Everyone is trying to keep secrets or make money. > > For the sake of the evolution of science lets > please gather together a collection of utility programs > free for universal use in this PSN group. > > I am assuming PSN means Public like WORLD PUBLIC and not just > California Public. > > One LAST thing for NOW. > Black and White and shades of gray is by far the best for resolution > and universal readability. > If a person is lucky to get a totally black and white monitor or green > you will see no sharper images than with such an analog electrostatic > scanning device. > The military used to preferr these over color since it used to be all > male > (for warships) > and males have the highest incident of color blindness. > > 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: FFT BASIC Source Code From: "Geoffrey" gmvoeth@........... Date: Sun, 8 Jul 2007 12:41:22 -0700 Hello PSN; I found my very old notes from ASU Nobel Science Library regarding FFT basic program and I think it shows the source material it was found in. Can someone who understands FFT please look at this and comment to me at my address gmvoeth@........... or to PSN or to Both. I intend to make a DOS executable program to use 8 bit data that will display the results in 640X480X256 if at all possible. I will share my results if things look good. The only question I have is that about real and imaginary. I assume real means sine of the data and imaginary means cosine of the data and the angle relates to the sample rate vs the desired frequency and summed acxcording to the sample number and that the complete butterfly operation needs to be done 1024 times for each desired freq to look at. The bandwidth of each freq will be related to the number of samples processed. What I do not understand is how can you measure frequency unless you start out in phase with the freq you are looking for ?? Basic Source code for the FFT is very hard to find. Out of that whole library in the 1980s this is the only basic example I found. Maybe one of you experts can tell me if this program is honestly workable and the results will be proper ? I understand to save space you can use the same memory locations as the original data to put the results into but it (results) will be reversed and you need to start your freq display using the highest result (N) as the lowest Frq in the display (N). This computation although it is called FFT is very labor intensive and the time will increase exponentially to get the results according to the number of samples you process each line. If Im not mistaken it took me several minutes with the 10MHz VIC20 chip CPU to complete a single spectrum line using only 1024 samples. Today my machine is P4 3GHz so I should expect seconds instead of minutes. Notes: ***************************** http://gmvoeth.home.mchsi.com/FFT_Basic_Source.bmp ****************************** Regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: FFT Waterfall display From: Larry Conklin lconklin@............ Date: Sun, 08 Jul 2007 15:56:30 -0400 A couple of years ago I experimented with adding a real-time FFT waterfall display to my home brew data logging and display program. I got the waterfall working just fine but there is something wrong with the FFT calculation that I never got around to debugging. The current discussion may motivate me to take another look at it. If I manage to get something working, it wouldn't be much additional effort to adapt the code into an independent program that would take PSN files as a data source. Larry Conklin Liverpool, NY lconklin@............ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Most Recent Discover Magazine pp66-67 WaterFall Display From: "Geoffrey" gmvoeth@........... Date: Sun, 8 Jul 2007 13:36:02 -0700 Wonderful and thanks; It has been a few years since I looked and I never found anything like that. It (FFT) was classified Secret in the US Navy in the 1970s but after I saw my "secret" machine sold to foreign countries in a commissiond officers magazine (My dad was a retired officer) I no longer accepted the navys classification. for that machine. I now realize they want to keep it a secret only till they market the machine wherever. The secrecy is more for economic (manufacturing) than military reasons. We were probably only testing the device for Diagnostic Retreival Company. A general purpose computer like mine that works in a serial fashion can not match the speed of that parallel computing machine. The macine in question was the AN/SQR17 which did all this stuff in almost real time through dedicated circuitry. They used it in conjunction with the SKR4 telemetric receiver which was relayed sonobuoy data through the LAMPS helicopter. This machine SQR17 was all blue and blue means training and not war stuff. AN means Joint Army Navy which means the electronic circuitry is standard to both services. Everything I know is from 1970s and then it was old news so I am not worrying too much about talking today. One of my My old Ships the USS LONG BEACH is now atomic razor blades. The other Two Ellison and Willard Keith were sold to Turkey or South America and the only remaining one still alive might be the very old Bainbridge. I was on three of the several nuclear surface ships the only one i never boarded was the Truxton. I think you will not see any more because nuclear power is quite dangerous those ships are very fragile. It was funny when the russian trawlers would pick up the sonobuoys and you could hear them mutter over what they just found in their nets. Wish I could understand their words. Something like "More Alien Crap from the ocean". :-) I am now called Mentally Ill by the USA even tho I feel just the same now as when I was 17 and in Great Lakes Illinoise being poisoned with flouride treatment by a bad bad Dental Technician. Over xrayed by bad bad xray technicians. Even had to drink JP5 in our water once. Forced to go to etiquitte training because refused to go to church. I find it amazing we enlisted squids live as long as we do to enjoy any seismology at all. USW...the classification goes something like this: Confidential==Capabilities and limitations frequencies technical stuff etc.. (just about everyone) Secret==those things that might cause harm to the USA (Enlisted Stuff) Top Secret==those things that will cause harm to the USA (Commissioned Officers) Other agencies use different terms for the same ideas or spell out the dangers involved. I have never seen anything that was called top secret and only those things i needed to know at those times. I feel I have no knowledge valuable to the USA today. Everything I can think of except intellegence data bases is obsolete. And those are Protected libraries I no longer have access to. But we can make and share our own seismic stuff. In case you are wondering about my loyalties; I love MY Country (The one with Protected InAlienable Rights). regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: FFT BASIC Source Code From: Ben Bradley benbradley@............... Date: Sun, 08 Jul 2007 17:58:17 -0500 Geoffrey wrote: > Hello PSN; > > I found my very old notes from ASU Nobel Science Library regarding > FFT basic program and I think it shows > the source material it was found in. > > Can someone who understands FFT please look at this > and comment to me at my address gmvoeth@........... or to PSN or to Both. You can get a better understanding of the Fourier Transform and FFT from many places online. Here's one: http://www.dspguide.com/ > > I intend to make a DOS executable program to use > 8 bit data that will display the results in 640X480X256 if at all > possible. I will share my results if things look good. > > The only question I have is that about real and imaginary. > > I assume real means sine of the data and imaginary means cosine of the > data As I recall, Cosine is the "real" part and Sine is the "Imaginary" part. > and the angle relates to the sample rate vs the desired frequency and > summed acxcording to the sample number and that the complete butterfly > operation needs > to be done 1024 times for each desired freq to look at. > The bandwidth of each freq will be related to the number of samples > processed. What I do not understand is how > can you measure frequency unless you start out in phase > with the freq you are looking for ?? The complex Fourier Transform tells you both the frequency and the phase. It may seem like magic, but there's a graphical way of understanding it. > > Basic Source code for the FFT is very hard to find. I suppose BASIC is now considered obsolete, except for some of the Visual Basics found in Microsoft products, and even those may have been phased out by now. > > Out of that whole library in the 1980s this is the only basic example > I found. > > Maybe one of you experts can tell me if this program is honestly workable > and the results will be proper ? > > I understand to save space you can use > the same memory locations as the original data > to put the results into but it (results) will be reversed > and you need to start your freq display using the highest > result (N) as the lowest Frq in the display (N). > > This computation although it is called FFT is very > labor intensive and the time will increase exponentially > to get the results according to the number of samples > you process each line. > > If Im not mistaken it took me several minutes with the 10MHz VIC20 > chip CPU > to complete a single spectrum line using only 1024 samples. > Today my machine is P4 3GHz so I should expect seconds instead of > minutes. An optimized, compiled program on a modern PC should be able to do a 1024 point complex FFT in a very few milliseconds. This speed is helpful if you want to create waterfall plots, which (as I understand it) are made with many repeated FFT's over time. > > Notes: > ***************************** > http://gmvoeth.home.mchsi.com/FFT_Basic_Source.bmp Actually, that's a FORTRAN source. Offhand it looks okay to me, but don't take my word for it. > > ****************************** > > Regards; > geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Most Recent Discover Magazine pp66-67 WaterFall Display From: Mike Price mprice@........ Date: Sun, 08 Jul 2007 16:06:31 -0700 Geoff, A 3.2 GHz Pentium 4 with a vectorized FFT implementation using SSE2 (special extended 128-bit MMX instruction set of the Pentium) can execute a 1024 point FFT in well under 1mS. A 4096 FFT can be executed in under 6mS. This would blow the doors off any ca. 1972 implementation even if done entirely in HW. The number of points needed in an FFT is driven by the desired frequency resolution (bin width = sample_frequency / number_of_points). You may be able to get away with fewer number of points if you don't need fine frequency resolution. The FFT produces a complex number: a + bi. Think of it as a vector. You get magnitude and phase as follows: mag = sqrt( a^2 + b^2 ) phase = atan ( b / a ) Mike Price Geoffrey wrote: > Wonderful and thanks; > It has been a few years since I looked > and I never found anything like that. > > It (FFT) was classified Secret in the US Navy in the 1970s > but after I saw my "secret" machine sold to foreign > countries in a commissiond officers magazine > (My dad was a retired officer) I no longer accepted the navys > classification. > for that machine. > I now realize they want to keep it a secret > only till they market the machine wherever. > The secrecy is more for economic (manufacturing) > than military reasons. We were probably only > testing the device for Diagnostic Retreival Company. > > A general purpose computer like mine that works in a serial fashion > can not match the speed of that parallel computing machine. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: FFT Waterfall Display From: Bobhelenmcclure@....... Date: Sun, 8 Jul 2007 23:01:01 EDT The Cornell Lab of Ornithology offers a free program for displaying waterfall spectrograms of WAVE format sound files, which although intended primarily for the study of bird songs, would be useful for earthquakes as well. All you have to do is convert your event files to 16-bit monaural WAVE format and use Cornell's "Raven Lite 1.0" application. It is free, and can display spectrograms in color or black-and-white. See: _http://www.birds.cornell.edu/brp/raven/Raven.html_ (http://www.birds.cornell.edu/brp/raven/Raven.html) Bob ************************************** See what's free at http://www.aol.com.
  The Cornell Lab of Ornithology offers a free program for display= ing=20 waterfall spectrograms of WAVE format sound files, which although intended=20 primarily for the study of bird songs, would be useful for earthquakes as we= ll.=20 All you have to do is convert your event files to 16-bit monaural WAVE=20 format and use Cornell's "Raven Lite 1.0" application. It is free, and can=20 display spectrograms in color or black-and-white. See:
 
  http://www.birds.= cornell.edu/brp/raven/Raven.html
 
Bob



See what's free a= t AOL.com.
Subject: Re: FFT Waterfall Display From: "Michael Kimzey" mckimzey@........... Date: Mon, 09 Jul 2007 08:23:35 -0400 >The Cornell Lab of Ornithology offers a free program for displaying >waterfall spectrograms of WAVE format sound files, which although intended >primarily >for the study of bird songs, would be useful for earthquakes as well. All >you >have to do is convert your event files to 16-bit monaural WAVE format and >use Cornell's "Raven Lite 1.0" application. It is free, and can display >spectrograms in color or black-and-white. See: > > _http://www.birds.cornell.edu/brp/raven/Raven.html_ >(http://www.birds.cornell.edu/brp/raven/Raven.html) > Ok, so that begs the question, how do we convert an event to a 16 bit wave file? Actually, this is a question that has more implications, as some gentleman actually took USGS data and did convert it to a wave file, then sped it up and is using it as an art exhibit. See: http://www.jtbullitt.com/index.html So, if anyone knows how to convert events, or even WinSDR data to a "wave" file, it can be sped up and I think that one day's worth was approximately 4 minutes of sound. Interesting. - Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: FFT Waterfall Display From: Bobhelenmcclure@....... Date: Mon, 9 Jul 2007 22:48:01 EDT The WAVE format is described at: _http://www.borg.com/~jglatt/tech/wave.htm_ (http://www.borg.com/~jglatt/tech/wave.htm) The header data is 44 bytes long, and the remainder of the file consists usually of 16-bit data samples. __________________________ | RIFF WAVE Chunk | | groupID = 'RIFF' | | riffType = 'WAVE' | | __________________ | | | Format Chunk | | | | ckID = 'fmt ' | | | |__________________| | | __________________ | | | Sound Data Chunk | | | | ckID = 'data' | | | |__________________| | |__________________________| The PSN TYPE 4 file format is described at: _http://www.seismicnet.com/psnformat4.html_ (http://www.seismicnet.com/psnformat4.html) If you know how to program in QuickBasic, Visual Basic, or C the above documents provide enough information for writing an application to convert PSN files to WAVE format. I could easily add this function to my WQFilter.exe utility, but don't presently have the ambition to do so. Sorry about that. Bob ************************************** See what's free at http://www.aol.com.
  The WAVE format is described=20 at:
 
  http://www.borg.com/~jglatt/tech/wave.htm
 
The header data is 44 bytes long, and the=20 remainder of the file
consists usually of 16-bit data samples.=20
 __________________________
| RIFF WAVE=20 Chunk          |
|  =20 groupID  =3D 'RIFF'      |
|   ri= ffType=20 =3D 'WAVE'      |
|   =20 __________________    |
|   | Format=20 Chunk     |   |
|   | ckID=20= =3D=20 'fmt '    |   |
|  =20 |__________________|   |
|   =20 __________________    |
|   | Sound Data Chunk=20 |   |
|   | ckID =3D 'data'  =20  |   |
|   |__________________|  =20 |
|__________________________|
 
  The PSN TYPE 4 file format is describ= ed=20 at:
 
  http://www.seismicnet.com/psnformat4.html
 
  If you know how to program in QuickBa= sic,=20 Visual Basic, or C the above documents provide enough information for writin= g an=20 application to convert PSN files to WAVE format.  I could easily add th= is=20 function to my WQFilter.exe utility, but don't presently have the ambition t= o do=20 so. Sorry about that.
 
Bob



See what's free at AOL.com.
Subject: Re: FFT Waterfall Display From: "Michael Kimzey" mckimzey@........... Date: Tue, 10 Jul 2007 07:26:58 -0400 >The WAVE format is described at: > > _http://www.borg.com/~jglatt/tech/wave.htm_ >(http://www.borg.com/~jglatt/tech/wave.htm) > >The header data is 44 bytes long, and the remainder of the file >consists usually of 16-bit data samples. >__________________________ >| RIFF WAVE Chunk | >| groupID = 'RIFF' | >| riffType = 'WAVE' | >| __________________ | >| | Format Chunk | | >| | ckID = 'fmt ' | | >| |__________________| | >| __________________ | >| | Sound Data Chunk | | >| | ckID = 'data' | | >| |__________________| | >|__________________________| > > The PSN TYPE 4 file format is described at: > > _http://www.seismicnet.com/psnformat4.html_ >(http://www.seismicnet.com/psnformat4.html) > How about the format for a WinSDR data file (ie. seisdata.180) Is that documented anywhere as I think that it is different from the event file format. Just wondering. - Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Digest from 07/09/2007 00:00:06 From: "Randy" rpratt@............. Date: Tue, 10 Jul 2007 12:15:53 -0500 Hi, A couple of years ago one of the PSN members offered a program called 'RECENT' that created filtered displays and helicorder type output in HTML format. A side function was to create a sound file from the event with control of playback rate. It worked quite well. I don't know if it is available somewhere but if not I think I could find a copy somewhere in my files. The program operates in a batch mode and is quite easy to use. Randy ----- Original Message ----- From: To: Sent: Tuesday, July 10, 2007 02:01 Subject: Digest from 07/09/2007 00:00:06 > > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. > | Message 1 | > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' > Subject: Re: FFT Waterfall Display > From: "Michael Kimzey" > Date: Mon, 09 Jul 2007 08:23:35 -0400 > > > >The Cornell Lab of Ornithology offers a free program for displaying > >waterfall spectrograms of WAVE format sound files, which although intended > >primarily > >for the study of bird songs, would be useful for earthquakes as well. All > >you > >have to do is convert your event files to 16-bit monaural WAVE format and > >use Cornell's "Raven Lite 1.0" application. It is free, and can display > >spectrograms in color or black-and-white. See: > > > > _http://www.birds.cornell.edu/brp/raven/Raven.html_ > >(http://www.birds.cornell.edu/brp/raven/Raven.html) > > > > Ok, so that begs the question, how do we convert an event to a 16 bit wave > file? Actually, this is a question that has more implications, as some > gentleman actually took USGS data and did convert it to a wave file, then > sped it up and is using it as an art exhibit. See: > http://www.jtbullitt.com/index.html > So, if anyone knows how to convert events, or even WinSDR data to a "wave" > file, it can be sped up and I think that one day's worth was approximately 4 > minutes of sound. > Interesting. > > - Mike > > > > > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. > | Message 2 | > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' > Subject: Re: FFT Waterfall Display > From: Bobhelenmcclure@....... > Date: Mon, 9 Jul 2007 22:48:01 EDT > > > -------------------------------1184035681 > Content-Type: text/plain; charset="US-ASCII" > Content-Transfer-Encoding: 7bit > > The WAVE format is described at: > > _http://www.borg.com/~jglatt/tech/wave.htm_ > (http://www.borg.com/~jglatt/tech/wave.htm) > > The header data is 44 bytes long, and the remainder of the file > consists usually of 16-bit data samples. > __________________________ > | RIFF WAVE Chunk | > | groupID = 'RIFF' | > | riffType = 'WAVE' | > | __________________ | > | | Format Chunk | | > | | ckID = 'fmt ' | | > | |__________________| | > | __________________ | > | | Sound Data Chunk | | > | | ckID = 'data' | | > | |__________________| | > |__________________________| > > The PSN TYPE 4 file format is described at: > > _http://www.seismicnet.com/psnformat4.html_ > (http://www.seismicnet.com/psnformat4.html) > > If you know how to program in QuickBasic, Visual Basic, or C the above > documents provide enough information for writing an application to convert PSN > files to WAVE format. I could easily add this function to my WQFilter.exe > utility, but don't presently have the ambition to do so. Sorry about that. > > Bob > > > > ************************************** See what's free at http://www.aol.com. > > -------------------------------1184035681 > Content-Type: text/html; charset="US-ASCII" > Content-Transfer-Encoding: quoted-printable > > > > > > Arial"=20 > bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7> e_document=20 > face=3DArial color=3D#000000 size=3D2> >
  The WAVE format is described=20 > at:
>
 
>
  href=3D"http://www.borg.com/~jglatt/tech/wave.htm"> face=3D"Courier New">http://www.borg.com/~jglatt/tech/wave.htm IV> >
 
>
The header data is 44 bytes long, and the=20 > remainder of the file
consists usually of 16-bit data samples.=20 >
 __________________________
| RIFF WAVE=20 > Chunk          |
|  =20 > groupID  =3D 'RIFF'      |
|   ri= > ffType=20 > =3D 'WAVE'      |
|   =20 > __________________    |
|   | Format=20 > Chunk     |   |
|   | ckID=20= > =3D=20 > 'fmt '    |   |
|  =20 > |__________________|   |
|   =20 > __________________    |
|   | Sound Data Chunk=20 > |   |
|   | ckID =3D 'data'  =20 >  |   |
|   |__________________|  =20 > |
|__________________________|
>
 
>
  The PSN TYPE 4 file format is describ= > ed=20 > at:
>
 
>
  href=3D"http://www.seismicnet.com/psnformat4.html"> face=3D"Courier New">http://www.seismicnet.com/psnformat4.html IV> >
 
>
  If you know how to program in QuickBa= > sic,=20 > Visual Basic, or C the above documents provide enough information for writin= > g an=20 > application to convert PSN files to WAVE format.  I could easily add th= > is=20 > function to my WQFilter.exe utility, but don't presently have the ambition t= > o do=20 > so. Sorry about that.
>
 
>
Bob



T style=3D"color: black; font: normal 10pt ARIAL, SAN-SERIF;">
ARGIN-TOP: 10px">See what's free at LAOF00020000000503" href=3D"http://www.aol.com?ncid=3DAOLAOF00020000000503"=20= > target=3D"_blank">AOL.com.
> > -------------------------------1184035681-- > > > __________________________________________________________ > > 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 07/09/2007 00:00:06 From: Larry Conklin lconklin@............ Date: Tue, 10 Jul 2007 13:34:44 -0400 I still have a copy of that program, and use it daily to generate 24 hr. helicorder plots from my data files. It is a very nice program written, I believe, by Arie Verveer (sp?). If it can't be found elsewhere, I would be happy to send a copy to anyone who is interested. Larry Conklin Liverpool, NY lconklin@............ Randy wrote: > Hi, > > A couple of years ago one of the PSN members offered a program called > 'RECENT' that created filtered displays and helicorder type output in HTML > format. A side function was to create a sound file from the event with > control of playback rate. It worked quite well. I don't know if it is > available somewhere but if not I think I could find a copy somewhere in my > files. The program operates in a batch mode and is quite easy to use. > > Randy > > ----- Original Message ----- > From: > To: > Sent: Tuesday, July 10, 2007 02:01 > Subject: Digest from 07/09/2007 00:00:06 > > >> .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. >> | Message 1 | >> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' >> Subject: Re: FFT Waterfall Display >> From: "Michael Kimzey" >> Date: Mon, 09 Jul 2007 08:23:35 -0400 >> >> >>> The Cornell Lab of Ornithology offers a free program for displaying >>> waterfall spectrograms of WAVE format sound files, which although > intended >>> primarily >>> for the study of bird songs, would be useful for earthquakes as well. > All >>> you >>> have to do is convert your event files to 16-bit monaural WAVE format > and >>> use Cornell's "Raven Lite 1.0" application. It is free, and can display >>> spectrograms in color or black-and-white. See: >>> >>> _http://www.birds.cornell.edu/brp/raven/Raven.html_ >>> (http://www.birds.cornell.edu/brp/raven/Raven.html) >>> >> Ok, so that begs the question, how do we convert an event to a 16 bit wave >> file? Actually, this is a question that has more implications, as some >> gentleman actually took USGS data and did convert it to a wave file, then >> sped it up and is using it as an art exhibit. See: >> http://www.jtbullitt.com/index.html >> So, if anyone knows how to convert events, or even WinSDR data to a "wave" >> file, it can be sped up and I think that one day's worth was approximately > 4 >> minutes of sound. >> Interesting. >> >> - Mike >> >> >> >> >> .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. >> | Message 2 | >> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' >> Subject: Re: FFT Waterfall Display >> From: Bobhelenmcclure@....... >> Date: Mon, 9 Jul 2007 22:48:01 EDT >> >> >> -------------------------------1184035681 >> Content-Type: text/plain; charset="US-ASCII" >> Content-Transfer-Encoding: 7bit >> >> The WAVE format is described at: >> >> _http://www.borg.com/~jglatt/tech/wave.htm_ >> (http://www.borg.com/~jglatt/tech/wave.htm) >> >> The header data is 44 bytes long, and the remainder of the file >> consists usually of 16-bit data samples. >> __________________________ >> | RIFF WAVE Chunk | >> | groupID = 'RIFF' | >> | riffType = 'WAVE' | >> | __________________ | >> | | Format Chunk | | >> | | ckID = 'fmt ' | | >> | |__________________| | >> | __________________ | >> | | Sound Data Chunk | | >> | | ckID = 'data' | | >> | |__________________| | >> |__________________________| >> >> The PSN TYPE 4 file format is described at: >> >> _http://www.seismicnet.com/psnformat4.html_ >> (http://www.seismicnet.com/psnformat4.html) >> >> If you know how to program in QuickBasic, Visual Basic, or C the above >> documents provide enough information for writing an application to > convert PSN >> files to WAVE format. I could easily add this function to my > WQFilter.exe >> utility, but don't presently have the ambition to do so. Sorry about > that. >> Bob >> >> >> >> ************************************** See what's free at > http://www.aol.com. >> -------------------------------1184035681 >> Content-Type: text/html; charset="US-ASCII" >> Content-Transfer-Encoding: quoted-printable >> >> >> >> >> >> FONT-FAMILY:=20= >> Arial"=20 >> bottomMargin=3D7 leftMargin=3D7 topMargin=3D7 rightMargin=3D7> id=3Drol= >> e_document=20 >> face=3DArial color=3D#000000 size=3D2> >>
  The WAVE format is described=20 >> at:
>>
 
>>
  > href=3D"http://www.borg.com/~jglatt/tech/wave.htm">> face=3D"Courier > New">http://www.borg.com/~jglatt/tech/wave.htm> IV> >>
 
>>
The header data is 44 bytes long, and > the=20 >> remainder of the file
consists usually of 16-bit data samples.=20 >>
 __________________________
| RIFF WAVE=20 >> Chunk          > |
|  =20 >> groupID  =3D 'RIFF'      |
|   > ri= >> ffType=20 >> =3D 'WAVE'      |
|   =20 >> __________________    |
|   | Format=20 >> Chunk     |   |
|   > | ckID=20= >> =3D=20 >> 'fmt '    |   |
|  =20 >> |__________________|   |
|   =20 >> __________________    |
|   | Sound Data > Chunk=20 >> |   |
|   | ckID =3D 'data'  =20 >>  |   |
|   |__________________|  =20 >> |
|__________________________|
>>
 
>>
  The PSN TYPE 4 file format is > describ= >> ed=20 >> at:
>>
 
>>
  > href=3D"http://www.seismicnet.com/psnformat4.html">> face=3D"Courier > New">http://www.seismicnet.com/psnformat4.html> IV> >>
 
>>
  If you know how to program in > QuickBa= >> sic,=20 >> Visual Basic, or C the above documents provide enough information for > writin= >> g an=20 >> application to convert PSN files to WAVE format.  I could easily add > th= >> is=20 >> function to my WQFilter.exe utility, but don't presently have the ambition > t= >> o do=20 >> so. Sorry about that.
>>
 
>>
New">Bob



> T style=3D"color: black; font: normal 10pt ARIAL, SAN-SERIF;">
style=3D"M= >> ARGIN-TOP: 10px">See what's free at title=3D"http://www.aol.com?ncid=3DAO= >> LAOF00020000000503" > href=3D"http://www.aol.com?ncid=3DAOLAOF00020000000503"=20= >> target=3D"_blank">AOL.com.
>> >> -------------------------------1184035681-- >> >> >> __________________________________________________________ >> >> 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) > > 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: RECENT From: Angel sismos@.............. Date: Tue, 10 Jul 2007 20:59:56 +0000 Hello, I also use it everyday and have a copy if it is needed. It was written by Arie Verveer. Who I am am pretty sure is still on the list. Angel Tuesday, July 10, 2007, 5:34:44 PM, you wrote: > I still have a copy of that program, and use it daily to generate 24 hr. > helicorder plots from my data files. It is a very nice program > written, I believe, by C (sp?). If it can't be found > elsewhere, I would be happy to send a copy to anyone who is interested. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: FFT Waterfall display From: Angel sismos@.............. Date: Tue, 10 Jul 2007 21:09:29 +0000 Hello Larry, Swarm does realtime spectrogrmas of log of frequency and log of power displays of seismic signals. You could go directly to from winsdr to earthworm to a waveserver and from the wave server to Swarm. I know what I just said is cryptic but if you need more detail I would be glad to get it to you. I can send you a screen shot of what the display looks like if you want. Angel \ Sunday, July 8, 2007, 7:56:30 PM, you wrote: > A couple of years ago I experimented with adding a real-time FFT > waterfall display to my home brew data logging and display program. I > got the waterfall working just fine but there is something wrong with > the FFT calculation that I never got around to debugging. The current > discussion may motivate me to take another look at it. If I manage to > get something working, it wouldn't be much additional effort to adapt > the code into an independent program that would take PSN files as a data > source. > Larry Conklin > Liverpool, NY > lconklin@............ > __________________________________________________________ > 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: Re: FFT Waterfall display From: Larry Conklin lconklin@............ Date: Tue, 10 Jul 2007 17:49:44 -0400 Hi Angel, Thanks for the info. My original intention was to add a real time FFT waterfall display to my home brew data logging program. I thought it would be interesting to watch the spectrum of an incoming event in addition to the time domain signal. I'm not as interested in an after the fact, "postmortem" display. I used some public domain C code for the FFT that wasn't very well documented. I'm getting some sort of data in the waterfall, but it clearly ain't right. Got side tracked and didn't get back to it. Somebody posted a link to a site that evidently has source code for the FFT and much better documentation. When I get the time I'll take a look at it and perhaps replace what I had with something a little better written. Larry Angel wrote: > Hello Larry, > > Swarm does realtime spectrogrmas of log of frequency and log of power > displays of seismic signals. > > You could go directly to from winsdr to earthworm to a waveserver and > from the wave server to Swarm. I know what I just said is cryptic but > if you need more detail I would be glad to get it to you. I can send > you a screen shot of what the display looks like if you want. > > Angel > \ > Sunday, July 8, 2007, 7:56:30 PM, you wrote: > >> A couple of years ago I experimented with adding a real-time FFT >> waterfall display to my home brew data logging and display program. I >> got the waterfall working just fine but there is something wrong with >> the FFT calculation that I never got around to debugging. The current >> discussion may motivate me to take another look at it. If I manage to >> get something working, it wouldn't be much additional effort to adapt >> the code into an independent program that would take PSN files as a data >> source. > >> Larry Conklin >> Liverpool, NY >> lconklin@............ >> __________________________________________________________ > >> 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[2]: FFT Waterfall display From: Angel sismos@.............. Date: Wed, 11 Jul 2007 00:34:12 +0000 Hello Larry, What I mentioned would be in realtime, will a little itty bitty delay. but is is a mess to set up. Angel Tuesday, July 10, 2007, 9:49:44 PM, you wrote: > Hi Angel, > Thanks for the info. My original intention was to add a real time FFT > waterfall display to my home brew data logging program. I thought it > would be interesting to watch the spectrum of an incoming event in > addition to the time domain signal. I'm not as interested in an after > the fact, "postmortem" display. > I used some public domain C code for the FFT that wasn't very well > documented. I'm getting some sort of data in the waterfall, but it > clearly ain't right. Got side tracked and didn't get back to it. > Somebody posted a link to a site that evidently has source code for the > FFT and much better documentation. When I get the time I'll take a look > at it and perhaps replace what I had with something a little better written. > Larry > Angel wrote: >> Hello Larry, >> >> Swarm does realtime spectrogrmas of log of frequency and log of power >> displays of seismic signals. >> >> You could go directly to from winsdr to earthworm to a waveserver and >> from the wave server to Swarm. I know what I just said is cryptic but >> if you need more detail I would be glad to get it to you. I can send >> you a screen shot of what the display looks like if you want. >> >> Angel >> \ >> Sunday, July 8, 2007, 7:56:30 PM, you wrote: >> >>> A couple of years ago I experimented with adding a real-time FFT >>> waterfall display to my home brew data logging and display program. I >>> got the waterfall working just fine but there is something wrong with >>> the FFT calculation that I never got around to debugging. The current >>> discussion may motivate me to take another look at it. If I manage to >>> get something working, it wouldn't be much additional effort to adapt >>> the code into an independent program that would take PSN files as a data >>> source. >> >>> Larry Conklin >>> Liverpool, NY >>> lconklin@............ >>> __________________________________________________________ >> >>> 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: Re: FFT Waterfall Display - Record file format From: Larry Cochrane lcochrane@.............. Date: Tue, 10 Jul 2007 20:50:12 -0700 Hi Everyone, Michael Kimzey wrote: > How about the format for a WinSDR data file (ie. seisdata.180) Is that > documented anywhere as I think that it is different from the event file > format. Just wondering. I have some 'C' code that documents the format of WinSDR's daily record files. The file can be downloaded from here http://www.seismicnet.com/software/recordfile.zip. The PSN event file format is documented here http://www.seismicnet.com/psnformat4.html Regards, Larry Cochrane Redwood City, PSN __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re[2]: Digest from 07/09/2007 00:00:06 From: Angel sismos@.............. Date: Wed, 11 Jul 2007 03:50:43 +0000 Hello Randy, Come else just asked for it so I just placed it here for anyone to download and use. It took me a bit to find the manuals and some email from Arie. As you can see the files have dates from 2002. If you have any problems drop me a line. I placed it at www.volcanbaru.com/OSOP/Recent/Recent.zip Regards, Angel __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: FFT Waterfall display From: "Thomas Dick" dickthomas01@............. Date: Wed, 11 Jul 2007 15:34:56 -0500 Got a copy of the Recent program, but when I tired to load it, the exe program gives error message "No AutoFFT.ini file found". I guess I have to read the documentation? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re[2]: FFT Waterfall display From: Angel sismos@.............. Date: Wed, 11 Jul 2007 20:54:29 +0000 Hello Thomas, I hope the subject line has nothing to do with the subject of this message. I think I inlcuded an ini file in the zip I posted. angel Wednesday, July 11, 2007, 8:34:56 PM, you wrote: > Got a copy of the Recent program, but when I tired to load it, the exe > program gives error message "No AutoFFT.ini file found". I guess I have to > read the documentation? > __________________________________________________________ > 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: Re: Re[2]: Digest from 07/09/2007 00:00:06 From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Thu, 12 Jul 2007 04:22:39 +0000 Hi all Is there a program that allows me to create a list of the earthquakes I record, by week or monthly status. I want to put up a list of the earthquakes that my systems record. But it is impossible to do it by hand, since I often record more then 30 earthquakes pr week. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Re[2]: FFT Waterfall display From: "Geoffrey" gmvoeth@........... Date: Sat, 14 Jul 2007 03:20:48 -0700 The power needed for a raltime FFT display of any value just does not exist for a typical home computer. You would need a special card like these high speed video cards. I have seen the machines that do real time fft and back in the 1970s they were like 1000X faster than your home computer and would do 500 points and be only a few milli seconds behind real time. You most probably will have to stick with after the fact processing. those old machines were special purpose and would have circuits built specifically to work on each chosen freq. So if you wanted 500 points there would be 500 seperate circuits for each chosen freq. I suspect SETI is using the public to do what those old expensive machines used to do. Maybe if you got a CRAY supercomputer you might do real time ( HA! ) crunching. Since we all live normally about 0.1 seconds behind realtime anyway we all live in the past. We never can see reality in real time. Regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: FFT Waterfall display From: "Geoffrey" gmvoeth@........... Date: Sat, 14 Jul 2007 03:38:46 -0700 It Is My Sincere Belief that you will not be able to get anywhere near realtime with a home PC simply because too many complicated iterations must be made for many discrete points. You will have to settle with after the fact processing. I have tried a FFT program myself using my own data on a 3GHz machine and it takes 11 seconds to process 29 minutes of data each line of spectrum being seperated by 4.5 seconds in time. Each line pass representing 56.2 seconds of time. ----- Original Message ----- From: "Larry Conklin" To: "PSN List" Sent: Sunday, July 08, 2007 12:56 Subject: FFT Waterfall display >A couple of years ago I experimented with adding a real-time FFT > waterfall display to my home brew data logging and display program. I > got the waterfall working just fine but there is something wrong with > the FFT calculation that I never got around to debugging. The current > discussion may motivate me to take another look at it. If I manage to > get something working, it wouldn't be much additional effort to adapt > the code into an independent program that would take PSN files as a data > source. > > Larry Conklin > Liverpool, NY > lconklin@............ > __________________________________________________________ > > 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: FFT Waterfall Display From: "Geoffrey" gmvoeth@........... Date: Sat, 14 Jul 2007 03:42:48 -0700 I convert my data to 8 bit mono wav files and speed them up to about 300X so my 30 minute files will last only 6 seconds or so but you can hear very clearly the differences between man made sounds and EQs. You simply have to understand the headers to program the conversion. ----- Original Message ----- From: "Michael Kimzey" To: Sent: Monday, July 09, 2007 05:23 Subject: Re: FFT Waterfall Display > >>The Cornell Lab of Ornithology offers a free program for displaying >>waterfall spectrograms of WAVE format sound files, which although intended >>primarily >>for the study of bird songs, would be useful for earthquakes as well. All >>you >>have to do is convert your event files to 16-bit monaural WAVE format and >>use Cornell's "Raven Lite 1.0" application. It is free, and can display >>spectrograms in color or black-and-white. See: >> >> _http://www.birds.cornell.edu/brp/raven/Raven.html_ >>(http://www.birds.cornell.edu/brp/raven/Raven.html) >> > > Ok, so that begs the question, how do we convert an event to a 16 bit wave > file? Actually, this is a question that has more implications, as some > gentleman actually took USGS data and did convert it to a wave file, then > sped it up and is using it as an art exhibit. See: > http://www.jtbullitt.com/index.html > So, if anyone knows how to convert events, or even WinSDR data to a "wave" > file, it can be sped up and I think that one day's worth was approximately 4 > minutes of sound. > Interesting. > > - Mike > > > __________________________________________________________ > > 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: Most Recent Discover Magazine pp66-67 WaterFall Display From: "Geoffrey" gmvoeth@........... Date: Sat, 14 Jul 2007 03:53:53 -0700 Thanks for the Info. I searched and searched and found only one PDF file that explained things in ways I could somewhat understand. It seems the data fed into an fft routine needs to be symmetrical +/- between one and zero in magnitude as samples voltages or whatever and the results is given as a series of freq points that are the original sample points / two. You start out with 1024 samples and end up with 512 freq points that are in two arrays of Sin and Cosin data. to get the final results you need to use the pythagoras formula to combine the two a = sqr(r^2 + I^2) maybe x 0.7071 to get the RMS value. The data can be any sample rate and the results will be interpreted according to the sample rate of the original data. The freq spread will be sample rate divided by two. DC to that freq. It will be a slow process to calculate a decent length of time. But it will let you look at the overall response of your system especially when you record storm noise of a passing storm which is like infrared noise. The noise will show the passband of your SP system. regards; geoff ----- Original Message ----- From: "Mike Price" To: Sent: Sunday, July 08, 2007 11:39 Subject: Re: Most Recent Discover Magazine pp66-67 WaterFall Display > Geoff, > The FFT algorithm is well documented and implementations abound. The FFT > is widely used by anyone interested in exploring data in the frequency > domain and it would be hard to find an algorithm better explained or > more readily available. A Google search for "fft source code" generates > 1.3M hits; indeed, the first one is www.fftw.org which has downloadable > C source and links to many other sites containing source in several > languages. You can find a basic implementation at: > http://logosfoundation.org/fft/fft.html for example. > > The notion that access to FFT code is somehow restricted is misguided. > > Mike > > > Geoffrey wrote: >> This program seems to not use data files >> but wants you to build a custom A/D that >> will be read by the program itself. >> Not sure a sound card will take sample rates >> as low as 20Hz because most sound hardware >> has a capacitor input that rejects DC or freqs >> below the sense of hearing. >> >> It would be so nice to have this feature in Winquake to >> do an Analysis of file data in TXT/8/12/16/24 bit form >> or text form all you have to do is limit the frq >> between Dc and 5 Hz or so and make atleast >> 1024 samples per spectrum line. >> >> I have seen the routine in the library at ASU >> to FFT and there seems to be several ways. >> The best i like seems to result in the final >> results with the number of samples to be worked >> setting the resolution over the band. >> >> These people who write these books on FFT are oriented >> only to their own kind so if you do not know calculus or higher >> transforming their ideas into a computer program is very difficult. >> >> But I have in the past done this successfully myself. >> On a very small scale with a VIC20 machine running 10MHz. >> >> You need to take the first 1024 samples then make an imaginary >> set from the same ones then do a butterfly operation >> (some kind of fancy math) that results in a backward >> spectrum with each sample now representing a frequency band. >> >> Then you straighten out the results to get the low freq at the low >> sample number position. >> >> The final results is the freq range represented within the sample set >> chosen >> and that would be line one. >> >> Then you advance one sample in the data and do the same for the >> next contiguous 1024 samples. >> >> This is repeated until you have built a picture of your entire data file. >> >> The sample rate determins the freq limits I think. >> >> Why do not more people take an interest >> in the math and programming and hardware >> because seismology is just a fine specialty >> and I think more serious PROs should take an >> interest in fostering human interests in all lines of Science. >> >> You got to be an MD or equiv before you can >> get into forensic medicine ot Toxicology but this >> Seismology stuff is non license stuff and great way to >> learn many facets of science. >> >> Please someone with Math background make us a >> Basic Program like QBASIC or POWERBASIC >> to do one line of FFT and I will take it from there >> to make the whole program. >> >> I did this once myself but did not record the final >> program and would have to learn everything all over >> again to do this program again. >> A Burgler stole the VIC20 laptop with all my programs >> several years ago so those programs are lost. >> >> There is more to amateur stuff then just watching the waves >> and building things with your hands. It is a great chance >> to play general science and bring most everything together >> to see how it works with NO MYSTRIES. >> >> There seems to be effort to compartmentize information >> in the USA because of its capitalistic nature forcing one >> to become a college goon before you are able to >> do anything academic. The truth of the matter >> is to get a formal degree the system studies you as much >> as you study your subject so there is no real privacy >> or artisic freedom for the adventerous academic without >> government awareness. The Counter Intelligence peoples >> do not want Academic Freedom in the USA. >> Even tho we are playing with this harmless passive seismology stuff. >> >> I have come to realize that in some European Countries >> they have laws amounting to NEPLEONIC LAW which basically >> says everything is illegal except that which is specified by government. >> >> These kinds of forces are what we up against even in this >> relatively harmless area of seismology. >> >> If there is no common place to get knowledge we must make it ourselves >> even if it angers the powers that be. >> >> It is no accident we can not find a simple BASIC FFT source code >> with logic trees etc in laymen terms for our interest area. >> Everyone is trying to keep secrets or make money. >> >> For the sake of the evolution of science lets >> please gather together a collection of utility programs >> free for universal use in this PSN group. >> >> I am assuming PSN means Public like WORLD PUBLIC and not just >> California Public. >> >> One LAST thing for NOW. >> Black and White and shades of gray is by far the best for resolution >> and universal readability. >> If a person is lucky to get a totally black and white monitor or green >> you will see no sharper images than with such an analog electrostatic >> scanning device. >> The military used to preferr these over color since it used to be all >> male >> (for warships) >> and males have the highest incident of color blindness. >> >> 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: Most Recent Discover Magazine pp66-67 WaterFall Display From: "Geoffrey" gmvoeth@........... Date: Sat, 14 Jul 2007 03:57:52 -0700 Hey thats far out. If only i knew how to program such stuff myself using PowerBasic. It takes me now 11 seconds to look at only 384 lines of data covering about 30 minutes of time. If I could somehow speed that up I would sure like to know how. Regards; geoff ----- Original Message ----- From: "Mike Price" To: Sent: Sunday, July 08, 2007 16:06 Subject: Re: Most Recent Discover Magazine pp66-67 WaterFall Display > Geoff, > A 3.2 GHz Pentium 4 with a vectorized FFT implementation using SSE2 > (special extended 128-bit MMX instruction set of the Pentium) can > execute a 1024 point FFT in well under 1mS. A 4096 FFT can be executed > in under 6mS. This would blow the doors off any ca. 1972 implementation > even if done entirely in HW. > > The number of points needed in an FFT is driven by the desired frequency > resolution (bin width = sample_frequency / number_of_points). You may be > able to get away with fewer number of points if you don't need fine > frequency resolution. > > The FFT produces a complex number: a + bi. Think of it as a vector. You > get magnitude and phase as follows: > mag = sqrt( a^2 + b^2 ) > phase = atan ( b / a ) > > Mike Price > > > Geoffrey wrote: >> Wonderful and thanks; >> It has been a few years since I looked >> and I never found anything like that. >> >> It (FFT) was classified Secret in the US Navy in the 1970s >> but after I saw my "secret" machine sold to foreign >> countries in a commissiond officers magazine >> (My dad was a retired officer) I no longer accepted the navys >> classification. >> for that machine. >> I now realize they want to keep it a secret >> only till they market the machine wherever. >> The secrecy is more for economic (manufacturing) >> than military reasons. We were probably only >> testing the device for Diagnostic Retreival Company. >> >> A general purpose computer like mine that works in a serial fashion >> can not match the speed of that parallel computing machine. >> > __________________________________________________________ > > 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: Re[2]: FFT Waterfall display From: "Michael Kimzey" mckimzey@........... Date: Sat, 14 Jul 2007 08:09:29 -0400 Hi all. >The power needed for a realtime FFT display >of any value just does not exist for a typical >home computer. You would need a special >card like these high speed video cards. > >I have seen the machines that do real time fft >and back in the 1970s they were like 1000X faster >than your home computer and would do 500 points >and be only a few milli seconds behind real time. > I'm don't completely understand all this FFT stuff, but a search of google revealed that you can get several programs for FFT and waterfall display. Spectrogram 5.1 http://www.relisoft.com/science/Physics/fft.html <- provides a discussion of FFT and source code. Digipan - this is a amature radio program for communicating digitally using audio output from your sound card and has a very nice waterfall display. Spectran 2.0 Maybe these are not doing something "FFT-wise", but Spectrograph and Spectran both allow you to set the FFT size and both have the moving graphical display...and are working on signals with sample rates of 44,000 per second. I think that any seismological waterfall display would move -very- slowly...my samples-per-second are only 10 and should be able to perform some type of FFT. Even Win-Quake does FFT. Maybe I'm missing something... - Mike __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Re[2]: FFT Waterfall display From: ChrisAtUpw@....... Date: Sat, 14 Jul 2007 09:48:18 EDT In a message dated 2007/07/14, gmvoeth@........... writes: > The power needed for a real-time FFT display of any value just does not > exist for a typical home computer. You would need a special card like these high > speed video cards. > > I have seen the machines that do real time fft and back in the 1970s they > were like 1000X faster than your home computer and would do 500 points and be > only a few milli seconds behind real time. You most probably will have to > stick with after the fact processing. Hi Geoff, There have been several developments in FFTs since the 1970s!! The amount of maths required to produce a FFT has been drastically reduced by new algorithms. The processors are now thousands of times faster, several may be included on one chip and they can use vectored instructions. It is largely a question of what you are calling 'real time'. If you use a multitasking processor, the interrupts are maybe 20 to a few milliseconds or less. Such time delays are not usually important in amateur seismology. The most likely delay is the relatively slow rate of seismic sampling. By opting for a 10 Hz low pass filter, you are accepting a 50 milli second delay minimum. I would not expect there to be a problem in providing a FFT display to update at this rate. I note quoted times of less than 1 milli second to complete a FFT sample. Regards, Chris Chapman In a me= ssage dated 2007/07/14, gmvoeth@........... writes:

The power needed for a real-tim= e FFT display of any value just does not exist for a typical home computer.=20= You would need a special card like these high speed video cards.

I have seen the machines that do real time fft and back in the 1970s they we= re like 1000X faster than your home computer and would do 500 points and be=20= only a few milli seconds behind real time. You most probably will have to st= ick with after the fact processing.


Hi Geoff,

       There have been several developments in= FFTs since the 1970s!!

       The amount of maths required to produce= a FFT has been drastically reduced by new algorithms.
       The processors are now thousands of tim= es faster, several may be included on one chip and they can use vectored ins= tructions.

       It is largely a question of what you ar= e calling 'real time'.
       If you use a multitasking processor, th= e interrupts are maybe 20 to a few milliseconds or less. Such time delays ar= e not usually important in amateur seismology. The most likely delay is the=20= relatively slow rate of seismic sampling. By opting for a 10 Hz low pass fil= ter, you are accepting a 50 milli second delay minimum.

       I would not expect there to be a proble= m in providing a FFT display to update at this rate. I note quoted times of=20= less than 1 milli second to complete a FFT sample.

       Regards,

       Chris Chapman Subject: Re: FFT Waterfall display From: Larry Conklin lconklin@............ Date: Sat, 14 Jul 2007 10:28:46 -0400 OooooH Kay... Now I'm beginning to get motivated. I've already got something running real time, just have to debug the thing to make the FFT algorithm run correctly. Nothing like a declaration of impossibility to get the old juices flowing again. Larry Geoffrey wrote: > It Is My Sincere Belief that you will > not be able to get anywhere near > realtime with a home PC simply because > too many complicated iterations must > be made for many discrete points. > > You will have to settle with after the fact > processing. > > I have tried a FFT program myself using > my own data on a 3GHz machine and it takes > 11 seconds to process 29 minutes of data > each line of spectrum being seperated by > 4.5 seconds in time. > Each line pass representing 56.2 seconds of time. > > ----- Original Message ----- From: "Larry Conklin" > To: "PSN List" > Sent: Sunday, July 08, 2007 12:56 > Subject: FFT Waterfall display > > >> A couple of years ago I experimented with adding a real-time FFT >> waterfall display to my home brew data logging and display program. I >> got the waterfall working just fine but there is something wrong with >> the FFT calculation that I never got around to debugging. The current >> discussion may motivate me to take another look at it. If I manage to >> get something working, it wouldn't be much additional effort to adapt >> the code into an independent program that would take PSN files as a >> data source. >> >> Larry Conklin >> Liverpool, NY >> lconklin@............ >> __________________________________________________________ >> >> 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: Re[2]: FFT Waterfall display From: "Geoffrey" gmvoeth@........... Date: Sat, 14 Jul 2007 15:55:09 -0700 Hello Chris and PSN; I believe everything you are telling me. BUT, Real time is not really real time. The speed can be tremendous and possibly a sample rate of a megaherts and special whatever will produce a spectrum line in record time. BUT as a human looking at things you will not see reality in your brain until you can perceive it and that takes time. What we call real time is possibly 100ms behind real time. To see real time you must see into the future ahead of where you really are and since I do not believe in time travel in the sci-fi sense We as human beings are prisoners of only the present minus the time it takes our souls to realize it. I myself do not need , Real Time, because I am not looking for enemies like the military always does. I only need to be able to analyze the data I produce to understand a bit better about the reality that surrounds me. I can now see partly with this new FFT thing I have put together with help from wherever that I seem to understand my hardware somewhat but most probably never completely. I am searching for free knowledge to help me use the current tools at my disposal to understand better this seismic hobby and its related sciences. I have no capitalistic intertests. I am sick from fighting humanity. The USA calls me mentally ill but I happen to believe the sickness is really theirs. Thanks for your response. Regards; geoff ----- Original Message ----- From: To: ; Sent: Saturday, July 14, 2007 06:48 Subject: Re: Re[2]: FFT Waterfall display > In a message dated 2007/07/14, gmvoeth@........... writes: > >> The power needed for a real-time FFT display of any value just does not >> exist for a typical home computer. You would need a special card like these high >> speed video cards. >> >> I have seen the machines that do real time fft and back in the 1970s they >> were like 1000X faster than your home computer and would do 500 points and be >> only a few milli seconds behind real time. You most probably will have to >> stick with after the fact processing. > > Hi Geoff, > > There have been several developments in FFTs since the 1970s!! > > The amount of maths required to produce a FFT has been drastically > reduced by new algorithms. > The processors are now thousands of times faster, several may be > included on one chip and they can use vectored instructions. > > It is largely a question of what you are calling 'real time'. > If you use a multitasking processor, the interrupts are maybe 20 to a > few milliseconds or less. Such time delays are not usually important in > amateur seismology. The most likely delay is the relatively slow rate of seismic > sampling. By opting for a 10 Hz low pass filter, you are accepting a 50 milli > second delay minimum. > > I would not expect there to be a problem in providing a FFT display to > update at this rate. I note quoted times of less than 1 milli second to > complete a FFT sample. > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: FFT Waterfall display From: "Geoffrey" gmvoeth@........... Date: Sat, 14 Jul 2007 16:08:25 -0700 Hello Larry and PSN; LOL, I will never believe real time unless you can see the future. My wishes are with you but I fear that what you produce will not be affordable for ME to possess. What is most important to me is to VISUALIZE that which the designs tell me about my circuitry. If I am supposed to see a certain bandwidth I would like to see the data that proves my equipment is functioning properly. A waterfall of a passing storm might reveal the true bandwidth of my circuitry because it is rich in low freq. noise. This does not need to be Real Time so to speak. The FFT does not need to be real time for me to see where all the signals are falling. If you are looking for something going on like TORNADOES or Tunnel Diggers then you need something that is very very fast and almost real time. But Earthquakes have already happened and everything relating to them are simply After-The-Fact. I am still interested in knowing more about everything science\math related. Law Enforcement or Military could probably use real time stuff. But for me it would only be an expensive luxury. Regards; geoff ----- Original Message ----- From: "Larry Conklin" To: Sent: Saturday, July 14, 2007 07:28 Subject: Re: FFT Waterfall display > OooooH Kay... Now I'm beginning to get motivated. I've already got > something running real time, just have to debug the thing to make the > FFT algorithm run correctly. Nothing like a declaration of > impossibility to get the old juices flowing again. > > Larry > > Geoffrey wrote: >> It Is My Sincere Belief that you will >> not be able to get anywhere near >> realtime with a home PC simply because >> too many complicated iterations must >> be made for many discrete points. >> >> You will have to settle with after the fact >> processing. >> >> I have tried a FFT program myself using >> my own data on a 3GHz machine and it takes >> 11 seconds to process 29 minutes of data >> each line of spectrum being seperated by >> 4.5 seconds in time. >> Each line pass representing 56.2 seconds of time. >> >> ----- Original Message ----- From: "Larry Conklin" >> To: "PSN List" >> Sent: Sunday, July 08, 2007 12:56 >> Subject: FFT Waterfall display >> >> >>> A couple of years ago I experimented with adding a real-time FFT >>> waterfall display to my home brew data logging and display program. I >>> got the waterfall working just fine but there is something wrong with >>> the FFT calculation that I never got around to debugging. The current >>> discussion may motivate me to take another look at it. If I manage to >>> get something working, it wouldn't be much additional effort to adapt >>> the code into an independent program that would take PSN files as a >>> data source. >>> >>> Larry Conklin >>> Liverpool, NY >>> lconklin@............ >>> __________________________________________________________ >>> >>> 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: Re[2]: FFT Waterfall display From: "Geoffrey" gmvoeth@........... Date: Sat, 14 Jul 2007 16:15:50 -0700 Hello Michael and PSN; LOL, do you really understand all that MATH gobblygoop. I am not a Mathmatician and not even pretend to be a programmer or Engineer. I need the exact PowerBasic\Dos Source code to compile a program useful with raw binary data. Everyone seems to avoid BASIC and want to use C because thats what they teach at the University. C is like a foreign language to me and if it is not BASIC or Assembly I can not understand it. Point me to a FREE FFT Basic Source Code that does a complete conversion and my ears will perk up. The USN has spoiled me by being able to talk to laymen. Cheers :-) geoff ----- Original Message ----- From: "Michael Kimzey" To: Sent: Saturday, July 14, 2007 05:09 Subject: Re: Re[2]: FFT Waterfall display > Hi all. > >>The power needed for a realtime FFT display >>of any value just does not exist for a typical >>home computer. You would need a special >>card like these high speed video cards. >> >>I have seen the machines that do real time fft >>and back in the 1970s they were like 1000X faster >>than your home computer and would do 500 points >>and be only a few milli seconds behind real time. >> > I'm don't completely understand all this FFT stuff, but a search of google > revealed that you can get several programs for FFT and waterfall display. > Spectrogram 5.1 > http://www.relisoft.com/science/Physics/fft.html <- provides a discussion > of FFT and source code. > Digipan - this is a amature radio program for communicating digitally using > audio output from your sound card and has a very nice waterfall display. > Spectran 2.0 > > Maybe these are not doing something "FFT-wise", but Spectrograph and > Spectran both allow you to set the FFT size and both have the moving > graphical display...and are working on signals with sample rates of 44,000 > per second. I think that any seismological waterfall display would move > -very- slowly...my samples-per-second are only 10 and should be able to > perform some type of FFT. Even Win-Quake does FFT. Maybe I'm missing > something... > > - Mike > > > __________________________________________________________ > > 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: FFT Code From: Bobhelenmcclure@....... Date: Sat, 14 Jul 2007 21:46:27 EDT Hi Geoff, I write my code in Visual Basic, and also have another FFT routine written in QBasic. The code listing below is what I use in my FFTDemo program, which you can access from _http://www.jclahr.com/science/psn/mcclure/index.html_ (http://www.jclahr.com/science/psn/mcclure/index.html) Cheers, Bob ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Private Sub FFT(Z() As Single) Inv = 0 Call FT(Inv, Npwr, Z()) End Sub Private Sub IFT(Z() As Single) Inv = 1 Call FT(Inv, Npwr, Z()) End Sub Private Sub FT(Inv As Long, Npwr As Long, Z() As Single) Dim PI As Single, Isi As Long, ex As Single Dim I As Long, n As Long, J As Long, m As Long, Mmax As Long Dim Ang As Single, wr As Single, wi As Single, tr As Single Dim ti As Single, istep As Long PI = 4# * Atn(1#) Isi = -1 If Inv > 0 Then Isi = 1 n = 1 For I = 1 To Npwr n = 2 * n Next I J = 0 For I = 0 To n - 2 If I < J Then ex = Z(0, I) Z(0, I) = Z(0, J) Z(0, J) = ex ex = Z(1, I) Z(1, I) = Z(1, J) Z(1, J) = ex End If m = n / 2 While m <= J J = J - m m = m / 2 Wend J = J + m Next I Mmax = 1 While Mmax <> n istep = 2 * Mmax For m = 0 To Mmax - 1 Ang = PI * Isi * m / Mmax wr = Cos(Ang) wi = Sin(Ang) For I = m To n - 1 Step istep J = I + Mmax tr = wr * Z(0, J) - wi * Z(1, J) ti = wi * Z(0, J) + wr * Z(1, J) Z(0, J) = Z(0, I) - tr Z(1, J) = Z(1, I) - ti Z(0, I) = Z(0, I) + tr Z(1, I) = Z(1, I) + ti Next I Next m Mmax = istep Wend If Isi > 0 Then For I = 0 To n - 1 Z(0, I) = (1 / n) * Z(0, I) Z(1, I) = (1 / n) * Z(1, I) Next I End If End Sub ************************************** Get a sneak peak of the all-new AOL at http://discover.aol.com/memed/aolcom30tour
Hi Geoff,
 
  I write my code in Visual Basic, and also have another FFT routi= ne=20 written in QBasic. The code listing below is what I use in my FFTDemo progra= m,=20 which you can access from http://www.jcl= ahr.com/science/psn/mcclure/index.html=20
 
Cheers,
 
Bob
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
Private Sub FFT(Z() As Single)
Inv =3D 0<= BR>Call=20 FT(Inv, Npwr, Z())
End Sub
 

Private Sub IFT(Z() As Single)
Inv=20= =3D=20 1
Call FT(Inv, Npwr, Z())
End Sub
 

Private Sub FT(Inv As Long, Npwr As Long= , Z()=20 As Single)
Dim PI As Single, Isi As Long, ex As Single
Dim I As Long,=20= n As=20 Long, J As Long, m As Long, Mmax As Long
Dim Ang As Single, wr As Single,= wi=20 As Single, tr As Single
Dim ti As Single, istep As Long
 PI =3D 4= # *=20 Atn(1#)
 Isi =3D -1
 If Inv > 0 Then Isi =3D 1
 n= =3D=20 1
 For I =3D 1 To Npwr
  n =3D 2 * n
 Next I
&nbs= p;J =3D=20 0
 For I =3D 0 To n - 2
  If I < J Then
   e= x =3D=20 Z(0, I)
   Z(0, I) =3D Z(0, J)
   Z(0, J) =3D=20 ex
   ex =3D Z(1, I)
   Z(1, I) =3D Z(1,=20 J)
   Z(1, J) =3D ex
  End If
  m =3D n / 2
=  =20 While m <=3D J
   J =3D J - m
   m =3D m / 2 =20 Wend
  J =3D J + m
  Next I
  Mmax =3D 1
 Wh= ile Mmax=20 <> n
   istep =3D 2 * Mmax
   For m =3D 0 To= Mmax -=20 1
    Ang =3D PI * Isi * m / Mmax
    wr= =3D=20 Cos(Ang)
    wi =3D Sin(Ang)
    For I=20= =3D m To=20 n - 1 Step istep
     J =3D I +=20 Mmax
     tr =3D wr * Z(0, J) - wi * Z(1,=20 J)
     ti =3D wi * Z(0, J) + wr * Z(1,=20 J)
     Z(0, J) =3D Z(0, I) -=20 tr
     Z(1, J) =3D Z(1, I) -=20 ti
     Z(0, I) =3D Z(0, I) +=20 tr
     Z(1, I) =3D Z(1, I) + ti
   = ; Next=20 I
   Next m
   Mmax =3D istep
  Wend
If= Isi=20 > 0 Then
   For I =3D 0 To n - 1
    Z(0,=20= I) =3D=20 (1 / n) * Z(0, I)
    Z(1, I) =3D (1 / n) * Z(1,=20 I)
   Next I
  End If
 End Sub
 
 



Get a sneak pe= ak of the all-new AOL.com.
<= /BODY> Subject: Re: FFT Waterfall Display From: Bobhelenmcclure@....... Date: Sat, 14 Jul 2007 23:09:39 EDT All of the discussion about waterfall displays finally moved me to make up WAVE files of my data from the M8.2 Kiril Island event of 01/13/2007. I used Raven to listen to the files and look at the waterfall display. I must say that the sound was a lot more interesting than the waterfall display. In my experience, waterfall displays for seismic events is underwhelming. I am willing to send the WAVE files to anybody that might want them. The data was recorded at 5 samples per second. The WAVE file plays back at 8,000 samples per second, and is about 2 seconds in duration. I am at aol dot com. ---Bob ************************************** Get a sneak peak of the all-new AOL at http://discover.aol.com/memed/aolcom30tour
  All of the discussion about waterfall displays finally moved me=20= to=20 make up WAVE files of my data from the M8.2 Kiril Island event of 01/13/2007= .. I=20 used Raven to listen to the files and look at the waterfall display. I must=20= say=20 that the sound was a lot more interesting than the waterfall display. In my=20 experience, waterfall displays for seismic events is underwhelming.
 
  I am willing to send the WAVE files to anybody that might want t= hem.=20 The data was recorded at 5 samples per second. The WAVE file plays back at 8= ,000=20 samples per second, and is about 2 seconds in duration. I am at aol dot=20 com.
 
---Bob



Get a sneak pe= ak of the all-new AOL.com.
<= /BODY> Subject: Re: FFT Waterfall Display From: rbenitez@........ Date: Sat, 14 Jul 2007 23:19:47 -0500 (CDT) Hi Bob, Greetings from Guatemala. I would love to have that M8.2 quake WAVE file. Please send it to me. Best regards, Rolando Fraijanes > All of the discussion about waterfall displays finally moved me to make > up > WAVE files of my data from the M8.2 Kiril Island event of 01/13/2007. I > used > Raven to listen to the files and look at the waterfall display. I must say > that the sound was a lot more interesting than the waterfall display. In > my > experience, waterfall displays for seismic events is underwhelming. > > I am willing to send the WAVE files to anybody that might want them. > The > data was recorded at 5 samples per second. The WAVE file plays back at > 8,000 > samples per second, and is about 2 seconds in duration. I am at aol dot > com. > > ---Bob > > > > ************************************** Get a sneak peak of the all-new AOL > at > http://discover.aol.com/memed/aolcom30tour > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Large earthquake coming ? From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Sun, 15 Jul 2007 20:05:29 +0000 Hi all I am execting a large earthquake near Fox Islands. I base that opinion of a sharp rise in mid size earthquake there over the past few hours. I will see what happens. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Sharing images From: John or Jan Lahr JohnJan@........ Date: Mon, 16 Jul 2007 21:49:04 -0700 Google allows 1 GB of free storage for images. This is better than E-mail for sharing images, as not everyone has the bandwidth to accept large messages (and they aren't allowed on PSN). Check out: http://picasaweb.google.com/home I think you need to use the free Picasa program to do this. Picasa is quite nice program for keeping track of lots of images, and it's also free. Cheers, John __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Springs again From: "Paul Cianciolo" Paulc@........ Date: Tue, 17 Jul 2007 12:07:36 -0400 Hello Folks, I have been building a vertical sensor for the past few weeks, doing lots of experiments. It seems that the longer the spring, the longer the period... As a rough rule of thumb. I also remember Chris explaining about a "Zero Length" spring. My vertical sensor is the type with a lever arm that is 26" long with a mass at one end. The other end of the lever arm has a pivot point about 2" from the end, and a spring on the end to a base plate. This arrangement certainly not a new idea, is new to me., This arrangement yields a 1.1 approx. sec period. By careful adjustment of the pivot point and spring location, I can vary the period and the mass needed to achieve balance. 2 questions. 1) What is the relationship between spring position, pivot location, and mass weight. As I would like to try to optimize this design , if indeed this is a valid path to follow. 2) If a rule of thumb....the longer the spring, the greater the period, within the obvious constraints applies. Has or why not has a vertical sensor been tried with a watch spring, mainspring, arrangement been tried. Sort of a torsion spring, but one with many turns and greater length. Perhaps my assumption that the main spring arrangement equates to a longer spring is faulty? Please comment Thank You PauLC W1VLF Station VLF in Connecticut. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Springs again From: ChrisAtUpw@....... Date: Tue, 17 Jul 2007 22:26:18 EDT In a message dated 2007/07/17, Paulc@........ writes: > My vertical sensor is the type with a lever arm that is 26" long with a > mass > at one end. > The other end of the lever arm has a pivot point about 2" from the end, and > a spring on the end to a base plate. Hi Paul, This is a bit difficult to visualise. Can you make a rough drawing using text characters? > This arrangement certainly not a new idea, is new to me., > This arrangement yields a 1.1 approx. sec period. > By careful adjustment of the pivot point and spring location, I can vary the > period and the mass needed to achieve balance. You can get out to 4 or 5 seconds, but beyond this you need NiSpanC springs to keep the system stable with ambient temperature variations. However, you can extend this period either electronically or using software up to ~x10. See the Roberts circuit for geophones in psn references and on John Lahr's website. It may be easier to make a system for 2.5 seconds and then extend this to 25 seconds. The spring attachment point needs to be maybe 1/2" to 1" above the horizontal arm. > 2 questions. > > 1) What is the relationship between spring position, pivot location, and > mass weight. > As I would like to try to optimize this design , if indeed this is a valid > path to follow. How good is your applied maths? This is a fairly simple triangle of forces problem. You usually start with a coil spring and adjust the arm, mass etc to suit. See the spring calculator at http://jclahr.com/science/psn/mcclure/springcalc/index.html and also http://jclahr.com/science/psn/mcclure/vert1/vert2.html Is your seismometer design anything like http://jclahr.com/science/psn/hill/index.html ? I would strongly advise you to use electromagnetic damping as opposed to oil. Have a look at http://quake.eas.gatech.edu/Instruments/LPVERT0.htm > 2) If a rule of thumb....the longer the spring, the greater the period, > within the obvious constraints applies. > Has or why not has a vertical sensor been tried with a watch spring, > mainspring, arrangement been tried. This is just how long period verticals are designed, but using long triangular shaped leaf springs. Clock type coil springs have too many vibration modes. 'Mouse trap' type torsion coil springs have been used. For a simple spring, the extension E = g x T^2 / (2 x Pi)^2, where T is the period. Thus to get a period of say 10 sec, you need an extension of ~25 metres.... > Sort of a torsion spring, but one with many turns and greater length. > Perhaps my assumption that the main spring arrangement equates to a longer > spring is faulty? No, but this cannot be extended very far, or you start to see the spring vibration modes. You can also make a very good horizontal seismometer using a U tube water manometer. Regards, Chris Chapman In a me= ssage dated 2007/07/17, Paulc@........ writes:

My vertical sensor is the type=20= with a lever arm that is 26" long with a mass
at one end.
The other end of the lever arm has a pivot point about 2" from the end, and<= BR> a spring on the end to a base plate.


Hi Paul,

       This is a bit difficult to visualise. C= an you make a rough drawing using text characters?

This arrangement certainly not=20= a new idea, is new to me.,
This arrangement yields a 1.1 approx. sec period.
By careful adjustment of the pivot point and spring location, I can vary the=
period and the mass needed to achieve balance.


       You can get out to 4 or 5 seconds, but= beyond this you need NiSpanC springs to keep the system stable with ambient= temperature variations. However, you can extend this period either electron= ically or using software up to ~x10. See the Roberts circuit for geophones i= n psn references and on John Lahr's website. It may be easier to make a syst= em for 2.5 seconds and then extend this to 25 seconds.
       The spring attachment point needs to be= maybe 1/2" to 1" above the horizontal arm.

2 questions.

1) What is the relationship between spring position, pivot location, and
mass weight.
As I would like to try to optimize this design , if indeed this is a valid path to follow.


       How good is your applied maths? This is= a fairly simple triangle of forces problem. You usually start with a coil s= pring and adjust the arm, mass etc to suit.

       See the spring calculator at http://jcl= ahr.com/science/psn/mcclure/springcalc/index.html and also http://jclahr.com= /science/psn/mcclure/vert1/vert2.html

       Is your seismometer design anything lik= e http://jclahr.com/science/psn/hill/index.html ? I would strongly advise yo= u to use electromagnetic damping as opposed to oil.

       Have a look at http://quake.eas.gatech.= edu/Instruments/LPVERT0.htm

2) If a rule of thumb....the lo= nger the spring, the greater the period,
within the obvious constraints applies.
Has or why not has a vertical sensor been tried with a watch spring,
mainspring,  arrangement been tried.


       This is just how long period verticals= are designed, but using long triangular shaped leaf springs. Clock type coi= l springs have too many vibration modes. 'Mouse trap' type torsion coil spri= ngs have been used.

        For a simple spring, the extensio= n E =3D g x T^2 / (2 x Pi)^2, where T is the period. Thus to get a period of= say 10 sec, you need an extension of ~25 metres....

Sort of a torsion spring, but o= ne with many turns and greater length.
Perhaps my assumption that the main spring arrangement equates to a longer spring is faulty?


       No, but this cannot be extended very fa= r, or you start to see the spring vibration modes.

       You can also make a very good horizonta= l seismometer using a U tube water manometer.

       Regards,

       Chris Chapman Subject: Re: FFT Code From: Barry Lotz barry_lotz@............. Date: Tue, 17 Jul 2007 21:22:37 -0700 (PDT) Hi Bob this thread reminds me - I had a Fortran fft program that I picked up years ago. I converted it to Quick Basic with success. I tried to convert it to assembly language to run faster but I had problems with the rounding off of numbers. I wrote a triggering program with the fft routine to do short term /long term averaging with frequency rather than amplitude. You could choose the frequency zones for monitoring (avoiding known noisy frequencies). It also worked well . (written in Quick basic) I wanted the program to be able to learn the difference between a near and teleseismic event but never got there. When the recording of the "fft amplitude/area under the curve" fell below the running long term average the recording of the event stopped. I could look at my computer screen after coming home from work an could instantly see blips on the screen from possible events. I fell in to the easy mode now by recording continuously and then looking on the internet every couple of days for events that I think may have been recorded by my sensors. I am thinking of "blowing the dust off and starting again with the investigation. regards Barry PS back when computers were slow the was a frequency transform called a Walsh transform which used square waves rather than sine waves. It ran quite fast but I guess became useless when processors stepped up.
Hi Bob
this thread reminds me - 
 
I had a Fortran fft program that I picked up years ago. I converted it to Quick Basic with success. I tried to convert it to assembly language to run faster but I had problems with the rounding off of numbers. I wrote a triggering program with the fft routine to do short term /long term averaging with frequency rather than amplitude. You could choose the frequency zones for monitoring (avoiding known noisy frequencies). It also worked well . (written in Quick basic) I wanted the program to be able to learn the difference between a near and teleseismic event but never got there. When the recording of the "fft amplitude/area under the curve" fell below the running long term average the recording of the event stopped. I could look at my computer screen after coming home from work an could instantly see blips on the screen from possible events. I fell in to the easy mode now by recording continuously and then looking on the internet every couple of days for events that I think may have been recorded by my sensors. I am thinking of "blowing the dust off and starting again with the investigation.
regards
Barry
PS  back when computers were slow the was a frequency transform called a Walsh transform which used square waves rather than sine waves. It ran quite fast but I guess became useless when processors stepped up.

Subject: Re: FFT Code From: "Geoffrey" gmvoeth@........... Date: Wed, 18 Jul 2007 01:30:56 -0700 WunderBar; I appreciate this since i am having great difficulty understanding it. It seems simple at first but i quickly get lost in the math and juggling of data. I will be sure to play with these ideas and show you results if they amount to anything. If I can get the conversion it is easy to build a BMP file of the results that can be universally shared. I have not yet been able to get a (self programmed) FFT to really work but have a nice little program called SPECTRA that Nuhertz will not let me have the source code. If I could get their code it would be an easy matter to tack on a recursive feature to build the lines of the display history. regards; geoff ----- Original Message ----- From: To: ; Sent: Saturday, July 14, 2007 18:46 Subject: FFT Code > Hi Geoff, > > I write my code in Visual Basic, and also have another FFT routine written > in QBasic. The code listing below is what I use in my FFTDemo program, which > you can access from _http://www.jclahr.com/science/psn/mcclure/index.html_ > (http://www.jclahr.com/science/psn/mcclure/index.html) > > Cheers, > > Bob > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Private Sub FFT(Z() As Single) > Inv = 0 > Call FT(Inv, Npwr, Z()) > End Sub > > > Private Sub IFT(Z() As Single) > Inv = 1 > Call FT(Inv, Npwr, Z()) > End Sub > > > Private Sub FT(Inv As Long, Npwr As Long, Z() As Single) > Dim PI As Single, Isi As Long, ex As Single > Dim I As Long, n As Long, J As Long, m As Long, Mmax As Long > Dim Ang As Single, wr As Single, wi As Single, tr As Single > Dim ti As Single, istep As Long > PI = 4# * Atn(1#) > Isi = -1 > If Inv > 0 Then Isi = 1 > n = 1 > For I = 1 To Npwr > n = 2 * n > Next I > J = 0 > For I = 0 To n - 2 > If I < J Then > ex = Z(0, I) > Z(0, I) = Z(0, J) > Z(0, J) = ex > ex = Z(1, I) > Z(1, I) = Z(1, J) > Z(1, J) = ex > End If > m = n / 2 > While m <= J > J = J - m > m = m / 2 > Wend > J = J + m > Next I > Mmax = 1 > While Mmax <> n > istep = 2 * Mmax > For m = 0 To Mmax - 1 > Ang = PI * Isi * m / Mmax > wr = Cos(Ang) > wi = Sin(Ang) > For I = m To n - 1 Step istep > J = I + Mmax > tr = wr * Z(0, J) - wi * Z(1, J) > ti = wi * Z(0, J) + wr * Z(1, J) > Z(0, J) = Z(0, I) - tr > Z(1, J) = Z(1, I) - ti > Z(0, I) = Z(0, I) + tr > Z(1, I) = Z(1, I) + ti > Next I > Next m > Mmax = istep > Wend > If Isi > 0 Then > For I = 0 To n - 1 > Z(0, I) = (1 / n) * Z(0, I) > Z(1, I) = (1 / n) * Z(1, I) > Next I > End If > End Sub > > > > > > ************************************** Get a sneak peak of the all-new AOL at > http://discover.aol.com/memed/aolcom30tour > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Kiril sound files From: "Dale Hardy" photon1@........... Date: Wed, 18 Jul 2007 20:05:02 +1000 On a lighter side, I have been musing with soundfiles from Earthquakes, = so have created a web page with a few examples. I think a few will have a 'play' enjoy link http://www.daleh.id.au/earthquake_sounds.html regards Dale
 On a lighter side, I have been musing with soundfiles from=20 Earthquakes, so have created a web page with a few
examples. I think a few will have a 'play'
enjoy
 
link  http://www.daleh.i= d.au/earthquake_sounds.html
 
regards
Dale
Subject: Trigger From: tchannel1@............ Date: Wed, 18 Jul 2007 08:14:53 -0600 Hi Folks, I would like to have or create a trigger program to work with = AmaSeis. I know very little about a trigger program, but I guess it = runs in the background and when an earthquake occurs it set off an = alarm, of some kind. I see some helicorders which show earthquakes in red and background = noise in black, and there maybe programs which trigger a .wav file or = something. If someone has info and experience on this subject, or even a program = please contact me. The only thing I would like, is so that it works = with AmaSeis as I use it as my helcorder. Thanks, Ted
Hi Folks,  I would like to have or = create a=20 trigger program to work with AmaSeis.  I know very little about a = trigger=20 program, but I guess it runs in the background and when an earthquake = occurs it=20 set off an alarm, of some kind.
 
I see some helicorders which show = earthquakes in=20 red and background noise in black, and there maybe programs which = trigger a .wav=20 file or something.
 
If someone has info and experience on = this subject,=20 or even a program please contact me.  The only thing I would like, = is so=20 that it works with AmaSeis as I use it as my helcorder.
 
Thanks, Ted
 
 
Subject: Re: Trigger From: ChrisAtUpw@....... Date: Wed, 18 Jul 2007 12:26:54 EDT In a message dated 2007/07/18, tchannel1@............ writes: > Hi Folks, I would like to have or create a trigger program to work with > AmaSeis. I know very little about a trigger program, but I guess it runs in > the background and when an earthquake occurs it set off an alarm, of some kind. Hi Ted, Amaseis is designed for continuous recording in 1 hour files. You can set the display high and low pass filters to 1 Hz and enhance the P waves. I don't see why a STA/LTA filter could not be provided to run a 'beep' on the computer, but you will have to ask Alan Jones about this. Regards, Chris Chapman In a me= ssage dated 2007/07/18, tchannel1@............ writes:

Hi Folks,  I would like to= have or create a trigger program to work with AmaSeis.  I know very li= ttle about a trigger program, but I guess it runs in the background and when= an earthquake occurs it set off an alarm, of some kind.


Hi Ted,

       Amaseis is designed for continuous reco= rding in 1 hour files. You can set the display high and low pass filters to=20= 1 Hz and enhance the P waves.

       I don't see why a STA/LTA filter could=20= not be provided to run a 'beep' on the computer, but you will have to ask Al= an Jones about this.

       Regards,

       Chris Chapman Subject: Mass vs. Coil From: "Jerry Payton" gpayton880@....... Date: Wed, 18 Jul 2007 15:49:24 -0500 You gentlemen are so much advanced and more educate than I that I almost hesitate to ask this question. A lot of your discussions, especially math and physics, go right over my head. However, here goes: I have always wondered why a mass is needed. Why could not the coil itself be used as the mass on a pendulum seismometer? If I understand what I have read in my books (questionable), the size and weight of a mass has nothing to do with the period. Futhermore, I believe the length of the pendulum and supporting spring or wire on a horizontal or vertical sensor matters more for obtaining the wanted period, excluding friction loses etc. The coil is only the desired method of detecting movement. Regards, Jerry Payton
You gentlemen are so much advanced and more educate than I that I = almost=20 hesitate to ask this question.  A lot of your discussions, = especially math=20 and physics, go right over my head.  However, here goes:
 
I have always wondered why a mass is needed.  Why could = not the=20 coil itself  be used as the mass on a pendulum seismometer?  =
 
If  I understand what I have read in my books (questionable), = the size=20 and weight of a mass has nothing to do with the period.  = Futhermore, I=20 believe the length of the pendulum and supporting spring or wire on a = horizontal=20 or vertical sensor matters more for obtaining the wanted period, = excluding=20 friction loses etc.  The coil is only the desired method = of=20 detecting movement.
 
Regards,
Jerry Payton
 
 
Subject: Re: Mass vs. Coil From: tchannel1@............ Date: Wed, 18 Jul 2007 15:30:16 -0600 Hi Jerry, A lot of these discussions go over my head, for sure! However = Someone usually explains its in terms I can understand. A great thing = about the group is there are many levels of education, and just as = important, experiences. Someone will answer your question, better than me, but let me try just = from my experience. If the coil was large enough, you might use it as your mass. I have = seen horz sensors with large and small masses, from 8 ounces to 5 lbs. = Your period, will not change because of your mass. One to two kgs has = been recommended. Someone said the more mass the less movement from air = currents etc. I have one horz with 3 lbs, one with 5 lbs both work well = for me. On my sensors, don't know why, 1 lbs seemed too lite and 6 lbs = seemed too heavy. You might try 3...? On the vertical sensor the mass is whatever is necessary to balance the = spring. On my vertical, I placed a 1/4" threaded bolt and added washers = until it balanced the spring at the correct position.=20 If you are about to build your first sensor, let me know, as I have two = simple vertical versions, very low tech. which work well. Good luck, Ted ----- Original Message -----=20 From: Jerry Payton=20 To: psn-l@................. Sent: Wednesday, July 18, 2007 2:49 PM Subject: Mass vs. Coil You gentlemen are so much advanced and more educate than I that I = almost hesitate to ask this question. A lot of your discussions, = especially math and physics, go right over my head. However, here goes: I have always wondered why a mass is needed. Why could not the coil = itself be used as the mass on a pendulum seismometer? =20 If I understand what I have read in my books (questionable), the size = and weight of a mass has nothing to do with the period. Futhermore, I = believe the length of the pendulum and supporting spring or wire on a = horizontal or vertical sensor matters more for obtaining the wanted = period, excluding friction loses etc. The coil is only the desired = method of detecting movement.=20 Regards, Jerry Payton
Hi Jerry, A lot of these discussions go = over my=20 head, for sure!  However Someone usually explains its in terms I = can=20 understand.   A great thing about the group is there are many = levels=20 of education, and just as important, experiences.
Someone will answer your question, = better than me,=20 but let me try just from my experience.
 
If the coil was large enough, you might = use it as=20 your mass.  I have seen horz sensors with large and small masses, = from 8=20 ounces to 5 lbs.  Your period, will not change because of your = mass.=20  One  to two kgs has been recommended.  Someone said the = more=20 mass the less movement from air currents etc.  I have one horz with = 3 lbs,=20 one with 5 lbs both work well for me.  On my sensors, don't = know why,=20 1 lbs seemed too lite and 6 lbs seemed too heavy.  You might try=20 3...?
 
On the vertical sensor the mass is = whatever is=20 necessary to balance the spring.  On my vertical, I = placed a 1/4"=20 threaded bolt and added washers until = it balanced=20 the spring at the correct position.
 
If you are about to build your first = sensor, let me=20 know, as I have two simple vertical versions, very low tech. which work=20 well.
 
 
Good luck, Ted
 
 
 
----- Original Message -----
From:=20 Jerry = Payton=20
Sent: Wednesday, July 18, 2007 = 2:49=20 PM
Subject: Mass vs. Coil

You gentlemen are so much advanced and more educate than I that I = almost=20 hesitate to ask this question.  A lot of your discussions, = especially=20 math and physics, go right over my head.  However, here = goes:
 
I have always wondered why a mass is needed.  Why could = not the=20 coil itself  be used as the mass on a pendulum seismometer?  =
 
If  I understand what I have read in my books = (questionable), the=20 size and weight of a mass has nothing to do with the period.  = Futhermore,=20 I believe the length of the pendulum and supporting spring or wire on = a=20 horizontal or vertical sensor matters more for obtaining the wanted = period,=20 excluding friction loses etc.  The coil is only the = desired=20 method of detecting movement.
 
Regards,
Jerry Payton
 
 
Subject: Re: Mass vs. Coil From: "Jerry Payton" gpayton880@....... Date: Wed, 18 Jul 2007 16:55:26 -0500 > Someone said the more mass the less movement from air currents etc. That is one good reason, that had not occurred to me, but might also be offset by a large coil of sufficient size & weight. > On the vertical sensor the mass is whatever is necessary to balance the > spring. By "balancing the spring", I assume you mean a pendulum suspended horizontally by a diagonal spring? > If you are about to build your first sensor, let me know, as I have two > simple vertical versions, very low tech. which work well. Ted, I had two sensors built by John Cole from Texas. One was a Lehman horz. and a custom vertical which was basically two custom-wound springs supporting a connecting metal beam that supported the coil which was suspended between the poles of the magnet. I "fiddled" with those two sensors for almost a year, spend hundreds of dollars in texts and finally gave up. I returned the devices to john, as he had requested. I'm still interested in seismology as witnessed by my monitoring this group. BUT, much of what is discussed is frankly over my head. Sensor "kits" are not available. Therefore, I remain somewhere between a "dumb ass" and a "wanta-be." Yes, I would like to see these low tech designs that you have and you may send them directly to me at ab5r @ cox dot net, if you wish. (BTW I still have Larry Cochran's electronics configured for two sensors and his software) Regards, Jerry
> Someone said the more mass the = less movement=20 from air currents etc. 
 
That = is one good=20 reason, that had not occurred to me, but might also be offset by a large = coil of=20 sufficient size & weight. 
 
> On the vertical sensor the mass is = whatever is=20 necessary to balance the spring. 
 
By "balancing the spring", I assume you = mean a=20 pendulum suspended horizontally by a diagonal spring?
 
> If you are about to build your = first sensor,=20 let me know, as I have two simple vertical versions, very low tech. = which work=20 well.
 
Ted, I had two sensors built by John = Cole from=20 Texas.  One was a Lehman horz. and a custom vertical which was = basically=20 two custom-wound springs supporting a connecting metal beam that = supported the=20 coil which was suspended between the poles of the magnet.  =
 
I "fiddled" with those two sensors for = almost a=20 year, spend hundreds of dollars in texts and finally gave up.  I = returned=20 the devices to john, as he had requested. 
 
I'm still interested in seismology as = witnessed by=20 my monitoring this group.  BUT, much of what is discussed is = frankly over=20 my head.  Sensor "kits" are not available. Therefore, I remain = somewhere=20 between a "dumb ass" and a "wanta-be." 
 
Yes, I would like to see these low tech = designs=20 that you have and you may send them directly to me at ab5r @ cox dot = net, if you=20 wish.
 
(BTW  I still have Larry Cochran's = electronics=20 configured for two sensors and his software)
 
Regards,
Jerry
 
 
Subject: Re: Mass vs. Coil From: Mark Robinson mark.robinson@............... Date: Thu, 19 Jul 2007 10:19:23 +1200 Jerry Payton wrote: > If I understand what I have read in my books (questionable), the size > and weight of a mass has nothing to do with the period. Hi jerry, I suggest you perform a simple experiment: Take a spring, perhaps the spatula for the kitchen. Clamp the handle to the edge of a table with your hand and give the blade a twang. Note the frequency. Now add some mass to the end. Perhaps some blu-tack and coins. Twang again and note the frequency. Cheers Mark __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mass vs. Coil From: "Geoffrey" gmvoeth@........... Date: Wed, 18 Jul 2007 18:19:33 -0700 The spring constant dictates the period and all simple extension springs seem to behave according to the period and length of a pendulum. If you need 10 to 12 inched of wire to make a 1 second pendulum then whatever weight of mass will cause the sprint to drop ten or twelve inches from rest will give you the same period. This assumes no pretensioning of the extension spring and that it is linear in its response. The inches/pound spring constant will dictate the period depending upon the weight/mass applied. The longer the spring the more intense the temperature affects I do not know how to deal cheaply with the physical constants that are a nusance. Regards; geoff ----- Original Message ----- From: "Jerry Payton" To: Sent: Wednesday, July 18, 2007 13:49 Subject: Mass vs. Coil > You gentlemen are so much advanced and more educate than I that I almost > hesitate to ask this question. A lot of your discussions, especially math > and physics, go right over my head. However, here goes: > > I have always wondered why a mass is needed. Why could not the coil itself > be used as the mass on a pendulum seismometer? > > If I understand what I have read in my books (questionable), the size and > weight of a mass has nothing to do with the period. Futhermore, I believe > the length of the pendulum and supporting spring or wire on a horizontal or > vertical sensor matters more for obtaining the wanted period, excluding > friction loses etc. The coil is only the desired method of detecting > movement. > > Regards, > Jerry Payton > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Springs again From: Bobhelenmcclure@....... Date: Wed, 18 Jul 2007 21:33:56 EDT Hi Paul, Have you looked at my web pages at _http://www.jclahr.com/science/psn/mcclure/index.html_ (http://www.jclahr.com/science/psn/mcclure/index.html) There you will find a description and picture of my vertical sensor, which operates at a period of about 5 seconds. By the way, the coil is the most of the mass. Also there is a page describing my spring calculator for use in vertical seismometers. You would do well to download and experiment with the calculator. The trick to getting a long period is to arrange the geometry of the spring so that a decentering force is created to offset most of the restoring force of the spring. A zero-length spring automatically does this. You have to relocate the support point of the spring if it is not zero length. For an AS-1 type of seismometer, the upper end support of the spring should not be directly above the hinge, but back of it. This adjustment is very delicate if long period is the goal. For a sensor of the type you describe, the following links may be helpful: _http://quake.eas.gatech.edu/Instruments/LPVERT0.htm_ (http://quake.eas.gatech.edu/Instruments/LPVERT0.htm) _http://www.eas.slu.edu/People/STMorrissey/index.html_ (http://www.eas.slu.edu/People/STMorrissey/index.html) Cheers, Bob ************************************** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour
Hi Paul,
 
  Have you looked at my web pages at
 
  http://www.jcl= ahr.com/science/psn/mcclure/index.html
 
  There you will find a description and picture of my vertical sen= sor,=20 which operates at a period of about 5 seconds. By the way, the coil is the m= ost=20 of the mass.
 
  Also there is a page describing my spring calculator for use in=20 vertical seismometers. You would do well to download and experiment with the= =20 calculator. The trick to getting a long period is to arrange the geometry of= the=20 spring so that a decentering force is created to offset most of the restorin= g=20 force of the spring. A zero-length spring automatically does this. You have=20= to=20 relocate the support point of the spring if it is not zero length. For an AS= -1=20 type of seismometer, the upper end support of the spring should not be direc= tly=20 above the hinge, but back of it. This adjustment is very delicate if long pe= riod=20 is the goal.
 
  For a sensor of the type you describe, the following links may b= e=20 helpful:
 
  http://quake.ea= s.gatech.edu/Instruments/LPVERT0.htm
 
  http://www.eas= ..slu.edu/People/STMorrissey/index.html
 
Cheers,
 
Bob



Get a snea= k peek of the all-new AOL.com. Subject: Re: Trigger From: "Geoffrey" gmvoeth@........... Date: Wed, 18 Jul 2007 18:36:44 -0700 By trigger I assume you mean an ALARM it might be best as a TRIGGER/ALARM combination. That is what i do here at GVA. I recommend a frequency sensitive trigger that will respond only at or below one or two hertz. Look at only the positive half cycle and look at the contiguous ( yes contiguous) string of samples on the plus side that represents the freq of interest. Set a thresh hold above the baseline to measure the contiguous samples. Like a venus fly trap look for three triggers in a certain length of time. If you do not achive the proper alarm conditions reset everything to zero and start looking again. Make your recorder modulo 12 or 15 minutes and you should never miss any worthwhile Earthquakes. Make it modulo in RAM then when the recording is triggered complete the data set. Straighten out the modulo stuff just before you save the EQ file. When the alarm is triggered jump to the end of modulo secton to continue the recording in RAM to its ultimate limit before saving. You can do this all automatically with home written code. It would be nice if it were standardized tho. Use an UPS system to guard against power failures. One that will allow an hour or more of power loss. Make the numbers adjustable during operation so you do not have to recompile the program each time you want to make any changes. Regards; geoff ----- Original Message ----- From: To: Sent: Wednesday, July 18, 2007 07:14 Subject: Trigger Hi Folks, I would like to have or create a trigger program to work with AmaSeis. I know very little about a trigger program, but I guess it runs in the background and when an earthquake occurs it set off an alarm, of some kind. I see some helicorders which show earthquakes in red and background noise in black, and there maybe programs which trigger a .wav file or something. If someone has info and experience on this subject, or even a program please contact me. The only thing I would like, is so that it works with AmaSeis as I use it as my helcorder. Thanks, Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Kiril sound files From: "Geoffrey" gmvoeth@........... Date: Wed, 18 Jul 2007 18:41:13 -0700 I have noticed in my files that are limited to 0.2 to 2 Hz that the teleseismic waves make a BOOM like thunder and the regional ones sound like books being dropped and bouncing. Also that human activity other than mining would have a hard time impersonating these sounds. Regards; geoff ----- Original Message ----- From: "Dale Hardy" To: Sent: Wednesday, July 18, 2007 03:05 Subject: Re: Kiril sound files On a lighter side, I have been musing with soundfiles from Earthquakes, so have created a web page with a few examples. I think a few will have a 'play' enjoy link http://www.daleh.id.au/earthquake_sounds.html regards Dale __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Mass vs. Coil From: ChrisAtUpw@....... Date: Wed, 18 Jul 2007 22:15:53 EDT In a message dated 2007/07/18, gpayton880@....... writes: > I have always wondered why a mass is needed. Why could not the coil itself > be used as the mass on a pendulum seismometer? Hi Jerry, It could be and it has been. But a coil may not be quite as dimensionally stable as a solid mass and you don't really need large coils in these days, with NdFeB magnets readily available. One substitute for a mass is to use a 1/4" to 3/8" thick horizontal copper plate for both the mass and the damping blade. Winding a coil of maybe 1 lb of wire takes a lot of time and care - apart from the cost! I find coil winding an effort, not a pleasure! The biggest coil that I ever wound was 80,000 turns and it took several days to make with interleaved doped paper layers. You need a certain mass for the motion not to be swamped by thermal or environmental agitation / noise. It is the product M x T x Q, which is important for noise considerations, not just the mass M. T is the set period and Q is the mechanical analogue of the intrinsic damping (w x L / R for an oscillating circuit). > If I understand what I have read in my books (questionable), the size and > weight of a mass has nothing to do with the period. Certainly in theory, but you have to suspend the mass at the end of an arm, which needs to be light in comparison to the mass - otherwise it seriously shortens the period. You are in practice limited by the materials that you can easily buy. You need the distance between the centre of mass and the hinge to be maximised. You need a certain minimum mass to get over thermal excitation, but usually a lot more to avoid the effects of small air currents and tiny losses in the suspension system. The arm / suspension needs to be very rigid. Very light mass systems may appear unstable, noisy or 'sticky'. Not all suspension systems are equal, some have much more inbuilt friction / losses than others. The point in a cup and the real knife edge suspensions are particularly poor. The ball on a plane and crossed cylinders are much better. Furthermore, I believe the length of the pendulum and supporting spring or wire on a > horizontal or vertical sensor matters more for obtaining the wanted period, > excluding friction loses etc. The coil is only the desired method of > detecting movement. If you hang up the mass by the boom and hinge vertically, it will have a period given ~by the usual formula 2 x Pi x Sqrt(L/g). You then reduce the restoring force by suspending it a small angle to the vertical to get the 'garden gate' arrangement. Getting an increase in period of x10 is not difficult (1/100 of g), but larger increases get progressively more difficult, as the suspension angle gets below 0.3 of a degree. This also makes the system highly sensitive to ground tilt effects, more difficult to adjust and keep in adjustment and it requires a very good low loss suspension or you will find that you can't get stable long periods. Electromagnetic damping is usually used. It can be made simple and easy to adjust. You can use quad magnets on mild steel backing plates and a Copper blade, or you can use larger quad magnets to drive the sensor coil and put a variable load resistor across that. I prefer the damping blade, since you can use it to limit the swing of the arm and it has the lowest noise. Oil damping tends to be relatively difficult to adjust, non linear in it's effect and very temperature sensitive. It is also messy. Oil creeps over most surfaces and they then collect dust and dirt. The operation looks superficially simple, but it is a headache waiting to happen. Verticals use a spring of some sort to counterbalance the gravitational force. You can get periods out to about 5 seconds with ordinary steel springs, but the thermal drift of the spring constant limits you. The system just 'collapses'. Professional systems use NiSpanC springs which are extremely stable. There are a variety of possible sensors. The simplest is the magnet + coil velocity sensor. These are OK for 'normal' use, but are noise limited at long periods, say over 60 seconds. Optical and Hall magnetic effect position sensors can also be used on amateur equipment. Professional equipment tends to use LVDT magnetic or LCDT capacitative sensors. The LVDT types have a noise limit of about 0.1 nm. Capacitative types can get an extra factor of 100 on this. Force feedback may be used with a position sensor to stabilise the operating position and to extend the natural period of the seismometer. This is a very rough description of the 'background' to amateur seismometer design. Most of the limitations are practical - there are good and not so good ways of making things, relatively cheap and quite expensive materials. Choosing only the cheapest options are likely to limit the performance. Hope that it is of some help / interest. Regards, Chris Chapman In a me= ssage dated 2007/07/18, gpayton880@....... writes:

I have always wondered why a ma= ss is needed.  Why could not the coil itself be used as the mass on a p= endulum seismometer?


Hi Jerry,

       It could be and it has been. But a coil= may not be quite as dimensionally stable as a solid mass and you don't real= ly need large coils in these days, with NdFeB magnets readily available. One= substitute for a mass is to use a 1/4" to 3/8" thick horizontal copper plat= e for both the mass and the damping blade. Winding a coil of maybe 1 lb of w= ire takes a lot of time and care - apart from the cost! I find coil winding=20= an effort, not a pleasure! The biggest coil that I ever wound was 80,000 tur= ns and it took several days to make with interleaved doped paper layers.

       You need a certain mass for the motion=20= not to be swamped by thermal or environmental agitation / noise.
    It is the product M x T x Q, which is important for noise= considerations, not just the mass M. T is the set period and Q is the mecha= nical analogue of the intrinsic damping (w x L / R for an oscillating circui= t).

If I understand what I have re= ad in my books (questionable), the size and weight of a mass has nothing to=20= do with the period. 


       Certainly in theory, but you have to s= uspend the mass at the end of an arm, which needs to be light in comparison=20= to the mass - otherwise it seriously shortens the period. You are in practic= e limited by the materials that you can easily buy. You need the distance be= tween the centre of mass and the hinge to be maximised. You need a certain m= inimum mass to get over thermal excitation, but usually a lot more to avoid=20= the effects of small air currents and tiny losses in the suspension system.=20= The arm / suspension needs to be very rigid. Very light mass systems may app= ear unstable, noisy or 'sticky'.
       Not all suspension systems are equal, s= ome have much more inbuilt friction / losses than others. The point in a cup= and the real knife edge suspensions are particularly poor. The ball on a pl= ane and crossed cylinders are much better.

Furthermore, I believe the length of the pendulum and supporting spring or w= ire on a
horizontal or vertical sensor=20= matters more for obtaining the wanted period, excluding friction loses etc.&= nbsp; The coil is only the desired method of detecting movement.

       If you hang up the mass by the boom and= hinge vertically, it will have a period given ~by the usual formula 2 x Pi=20= x Sqrt(L/g). You then reduce the restoring force by suspending it a small an= gle to the vertical to get the 'garden gate' arrangement. Getting an increas= e in period of x10 is not difficult (1/100 of g), but larger increases get p= rogressively more difficult, as the suspension angle gets below 0.3 of a deg= ree. This also makes the system highly sensitive to ground tilt effects, mor= e difficult to adjust and keep in adjustment and it requires a very good low= loss suspension or you will find that you can't get stable long periods.
       Electromagnetic damping is usually used= .. It can be made simple and easy to adjust. You can use quad magnets on mild= steel backing plates and a Copper blade, or you can use larger quad magnets= to drive the sensor coil and put a variable load resistor across that. I pr= efer the damping blade, since you can use it to limit the swing of the arm a= nd it has the lowest noise.
       Oil damping tends to be relatively diff= icult to adjust, non linear in it's effect and very temperature sensitive. I= t is also messy. Oil creeps over most surfaces and they then collect dust an= d dirt. The operation looks superficially simple, but it is a headache waiti= ng to happen.

       Verticals use a spring of some sort to=20= counterbalance the gravitational force. You can get periods out to about 5 s= econds with ordinary steel springs, but the thermal drift of the spring cons= tant limits you. The system just 'collapses'. Professional systems use NiSpa= nC springs which are extremely stable.

       There are a variety of possible sensors= .. The simplest is the magnet + coil velocity sensor. These are OK for 'norma= l' use, but are noise limited at long periods, say over 60 seconds. Optical=20= and Hall magnetic effect position sensors can also be used on amateur equipm= ent. Professional equipment tends to use LVDT magnetic or LCDT capacitative=20= sensors. The LVDT types have a noise limit of about 0.1 nm. Capacitative typ= es can get an extra factor of 100 on this.

       Force feedback may be used with a posit= ion sensor to stabilise the operating position and to extend the natural per= iod of the seismometer.

       This is a very rough description of the= 'background' to amateur seismometer design. Most of the limitations are pra= ctical - there are good and not so good ways of making things, relatively ch= eap and quite expensive materials. Choosing only the cheapest options are li= kely to limit the performance.

       Hope that it is of some help / interest= ..

       Regards,

       Chris Chapman Subject: Re: Digest from 07/17/2007 00:01:20 From: Randall Peters PETERS_RD@.......... Date: Thu, 19 Jul 2007 11:52:05 -0400 Because of the recent interest in FFT's, I have posted some files on my webpage at http://physics.mercer.edu/hpage/psn/psn.html The pdf's should help those of you who have been wondering how the Fourier transform works and why the Cooley-Tukey form (Fast version) is SO MUCH better than the discrete FT (for which there is much needless, repetitive calculations). The executable can be downloaded (I promise that it is safe to use) and some data files have been posted to the site so that you can run test cases. test and test 2 are pure sine signals, one with a period of 17 s and the other 1000 s. The 0704 file is a record of the Solomon Islands EQ recorded wtih Larry Cochrane's VolksMeter. Before you can use the files you must rename your saved version (*.txt) to *.dat. This suffix must be typed in along with the filename when you are prompted for the input file. I have included the basic file from which the executable was created by QuickBasic (dos version which I've used for about 15 years). For those who might want to create a 'streaming' executable that operates on binary data, I can give you a sample file to look at--from there you will be 'on your own'. The FFT code that I've used is based on the structure given in the very excellent "Numerical Recipes" book by Press et al, with which most scientists are familiar. I hope that many of you will want to also transition from the FFT to the power spectral density (PSD), since the former is instrument dependent, whereas the latter is not (transfer function of the instrument used to provide correction). With the PSD, individuals having different hardware designs could still do meaningful comparison of their data. Some of you may wonder how I ever learned how to do the things posted on this webpage. Answer--years ago I became interested in the Fourier Transform because of its enormous importance to physics in general. I actually coded some early personal computers (with abysmally small memory) to do the necessary calculations. When speed was also abysmally slow, I became interested in the incredible improvement to be realized with the 'fast' version. The vector graphics form that I've provided in the pdf descriptions enables one to appreciate why the Cooley-Tukey algorithm allow 'technology to fly'. I enjoy the discussions on the listserve even though I have not been a frequent contributor to them. Keep up the good work; you guys are great! Randall psn-l-digest-request@.............. wrote: > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. > | Message 1 | > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' > Subject: Springs again > From: "Paul Cianciolo" > Date: Tue, 17 Jul 2007 12:07:36 -0400 > > Hello Folks, > > I have been building a vertical sensor for the past few weeks, doing lots of > experiments. > > It seems that the longer the spring, the longer the period... As a rough > rule of thumb. > I also remember Chris explaining about a "Zero Length" spring. > > My vertical sensor is the type with a lever arm that is 26" long with a mass > at one end. > The other end of the lever arm has a pivot point about 2" from the end, and > a spring on the end to a base plate. > > This arrangement certainly not a new idea, is new to me., > This arrangement yields a 1.1 approx. sec period. > By careful adjustment of the pivot point and spring location, I can vary the > period and the mass needed to achieve balance. > > 2 questions. > > 1) What is the relationship between spring position, pivot location, and > mass weight. > As I would like to try to optimize this design , if indeed this is a valid > path to follow. > > 2) If a rule of thumb....the longer the spring, the greater the period, > within the obvious constraints applies. > Has or why not has a vertical sensor been tried with a watch spring, > mainspring, arrangement been tried. > > Sort of a torsion spring, but one with many turns and greater length. > Perhaps my assumption that the main spring arrangement equates to a longer > spring is faulty? > > Please comment > > Thank You > > PauLC > W1VLF > Station VLF in Connecticut. > > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. > | Message 2 | > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' > Subject: Re: Springs again > From: ChrisAtUpw@....... > Date: Tue, 17 Jul 2007 22:26:18 EDT > > --part1_c43.15acd5bc.33ced44a_boundary > Content-Type: text/plain; charset="US-ASCII" > Content-Transfer-Encoding: 7bit > > In a message dated 2007/07/17, Paulc@........ writes: > > > My vertical sensor is the type with a lever arm that is 26" long with a > > mass > > at one end. > > The other end of the lever arm has a pivot point about 2" from the end, and > > a spring on the end to a base plate. > > Hi Paul, > > This is a bit difficult to visualise. Can you make a rough drawing > using text characters? > > > This arrangement certainly not a new idea, is new to me., > > This arrangement yields a 1.1 approx. sec period. > > By careful adjustment of the pivot point and spring location, I can vary the > > period and the mass needed to achieve balance. > > You can get out to 4 or 5 seconds, but beyond this you need NiSpanC > springs to keep the system stable with ambient temperature variations. However, > you can extend this period either electronically or using software up to ~x10. > See the Roberts circuit for geophones in psn references and on John Lahr's > website. It may be easier to make a system for 2.5 seconds and then extend this > to 25 seconds. > The spring attachment point needs to be maybe 1/2" to 1" above the > horizontal arm. > > > 2 questions. > > > > 1) What is the relationship between spring position, pivot location, and > > mass weight. > > As I would like to try to optimize this design , if indeed this is a valid > > path to follow. > > How good is your applied maths? This is a fairly simple triangle of > forces problem. You usually start with a coil spring and adjust the arm, mass > etc to suit. > > See the spring calculator at > http://jclahr.com/science/psn/mcclure/springcalc/index.html and also > http://jclahr.com/science/psn/mcclure/vert1/vert2.html > > Is your seismometer design anything like > http://jclahr.com/science/psn/hill/index.html ? I would strongly advise you to use electromagnetic damping > as opposed to oil. > > Have a look at http://quake.eas.gatech.edu/Instruments/LPVERT0.htm > > > 2) If a rule of thumb....the longer the spring, the greater the period, > > within the obvious constraints applies. > > Has or why not has a vertical sensor been tried with a watch spring, > > mainspring, arrangement been tried. > > This is just how long period verticals are designed, but using long > triangular shaped leaf springs. Clock type coil springs have too many vibration > modes. 'Mouse trap' type torsion coil springs have been used. > > For a simple spring, the extension E = g x T^2 / (2 x Pi)^2, where T > is the period. Thus to get a period of say 10 sec, you need an extension of > ~25 metres.... > > > Sort of a torsion spring, but one with many turns and greater length. > > Perhaps my assumption that the main spring arrangement equates to a longer > > spring is faulty? > > No, but this cannot be extended very far, or you start to see the > spring vibration modes. > > You can also make a very good horizontal seismometer using a U tube > water manometer. > > Regards, > > Chris Chapman > > --part1_c43.15acd5bc.33ced44a_boundary > Content-Type: text/html; charset="US-ASCII" > Content-Transfer-Encoding: quoted-printable > > In a me= > ssage dated 2007/07/17, Paulc@........ writes:
>
>
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">My vertical sensor is the type=20= > with a lever arm that is 26" long with a mass
> at one end.
> The other end of the lever arm has a pivot point about 2" from the end, and<= > BR> > a spring on the end to a base plate. #ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"= > SANSSERIF" FACE=3D"Arial" LANG=3D"0">

>
> #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"= > >Hi Paul,
>
>        This is a bit difficult to visualise. C= > an you make a rough drawing using text characters? 0000" BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE= > =3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">
> #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"= > >
>
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">This arrangement certainly not=20= > a new idea, is new to me.,
> This arrangement yields a 1.1 approx. sec period.
> By careful adjustment of the pivot point and spring location, I can vary the= >
> period and the mass needed to achieve balance. " BACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10=20= > FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">

>
> #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"= > >       You can get out to 4 or 5 seconds, but= > beyond this you need NiSpanC springs to keep the system stable with ambient= > temperature variations. However, you can extend this period either electron= > ically or using software up to ~x10. See the Roberts circuit for geophones i= > n psn references and on John Lahr's website. It may be easier to make a syst= > em for 2.5 seconds and then extend this to 25 seconds.
>        The spring attachment point needs to be= > maybe 1/2" to 1" above the horizontal arm. ACK=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAM= > ILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">
> #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"= > >
>
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">2 questions.
>
> 1) What is the relationship between spring position, pivot location, and
> mass weight.
> As I would like to try to optimize this design , if indeed this is a valid R> > path to follow. KGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Ar= > ial" LANG=3D"0">

> #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"= > >
>        How good is your applied maths? This is= > a fairly simple triangle of forces problem. You usually start with a coil s= > pring and adjust the arm, mass etc to suit.
>
>        See the spring calculator at http://jcl= > ahr.com/science/psn/mcclure/springcalc/index.html and also http://jclahr.com= > /science/psn/mcclure/vert1/vert2.html
>
>        Is your seismometer design anything lik= > e http://jclahr.com/science/psn/hill/index.html ? I would strongly advise yo= > u to use electromagnetic damping as opposed to oil.
>
>        Have a look at http://quake.eas.gatech.= > edu/Instruments/LPVERT0.htm style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF= > " FACE=3D"Arial" LANG=3D"0">
> #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"= > >
>
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">2) If a rule of thumb....the lo= > nger the spring, the greater the period,
> within the obvious constraints applies.
> Has or why not has a vertical sensor been tried with a watch spring,
> mainspring,  arrangement been tried. K=3D"#ffffff" style=3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAMIL= > Y=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">

>
> #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"= > >       This is just how long period verticals= > are designed, but using long triangular shaped leaf springs. Clock type coi= > l springs have too many vibration modes. 'Mouse trap' type torsion coil spri= > ngs have been used. =3D"BACKGROUND-COLOR: #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FAC= > E=3D"Arial" LANG=3D"0">
> #ffffff" SIZE=3D2 PTSIZE=3D10 FAMILY=3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0"= > >
>         For a simple spring, the extensio= > n E =3D g x T^2 / (2 x Pi)^2, where T is the period. Thus to get a period of= > say 10 sec, you need an extension of ~25 metres....
>
>
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Sort of a torsion spring, but o= > ne with many turns and greater length.
> Perhaps my assumption that the main spring arrangement equates to a longer R> > spring is faulty?

>
>        No, but this cannot be extended very fa= > r, or you start to see the spring vibration modes.
>
>        You can also make a very good horizonta= > l seismometer using a U tube water manometer.
>
>        Regards,
>
>        Chris Chapman > > --part1_c43.15acd5bc.33ced44a_boundary-- > > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. > | Message 3 | > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' > Subject: Re: FFT Code > From: Barry Lotz > Date: Tue, 17 Jul 2007 21:22:37 -0700 (PDT) > > --0-1895494773-1184732557=:22985 > Content-Type: text/plain; charset=iso-8859-1 > Content-Transfer-Encoding: 8bit > > Hi Bob > this thread reminds me - > > I had a Fortran fft program that I picked up years ago. I converted it to Quick Basic with success. I tried to convert it to assembly language to run faster but I had problems with the rounding off of numbers. I wrote a triggering program with the fft routine to do short term /long term averaging with frequency rather than amplitude. You could choose the frequency zones for monitoring (avoiding known noisy frequencies). It also worked well . (written in Quick basic) I wanted the program to be able to learn the difference between a near and teleseismic event but never got there. When the recording of the "fft amplitude/area under the curve" fell below the running long term average the recording of the event stopped. I could look at my computer screen after coming home from work an could instantly see blips on the screen from possible events. I fell in to the easy mode now by recording continuously and then looking on the internet every couple of days for events that I > think may have been recorded by my sensors. I am thinking of "blowing the dust off and starting again with the investigation. > regards > Barry > PS back when computers were slow the was a frequency transform called a Walsh transform which used square waves rather than sine waves. It ran quite fast but I guess became useless when processors stepped up. > > --0-1895494773-1184732557=:22985 > Content-Type: text/html; charset=iso-8859-1 > Content-Transfer-Encoding: 8bit > >
Hi Bob
this thread reminds me - 
 
I had a Fortran fft program that I picked up years ago. I converted it to Quick Basic with success. I tried to convert it to assembly language to run faster but I had problems with the rounding off of numbers. I wrote a triggering program with the fft routine to do short term /long term averaging with frequency rather than amplitude. You could choose the frequency zones for monitoring (avoiding known noisy frequencies). It also worked well . (written in Quick basic) I wanted the program to be able to learn the difference between a near and teleseismic event but never got there. When the recording of the "fft amplitude/area under the curve" fell below the running long term average the recording of the event stopped. I could look at my computer screen after coming home from work an could instantly see blips on the screen from possible events. I fell in to the easy mode > now by recording continuously and then looking on the internet every couple of days for events that I think may have been recorded by my sensors. I am thinking of "blowing the dust off and starting again with the investigation.
regards
Barry
PS  back when computers were slow the was a frequency transform called a Walsh transform which used square waves rather than sine waves. It ran quite fast but I guess became useless when processors stepped up.

> --0-1895494773-1184732557=:22985-- > > __________________________________________________________ > > 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. Subject: RE: Springs again From: "Paul Cianciolo" Paulc@........ Date: Thu, 19 Jul 2007 13:46:51 -0400 Hello Chris, Thanks again as always for the help. I have abandoned the geometry I was using (at least for the moment) in favor of the the" AS-1 like" geometry you suggested. A very quick couple of experiments on the bench showed with the same pendulum length that I had been using, period went from 1.1 secs to a bit over 3 secs. This was done using springs that I had in the junk drawer, but had overlooked since the previous model used a much shorter spring. Pivot I MASS ----@----@--------------------------------------------------- MASS S MASS P R I N G __________________________________________________________________________ __________ Chris, In the picture above the spring provides upward restoration. The pivot is a hard steel rod with its axis horizontal and perpendicular with the pendulum. The springs was a valve spring several types from different engines. My thought was if I could get a "clock" spring to work, place it at the pivot point and then build lateral bearings. The assumption was that the clock spring would appear as a very long spring since it was wound on itself. For the time being I will stick with the AS-1 architecture. The purpose here is to log close in events. Thank you PauLC iginal Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of ChrisAtUpw@....... Sent: Tuesday, July 17, 2007 10:26 PM To: psn-l@.............. Subject: Re: Springs again In a message dated 2007/07/17, Paulc@........ writes: My vertical sensor is the type with a lever arm that is 26" long with a mass at one end. The other end of the lever arm has a pivot point about 2" from the end, and a spring on the end to a base plate. Hi Paul, This is a bit difficult to visualise. Can you make a rough drawing using text characters? This arrangement certainly not a new idea, is new to me., This arrangement yields a 1.1 approx. sec period. By careful adjustment of the pivot point and spring location, I can vary the period and the mass needed to achieve balance. You can get out to 4 or 5 seconds, but beyond this you need NiSpanC springs to keep the system stable with ambient temperature variations. However, you can extend this period either electronically or using software up to ~x10. See the Roberts circuit for geophones in psn references and on John Lahr's website. It may be easier to make a system for 2.5 seconds and then extend this to 25 seconds. The spring attachment point needs to be maybe 1/2" to 1" above the horizontal arm. 2 questions. 1) What is the relationship between spring position, pivot location, and mass weight. As I would like to try to optimize this design , if indeed this is a valid path to follow. How good is your applied maths? This is a fairly simple triangle of forces problem. You usually start with a coil spring and adjust the arm, mass etc to suit. See the spring calculator at http://jclahr.com/science/psn/mcclure/springcalc/index.html and also http://jclahr.com/science/psn/mcclure/vert1/vert2.html Is your seismometer design anything like http://jclahr.com/science/psn/hill/index.html ? I would strongly advise you to use electromagnetic damping as opposed to oil. Have a look at http://quake.eas.gatech.edu/Instruments/LPVERT0.htm 2) If a rule of thumb....the longer the spring, the greater the period, within the obvious constraints applies. Has or why not has a vertical sensor been tried with a watch spring, mainspring, arrangement been tried. This is just how long period verticals are designed, but using long triangular shaped leaf springs. Clock type coil springs have too many vibration modes. 'Mouse trap' type torsion coil springs have been used. For a simple spring, the extension E = g x T^2 / (2 x Pi)^2, where T is the period. Thus to get a period of say 10 sec, you need an extension of ~25 metres.... Sort of a torsion spring, but one with many turns and greater length. Perhaps my assumption that the main spring arrangement equates to a longer spring is faulty? No, but this cannot be extended very far, or you start to see the spring vibration modes. You can also make a very good horizontal seismometer using a U tube water manometer. Regards, Chris Chapman
Hello=20 Chris,
 
Thanks=20 again as always for the help.
 
I have=20 abandoned the geometry I was using (at least for the moment) in favor of = the=20 the" AS-1 like" geometry you suggested.
A very=20 quick couple of experiments on the bench showed with the = same pendulum=20 length that I had been using,  period went from 1.1 secs to a bit = over 3=20 secs.
 
This=20 was done using springs that I had in the junk drawer, but had overlooked = since=20 the previous model used a much shorter spring.
          &nbs= p;            = ;        
          &nbs= p;            = ;        =20 Pivot      
          &nbs= p;          =20             &= nbsp;I         &n= bsp;           &nb= sp;           &nbs= p;            = ;            =             &= nbsp;           &n= bsp;           &nb= sp;           &nbs= p;        =20   MASS
          &nbs= p;   =20 ----@----@---------------------------------------------------MASS<= /SPAN>
     =20             &= nbsp;       =20 S         &n= bsp;           &nb= sp;           &nbs= p;            = ;          =20    =20 MASS           &nb= sp;           &nbs= p; =20
           &nbs= p;            = ;            =          =20 P
          &nbs= p;            = ;        =20             &= nbsp; =20 R
          &nbs= p;            = ;            =        =20      I
          &nbs= p;            = ;            =          =20   N
          &nbs= p;            = ;            =        =20    G
 =20 _________________________________________________________________________= ___________
       &nbs= p;            = ;            =             &= nbsp;                 &nbs= p;            = ;            =                   &nbs= p;            = ;            =             &= nbsp;           &n= bsp;           &nb= sp;           
Chris,
 
In the picture above the spring = provides upward=20 restoration.
The pivot is a hard = steel rod with=20 its axis horizontal and perpendicular with the pendulum.
 
The springs was a valve = spring=20 several types from different engines.
 
My thought was if I = could get a=20 "clock" spring to work, place it at the pivot point and then build = lateral=20 bearings.
 
The assumption was that = the clock=20 spring would appear as a very long spring since it was wound on=20 itself.
 
For the time being I = will stick with=20 the AS-1 architecture.
 
The purpose here is to = log close in=20 events.
 
Thank you
 
PauLC
 
 
 
 
 
 
iginal Message-----
From:=20 psn-l-request@.............. [mailto:psn-l-request@...............On = Behalf=20 Of ChrisAtUpw@.......
Sent: Tuesday, July 17, 2007 10:26=20 PM
To: psn-l@..............
Subject: Re: Springs=20 again

In = a message=20 dated 2007/07/17, Paulc@........ writes:

My vertical sensor is the type with a lever arm that is = 26" long=20 with a mass
at one end.
The other end of the lever arm has a = pivot=20 point about 2" from the end, and
a spring on the end to a base=20 plate.


Hi=20 Paul,

       This is a bit = difficult to=20 visualise. Can you make a rough drawing using text = characters?

This arrangement certainly not a new idea, is new to=20 me.,
This arrangement yields a 1.1 approx. sec period.
By = careful=20 adjustment of the pivot point and spring location, I can vary = the
period=20 and the mass needed to achieve balance.


       You can=20 get out to 4 or 5 seconds, but beyond this you need NiSpanC springs to = keep=20 the system stable with ambient temperature variations. However, you = can extend=20 this period either electronically or using software up to ~x10. See = the=20 Roberts circuit for geophones in psn references and on John Lahr's = website. It=20 may be easier to make a system for 2.5 seconds and then extend this to = 25=20 seconds.
       The spring attachment = point=20 needs to be maybe 1/2" to 1" above the horizontal arm.

2 questions.

1) What is the relationship between = spring=20 position, pivot location, and
mass weight.
As I would like to = try to=20 optimize this design , if indeed this is a valid
path to=20 follow.

       How=20 good is your applied maths? This is a fairly simple triangle of forces = problem. You usually start with a coil spring and adjust the arm, mass = etc to=20 suit.

       See the spring = calculator at=20 http://jclahr.com/science/psn/mcclure/springcalc/index.html and also=20 = http://jclahr.com/science/psn/mcclure/vert1/vert2.html

  = ;    =20 Is your seismometer design anything like=20 http://jclahr.com/science/psn/hill/index.html ? I would strongly = advise you to=20 use electromagnetic damping as opposed to=20 oil.

       Have a look at=20 http://quake.eas.gatech.edu/Instruments/LPVERT0.htm

2) If a rule of thumb....the longer the spring, the = greater the=20 period,
within the obvious constraints applies.
Has or why not = has a=20 vertical sensor been tried with a watch spring,
mainspring,  = arrangement been tried.

       This is=20 just how long period verticals are designed, but using long triangular = shaped=20 leaf springs. Clock type coil springs have too many vibration modes. = 'Mouse=20 trap' type torsion coil springs have been used.

        For a = simple=20 spring, the extension E =3D g x T^2 / (2 x Pi)^2, where T is the = period. Thus to=20 get a period of say 10 sec, you need an extension of ~25 = metres....

Sort of a torsion spring, but one with many turns and = greater=20 length.
Perhaps my assumption that the main spring arrangement = equates to=20 a longer
spring is=20 faulty?

       No, = but this=20 cannot be extended very far, or you start to see the spring vibration = modes.=20

       You can also make a very = good=20 horizontal seismometer using a U tube water=20 manometer.

      =20 Regards,

       Chris = Chapman=20 Subject: Re: Digest from 07/17/2007 00:01:20 From: Bobhelenmcclure@....... Date: Sat, 21 Jul 2007 11:04:26 EDT Hi Randall, I tried out your QuickBasic program using the compiled program and running from the source code. Changing the file name is not necessary, so long as you enter the complete name. You neglected to tell users what keys to use to re-run or terminate the program. Cheers, Bob ~~~~~~~~~~Original Message~~~~~~~~~~~ Subject: Re: Digest from 07/17/2007 00:01:20 From: Randall Peters PETERS_RD@.......... Date: Thu, 19 Jul 2007 11:52:05 -0400 Because of the recent interest in FFT's, I have posted some files on my webpage at _http://physics.mercer.edu/hpage/psn/psn.html_ (http://physics.mercer.edu/hpage/psn/psn.html) The pdf's should help those of you who have been wondering how the Fourier transform works and why the Cooley-Tukey form (Fast version) is SO MUCH better than the discrete FT (for which there is much needless, repetitive calculations). The executable can be downloaded (I promise that it is safe to use) and some data files have been posted to the site so that you can run test cases. test and test 2 are pure sine signals, one with a period of 17 s and the other 1000 s. The 0704 file is a record of the Solomon Islands EQ recorded wtih Larry Cochrane's VolksMeter. Before you can use the files you must rename your saved version (*.txt) to *.dat. This suffix must be typed in along with the filename when you are prompted for the input file. ************************************** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour
Hi Randall,
 
  I tried out your QuickBasic program using the compiled program a= nd=20 running from the source code. Changing the file name is not necessary, so lo= ng=20 as you enter the complete name.
 
  You neglected to tell users what keys to use to re-run or termin= ate=20 the program. 
 
Cheers,
 
Bob
 
~~~~~~~~~~Original Message~~~~~~~~~~~
Subject: Re: Digest from 07/17/2007 00:01:20
From: Randall Peters=20 PETERS_RD@..........
Date: Thu, 19 Jul 2007 11:52:05 -0400
 
Because of  the recent interest in FFT's, I have posted some files= on=20 my webpage at
http://physics.mercer.= edu/hpage/psn/psn.html
 =20 The pdf's should help those of you who have been wondering how the Fourier=20 transform works and why the Cooley-Tukey form (Fast version)
is SO MUCH=20 better than the discrete FT (for which there is much needless, repetitive=20 calculations).
  The executable can be downloaded (I promise that it= is=20 safe to use) and some data files have been posted to the site so that you ca= n=20 run test cases.  test and test 2 are pure sine signals, one with a peri= od=20 of 17 s and the other 1000 s.  The 0704 file is a record of the Solomon= =20 Islands EQ recorded wtih Larry Cochrane's VolksMeter.  Before you can u= se=20 the files you must rename your saved version (*.txt) to *.dat.  This su= ffix=20 must be typed in along with the filename when you are prompted for the input= =20 file.



Get a sneak p= eek of the all-new AOL.com.
= Subject: RE: Digest from 07/17/2007 00:01:20 From: "Stephen Hammond" shammon1@............. Date: Sat, 21 Jul 2007 10:25:46 -0700 I was wondering if anybody has written a Java program that uses Larry's PSN formatted data. I would be interested in seeing the source code and what they did with it. Steve Hammond PSN San Jose, CA -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Bobhelenmcclure@....... Sent: Saturday, July 21, 2007 8:04 AM To: psn-l@............... PETERS_RD@.......... Subject: Re: Digest from 07/17/2007 00:01:20 Hi Randall, I tried out your QuickBasic program using the compiled program and running from the source code. Changing the file name is not necessary, so long as you enter the complete name. You neglected to tell users what keys to use to re-run or terminate the program. Cheers, Bob ~~~~~~~~~~Original Message~~~~~~~~~~~ Subject: Re: Digest from 07/17/2007 00:01:20 From: Randall Peters PETERS_RD@.......... Date: Thu, 19 Jul 2007 11:52:05 -0400 Because of the recent interest in FFT's, I have posted some files on my webpage at http://physics.mercer.edu/hpage/psn/psn.html The pdf's should help those of you who have been wondering how the Fourier transform works and why the Cooley-Tukey form (Fast version) is SO MUCH better than the discrete FT (for which there is much needless, repetitive calculations). The executable can be downloaded (I promise that it is safe to use) and some data files have been posted to the site so that you can run test cases. test and test 2 are pure sine signals, one with a period of 17 s and the other 1000 s. The 0704 file is a record of the Solomon Islands EQ recorded wtih Larry Cochrane's VolksMeter. Before you can use the files you must rename your saved version (*.txt) to *.dat. This suffix must be typed in along with the filename when you are prompted for the input file. _____ Get a sneak peek of the all-new AOL.com .

I was wondering = if anybody has written a Java program that uses Larry’s PSN formatted = data. I would be interested in seeing the source code and what they did with it. =

Steve Hammond PSN = San Jose, CA

 

-----Original = Message-----
From: = psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Bobhelenmcclure@.......
Sent: Saturday, July 21, = 2007 8:04 AM
To: psn-l@............... PETERS_RD@..........
Subject: Re: Digest from 07/17/2007 00:01:20

 

Hi = Randall,

 

  I tried out your QuickBasic program using the compiled program and = running from the source code. Changing the file name is not necessary, so long as you = enter the complete name.

 

  You neglected to tell users what keys to use to re-run or terminate the program. 

 

Cheers,

 

Bob

 

~~~~~~~~~~Origin= al Message~~~~~~~~~~~

Subject: Re: Digest from 07/17/2007 00:01:20
From: Randall Peters PETERS_RD@..........
Date: Thu, 19 Jul 2007 11:52:05 -0400

 

Because of  the recent interest in FFT's, I have posted some files on my = webpage at
http://physics.merc= er.edu/hpage/psn/psn.html
  The pdf's should help those of you who have been wondering how = the Fourier transform works and why the Cooley-Tukey form (Fast version)
is SO MUCH better than the discrete FT (for which there is much = needless, repetitive calculations).
  The executable can be downloaded (I promise that it is safe to = use) and some data files have been posted to the site so that you can run test cases.  test and test 2 are pure sine signals, one with a period of = 17 s and the other 1000 s.  The 0704 file is a record of the Solomon = Islands EQ recorded wtih Larry Cochrane's VolksMeter.  Before you can use the = files you must rename your saved version (*.txt) to *.dat.  This suffix = must be typed in along with the filename when you are prompted for the input = file.



Get a sneak peek of the all-new AOL.com.

Subject: Re: Digest from 07/17/2007 00:01:20 From: Randall Peters PETERS_RD@.......... Date: Sat, 21 Jul 2007 20:04:33 -0400 Thanks, Bob. I did eventually realize my failure to mention 'x' to terminate and 'r' to rerun. Randall Bobhelenmcclure@....... wrote: > Hi Randall, I tried out your QuickBasic program using the compiled > program and running from the source code. Changing the file name is > not necessary, so long as you enter the complete name. You neglected > to tell users what keys to use to re-run or terminate the > program. Cheers, Bob ~~~~~~~~~~Original Message~~~~~~~~~~~Subject: Re: > Digest from 07/17/2007 00:01:20 > From: Randall Peters PETERS_RD@.......... > Date: Thu, 19 Jul 2007 11:52:05 -0400 Because of the recent interest > in FFT's, I have posted some files on my webpage at > http://physics.mercer.edu/hpage/psn/psn.html > The pdf's should help those of you who have been wondering how the > Fourier transform works and why the Cooley-Tukey form (Fast version) > is SO MUCH better than the discrete FT (for which there is much > needless, repetitive calculations). > The executable can be downloaded (I promise that it is safe to use) > and some data files have been posted to the site so that you can run > test cases. test and test 2 are pure sine signals, one with a period > of 17 s and the other 1000 s. The 0704 file is a record of the > Solomon Islands EQ recorded wtih Larry Cochrane's VolksMeter. Before > you can use the files you must rename your saved version (*.txt) to > *.dat. This suffix must be typed in along with the filename when you > are prompted for the input file. > > > ----------------------------------------------------------------------- > Get a sneak peek of the all-new AOL.com. Thanks, Bob.  I did eventually realize my failure to mention 'x' to terminate and 'r' to rerun.
   Randall

Bobhelenmcclure@....... wrote:

 Hi Randall,   I tried out your QuickBasic program using the compiled program and running from the source code. Changing the file name is not necessary, so long as you enter the complete name.   You neglected to tell users what keys to use to re-run or terminate the program. Cheers, Bob ~~~~~~~~~~Original Message~~~~~~~~~~~Subject: Re: Digest from 07/17/2007 00:01:20
From: Randall Peters PETERS_RD@..........
Date: Thu, 19 Jul 2007 11:52:05 -0400 Because of  the recent interest in FFT's, I have posted some files on my webpage at
http://physics.mercer.edu/hpage/psn/psn.html
  The pdf's should help those of you who have been wondering how the Fourier transform works and why the Cooley-Tukey form (Fast version)
is SO MUCH better than the discrete FT (for which there is much needless, repetitive calculations).
  The executable can be downloaded (I promise that it is safe to use) and some data files have been posted to the site so that you can run test cases.  test and test 2 are pure sine signals, one with a period of 17 s and the other 1000 s.  The 0704 file is a record of the Solomon Islands EQ recorded wtih Larry Cochrane's VolksMeter.  Before you can use the files you must rename your saved version (*.txt) to *.dat.  This suffix must be typed in along with the filename when you are prompted for the input file.
 
 
Get a sneak peek of the all-new AOL.com.
Subject: Re: Digest from 07/21/2007 00:00:38 From: Bobhelenmcclure@....... Date: Sun, 22 Jul 2007 21:24:22 EDT Hi Steve, I do not code in Java, but I have code in Visual Basic 6.0 which reads, filters, and writes PSN files (my WQFilter.exe utility). Alan Jones is working on a Java version of AmaSeis. He probably has a Java routine for making PSN files. Bob McClure In a message dated 07/22/2007 03:00:33 AM Eastern Daylight Time, _shammon1@.......... (mailto:shammon1@.......... writes: I was wondering if anybody has written a Java program that uses Larry's PSN formatted data. I would be interested in seeing the source code and what they did with it. Steve Hammond PSN San Jose, CA ************************************** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour
Hi Steve,
 
  I do not code in Java, but I have code in Visual Basic 6.0=20 which reads, filters, and writes PSN files (my WQFilter.exe utility). Alan J= ones=20 is working on a Java version of AmaSeis. He probably has a Java routine for=20 making PSN files.
 
Bob McClure
 
In a message dated 07/22/2007 03:00:33 AM Eastern Daylight Time, shammon1@......... writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>I was=20 wondering if anybody has written a Java program that uses Larry's
PSN=20 formatted data. I would be interested in seeing the source code and
wha= t=20 they did with it.
Steve Hammond PSN San Jose,=20 CA
 



Get a sneak pe= ek of the all-new AOL.com.
<= /BODY> Subject: =?ISO-8859-1?Q?Kverkfj=F6ll?= Volcano activite update notice #1 From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Mon, 23 Jul 2007 02:14:08 +0000 Hi all This is my first offical volcano update notice on a possible eruption in Iceland. It appears that the volcano system Kverkfj=F6ll is on the move, but there has been a series of small earthquakes in the Kverkfj=F6ll fissure swarm. There have been many small earthquakes recorded, most of them happen at the depth of ~20 km, but the depth is down to 1 km. But since the swarm started six months ago. Icelandic Met office has recored about ~2000 earthquakes at the location, but the location is called "Upptyppinga", but that are a mountin far as I can tell. IMO has incresed it's survilance of the area. I will send out a new upate notice on the activie soon as I know more. Here are information on the volcano. http://www.volcano.si.edu/world/volcano.cfm?vnum=3D1703-05=3D I have recored few earthquakes from that area, but the strongest onces did go up to ~2.7M. But most of the earthquakes are mag -1.0 to 2.7 at 20 to 1 km depth. This notice is based on a news I did see on a Icelandic news web. I am going to collect more info tomorrow (Monday). Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: winquake event report From: Barry Lotz barry_lotz@............. Date: Sun, 22 Jul 2007 20:18:25 -0700 (PDT) Hi I have had some recent problems with obtaining event reports via an historical lookup using data@............... I has worked well in the recent past. Has something changed? regards Barry
Hi
  I have had some recent problems with obtaining event reports via an historical lookup using data@binghamton.edu. I has worked well in the recent past. Has something changed?
regards
Barry
 
Subject: Spring Damping. From: "Paul Cianciolo" Paulc@........ Date: Mon, 23 Jul 2007 14:58:32 -0400 Folks, I just finished up a vertical sensor with an AS-1 like suspension. After looking at the AS-1 pictures, and reading about it, I cannot see any information about the damping of the suspension spring. Does any one have one of these? What am I missing because the spring being used here while allow in for almost 4 sec. period, once excited rings for a long time. It seems that a magnet mounted in the center of the spring, and an aluminum plate is very effective in reducing these. Any ideas? My spring is ferrous, and I would like to get a non ferrous replacement. PauLC W1VLF
Folks,
 
I just=20 finished up a  vertical  sensor with an AS-1 like=20 suspension.
After=20 looking at the AS-1 pictures, and reading about it, I cannot see any = information=20 about the damping of the suspension spring.
 
Does=20 any one have one of these?  What am I missing because the spring = being used=20 here while allow in for almost 4 sec. period, once = excited rings for a=20 long time.
 
It=20 seems that a magnet mounted in the center of the spring, and an = aluminum=20 plate is very effective in reducing these.
 
Any=20 ideas?
 
My spring is ferrous, and I would like to get a non = ferrous=20 replacement.
 
PauLC
W1VLF  
Subject: Re: Spring Damping. From: John Lahr johnjan@........ Date: Mon, 23 Jul 2007 12:11:36 -0700 Hi Paul, The damping for the AS-1 is via an attachment to the lower side of the boom. The best method is to use magnetic damping. Here's a design by Chris Chapman: http://jclahr.com/science/psn/chapman/as1%20damping/index.html Cheers, John At 11:58 AM 7/23/2007, you wrote: >Folks, > >I just finished up a vertical sensor with an AS-1 like suspension. >After looking at the AS-1 pictures, and reading about it, I cannot >see any information about the damping of the suspension spring. > >Does any one have one of these? What am I missing because the >spring being used here while allow in for almost 4 sec. period, once >excited rings for a long time. > >It seems that a magnet mounted in the center of the spring, and an >aluminum plate is very effective in reducing these. > >Any ideas? > >My spring is ferrous, and I would like to get a non ferrous replacement. > >PauLC >W1VLF __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Spring Damping. From: ChrisAtUpw@....... Date: Mon, 23 Jul 2007 15:42:42 EDT In a message dated 2007/07/23, Paulc@........ writes: > I just finished up a vertical sensor with an AS-1 like suspension. > After looking at the AS-1 pictures, and reading about it, I cannot see any > information about the damping of the suspension spring. Hi Paul, You don't try to damp the spring itself, but you do damp the arm. For suggestions see http://jclahr.com/science/psn/chapman/as1%20damping/index.html It can be an advantage to mount the damping blade close to the mass. This system is very flexible. You just slide the magnet fixture further over the damping blade until you get the correct damping. I have tried 1/16" Al sheet for the blade glued to SS threaded rod with two part acrylic glue. It works OK, but it is not so effective. Regards, Chris Chapman In a me= ssage dated 2007/07/23, Paulc@........ writes:

I just finished up a  ver= tical  sensor with an AS-1 like suspension.
After looking at the AS-1 pictures, and reading about it, I cannot see any=20= information about the damping of the suspension spring.


Hi Paul,

       You don't try to damp the spring itself= , but you do damp the arm. For suggestions see http://jclahr.com/science/psn= /chapman/as1%20damping/index.html
       It can be an advantage to mount the dam= ping blade close to the mass. This system is very flexible. You just slide t= he magnet fixture further over the damping blade until you get the correct d= amping. I have tried 1/16" Al sheet for the blade glued to SS threaded rod w= ith two part acrylic glue. It works OK, but it is not so effective.

       Regards,

       Chris Chapman Subject: RE: Spring Damping to Chris and John From: "Paul Cianciolo" Paulc@........ Date: Mon, 23 Jul 2007 16:07:56 -0400 Chris, John, I understand about the damping of the arm on the AS-1. Later I put up some pix on my website to illustrate, this. If I depress the arm say 3/4" on my sensor, the arm will return to zero position overshoot about 1/2 cycle and return to rest at zero. However the suspension spring rings, resonates at a rate of a few hertz, imparting its resonance on top of the 4 sec period of the sensor. This is what I need to stop. If the suspension spring on the AS-1 is plucked does it not vibrate at some frequency and impart that noise into the machine?? PaulC -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of ChrisAtUpw@....... Sent: Monday, July 23, 2007 3:43 PM To: psn-l@.............. Subject: Re: Spring Damping. In a message dated 2007/07/23, Paulc@........ writes: I just finished up a vertical sensor with an AS-1 like suspension. After looking at the AS-1 pictures, and reading about it, I cannot see any information about the damping of the suspension spring. Hi Paul, You don't try to damp the spring itself, but you do damp the arm. For suggestions see http://jclahr.com/science/psn/chapman/as1%20damping/index.html It can be an advantage to mount the damping blade close to the mass. This system is very flexible. You just slide the magnet fixture further over the damping blade until you get the correct damping. I have tried 1/16" Al sheet for the blade glued to SS threaded rod with two part acrylic glue. It works OK, but it is not so effective. Regards, Chris Chapman
Chris,=20 John,
 
I=20 understand about the damping of the arm on the AS-1.
Later=20 I put up some pix on my website to illustrate, this.
 
If I=20 depress the arm say 3/4" on my sensor, the arm will return to zero = position=20 overshoot about 1/2 cycle and return to rest at = zero.
However the suspension spring rings, resonates at a rate of a = few hertz,=20 imparting its resonance on top of the  4 sec period of the sensor.
 
This=20 is what I need to stop.
 
If the=20 suspension spring on the AS-1 is plucked does it not vibrate at = some=20 frequency and impart that noise into the machine??
 
PaulC
 
 
-----Original Message-----
From: = psn-l-request@................. [mailto:psn-l-request@...............On Behalf Of=20 ChrisAtUpw@.......
Sent: Monday, July 23, 2007 3:43=20 PM
To: psn-l@..............
Subject: Re: Spring=20 Damping.

In a message dated 2007/07/23, Paulc@........... writes:

 I just finished up a  vertical  sensor with an = AS-1=20 like suspension.
After looking at the AS-1 pictures, and reading = about it, I=20 cannot see any information about the damping of the suspension=20 spring.


Hi=20 Paul,

       You don't try to = damp the=20 spring itself, but you do damp the arm. For suggestions see=20 = http://jclahr.com/science/psn/chapman/as1%20damping/index.html
 &= nbsp;    =20 It can be an advantage to mount the damping blade close to the mass. = This=20 system is very flexible. You just slide the magnet fixture further = over the=20 damping blade until you get the correct damping. I have tried 1/16" Al = sheet=20 for the blade glued to SS threaded rod with two part acrylic glue. It = works=20 OK, but it is not so effective. =

      =20 Regards,

       Chris = Chapman=20 Subject: Re: Spring Damping to Chris and John From: ChrisAtUpw@....... Date: Mon, 23 Jul 2007 18:47:47 EDT In a message dated 2007/07/23, Paulc@........ writes: > If I depress the arm say 3/4" on my sensor, the arm will return to zero > position overshoot about 1/2 cycle and return to rest at zero. Hi Paul, The damping need to set so that if you displace the arm by 10 mm, it just swings back through the zero position by ~0.5 mm. > However the suspension spring rings, resonates at a rate of a few hertz, > imparting its resonance on top of the 4 sec period of the sensor. > This is what I need to stop. Maybe increase the spring tension so that it resonates at >10 Hz and set the low pass filter to reject everything above 5 Hz? > If the suspension spring on the AS-1 is plucked does it not vibrate at some > frequency and impart that noise into the machine? Certainly it will resonate if you do that, but are you really planning for >M6 local quakes? I would be surprised if you ever saw significant spring resonance effects. The whole system would need to be shaken at the resonant frequency, or by a seismic signal which has a rise time shorter than this. High frequency movements are severely damped. You can attach tiny cubic NdFeB magnets at points on a spring and mount a copper plate or tube close to them. This is sometimes done for leaf springs. Regards, Chris Chapman In a me= ssage dated 2007/07/23, Paulc@........ writes:

If I depress the arm say 3/4"=20= on my sensor, the arm will return to zero position overshoot about 1/2 cycle= and return to rest at zero.


Hi Paul,
      
       The damping need to set so that if you=20= displace the arm by 10 mm, it just swings back through the zero position by=20= ~0.5 mm.

However the suspension spring=20= rings, resonates at a rate of a few hertz, imparting its resonance on top of= the  4 sec period of the sensor.
This is what I need to stop.


       Maybe increase the spring tension so t= hat it resonates at >10 Hz and set the low pass filter to reject everythi= ng above 5 Hz?

If the suspension spring on th= e AS-1 is plucked does it not vibrate at some frequency and impart that nois= e into the machine?


       Certainly it will resonate if you do th= at, but are you really planning for >M6 local quakes? I would be surprise= d if you ever saw significant spring resonance effects. The whole system wou= ld need to be shaken at the resonant frequency, or by a seismic signal which= has a rise time shorter than this. High frequency movements are severely da= mped. You can attach tiny cubic NdFeB magnets at points on a spring and moun= t a copper plate or tube close to them. This is sometimes done for leaf spri= ngs.

       Regards,

       Chris Chapman Subject: RE: Spring Damping to Chris and John From: "Paul Cianciolo" Paulc@........ Date: Mon, 23 Jul 2007 19:31:11 -0400 Chris, Maybe I am making too much out of this problem, but I will try the tiny neo's and see what happens. Thanks for giving a push into back into the world of reality. Plucking the spring is really not a realistic situation. PauLC -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@................. Behalf Of ChrisAtUpw@....... Sent: Monday, July 23, 2007 6:48 PM To: psn-l@.............. Subject: Re: Spring Damping to Chris and John In a message dated 2007/07/23, Paulc@........ writes: If I depress the arm say 3/4" on my sensor, the arm will return to zero position overshoot about 1/2 cycle and return to rest at zero. Hi Paul, The damping need to set so that if you displace the arm by 10 mm, it just swings back through the zero position by ~0.5 mm. However the suspension spring rings, resonates at a rate of a few hertz, imparting its resonance on top of the 4 sec period of the sensor. This is what I need to stop. Maybe increase the spring tension so that it resonates at >10 Hz and set the low pass filter to reject everything above 5 Hz? If the suspension spring on the AS-1 is plucked does it not vibrate at some frequency and impart that noise into the machine? Certainly it will resonate if you do that, but are you really planning for >M6 local quakes? I would be surprised if you ever saw significant spring resonance effects. The whole system would need to be shaken at the resonant frequency, or by a seismic signal which has a rise time shorter than this. High frequency movements are severely damped. You can attach tiny cubic NdFeB magnets at points on a spring and mount a copper plate or tube close to them. This is sometimes done for leaf springs. Regards, Chris Chapman
Chris,
 
Maybe=20 I am making too much out of this = problem, but I will try=20 the tiny neo's and see what happens.
 
Thanks=20 for giving a push into back into the world of = reality.
Plucking the spring is really not a realistic=20 situation.
 
PauLC
 
 
-----Original Message-----
From: = psn-l-request@................. [mailto:psn-l-request@...............On Behalf Of=20 ChrisAtUpw@.......
Sent: Monday, July 23, 2007 6:48=20 PM
To: psn-l@..............
Subject: Re: Spring = Damping to=20 Chris and John

In a message dated 2007/07/23, Paulc@........... writes:

 If I depress the arm say 3/4" on my sensor, the arm will = return=20 to zero position overshoot about 1/2 cycle and return to rest at=20 zero.


Hi=20 Paul,
      =20
       The damping need to set so = that if=20 you displace the arm by 10 mm, it just swings back through the zero = position=20 by ~0.5 mm.

 However the suspension spring rings, resonates at a rate = of a=20 few hertz, imparting its resonance on top of the  4 sec period of = the=20 sensor.
This is what I need to stop.

       Maybe=20 increase the spring tension so that it resonates at >10 Hz and set = the low=20 pass filter to reject everything above 5 Hz?

 If the suspension spring on the AS-1 is plucked does it = not=20 vibrate at some frequency and impart that noise into the=20 machine?

      =20 Certainly it will resonate if you do that, but are you really planning = for=20 >M6 local quakes? I would be surprised if you ever saw significant = spring=20 resonance effects. The whole system would need to be shaken at the = resonant=20 frequency, or by a seismic signal which has a rise time shorter than = this.=20 High frequency movements are severely damped. You can attach tiny = cubic NdFeB=20 magnets at points on a spring and mount a copper plate or tube close = to them.=20 This is sometimes done for leaf springs.=20

      =20 Regards,

       Chris = Chapman=20 Subject: Re: Spring Damping From: Bobhelenmcclure@....... Date: Tue, 24 Jul 2007 00:27:39 EDT The discussion of the effects of spring vibration made me look up the following paragraph from the Physics section of the downloaded manual. It seems that vibration has no first order effect on vertical sensor performance if the spring is zero length. Bob LaCoste & Romberg INSTRUCTION MANUAL MODEL G & D GRAVITY METERS _Http://www.LaCosteRomberg.com_ (http://www.LaCosteRomberg.com) "An important feature of the zero length spring suspension is its insensitivity to longitudinal and transverse vibrations (Harrison 1960, LaCoste 1967). Consider the spring to be made of identical masses with segments of weightless zero length spring between the masses. The top end of the spring is attached to A and the bottom to B. Since the spring segments are zero length springs, the forces each spring exerts on the adjacent masses are proportional to the spring length. Therefore, if the masses are equally spaced vertically, the vertical component of force exerted on each mass will be zero regardless of its horizontal position or horizontal motion. Also, the vertical components of force are proportional to the vertical component of spring length. (The vertical component of the force vector remains the same.) Also, the vertical force on A and B will be independent of any horizontal motions." ************************************** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour
The discussion of the effects of spring vibration made me look up the=20 following paragraph from the Physics section of the downloaded manual. It se= ems=20 that vibration has no first order effect on vertical sensor performance if t= he=20 spring is zero length.
 
Bob
 
LaCoste & Romberg
INSTRUCTION MANUAL
MODEL G & D GRAVITY=20 METERS
Http://www.LaCosteRomberg.com

"An important feature of the zero length spring suspension is=20 its
insensitivity to longitudinal and transverse vibrations=20 (Harrison
1960, LaCoste 1967). Consider the spring to be made of=20 identical
masses with segments of weightless zero length spring between=20 the
masses. The top end of the spring is attached to A and the bottom
= to=20 B. Since the spring segments are zero length springs, the forces
each spr= ing=20 exerts on the adjacent masses are proportional to the
spring length.=20 Therefore, if the masses are equally spaced vertically,
the vertical=20 component of force exerted on each mass will be
zero regardless of its=20 horizontal position or horizontal motion.
Also, the vertical components o= f=20 force are proportional to the
vertical component of spring length. (The=20 vertical component of
the force vector remains the same.) Also, the verti= cal=20 force on A
and B will be independent of any horizontal=20 motions."



Get a sneak peek= of the all-new AOL.com.
Subject: Re: Spring Damping. From: "Geoffrey" gmvoeth@........... Date: Tue, 24 Jul 2007 00:56:28 -0700 I understand that no matter what the setup you want the whatever to achive a damping where after relese the object attains an amplitude on the backswing of about 0.1 of the relese height. It would be nice to understand how this translates to Q which is simply the inverse of damping. I have found it best to use as little damping as possible with a geophone that already has internal damping related to construction. especially if you are looking below the F0 point. If you are only looking for first time of arrival you want the greatest sensitivity possible. I get the best pictures when my geophone is damped the least so i do not understand why everyone wants so much damping. But I was told by Mr.Willis Jacobs of the USGS that they wanted a 10:1 damping ratio. Release at 10 and on each half cycle it will be only 10% the previous amplitude. Does anyone know the proper formula to translate swing amplitude to Q or its inverse called damping ? 10:1 = _____Q ???? Regards; geoff ----- Original Message ----- From: "Paul Cianciolo" To: Sent: Monday, July 23, 2007 11:58 Subject: Spring Damping. > Folks, > > I just finished up a vertical sensor with an AS-1 like suspension. > After looking at the AS-1 pictures, and reading about it, I cannot see any > information about the damping of the suspension spring. > > Does any one have one of these? What am I missing because the spring being > used here while allow in for almost 4 sec. period, once excited rings for a > long time. > > It seems that a magnet mounted in the center of the spring, and an aluminum > plate is very effective in reducing these. > > Any ideas? > > My spring is ferrous, and I would like to get a non ferrous replacement. > > PauLC > W1VLF > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Digest from 07/17/2007 00:01:20 From: "Geoffrey" gmvoeth@........... Date: Tue, 24 Jul 2007 01:12:25 -0700 Hello All; I just ran a Compiled fft routine on a 3GHz Pentium4 machine with 3G ram under WINXP-PRO and it ran slower then on my WIN98SE Presario 5528 with a 75MHz plain old pentium running in MSDOS mode. Now one machine is 40 times faster then the other but there was little difference in run time between the two ?? Does anyone know how to make a MSDOS program run full speed on a Windows XP machine ??? It seems somethings throttling the speed back and i would greatly like to change that. When I get A-Round-Tuit I will boot my WINXP machine with MSDOS and try running the program there but I would really rather use windows. Regards; geoff ----- Original Message ----- From: "Randall Peters" To: Cc: Sent: Saturday, July 21, 2007 17:04 Subject: Re: Digest from 07/17/2007 00:01:20 > Thanks, Bob. I did eventually realize my failure to mention 'x' to > terminate and 'r' to rerun. > Randall > > Bobhelenmcclure@....... wrote: > >> Hi Randall, I tried out your QuickBasic program using the compiled >> program and running from the source code. Changing the file name is >> not necessary, so long as you enter the complete name. You neglected >> to tell users what keys to use to re-run or terminate the >> program. Cheers, Bob ~~~~~~~~~~Original Message~~~~~~~~~~~Subject: Re: >> Digest from 07/17/2007 00:01:20 >> From: Randall Peters PETERS_RD@.......... >> Date: Thu, 19 Jul 2007 11:52:05 -0400 Because of the recent interest >> in FFT's, I have posted some files on my webpage at >> http://physics.mercer.edu/hpage/psn/psn.html >> The pdf's should help those of you who have been wondering how the >> Fourier transform works and why the Cooley-Tukey form (Fast version) >> is SO MUCH better than the discrete FT (for which there is much >> needless, repetitive calculations). >> The executable can be downloaded (I promise that it is safe to use) >> and some data files have been posted to the site so that you can run >> test cases. test and test 2 are pure sine signals, one with a period >> of 17 s and the other 1000 s. The 0704 file is a record of the >> Solomon Islands EQ recorded wtih Larry Cochrane's VolksMeter. Before >> you can use the files you must rename your saved version (*.txt) to >> *.dat. This suffix must be typed in along with the filename when you >> are prompted for the input file. >> >> >> ----------------------------------------------------------------------- >> Get a sneak peek of the all-new AOL.com. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Coil Wire Sources From: "Jerry Payton" gpayton880@....... Date: Tue, 24 Jul 2007 08:38:11 -0500 I am having a difficult time locating a source(s) for 38AGW Polyurethane coated Cu wire for winding a coil. If someone would send me a source, I'd sure appreciate it. I can find up to 36 gauge, but not 38AGW. Thanks, Jerry
I am having a difficult = time locating a=20 source(s) for 38AGW Polyurethane coated Cu wire for winding a = coil.  If=20 someone would send me a source, I'd sure appreciate it.  =
 
I can find up to 36 gauge, = but not=20 38AGW.
 
Thanks,
Jerry
Subject: Re: Coil Wire Sources From: tchannel1@............ Date: Tue, 24 Jul 2007 07:56:42 -0600 Hi Jerry, Have you tried this site? 38 Gauge - Magnet Wire - 96W038 = http://www.alltronics.com/cgi-bin/category.cgi?&category=3DMW&start=3D20 Ted ----- Original Message -----=20 From: Jerry Payton=20 To: psn-l@................. Sent: Tuesday, July 24, 2007 7:38 AM Subject: Coil Wire Sources I am having a difficult time locating a source(s) for 38AGW = Polyurethane coated Cu wire for winding a coil. If someone would send = me a source, I'd sure appreciate it. =20 I can find up to 36 gauge, but not 38AGW. Thanks, Jerry
 
Hi Jerry,  Have you tried this site?
 
 
38 Gauge - Magnet Wire - 96W038  http://www.alltronics.com/cgi-bin/category.cgi?&cate= gory=3DMW&start=3D20
 
Ted
 
 
----- Original Message -----
From:=20 Jerry = Payton=20
Sent: Tuesday, July 24, 2007 = 7:38=20 AM
Subject: Coil Wire = Sources

I am having a difficult = time locating=20 a source(s) for 38AGW Polyurethane coated Cu wire for winding a = coil.  If=20 someone would send me a source, I'd sure appreciate it.  =
 
I can find up to 36 = gauge, but not=20 38AGW.
 
Thanks,
Jerry
Subject: Re: Coil Wire Sources From: Barry Lotz barry_lotz@............. Date: Tue, 24 Jul 2007 19:24:01 -0700 (PDT) Jerry I've bought surplus coated wire spools even finer (48 ga) from HSC electronics. They have a small store in sacramento,ca and san jose, ca (I think). Barry Jerry Payton wrote: I am having a difficult time locating a source(s) for 38AGW Polyurethane coated Cu wire for winding a coil. If someone would send me a source, I'd sure appreciate it. I can find up to 36 gauge, but not 38AGW. Thanks, Jerry
Jerry
 I've bought surplus coated wire spools even finer (48 ga) from HSC electronics. They have a small store in sacramento,ca and san jose, ca (I think).
Barry


Jerry Payton <gpayton880@.......> wrote:
I am having a difficult time locating a source(s) for 38AGW Polyurethane coated Cu wire for winding a coil.  If someone would send me a source, I'd sure appreciate it. 
 
I can find up to 36 gauge, but not 38AGW.
 
Thanks,
Jerry

Subject: Re: Coil Wire Sources From: "Jerry Payton" gpayton880@....... Date: Tue, 24 Jul 2007 21:36:44 -0500 Yes, thanks Barry. The HSC Electronics' URL is http://www.halted.com/ . I also was directed to http://www.alltronics.com/cgi-bin/category.cgi?&category=MW&start=20 . Both have the wire. Thanks to all that responded. Regards, Jerry ----- Original Message ----- From: Barry Lotz To: psn-l@.............. Sent: Tuesday, July 24, 2007 9:24 PM Subject: Re: Coil Wire Sources Jerry I've bought surplus coated wire spools even finer (48 ga) from HSC electronics. They have a small store in sacramento,ca and san jose, ca (I think). Barry Jerry Payton wrote: I am having a difficult time locating a source(s) for 38AGW Polyurethane coated Cu wire for winding a coil. If someone would send me a source, I'd sure appreciate it. I can find up to 36 gauge, but not 38AGW. Thanks, Jerry
Yes, thanks Barry.  The HSC Electronics' URL is  http://www.halted.com/ .  = I also was=20 directed to  http://www.alltronics.com/cgi-bin/category.cgi?&cate= gory=3DMW&start=3D20 . =20 Both have the wire.  Thanks to all that responded.
 
Regards,
Jerry
----- Original Message -----
From:=20 Barry=20 Lotz
Sent: Tuesday, July 24, 2007 = 9:24=20 PM
Subject: Re: Coil Wire = Sources

Jerry
 I've bought surplus coated wire spools even finer (48 = ga) from=20 HSC electronics. They have a small store in sacramento,ca and san = jose, ca (I=20 think).
Barry


Jerry Payton <gpayton880@.......>=20 wrote:
I am having a difficult = time=20 locating a source(s) for 38AGW Polyurethane coated Cu wire for = winding a=20 coil.  If someone would send me a source, I'd sure appreciate = it. =20
 
I can find up to 36 = gauge, but not=20 38AGW.
 
Thanks,
Jerry

Subject: Re: Spring Damping. From: Mark Robinson mark.robinson@............... Date: Wed, 25 Jul 2007 15:24:50 +1200 Geoffrey wrote: > I understand that no matter what the setup > you want the whatever to achive a damping > where after relese the object attains an > amplitude on the backswing of about 0.1 > of the relese height. > It would be nice to understand how this > translates to Q which is simply the inverse of damping. > I have found it best to use as little damping as possible > with a geophone that already has internal damping > related to construction. especially if you are > looking below the F0 point. > If you are only looking for first time of arrival you want > the greatest sensitivity possible. > I get the best pictures when my geophone is damped > the least so i do not understand why everyone > wants so much damping. But I was told by Mr.Willis Jacobs > of the USGS that they wanted a 10:1 damping ratio. > Release at 10 and on each half cycle it will be > only 10% the previous amplitude. > > Does anyone know the proper formula to > translate swing amplitude to Q or its inverse > called damping ? > > 10:1 = _____Q ???? Hi Geoffrey, A tuned radio frequency circuit and a seismometer have opposite goals, especially if you are interested in the spectrum of the signal per your discussion of FFT techniques. In order for the FFT to have any meaning you need a dataset produced by a broadband sensor with as near as possible a flat frequency response. This is what you get with a critically damped system and is precisely not what you get with a high Q tuned system. I am unfamiliar with WinXP, but on Win98 getting a full screen MS-DOS type window by holding down Alt and pressing Enter while in an MS-DOS command prompt window seems to dispose of much of the Windows overhead. I assume that QuickBasic is a compiled Basic and not an interpreted one. A compiled language usually runs at least ten times faster than an interpreted one. -- regards Mark Robinson ------------- 24 Jul 1952 Democrats choose Adali Stevenson and Alabama Senator John Sparkman to run for the White House. 24 Jul 1982 Anna Pacquin, actress, born. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Spring Damping From: Bobhelenmcclure@....... Date: Tue, 24 Jul 2007 23:34:12 EDT > Does anyone know the proper formula to > translate swing amplitude to Q or its inverse > called damping? Yes. See _http://jclahr.com/science/math/calculators/scientific_calculator.html_ (http://jclahr.com/science/math/calculators/scientific_calculator.html) Bob ************************************** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour
> Does anyone know the proper formula to
> translate swing=20 amplitude to Q or its inverse
> called damping?
 
Yes. See
 
http://jclahr.com/science/math/calculators/scientific_calculator.html=
 
Bob



Get a sneak peek=20= of the all-new AOL.com.
Subject: Volcanoes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 25 Jul 2007 14:58:36 +0000 Hi all I am wondering how many people on the psn postlist are close to a active volcano. I ask because I have intrest in figuring out how many earthquakes and other types of activie is detect by ameatur seismographs. I am also looking for people intrested in both earthquakes and volcanoes. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Volcanoes From: George Bush ke6pxp@....... Date: Wed, 25 Jul 2007 09:47:59 -0700 Hi J=F3n- I live less than 50Km from the Geysers that is a geothermal area associated with volcanism. There is no active volcano there now, but the obsidian rock in the area is less than 1000 years old. I also live less than 1Km fron the San Andreas fault in Northern California.=20 I detect M3 quakes from the Geysers almost weekly and detect small quakes from faults parallel to the San Andreas a few time a year. I am interested in both earthquakes and volcanoes. At 02:58 PM 7/25/2007 +0000, you wrote: >Hi all > >I am wondering how many people on the psn postlist are close to a active >volcano. I ask because I have intrest in figuring out how many >earthquakes and other types of activie is detect by ameatur >seismographs. I am also looking for people intrested in both earthquakes >and volcanoes. > >Regards. >--=20 >J=F3n Fr=EDmann >http://www.jonfr.com >http://www.simnet.is/jonfr500/earthquake/ > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with=20 >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. > George Bush Sea Ranch, CA, USA 38.73775N, 123.48882W __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Noise floor From: "Paul Cianciolo" Paulc@........ Date: Wed, 25 Jul 2007 13:33:10 -0400 Hello Folks, I have uploaded to The PSN events page a file called vertical noise floor. This is the Noise floor of my new vertical sensor that has a period of 4 secs. Can someone please download the file with Winquake and do an FFT on the file. What you will see is a signature waveform that seems to be part of the machine I built. There always seems to be a lot of energy at .2 HZ with a roll of toward 1 HZ Does this being a log scale, mean I has some noise peak, at .2 Hz ??? Is this real? or an artifact? Ted TCID sent me a raw file from his machine, and the response is much flatter. My next test is to lock down the coil/magnet sensor and take a reading and see what the noise floor looks like. When I replace the coil with a short circuit across the input of the seismic amplifier, I get what looks like a flat response line. Any ideas comments welcome. PauLC W1VLF __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Volcanoes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 25 Jul 2007 17:59:02 +0000 Hi George I am wondering if there is any intrest in creating a specal volcano postlist for those how are intrested in volcanoes. So discussions about volcanoes can stay in one place, away from the earthquake discussions. I can setup that type of post list with much problem, even on a specal domain if I want to. The closest hotspring area to where I live is ~85 km away. The second sensor has more hot springs closer to his location then that (Reykjanes, Geysir area and other areas). Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Volcanoes From: "Bob Hancock" carpediem1@......... Date: Wed, 25 Jul 2007 11:21:06 -0700 George / Jon For those interested in Volcanoes, there is a blog maintained by Arizona State University, Tempe, AZ. Here is the link to subscribe to the list. http://lists.asu.edu/archives/volcano.html You can check out their archives to see what is listed. Bob Hancock __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Coil Wire Sources From: "Stephen Hammond" shammon1@............. Date: Wed, 25 Jul 2007 11:32:06 -0700 I just talked via phone to the owner of Alltronics and he does have the coil wire you are looking for. When he had his store in San Jose (now closed) Bob Ogburn, a PSN member, worked for him before moving to Texas. In chatting with the owner, he also mentioned he has super magnets and some small speakers that PSN members might be interested in. Regards, Steve Hammond PSN San Jose, Aptos CA. -----Original Message----- From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Jerry Payton Sent: Tuesday, July 24, 2007 7:37 PM To: psn-l@.............. Subject: Re: Coil Wire Sources Yes, thanks Barry. The HSC Electronics' URL is http://www.halted.com/ .. I also was directed to http://www.alltronics.com/cgi-bin/category.cgi? &category=MW&start=20 . Both have the wire. Thanks to all that responded. Regards, Jerry ----- Original Message ----- From: Barry Lotz To: psn-l@.............. Sent: Tuesday, July 24, 2007 9:24 PM Subject: Re: Coil Wire Sources Jerry I've bought surplus coated wire spools even finer (48 ga) from HSC electronics. They have a small store in sacramento,ca and san jose, ca (I think). Barry Jerry Payton wrote: I am having a difficult time locating a source(s) for 38AGW Polyurethane coated Cu wire for winding a coil. If someone would send me a source, I'd sure appreciate it. I can find up to 36 gauge, but not 38AGW. Thanks, Jerry

I just talked via phone to the = owner of Alltronics and he does have the coil wire you are looking for. When he had his = store in San Jose (now closed) Bob Ogburn, a PSN member, worked for him = before moving to Texas. In chatting with the owner, he also mentioned he has super magnets and some small speakers that PSN members might be interested = in.

Regards, Steve = Hammond PSN San Jose, = Aptos CA.

 

-----Original = Message-----
From: = psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of Jerry Payton
Sent: = Tuesday, July 24, = 2007 7:37 PM
To: = psn-l@..............
Subject: Re: Coil Wire = Sources

 

Yes, thanks Barry.  The HSC Electronics' = URL is  http://www.halted.com/ .  I also was directed to  http://www.alltronics.com/cgi-bin/category.cgi?&cate= gory=3DMW&start=3D20 .  Both have the wire.  Thanks to all that = responded.

 

Regards,

Jerry

----- Original Message = -----

From: Barry Lotz

To:<= /font> psn-l@..............

Sent: Tuesday, July 24, = 2007 9:24 PM

Subject: Re: Coil Wire Sources

 

Jerry

 I've bought surplus coated = wire spools even finer (48 ga) from HSC electronics. They have a small store in = sacramento,ca and san jose, ca (I = think).

Barry



Jerry Payton = <gpayton880@.......><= /b> wrote:

I am having a difficult time locating a = source(s) for 38AGW Polyurethane coated Cu wire for winding a coil.  If someone = would send me a source, I'd sure appreciate it.  =

 

I can find up to 36 gauge, but not = 38AGW.

 

Thanks,

Jerry

 

Subject: RE: Volcanoes From: =?ISO-8859-1?Q?J=F3n_Fr=EDmann?= jonfr@......... Date: Wed, 25 Jul 2007 18:45:29 +0000 Hi Bob I am already using that post list. But it dosen't offers a lot of dissussions about volcanoes and current changes in volcones, that can happen without a lot of notice. Regards. --=20 J=F3n Fr=EDmann http://www.jonfr.com http://www.simnet.is/jonfr500/earthquake/ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Noise floor From: "Geoffrey" gmvoeth@........... Date: Wed, 25 Jul 2007 22:28:56 -0700 Hello Paul; At about 0.2 Hz is what I understand to be natural microseismic waves relating to ocean waves striking the shores. I have noticed a quietness at the fundamental freq of the sensor. Like, my geophone is about 1Hz and the noise seems quietest at 1Hz. If the electronics is poorly built by this I mean the components are not proper, you can get peaks in your filters profile that will show up as increased noise at that freq. If your electronics is good enough you can dummy load the input and get a flat line on the output of your electronics. I have never been able to acieve this level of quiet. Noise is interesting because youd think if it were truly random it would be self canceling. The narrower the bandwidth the less the noise. The colder the less the noise. If there exists a specialty science of studing only noise Id like someone to tell me what it is. The best way to see earthquakes is to simply limit the bandwidth then amplify your sensors signals till you see the noise. These EQ waves seem to ride just above the "grass". Regards; geoff ----- Original Message ----- From: "Paul Cianciolo" To: Sent: Wednesday, July 25, 2007 10:33 Subject: Noise floor > Hello Folks, > > I have uploaded to The PSN events page a file called vertical noise floor. > > This is the Noise floor of my new vertical sensor that has a period of 4 > secs. > > Can someone please download the file with Winquake and do an FFT on the > file. > > What you will see is a signature waveform that seems to be part of the > machine I built. > There always seems to be a lot of energy at .2 HZ with a roll of toward 1 HZ > > Does this being a log scale, mean I has some noise peak, at .2 Hz ??? > Is this real? or an artifact? > > Ted TCID sent me a raw file from his machine, and the response is much > flatter. > > My next test is to lock down the coil/magnet sensor and take a reading and > see what the noise floor looks like. > > When I replace the coil with a short circuit across the input of the seismic > amplifier, I get what looks like a flat response line. > > Any ideas comments welcome. > > PauLC > W1VLF > > > > > __________________________________________________________ > > 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: Spring Damping From: "Geoffrey" gmvoeth@........... Date: Wed, 25 Jul 2007 23:02:00 -0700 Hello Bob & PSN; Im not so sure this stuff is correct because its my understanding that Q and Damping are simply inverses of each other just like Period and Frequency. I was unable to get the inverse result simply by alternately clicking the buttons using the same input values. Like Q = 1 then damping = 1 Like Q = 0.5 then Damping = 2 Like Q = 2 then damping = 0.5 ??? Also, Whats the proper symbol for damping ? My level of math is only high school to first year college. My brain has most probably been damaged by all those nut house drugs the Government has forced down my throat with coercion and duress. Im just hoping to easily get an answer that makes sense to me here. Regards; geoff ----- Original Message ----- From: To: ; Sent: Tuesday, July 24, 2007 20:34 Subject: Re: Spring Damping >> Does anyone know the proper formula to >> translate swing amplitude to Q or its inverse >> called damping? > > Yes. See > > _http://jclahr.com/science/math/calculators/scientific_calculator.html_ > (http://jclahr.com/science/math/calculators/scientific_calculator.html) > > Bob > > > > ************************************** Get a sneak peek of the all-new AOL at > http://discover.aol.com/memed/aolcom30tour > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Coil Wire Sources From: "Geoffrey" gmvoeth@........... Date: Wed, 25 Jul 2007 23:05:03 -0700 Wow, that sounds like the wire that might be used in XBT probes and wire guided whatevers. XBT = expendeble bathythermograph probes. I have never seen wire that fine before. Regards; geoff ----- Original Message ----- From: "Barry Lotz" To: Sent: Tuesday, July 24, 2007 19:24 Subject: Re: Coil Wire Sources > Jerry > I've bought surplus coated wire spools even finer (48 ga) from HSC electronics. They have a small store in sacramento,ca and san > jose, ca (I think). > Barry > > > Jerry Payton wrote: > I am having a difficult time locating a source(s) for 38AGW Polyurethane coated Cu wire for winding a coil. If someone > would send me a source, I'd sure appreciate it. > > I can find up to 36 gauge, but not 38AGW. > > Thanks, > Jerry > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: Volcanoes From: Barry Lotz barry_lotz@............. Date: Thu, 26 Jul 2007 05:25:53 -0700 (PDT) You might also look at http://www.dartmouth.edu/~volcano/ and http://www.volcano.si.edu/gvp/index.htm for a couple interesting sites Barry Bob Hancock wrote: George / Jon For those interested in Volcanoes, there is a blog maintained by Arizona State University, Tempe, AZ. Here is the link to subscribe to the list. http://lists.asu.edu/archives/volcano.html You can check out their archives to see what is listed. Bob Hancock __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
You might also look at http://www.dartmouth.edu/~volcano/  and 
http://www.volcano.si.edu/gvp/index.htm
 for a couple interesting sites
Barry

Bob Hancock <carpediem1@.........> wrote:
George / Jon

For those interested in Volcanoes, there is a blog maintained by Arizona
State University, Tempe, AZ. Here is the link to subscribe to the list.

http://lists.asu.edu/archives/volcano.html

You can check out their archives to see what is listed.

Bob Hancock



__________________________________________________________

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.

Subject: Re: Spring Damping From: Barry Lotz barry_lotz@............. Date: Thu, 26 Jul 2007 05:44:14 -0700 (PDT) I think it's z . Shows up as lower case Z in Word symbol font. My greek is rusty. Barry Geoffrey wrote: Hello Bob & PSN; Im not so sure this stuff is correct because its my understanding that Q and Damping are simply inverses of each other just like Period and Frequency. I was unable to get the inverse result simply by alternately clicking the buttons using the same input values. Like Q = 1 then damping = 1 Like Q = 0.5 then Damping = 2 Like Q = 2 then damping = 0.5 ??? Also, Whats the proper symbol for damping ? My level of math is only high school to first year college. My brain has most probably been damaged by all those nut house drugs the Government has forced down my throat with coercion and duress. Im just hoping to easily get an answer that makes sense to me here. Regards; geoff ----- Original Message ----- From: To: ; Sent: Tuesday, July 24, 2007 20:34 Subject: Re: Spring Damping >> Does anyone know the proper formula to >> translate swing amplitude to Q or its inverse >> called damping? > > Yes. See > > _http://jclahr.com/science/math/calculators/scientific_calculator.html_ > (http://jclahr.com/science/math/calculators/scientific_calculator.html) > > Bob > > > > ************************************** Get a sneak peek of the all-new AOL at > http://discover.aol.com/memed/aolcom30tour > __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
I think it's z . Shows up as lower case Z in Word symbol font. My greek is rusty.
Barry
 
 
Geoffrey <gmvoeth@...........> wrote:
Hello Bob & PSN;

Im not so sure this stuff is correct because
its my understanding that Q and Damping
are simply inverses of each other just like
Period and Frequency. I was unable to
get the inverse result simply by
alternately clicking the buttons
using the same input values.

Like Q = 1 then damping = 1
Like Q = 0.5 then Damping = 2
Like Q = 2 then damping = 0.5
???
Also, Whats the proper symbol for damping ?

My level of math is only high school
to first year college.

My brain has most probably been damaged
by all those nut house drugs the Government
has forced down my throat with coercion
and duress.

Im just hoping to easily get an answer that makes sense to me here.

Regards;
geoff

----- Original Message -----
From:
To: ;
Sent: Tuesday, July 24, 2007 20:34
Subject: Re: Spring Damping


>> Does anyone know the proper formula to
>> translate swing amplitude to Q or its inverse
>> called damping?
>
> Yes. See
>
> _http://jclahr.com/science/math/calculators/scientific_calculator.html_
> (http://jclahr.com/science/math/calculators/scientific_calculator.html)
>
> Bob
>
>
>
> ************************************** Get a sneak peek of the all-new AOL at
> http://discover.aol.com/memed/aolcom30tour
>
__________________________________________________________

Public Seismic Network Mailing List (PSN-L)

To leave this list email PSN-L-REQUEST@SEISMICNET.COM with
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Subject: "P" ky "Slinky" From: tchannel1@............ Date: Thu, 26 Jul 2007 09:51:58 -0600 Hi Folks, In the past I have asked the group questions about various = designs. I have made several sensors, some of no value and some which = work well for me in this location. We all learn from doing. I really = like the simplicity of the AS-1, but the cost keep me from purchasing = one, and started my efforts to make one from items I could get locally. = I also wanted to get kids involved in a project which would not require = a machine shop. My Grandkids in Alaska enjoyed their project for a=20 science class. One thing I could not do, was to build the Amp/Filter, I did try and got = the board working by not good enough. I solved that Big issue by purchasing Larry's board, which worked great. I think it was the sixth sensor I dubbed "P" ky-"Slinky" The idea = was to hang a long spring from the ceiling 7' overall. On the end of = the spring a magnet moving in and out of a coil. Add a damper, and = enclose it. A little like a very long geophone. I did a prototype and it worked. So I built one for real, I started = using 7' which included the entire unit. I later changed it to = 5'...........I thing the period is about 2.2 seconds. I made a few = modification and it has been trouble free and recording earthquakes from = all over the world, and in greater numbers than my Lehman. Obviously = not with all the phases, one would expect with a longer period sensor. The spring, perhaps the one at the bottom of the list of appropriate = choices, is working just fine. I see no temperature noise, although it = must be there, and since the spring is in a tube I don't get air = currents. The only issue I had with the spring is that it stretched = about one inch over one month, and now has stopped. I did not keep track of the cost, but I think it was maybe $50 - $75 = including everything for the sensor. For a full station one would need = all the other things, like the Amp/Filter, AD converter, cables Software = and an old computer, etc. I am now operating this unit and posting the recordings as TCIDzs as = z-vertical s-slinky. At night time the noise level is very low, during = the day the noise level is high, due to road construction. On the week = end the noise level is low. http://picasaweb.google.com/tchannel33 I have posted some picture = here. Just click on the album call "5' Slinky" and you can see 9 pictures, I hope. Notice one shows the tube 7' tall = and one 5' tall, after I modified it. This is an inexpressive unit, using simple materials, little machine = work, fun..........and I am please with its performance. Email me if you want to make one, and I will give you details. I can = sent or post .gif images of its recordings as well. It just a fun and easy project. tchannel1@............ Ted
Hi Folks,   In the past I = have asked the=20 group questions about various designs.  I have made several = sensors, some=20 of no value and some which work well for me in this = location.   We all=20 learn from doing.  I really like the simplicity of the AS-1, but = the cost=20 keep me from purchasing one, and started my efforts to make one from = items I=20 could get locally.   I also wanted to get kids involved in a = project=20 which would not require a machine shop.   My Grandkids in = Alaska=20 enjoyed their project for a
science class.
 
One thing I could not do, was to build = the=20 Amp/Filter, I did try and got the board working by not good = enough.
I solved that Big issue by purchasing = Larry's=20 board, which worked great.
 
I think it was the sixth sensor I=20 dubbed   "P" ky-"Slinky"   The idea was to hang a = long=20 spring from the ceiling 7' overall.  On the end of the spring a = magnet=20 moving in and out of a coil.   Add a damper, and enclose=20 it.
A little like a very long = geophone.
 
I did a prototype and it worked.  = So I built=20 one for real,  I started using 7'  which included the entire=20 unit.  I later changed it to 5'...........I thing the period is = about 2.2=20 seconds.  I made a few modification and it has been trouble free = and=20 recording earthquakes from all over the world, and in greater numbers = than my=20 Lehman.   Obviously not with all the phases, one would expect = with a=20 longer period sensor.
 
The spring, perhaps the one at the = bottom of the=20 list of appropriate choices, is working just fine.   I see no=20 temperature noise, although it must be there, and since the spring is in = a tube=20 I don't get air currents.   The only issue I had with the = spring is=20 that it stretched about one inch over one month, and now has=20 stopped.
 
I did not keep track of the cost, but I = think it=20 was maybe $50 - $75 including everything for the sensor.   For = a full=20 station one would need all the other things, like the Amp/Filter, AD = converter,=20 cables Software and an old computer, etc.
 
I am now operating this unit and = posting the=20 recordings as TCIDzs  as z-vertical s-slinky.   At night = time the=20 noise level is very low, during the day the noise level is high, due to = road=20 construction.  On the week end the noise level is low.
 
 
http://picasaweb.google.c= om/tchannel33  =20 I have posted some picture here.  Just click on the album call "5'=20 Slinky"
and you can see 9 pictures,  I = hope. =20 Notice one shows the tube 7' tall and one 5' tall, after I modified=20 it.
 
This is an inexpressive unit, using = simple=20 materials, little machine work, fun..........and I am please with its=20 performance.
Email me if you want to make one,  = and I will=20 give you details.  I can sent or post .gif images of its recordings = as=20 well.
 
It just a fun and easy=20 project.     tchannel1@............<= /DIV>
 
Ted
 
 
 
 
 
 
 
 
Subject: Re: "P" ky "Slinky" From: ChrisAtUpw@....... Date: Thu, 26 Jul 2007 12:36:51 EDT In a message dated 2007/07/26, tchannel1@............ writes: > http://picasaweb.google.com/tchannel33 I have posted some picture here. > Just click on the album call "5' Slinky" and you can see 9 pictures, I hope. > Hi Ted, The photos are OK , but the diagram is unreadable. It won't even print out. Regards, Chris Chapman In a me= ssage dated 2007/07/26, tchannel1@............ writes:

http://picasaweb.google.com/tchannel33   I= have posted some picture here.  Just click on the album call "5' Slink= y" and you can see 9 pictures,  I hope.


Hi Ted,

       The photos are OK , but the diagram is=20= unreadable. It won't even print out.

       Regards,

       Chris Chapman Subject: Re: "P" ky "Slinky" From: "Geoffrey" gmvoeth@........... Date: Thu, 26 Jul 2007 09:38:44 -0700 Far Out Man; Verticals are harder to make than horizontals. P = 2 Pi sqr( l / 386) l = 386((P/2Pi)^2) This tells me your spring probably hangs one foot without any weight and five feet with the weight. Does this sound right ? I wonder if you can use levitation to set your own period. It would be like putting most of the weight on the spring then using magnetic or other levitation to reduce the gravitational constant or changing electronically the spring constant. If you put your hand under the mass which is suspended on the spring and levitate it a couple mm then you most possibly could give it near any free period youd like to. Not sure about this but it might be interesting for someone with the resources to try. Regards; geoff __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: "P" ky "Slinky" From: "Geoffrey" gmvoeth@........... Date: Thu, 26 Jul 2007 09:43:47 -0700 If you right click and save the image you can then print it out from your hard drive. regards; geoff ----- Original Message ----- From: To: Sent: Thursday, July 26, 2007 09:36 Subject: Re: "P" ky "Slinky" > In a message dated 2007/07/26, tchannel1@............ writes: > >> http://picasaweb.google.com/tchannel33 I have posted some picture here. >> Just click on the album call "5' Slinky" and you can see 9 pictures, I hope. >> > > Hi Ted, > > The photos are OK , but the diagram is unreadable. It won't even print > out. > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: "P" ky "Slinky" From: John Lahr johnjan@........ Date: Thu, 26 Jul 2007 09:43:57 -0700 Hi Ted, Nice design! How do you damp out horizontal, swinging motion of the slinky system? What's the resonant period of this motion? Cheers, John At 08:51 AM 7/26/2007, you wrote: >Hi Folks, In the past I have asked the group questions about >various designs. I have made several sensors, some of no value and >some which work well for me in this location. We all learn from >doing. I really like the simplicity of the AS-1, but the cost keep >me from purchasing one, and started my efforts to make one from >items I could get locally. I also wanted to get kids involved in a >project which would not require a machine shop. My Grandkids in >Alaska enjoyed their project for a >science class. > >One thing I could not do, was to build the Amp/Filter, I did try and >got the board working by not good enough. >I solved that Big issue by purchasing Larry's board, which worked great. > >I think it was the sixth sensor I dubbed "P" ky-"Slinky" The >idea was to hang a long spring from the ceiling 7' overall. On the >end of the spring a magnet moving in and out of a coil. Add a >damper, and enclose it. >A little like a very long geophone. > >I did a prototype and it worked. So I built one for real, I >started using 7' which included the entire unit. I later changed >it to 5'...........I thing the period is about 2.2 seconds. I made >a few modification and it has been trouble free and recording >earthquakes from all over the world, and in greater numbers than my >Lehman. Obviously not with all the phases, one would expect with a >longer period sensor. > >The spring, perhaps the one at the bottom of the list of appropriate >choices, is working just fine. I see no temperature noise, >although it must be there, and since the spring is in a tube I don't >get air currents. The only issue I had with the spring is that it >stretched about one inch over one month, and now has stopped. > >I did not keep track of the cost, but I think it was maybe $50 - $75 >including everything for the sensor. For a full station one would >need all the other things, like the Amp/Filter, AD converter, cables >Software and an old computer, etc. > >I am now operating this unit and posting the recordings as >TCIDzs as z-vertical s-slinky. At night time the noise level is >very low, during the day the noise level is high, due to road >construction. On the week end the noise level is low. > > >http://picasaweb.google.com/tchannel33 >I have posted some picture here. Just click on the album call "5' Slinky" >and you can see 9 pictures, I hope. Notice one shows the tube 7' >tall and one 5' tall, after I modified it. > >This is an inexpressive unit, using simple materials, little machine >work, fun..........and I am please with its performance. >Email me if you want to make one, and I will give you details. I >can sent or post .gif images of its recordings as well. > >It just a fun and easy >project. tchannel1@............ > >Ted > > > > > > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: "P" ky "Slinky" Feint image From: ChrisAtUpw@....... Date: Thu, 26 Jul 2007 13:46:38 EDT In a message dated 2007/07/26, gmvoeth@........... writes: > If you right click and save the image you can then print it out from your > hard drive. Hi Geoff, This should work, but it does not. The original image is too feint. I suspect that it was a pencil drawing. Regards, Chris In a me= ssage dated 2007/07/26, gmvoeth@........... writes:

If you right click and save the= image you can then print it out from your
hard drive.


Hi Geoff,

       This should work, but it does not. The=20= original image is too feint. I suspect that it was a pencil drawing.

       Regards,

       Chris Subject: Re: "P" ky "Slinky" Feint image "Faint" From: "Geoffrey" gmvoeth@........... Date: Thu, 26 Jul 2007 11:54:19 -0700 Dont say p-aint.exe your mother will faint your father will fall in a bucket of paint. The best I can do with PAINT is to first save the image as a 16 color BMP file then go into the attributes and make the paint image black and white. Otherwise you need a utility like graphics workshop pro from Alchemy Mindworks to dither the image to black and white. You need to be able to select the black level etc but paint is terrible at that or so it seems. I am not pushing GWS3 but it seems to do quite well once you learn how to use it. There is most probably a freeware converter out there but the capitalistic internet mucks the searches up and makes them hard to find. I printed it out and the gray image is quite readable to me but i think you need to encourage people in the future to use GIF instead of JPG for line art stuff. Regards; geoff ----- Original Message ----- From: To: Sent: Thursday, July 26, 2007 10:46 Subject: Re: "P" ky "Slinky" Feint image > In a message dated 2007/07/26, gmvoeth@........... writes: > >> If you right click and save the image you can then print it out from your >> hard drive. > > Hi Geoff, > > This should work, but it does not. The original image is too feint. I > suspect that it was a pencil drawing. > > Regards, > > Chris > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: "P" ky "Slinky" From: tchannel1@............ Date: Thu, 26 Jul 2007 12:57:02 -0600 Hi Folks, Sorry about the drawing I will repost it, including the left = hand side which got cut off...I will also try to clean it up a bit. = And more pictures. This is just an idea sketch. We all learn things which are undeniable truths.....One for me is " I = must always make something three times to get it right" Maybe that's = were they get "the third times a charm" Anyhow, I would like to make another, so if someone is interested in = this concept, let me know and maybe I can help with some of the parts. = If someone has limited tools etc. Paul C. suggested I use two ring magnets, one entering the top of the = coil, and the other exiting the bottom of the coil. I started with one magnet 1/2 (deep inside the coil), but I did not like = the results. I then moved the magnet to the top of the coil, just = entering, that worked better. I then added another magnet, two = together, 1 and 1/2 magnets inside the top of the coil. This worked = well. To try Paul's idea, I would just need to open it up and move = the spacing nuts and magnets. To many details for this email, but its basically simple. A 12" brass = threaded rod hangs inside the two tees, on which are brass spacing nuts, = and three ring magnets. Two for the coil and one for the damper. Another thing I would maybe do different is to use the 3" black ABS? = pipe and tees, as they are thicker wall and straighter. With the rod+magnets+nuts there was no more room for a mass. I tried = addition mass and it pulled the spring too long. I wanted to limit the = total height to 7', but cut it down to 5'....I think at 7' the period = was 2.4, and at 5' it was 2.2? Thanks, Ted So give me a little time and check the site = again..........http://picasaweb.google.com/tchannel33 ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Thursday, July 26, 2007 10:36 AM Subject: Re: "P" ky "Slinky" In a message dated 2007/07/26, tchannel1@............ writes: http://picasaweb.google.com/tchannel33 I have posted some picture = here. Just click on the album call "5' Slinky" and you can see 9 = pictures, I hope.=20 Hi Ted, The photos are OK , but the diagram is unreadable. It won't = even print out. Regards, Chris Chapman
Hi Folks,  Sorry about the drawing = I will=20 repost it,  including the left hand side which got cut off...I will = also=20 try to clean it up a bit.    And  more = pictures.  =20 This is just an idea sketch.
 
We all learn things which are = undeniable=20 truths.....One for me is " I must always make something three times to = get it=20 right"   Maybe that's were they get "the third times a=20 charm"
 
Anyhow,  I would like to = make another,=20  so if someone is interested in this concept, let me know and maybe = I can=20 help with some of the parts.  If someone has limited tools=20 etc.
 
Paul C. suggested I use two ring = magnets, one=20 entering the top of the coil, and the other exiting the bottom of the=20 coil.
I started with one magnet 1/2 (deep = inside the=20 coil), but I did not like the results.  I then moved the magnet to = the top=20 of the coil, just entering, that worked better.   I then added = another=20 magnet, two together,  1 and 1/2 magnets inside the top of the=20 coil.   This worked well.    To try Paul's = idea, =20 I would just need to open it up and move the spacing nuts and=20 magnets.
 
To many details for this email, but its = basically=20 simple.   A 12" brass threaded rod hangs inside the two tees, = on which=20 are brass spacing nuts, and three ring magnets.  Two for the coil = and one=20 for the damper.
 
Another thing I would maybe do = different is to use=20 the 3" black ABS?  pipe and tees, as they are thicker wall and = straighter.
 
With the rod+magnets+nuts there was no = more room=20 for a mass.  I tried addition mass and it pulled the spring too = long. =20 I wanted to limit the total height to 7', but cut it down to 5'....I = think at 7'=20 the period was 2.4, and at 5' it was 2.2?
 
Thanks, Ted     So = give me a=20 little time and check the site=20 again..........http://picasaweb.google.com/tchannel33
 
 
----- Original Message -----
 
From:=20 ChrisAtUpw@.......
Sent: Thursday, July 26, 2007 = 10:36=20 AM
Subject: Re: "P" ky = "Slinky"

In a=20 message dated 2007/07/26, tchannel1@............=20 writes:

http://picasaweb.google.c= om/tchannel33  =20 I have posted some picture here.  Just click on the album call = "5'=20 Slinky" and you can see 9 pictures,  I hope.

Hi=20 Ted,

       The photos are OK , = but the=20 diagram is unreadable. It won't even print=20 out.

      =20 Regards,

       Chris = Chapman=20 Subject: Sketch From: tchannel1@............ Date: Thu, 26 Jul 2007 14:37:36 -0600 Hi All, I tried two more times to upload the sketch picture, with no = luck.....However just email me and I will send it as an attachment. Ted
Hi All, I tried two more times to = upload the sketch=20 picture, with no luck.....However just email me and I will send it as an = attachment.
 
Ted
Subject: Re: "P" ky "Slinky" From: ChrisAtUpw@....... Date: Thu, 26 Jul 2007 16:42:21 EDT In a message dated 2007/07/26, tchannel1@............ writes: > With the rod+magnets+nuts there was no more room for a mass. I tried > addition mass and it pulled the spring too long. I wanted to limit the total > height to 7', but cut it down to 5'....I think at 7' the period was 2.4, and at > 5' it was 2.2? Hi Ted, So why not chop a few turns off the spring? ! Maybe make two, with half length springs? > Paul C. suggested I use two ring magnets, one entering the top of the coil, > and the other exiting the bottom of the coil. > I started with one magnet 1/2 (deep inside the coil), but I did not like the > results. This would give ~zero output at the centre of the coil. I then moved the magnet to the top of the coil, just entering, that worked better. I > then added another magnet, two together, 1 and 1/2 magnets inside the top > of the coil. This worked well. To try Paul's idea, I would just need to open > it up and move the spacing nuts and magnets. You would probably need the magnets mounted in opposition, but this arrangement should reduce environmental magnetic forces on the seismometer. For the sensor you would probably do to better to make an analogue if a LVDT. Wind two coils end to end and connect them in opposition. Then place the magnet(s) in the centre. The output can be made nearly independent of the vertical position over the length of the magnet(s) / length of the coils, whichever is shorter. You could make an anti rotation, anti pendulum swing damper with two pairs of bar magnets in a cross inside a copper tube, or four copper plates. You could also try square Al tube, or bent sheet? You could probably adjust this to supply the vertical damping as well? You might find that about a 2 second period is optimal? This should bring in the P waves nicely, but reduce thermal and microseism disturbances. Have you tried putting thermal insulation around the tube? Regards, Chris Chapman In a me= ssage dated 2007/07/26, tchannel1@............ writes:

With the rod+magnets+nuts there= was no more room for a mass.  I tried addition mass and it pulled the=20= spring too long.  I wanted to limit the total height to 7', but cut it=20= down to 5'....I think at 7' the period was 2.4, and at 5' it was 2.2?=

Hi Ted,

       So why not chop a few turns off the spr= ing? ! Maybe make two, with half length springs?

Paul C. suggested I use two rin= g magnets, one entering the top of the coil, and the other exiting the botto= m of the coil.
I started with one magnet 1/2 (deep inside the coil), but I did not like th= e results. 


       This would give ~zero output at the ce= ntre of the coil.
      
I then moved the magnet to the top of the coil, just entering, that worked b= etter.  I
then added another magnet, two= together, 1 and 1/2 magnets inside the top of the coil. This worked well. T= o try Paul's idea, I would just need to open it up and move the spacing nuts= and magnets.


       You would probably need the magnets mou= nted in opposition, but this arrangement should reduce environmental magneti= c forces on the seismometer.

             For= the sensor you would probably do to better to make an analogue if a LVDT. W= ind two coils end to end and connect them in opposition. Then place the magn= et(s) in the centre. The output can be made nearly independent of the vertic= al position over the length of the magnet(s) / length of the coils, whicheve= r is shorter.

       You could make an anti rotation, anti p= endulum swing damper with two pairs of bar magnets in a cross inside a coppe= r tube, or four copper plates. You could also try square Al tube, or bent sh= eet? You could probably adjust this to supply the vertical damping as well?<= BR>
       You might find that about a 2 second pe= riod is optimal? This should bring in the P waves nicely, but reduce thermal= and microseism disturbances. Have you tried putting thermal insulation arou= nd the tube?

       Regards,

       Chris Chapman
 Subject: Re: "P" ky "Slinky" From: tchannel1@............ Date: Thu, 26 Jul 2007 15:42:56 -0600 Hi Chris, =20 >So why not chop a few turns off the spring? ! Maybe make two, with half = length springs?...........I could have, but gathering the loops aloud me = to add and subtract to adj the length. >Have you tried putting thermal insulation around the tube? ..........I = could, but the room is temperature stable, so I have not. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Thursday, July 26, 2007 2:42 PM Subject: Re: "P" ky "Slinky" In a message dated 2007/07/26, tchannel1@............ writes: With the rod+magnets+nuts there was no more room for a mass. I = tried addition mass and it pulled the spring too long. I wanted to = limit the total height to 7', but cut it down to 5'....I think at 7' the = period was 2.4, and at 5' it was 2.2? Hi Ted, So why not chop a few turns off the spring? ! Maybe make two, = with half length springs? Paul C. suggested I use two ring magnets, one entering the top of = the coil, and the other exiting the bottom of the coil. I started with one magnet 1/2 (deep inside the coil), but I did not = like the results. =20 This would give ~zero output at the centre of the coil. =20 I then moved the magnet to the top of the coil, just entering, that = worked better. I=20 then added another magnet, two together, 1 and 1/2 magnets inside = the top of the coil. This worked well. To try Paul's idea, I would just = need to open it up and move the spacing nuts and magnets. You would probably need the magnets mounted in opposition, but = this arrangement should reduce environmental magnetic forces on the = seismometer.=20 For the sensor you would probably do to better to make an = analogue if a LVDT. Wind two coils end to end and connect them in = opposition. Then place the magnet(s) in the centre. The output can be = made nearly independent of the vertical position over the length of the = magnet(s) / length of the coils, whichever is shorter. You could make an anti rotation, anti pendulum swing damper = with two pairs of bar magnets in a cross inside a copper tube, or four = copper plates. You could also try square Al tube, or bent sheet? You = could probably adjust this to supply the vertical damping as well? You might find that about a 2 second period is optimal? This = should bring in the P waves nicely, but reduce thermal and microseism = disturbances. Have you tried putting thermal insulation around the tube? Regards, Chris Chapman
Hi Chris, 
>So why not chop a few turns off the = spring? !=20 Maybe make two, with half length springs?...........I could have, but = gathering=20 the loops aloud me to add and subtract to adj the length.
 
 
>Have you tried putting thermal insulation around the=20 tube?  ..........I could, but the room is temperature stable, = so I=20 have not.
 
Thanks, Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Thursday, July 26, 2007 = 2:42=20 PM
Subject: Re: "P" ky = "Slinky"

In a=20 message dated 2007/07/26, tchannel1@............=20 writes:

With the rod+magnets+nuts there was no more room for a=20 mass.  I tried addition mass and it pulled the spring too = long.  I=20 wanted to limit the total height to 7', but cut it down to 5'....I = think at=20 7' the period was 2.4, and at 5' it was 2.2?

Hi=20 Ted,

       So why not chop a few = turns=20 off the spring? ! Maybe make two, with half length springs?

Paul C. suggested I use two ring magnets, one entering = the top=20 of the coil, and the other exiting the bottom of the = coil.
I started with = one magnet 1/2=20 (deep inside the coil), but I did not like the results.  =

       This=20 would give ~zero output at the centre of the=20 coil.
      
I then moved the = magnet to=20 the top of the coil, just entering, that worked better.  I =
then added another magnet, two together, 1 and 1/2 = magnets=20 inside the top of the coil. This worked well. To try Paul's idea, I = would=20 just need to open it up and move the spacing nuts and=20 magnets.

       You = would=20 probably need the magnets mounted in opposition, but this arrangement = should=20 reduce environmental magnetic forces on the seismometer.=20 =

           = ; =20 For the sensor you would probably do to better to make an analogue if = a LVDT.=20 Wind two coils end to end and connect them in opposition. Then place = the=20 magnet(s) in the centre. The output can be made nearly independent of = the=20 vertical position over the length of the magnet(s) / length of the = coils,=20 whichever is shorter.

       You = could=20 make an anti rotation, anti pendulum swing damper with two pairs of = bar=20 magnets in a cross inside a copper tube, or four copper plates. You = could also=20 try square Al tube, or bent sheet? You could probably adjust this to = supply=20 the vertical damping as = well?

       You=20 might find that about a 2 second period is optimal? This should bring = in the P=20 waves nicely, but reduce thermal and microseism disturbances. Have you = tried=20 putting thermal insulation around the=20 tube?

      =20 Regards,

       Chris=20 Chapman
 Subject: RE: "P" ky "Slinky" From: "Bob Hancock" carpediem1@......... Date: Thu, 26 Jul 2007 15:30:43 -0700 Ted - Interesting, very interesting - from a non-engineer, how do you plan to compensate for creep and eventual deformation in the metal slinky, and how close is your temperature control, plus or minus what number? Bob

Ted = –

 

Interesting, very interesting = – from a non-engineer, how do you plan to compensate for creep and eventual deformation in the metal slinky, and how close is your temperature = control, plus or minus what number?

 

Bob

 

Subject: Re: "P" ky "Slinky" From: tchannel1@............ Date: Thu, 26 Jul 2007 17:39:37 -0600 Hi Bob, The spring did stretch over about a month. 3/4"? Like a music = string.......... It may have stopped now, I can eyeball it thru the = window, and it seem to now be stable. The room ranges from about 65 to 75? A room in my finished basement, and I see no temperature effect. I = places a heater in the room to see if I could, but saw nothing change.=20 I don't have a lot of weight on the spring, so I am hoping it does not = deform. much.. Ted ----- Original Message -----=20 From: Bob Hancock=20 To: psn-l@................. Sent: Thursday, July 26, 2007 4:30 PM Subject: RE: "P" ky "Slinky" Ted - =20 Interesting, very interesting - from a non-engineer, how do you plan = to compensate for creep and eventual deformation in the metal slinky, = and how close is your temperature control, plus or minus what number? =20 Bob =20
Hi Bob,  The spring did stretch = over about a=20 month. 3/4"?  Like a music string.......... It may have = stopped=20 now, I can eyeball it thru the window, and it seem to now be=20 stable.
 
  The room ranges from about 65 to = 75?
A room in my finished basement, = and I see no=20 temperature effect.   I places a heater in the room to see if = I could,=20 but saw nothing change. 
 
  I don't have a lot of weight on = the spring,=20 so I am hoping it does not deform. much..
 
Ted
----- Original Message -----
From:=20 Bob=20 Hancock
Sent: Thursday, July 26, 2007 = 4:30=20 PM
Subject: RE: "P" ky = "Slinky"

Ted=20 =96

 

Interesting, very=20 interesting =96 from a non-engineer, how do you plan to compensate for = creep and=20 eventual deformation in the metal slinky, and how close is your = temperature=20 control, plus or minus what number?

 

Bob

 

Subject: Re: Spring damping From: Bobhelenmcclure@....... Date: Thu, 26 Jul 2007 21:11:23 EDT I do not know if there is a standard symbol for damping, but "Seismic Sensors and their Calibration" by Dr. Erhard Wielandt calls it "h". The relation between Q and h is Q=0.5/h. For critical damping, h=1.0 and Q=0.5. If the sensor Q is set to 0.707, the damping is also 0.707, and the sensor response is identical to a 2nd order Butterworth filter whose corner frequency is the natural frequency of the pendulum. The corresponding overshoot is 4.33 per cent. This is where I would like to keep my sensors, even though my WQFilter.exe" utility can compensate the data for almost any amount of under-or-over damping. Bob Geoffrey wrote: Hello Bob & PSN; Im not so sure this stuff is correct because its my understanding that Q and Damping are simply inverses of each other just like Period and Frequency. I was unable to get the inverse result simply by alternately clicking the buttons using the same input values. Like Q = 1 then damping = 1 Like Q = 0.5 then Damping = 2 Like Q = 2 then damping = 0.5 ??? Also, Whats the proper symbol for damping? ************************************** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour
 I do not know if there is a standard symbol for damping, but "Sei= smic=20 Sensors and their Calibration" by Dr. Erhard Wielandt calls it "h". The rela= tion=20 between Q and h is Q=3D0.5/h. For critical damping, h=3D1.0 and Q=3D0.5.
 
  If the sensor Q is set to 0.707, the damping is also 0.707,= and=20 the sensor response is identical to a 2nd order Butterworth filter whose cor= ner=20 frequency is the natural frequency of the pendulum. The corresponding oversh= oot=20 is 4.33 per cent. This is where I would like to keep my sensors, even=20 though my WQFilter.exe" utility can compensate the data for almost any amoun= t of=20 under-or-over damping.
 
Bob
 
  Geoffrey  wrote:
  Hello Bob & PSN;
 
Im not so sure this stuff is correct because
its my understanding th= at Q=20 and Damping
are simply inverses of each other just like
Period and=20 Frequency. I was unable to
get the inverse result simply by
alternatel= y=20 clicking the buttons
using the same input values.
 
Like Q =3D 1 then damping =3D 1
Like Q =3D 0.5 then Damping =3D 2Like Q =3D 2=20 then damping =3D 0.5
???
Also, Whats the proper symbol for=20 damping?



Get= a sneak peek of the all-new AOL.com.
Subject: Re: "P" ky "Slinky" From: ChrisAtUpw@....... Date: Fri, 27 Jul 2007 00:50:37 EDT In a message dated 2007/07/26, tchannel1@............ writes: > So why not chop a few turns off the spring? ! Maybe make two, with half > length springs?...........I could have, but gathering the loops aloud me to add > and subtract to adj the length. Hi Ted, Trim the extension by adding mass, eg large diameter washers? > >Have you tried putting thermal insulation around the tube? ..........I > could, but the room is temperature stable, so I have not. I suggest that you try it sometime? Maybe just wrap / hang a rug or a blanket around it for a rough test? It is likely to significantly reduce the noise. Does the increased daytime noise on the vertical correlate in time with the noise levels on the Lehman? Regards, Chris Chapman In a me= ssage dated 2007/07/26, tchannel1@............ writes:


So why not chop a few turns off= the spring? ! Maybe make two, with half length springs?...........I could h= ave, but gathering the loops aloud me to add and subtract to adj the length.=


Hi Ted,

       Trim the extension by adding mass, eg l= arge diameter washers?

>Have you tried putting the= rmal insulation around the tube?  ..........I could, but the room is te= mperature stable, so I have not.


       I suggest that you try it sometime? May= be just wrap / hang a rug or a blanket around it for a rough test?
       It is likely to significantly reduce th= e noise.
       Does the increased daytime noise on the= vertical correlate in time with the noise levels on the Lehman?

       Regards,

       Chris Chapman Subject: Re: "P" ky "Slinky" From: tchannel1@............ Date: Fri, 27 Jul 2007 08:18:41 -0600 Hi Chris, =20 >Does the increased daytime noise on the vertical correlate in time with = the noise levels on the Lehman? They are in two different location 7 miles apart. BUT =20 1. Night time both very quiet. 2. Weekends both very quiet. 3. Work day M-F 8-5 ..........Lehman not near road construction QUIET = with very little noise 4. .. .. .. .. .. Vertical "Slinky" 1.5 miles = to road construction very noisy. And as the work get closer to our = house the noise gets worse. I will insulate the tower, to see what happens. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Thursday, July 26, 2007 10:50 PM Subject: Re: "P" ky "Slinky" In a message dated 2007/07/26, tchannel1@............ writes: So why not chop a few turns off the spring? ! Maybe make two, with = half length springs?...........I could have, but gathering the loops = aloud me to add and subtract to adj the length. Hi Ted, Trim the extension by adding mass, eg large diameter washers? >Have you tried putting thermal insulation around the tube? = ...........I could, but the room is temperature stable, so I have not. I suggest that you try it sometime? Maybe just wrap / hang a = rug or a blanket around it for a rough test? It is likely to significantly reduce the noise.=20 Does the increased daytime noise on the vertical correlate in = time with the noise levels on the Lehman? Regards, Chris Chapman
Hi Chris,  
 
>Does the increased daytime noise on = the=20 vertical correlate in time with the noise levels on the = Lehman?
 
They are in two different = location 7 miles=20 apart.  BUT 
1.  Night time both very = quiet.
2.  Weekends both very = quiet.
3.  Work day M-F 8-5 = ...........Lehman=20 not near road construction QUIET with very little = noise
4.   =20 ...       ..   .. .. =20 ...            = ;=20 Vertical "Slinky"  1.5 miles to road construction very = noisy.  =20 And as the work get closer to our house the noise gets = worse.
 
I will insulate the tower, to see what=20 happens.
 
Thanks, Ted
----- Original Message -----
From:=20 ChrisAtUpw@.......
Sent: Thursday, July 26, 2007 = 10:50=20 PM
Subject: Re: "P" ky = "Slinky"

In a=20 message dated 2007/07/26, tchannel1@............=20 writes:


So why not chop a few turns off the spring? ! Maybe make = two,=20 with half length springs?...........I could have, but gathering the = loops=20 aloud me to add and subtract to adj the length.

Hi=20 Ted,

       Trim the extension by = adding=20 mass, eg large diameter washers?

>Have you tried putting thermal insulation around the = tube?  ..........I could, but the room is temperature stable, = so I have=20 not.

       I = suggest that=20 you try it sometime? Maybe just wrap / hang a rug or a blanket around = it for a=20 rough test?
       It is likely to=20 significantly reduce the noise. =
       Does=20 the increased daytime noise on the vertical correlate in time with the = noise=20 levels on the Lehman?

      =20 Regards,

       Chris = Chapman=20 Subject: GIF file showing a possible mine blast From: "Geoffrey" gmvoeth@........... Date: Sat, 28 Jul 2007 00:51:57 -0700 Hello PSN; you should be able to copy and paste this image file then name it (a.b64) or (a.uue) and open it using winzip. Id like you to read it and see if I got the P and S picks right. Regards; geoff ------=_NextPart_000_0003_01C7D0B0.6EA2E820 Content-Type: image/gif; name="gvaminea.GIF" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="gvaminea.GIF" R0lGODlhAwO8AfcAAAAAAIAAAACAAICAAAAAgIAAgACAgICAgMDAwP8AAAD/AP//AAAA//8A/wD/ /////wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMwAAZgAAmQAAzAAA/wAzAAAzMwAzZgAzmQAzzAAz/wBm AABmMwBmZgBmmQBmzABm/wCZAACZMwCZZgCZmQCZzACZ/wDMAADMMwDMZgDMmQDMzADM/wD/AAD/ MwD/ZgD/mQD/zAD//zMAADMAMzMAZjMAmTMAzDMA/zMzADMzMzMzZjMzmTMzzDMz/zNmADNmMzNm ZjNmmTNmzDNm/zOZADOZMzOZZjOZmTOZzDOZ/zPMADPMMzPMZjPMmTPMzDPM/zP/ADP/MzP/ZjP/ mTP/zDP//2YAAGYAM2YAZmYAmWYAzGYA/2YzAGYzM2YzZmYzmWYzzGYz/2ZmAGZmM2ZmZmZmmWZm zGZm/2aZAGaZM2aZZmaZmWaZzGaZ/2bMAGbMM2bMZmbMmWbMzGbM/2b/AGb/M2b/Zmb/mWb/zGb/ /5kAAJkAM5kAZpkAmZkAzJkA/5kzAJkzM5kzZpkzmZkzzJkz/5lmAJlmM5lmZplmmZlmzJlm/5mZ AJmZM5mZZpmZmZmZzJmZ/5nMAJnMM5nMZpnMmZnMzJnM/5n/AJn/M5n/Zpn/mZn/zJn//8wAAMwA 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tchannel1@............ Date: Sat, 28 Jul 2007 09:46:50 -0600 Hi All, I finished the Folded Pendulum Sensor. I will send pictures to = anyone interested. After I test it, and if it works, I will then post = the pictures on the internet, like I did on the "Slinky" All in all, it was a bit of a bear. I guess the fact it was a new = concept, for me, and that I could find only a couple examples, was part = of the issue. Thanks to all who helped me, or I would have never = gotten this far. At this point it seems to be working, but I can = qualify it's performance after it is tested. The two pendulum, one normal, one inverted have the same length, 7.625", = The box it is contained in is 32"x24". The best working natural period I could measure, was about 6 to 10 = seconds. I could obtain 15 seconds but it was too unstable. It has been pointed out to me that I should have achieved a longer = period using this approach. Perhaps other articles and examples may = show me how to improve the design. By the way if and when I record earthquakes using the sensor I will post = them on PSN as TCIDF, for "Folded Pendulum" TCIDzs=3D "Slinky is setting in the corner. I do have a question about measuring a sensor's period. I assume the = best way is to remove the damper, tap the arm, and time the cycles. Q. Is there another way, to estimate its period, with the damper = installed? On this sensor the damper is difficult to remove. =20 Different Subject Q. I don't really understand the FFT in AmaSeis. If I take one hour = of trace, containing road construction noise, and use Control/Fourier = Transform/Linear, I see a large spike at 1.607Hz another at 2.597Hz = and some other signals. Is this the frequency of the noise? Q. I highlighted an earthquake, and using the same steps I see a = section of spikes, starting at .2 and ending at .8Hz Is that the frequency of the recorded earthquake? Thanks Again, Ted
Hi All,  I finished the Folded = Pendulum=20 Sensor.  I will send pictures to anyone interested.  After I = test it,=20 and if it works, I will then post the pictures on the internet, like I = did on=20 the "Slinky"
 
All in all, it was a bit of a = bear.   I=20 guess the fact it was a new concept, for me, and that I could find = only a=20 couple examples, was part of the issue.   Thanks to all who = helped me,=20 or I would have never gotten this far.   At this point it = seems to be=20 working, but I can qualify it's performance after it is = tested.
 
The two pendulum, one normal, one = inverted have the=20 same length, 7.625",  The box it is contained in is = 32"x24".
The best working natural period I could = measure, was about 6 to 10 seconds.  I could obtain 15 seconds = but it=20 was too unstable.
It has been pointed out to me that I = should have=20 achieved a longer period using this approach.   Perhaps other = articles=20 and examples may show me how to improve the design.
 
By the way if and when I record = earthquakes using=20 the sensor I will post them on PSN as TCIDF, for "Folded = Pendulum"
TCIDzs=3D "Slinky is setting in the=20 corner.
 
I do have a question about measuring a = sensor's=20 period.  I assume the best way is to remove the damper, tap the = arm, and=20 time the cycles.
 
Q.   Is there another way, to = estimate=20 its period, with the damper installed?   On this sensor the = damper is=20 difficult to remove.
 
 
Different Subject
 
Q.   I don't really = understand the FFT in=20 AmaSeis.   If I take one hour of trace, containing road = construction=20 noise, and use Control/Fourier Transform/Linear,   I see a = large spike=20 at 1.607Hz another at 2.597Hz and some other signals.
Is this the frequency of the = noise?
 
Q.  I highlighted an earthquake, = and using the=20 same steps I see a section of spikes, starting at .2 and ending at=20 ..8Hz
Is that the frequency of the recorded=20 earthquake?
 
Thanks Again,  Ted
 
Subject: PSN to Wave File From: tchannel1@............ Date: Sat, 28 Jul 2007 14:37:00 -0600 Hi Folks, Bob created a "PSN-to_WavErev1.zip" which converts .psn to = ..wav, from Winquake. This is a neat thing! I ask permission to mention the program...and = Bob said "Yes, you have my permission. Everyone is welcome to use = whatever I come up with." I wish I knew how to do that stuff. The duration is about 2 sec. in = play time, from about 60 mins of .psn file. I did one and imported the .wav into a sound studio program.=20 I am having fun with it. I recorded twin earthquakes on 070727, off the = coast of Oregon, 4.7 and 4.6? Converted them to a .wav, using his = program, time stretch it, looped it, panned it L to R, and made it loop = for about 27 seconds. I then converted it into an mp3 to save space. It now is about 450K. When you play it, you can hear the two earthquakes, and their "P"s, it = pans from L to R, and then loops. Just fun. I will email the finished .mp3 to anyone who is interested. = tchannel1@............ Ted
Hi Folks,  Bob created a =20 "PSN-to_WavErev1.zip"  which converts .psn to .wav, from=20 Winquake.
This is a neat thing!   I ask = permission=20 to mention the program...and Bob said "Yes, you have my permission. = Everyone is=20 welcome to use whatever I come up with."
 
I wish I knew how to do that = stuff.  The=20 duration is about 2 sec. in play time, from about 60 mins of .psn=20 file.
 
I did one and imported the .wav into a = sound studio=20 program.
 
I am having fun with it.  I recorded twin earthquakes on = 070727,=20 off the coast of Oregon, 4.7 and 4.6?  Converted them to a .wav,=20 using his program,  time stretch it, looped it, panned it = L to R,=20 and made it loop for about 27 seconds.
 
I then converted it into an mp3 to save = space.  It now is about 450K.
When you play it, you can hear the two = earthquakes,=20 and their "P"s,  it pans from L to R, and then loops.
Just fun.
 
I will email the finished .mp3 to = anyone who is=20 interested.   tchannel1@............<= /DIV>
 
Ted
 
Subject: Re: PSN to Wave File From: "Geoffrey" gmvoeth@........... Date: Sun, 29 Jul 2007 05:26:38 -0700 Hello PSN; I think this WAV technique of analysis might be called signature analysis. It is a subjective and not objective thing because it is related to what is called psycho-acoustics and intuition. every type of natural noise most probably has a sound that will be unique and yiu can tell what it is just by listening. I have noticed over time that close quakes sound like a stack of books being dropped on the floor and the long distant quakes sound more like a booming echoy sound. It would be difficult for a person to recreate these sounds by trying to fake them into the ground. Also I have noticed with FFT and the waterfall display that a teleseismic event looks somewhat like the voltage measured across a resistor whan you discharge a capacitor across it. I seriously wonder if that is not the case ???? comments welcome here ?? The energy seems of a quake seems to decay at the similar rate as a discharging capacitor. You could simulate this via mathematics in a computer but it would be difficult in real life because the energy needed in the ground is normally too great for a human to do it thenselves. Some freq seem to arrive first but they are not always the very same freq. So I guess that is why you need to be wide band. You are really looking at a kind of noise when you see any earthquakes and not a genuine signal with any purity. Regards; geoff ----- Original Message ----- From: To: Sent: Saturday, July 28, 2007 13:37 Subject: PSN to Wave File Hi Folks, Bob created a "PSN-to_WavErev1.zip" which converts .psn to .wav, from Winquake. This is a neat thing! I ask permission to mention the program...and Bob said "Yes, you have my permission. Everyone is welcome to use whatever I come up with." I wish I knew how to do that stuff. The duration is about 2 sec. in play time, from about 60 mins of .psn file. I did one and imported the .wav into a sound studio program. I am having fun with it. I recorded twin earthquakes on 070727, off the coast of Oregon, 4.7 and 4.6? Converted them to a .wav, using his program, time stretch it, looped it, panned it L to R, and made it loop for about 27 seconds. I then converted it into an mp3 to save space. It now is about 450K. When you play it, you can hear the two earthquakes, and their "P"s, it pans from L to R, and then loops. Just fun. I will email the finished .mp3 to anyone who is interested. tchannel1@............ Ted __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Testing the Folded Pendulum From: "Geoffrey" gmvoeth@........... Date: Sun, 29 Jul 2007 05:29:16 -0700 Have you seen the seismometer they are building for a mars mission ? do you think you could duplicate one like that ??? I think it is only horizontal x-y. regards; geoff ----- Original Message ----- From: To: Sent: Saturday, July 28, 2007 08:46 Subject: Testing the Folded Pendulum Hi All, I finished the Folded Pendulum Sensor. I will send pictures to anyone interested. After I test it, and if it works, I will then post the pictures on the internet, like I did on the "Slinky" All in all, it was a bit of a bear. I guess the fact it was a new concept, for me, and that I could find only a couple examples, was part of the issue. Thanks to all who helped me, or I would have never gotten this far. At this point it seems to be working, but I can qualify it's performance after it is tested. The two pendul