Subject: Determining Mass Size for Lehman Seismometer From: "Gary Lindgren" gel@................. Date: Mon, 31 Mar 2008 17:40:48 -0700 How do I determine the mass size of the pendulum for a Lehman seismometer. Is there a method to the madness? Gary Gary Lindgren 585 Lincoln Ave Palo Alto CA 94301 650-326-0655 www.blue-eagle-technologies.com cymonsplace.blogspot.com

How do I determine the mass size of the pendulum for a Lehman seismometer. = Is there a method to the madness?

Gary

 

Gary Lindgren

585 Lincoln Ave

Palo = Alto CA 94301

 

650-326-0655

 

www.blue-eagle-technologi= es.com

cymonsplace.blogspot.com=  

 

 

Subject: Re: Determining Mass Size for Lehman Seismometer From: lehmancj@........... Date: Tue, 1 Apr 2008 00:55:38 GMT > How do I determine the mass size of the pendulum for a Lehman seismometer. > Is there a method to the madness? > > Gary--just a note on the original determination of the mass. I chose a 5lb. piece of lead as it was available & handy. For the dimensions of the boom, the lead was not excessive weight, and seemed to be sufficient mass for stability, and was able to be supported by piano wire without undo fatigue. The system worked beyond our original expectations, but there have been modifications & improvements, so don't fear to experiment around with other suggestions that float by. A working design is empirical by nature--best wishes--Jim Lehman > > > > Gary Lindgren > > 585 Lincoln Ave > > Palo Alto CA 94301 > > > > 650-326-0655 > > > > www.blue-eagle-technologies.com > > cymonsplace.blogspot.com > > > > > > --------------------------------------------- This message was sent using Shentel WebMail. http://WebMail.Shentel.Net __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Determining Mass Size for Lehman Seismometer From: ChrisAtUpw@....... Date: Mon, 31 Mar 2008 22:38:55 EDT In a message dated 2008/04/01, gel@................. writes: > How do I determine the mass size of the pendulum for a Lehman seismometer. > Is there a method to the madness? > Gary Hi Gary, There is method in the madness! The period of a pendulum is independant of the mass, since the gravitational attraction and the moment of inertia both depend on M ! But you need ~the maximum radius of gyration, so you make the mass several times larger than the weight of the arm on it's own. But you don't want to stress the suspension too much. A mass of 1 to about 5 lbs is generally OK. Lead is dense, but difficult to fasten, so I generally use brass. Avoid iron, which is magnetic. Hope that this helps! Regards, Chris Chapman In a me= ssage dated 2008/04/01, gel@................. writes:

How do I determine the mass siz= e of the pendulum for a Lehman seismometer. Is there a method to the madness= ?
Gary


Hi Gary,

       There is method in the madness!

       The period of a pendulum is independant= of the mass, since the gravitational attraction and the moment of inertia b= oth depend on M !

       But you need ~the maximum radius of gyr= ation, so you make the mass several times larger than the weight of the arm=20= on it's own. But you don't want to stress the suspension too much.  A m= ass of 1 to about 5 lbs is generally OK. Lead is dense, but difficult to fas= ten, so I generally use brass. Avoid iron, which is magnetic.

       Hope that this helps!

       Regards,

       Chris Chapman Subject: Re: Determining Mass Size for Lehman Seismometer From: "Geoff" gmvoeth@........... Date: Tue, 1 Apr 2008 07:39:18 -0700 If you consider the science of external ballistics you will find the greater the mass and density the less effect air movemenr will have on it. Otherwise use a small mass several times the boom mass and put in all under a vacuum with magnetic damping. Static friction is the only nasty thing to deal with as I understand it. It tends to lock things into place till you get enough force to overcome it. If you do not have the ability to produce and maintain a vacuum I think a spherical shape may be the best for the mass. I have often thought it would be nice to have a very very sensitive bathroom scale and put a gallon of water on it then look for the noise level. Not sure of any of this it just seems common senseical :-) ----- Original Message ----- From: "Gary Lindgren" To: Sent: Monday, March 31, 2008 5:40 PM Subject: Determining Mass Size for Lehman Seismometer > How do I determine the mass size of the pendulum for a Lehman seismometer. > Is there a method to the madness? > > Gary > > > > Gary Lindgren > > 585 Lincoln Ave > > Palo Alto CA 94301 > > > > 650-326-0655 > > > > www.blue-eagle-technologies.com > > cymonsplace.blogspot.com > > > > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Tiltmeter Electronics From: "Chuck Burch" cjburch@........... Date: Wed, 02 Apr 2008 20:43:27 -0700 I'm wondering about electronics for a tiltmeter with capacitive sensors I'm building. My current plan is to use a transformer coupled bridge, current-to-voltage amplifier, phase sensitive detector, followed by filter and final gain. I have a circuit diagram for this scheme, but it's circa 1970 and I assume it can be improved with modern chips. Any suggestions? Chuck Burch __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Tiltmeter Electronics From: ChrisAtUpw@....... Date: Wed, 2 Apr 2008 11:36:06 EDT In a message dated 2008/04/02, cjburch@........... writes: > I'm wondering about electronics for a tiltmeter with capacitive sensors I'm > building. > My current plan is to use a transformer coupled bridge, current-to-voltage > amplifier, > phase sensitive detector, followed by filter and final gain. I have a > circuit diagram for this scheme, but it's circa 1970 and I assume it can be > improved with modern chips. Hi Chuck, George Bush at ke6pxp@....... has done quite a lot of work on the Mercury Tiltmeter published by the Scientific American about then. The original circuit needs to be improved very considerably. I helped George over the design using an LTC1043 switched capacitor bridge. He has a website at http://ntweb.mcn.org/gbush/Tiltmeter/tiltmeter%20Main.html DON'T bother with the Nuts and Volts circuit. It does not work well. There is another seismometer / tiltmeter circuit using water, as opposed to mercury, which also works very well at FMES. Contact Dave Nelson at davefnelson@....... Design and circuits are available. Regards, Chris Chapman In a me= ssage dated 2008/04/02, cjburch@........... writes:

I'm wondering about electronics= for a tiltmeter with capacitive sensors I'm building. 
My current plan is to use a transformer coupled bridge, current-to-voltage a= mplifier,
phase sensitive detector, followed by filter and final gain.  I have a=20= circuit diagram for this scheme, but it's circa 1970 and I assume it can be=20= improved with modern chips. 


Hi Chuck,

       George Bush at ke6pxp@....... has done quite a lot of work on the Mercury&nbs= p; Tiltmeter published by the Scientific American about then. The original c= ircuit needs to be improved very considerably. I helped George over the desi= gn using an LTC1043 switched capacitor bridge.

       He has a website at http://ntweb.mcn.or= g/gbush/Tiltmeter/tiltmeter%20Main.html

       DON'T bother with the Nuts and Volts ci= rcuit. It does not work well.

       There is another seismometer / tiltmete= r circuit using water, as opposed to mercury, which also works very well at=20= FMES. Contact Dave Nelson at davefnelson@....... Design and circuits are ava= ilable.

       Regards,

       Chris Chapman Subject: Question regarding leveling of vertical seismometer From: "Kay Wyatt" kwyatt@............. Date: Wed, 2 Apr 2008 12:22:33 -0700 Folks, A quick question regarding the leveling screws for a vertical = seismosmeter... If you look at the three leveling screws on the AS-1 seismometer at = http://www.amateurseismologist.com/, you see that there are two screws = on the end with the vertical support and one screw on the end near the = coil. It is obvious why only three screws are used. But is their a = reason for putting the single screw near the coil and not near the = vertical support. Also, wouldn't there be greater stability if the = single screw was actually a fixed pin, leaving the other two to be = adjustable screws? =20 Just wondering before I drill the base in my next vertical seismometer. Thanks, Kay Wyatt
Folks,
 
A quick question regarding the leveling screws = for a=20 vertical seismosmeter...
 
If you look at the three leveling screws on the = AS-1=20 seismometer at http://www.amateurseismologi= st.com/,=20 you see that there are two screws on the end with the vertical support = and one=20 screw on the end near the coil.  It is obvious why only three = screws are=20 used.  But is their a reason for putting the single screw near the = coil and=20 not near the vertical support.  Also, wouldn't there be greater = stability=20 if the single screw was actually a fixed pin, leaving the other two to = be=20 adjustable screws? 
 
Just wondering before I drill the base in = my next=20 vertical seismometer.
 
Thanks,
Kay Wyatt
 
 
Subject: Re: Question regarding leveling of vertical seismometer From: ChrisAtUpw@....... Date: Wed, 2 Apr 2008 16:18:00 EDT In a message dated 2008/04/02, kwyatt@............. writes: > If you look at the three leveling screws on the AS-1 seismometer at > http://www.amateurseismologist.com/, you see that there are two screws on the end > with the vertical support and one screw on the end near the coil. It is > obvious why only three screws are used. But is their a reason for putting the > single screw near the coil and not near the vertical support. Also, wouldn't > there be greater stability if the single screw was actually a fixed pin, leaving > the other two to be adjustable screws? > > Just wondering before I drill the base in my next vertical seismometer. Hi Kay, It shouldn't matter, but it is generally easier to put the lateral adjustment screws either side of the vertical support column and the longitudinal adjustment at the end of the arm. You have 'free' space here. I suggest the you make all three mounting screws of identical construction. If you have one peg leg you will have the problem of matching it's expansion with the other two. This is not too important for vertical instruments, but it is very important on a Lehman. Also, you generally get presented with a site of unknown slope direction. Being able to adjust all three screws is an advantage. I use a fairly thick baseplate and stainless steel bolts, nuts and washers. I drill the hole the same nominal OD as the bolt. I stick a SS nut on the underside of the basplate with two component acrylic glue eg Devcon Plastic Welder S-220 22045. You can also buy 'nut-serts' which you press into suitable holes with a vice or a press. I centre drill the end of the bolts and stick a suitable OD SS ball bearing in the V. Alternatively, you can file the end of the bolt to a cone with a small domed end. This helps prevent the seismometer position wandering as you make adjustments. I thread an ordinary nut onto the bolt, add a wavy washer and screw this into the top of the frame. After adjusting the levels I tighten compress the wavy washer with the free top nut. This largely prevents any creep due to differential expansion. I also use three 2" square x 1/8" thick SS ground plates. What you MUST NOT do is to use bolts and nuts / threaded holes of DIFFERENT materials, with different expansion coefficients. This will ~guarantee creep / drift problems. Regards, Chris Chapman In a me= ssage dated 2008/04/02, kwyatt@............. writes:

If you look at the three leveli= ng screws on the AS-1 seismometer at http://www.amateurseismologist.com/, you see that there are two= screws on the end with the vertical support and one screw on the end near t= he coil.  It is obvious why only three screws are used.  But is th= eir a reason for putting the single screw near the coil and not near the ver= tical support.  Also, wouldn't there be greater stability if the single= screw was actually a fixed pin, leaving the other two to be adjustable scre= ws? 

Just wondering before I drill the base in my next vertical seismometer.

Hi Kay,

       It shouldn't matter, but it is generall= y easier to put the lateral adjustment screws either side of the vertical su= pport column and the longitudinal adjustment at the end of the arm. You have= 'free' space here.
       I suggest the you make all three mounti= ng screws of identical construction. If you have one peg leg you will have t= he problem of matching it's expansion with the other two. This is not too im= portant for vertical instruments, but it is very important on a Lehman.
       Also, you generally get presented with=20= a site of unknown slope direction. Being able to adjust all three screws is=20= an advantage.
       I use a fairly thick baseplate and stai= nless steel bolts, nuts and washers. I drill the hole the same nominal OD as= the bolt. I stick a SS nut on the underside of the basplate with two compon= ent acrylic glue eg Devcon Plastic Welder S-220 22045.
       You can also buy 'nut-serts' which you=20= press into suitable holes with a vice or a press.
       I centre drill the end of the bolts and= stick a suitable OD SS ball bearing in the V. Alternatively, you can file t= he end of the bolt to a cone with a small domed end. This helps prevent the=20= seismometer position wandering as you make adjustments.
       I thread an ordinary nut onto the bolt,= add a wavy washer and screw this into the top of the frame. After adjusting= the levels I tighten compress the wavy washer with the free top nut. This l= argely prevents any creep due to differential expansion.
       I also use three 2" square x 1/8" thick= SS ground plates.
       What you MUST NOT do is to use bolts an= d nuts / threaded holes of DIFFERENT materials, with different expansion coe= fficients. This will ~guarantee creep / drift problems.

       Regards,

       Chris Chapman Subject: Re: Question regarding leveling of vertical seismometer From: John Lahr johnjan@........ Date: Wed, 02 Apr 2008 23:10:26 -0700 Hi Kay, The problem with a fixed pin at one end is that to change to level in the long direction, both of the other screws would need to be turned. This would probably mess up the tilt in the short direction. With three screws, the short-direction tilt and the long-direction tilt can be adjusted independently. Cheers, John At 12:22 PM 4/2/2008, you wrote: >Folks, > >A quick question regarding the leveling screws for a vertical seismosmeter... > >If you look at the three leveling screws on the AS-1 seismometer at >http://www.amateurseismologist.com/, >you see that there are two screws on the end with the vertical >support and one screw on the end near the coil. It is obvious why >only three screws are used. But is their a reason for putting the >single screw near the coil and not near the vertical support. Also, >wouldn't there be greater stability if the single screw was actually >a fixed pin, leaving the other two to be adjustable screws? > >Just wondering before I drill the base in my next vertical seismometer. > >Thanks, >Kay Wyatt > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Question regarding leveling of vertical seismometer From: Charles Patton charles.r.patton@........ Date: Thu, 03 Apr 2008 10:41:07 -0700 Hi John, Not necessarily. The geometry used for mirror mounts in optical bench work is that the fixed point is at the intersection of two lines at right angles to one another. The two screws are then on each of the lines respectively. That way the screws do not interact, i.e., they cause only orthogonal tilt on their particular axis. So translating that to a seismometer, put the fixed pin near the pivot point of the boom and offside in the short dimension (perpendicular to the boom (if a Lehman style, but similar rules for a vertical) -- probably in one corner) Place one screw way down the base on a line through the fixed pin and parallel to the boom. This will become the leveling screw. Place the other screw on a line at right angles to the fixed point and the just placed screw (probably in the corner across the pivot. This is now the tilt. The only other trick is to put enough weight on the base so that the center-of-mass is within the triangle formed by the fixed point and two screws (or use a long, triangular shaped base where all the parts are within the triangle. Mirror mounts typically use springs to hold the mounts together, rather than gravity) So even if you use three screws, this geometry will make life much easier when adjusting as there won't be axis interactions when doing the final adjustments using only the two screws at the ends of the right angle. Refinements are to make the design fully kinematic by using a tetrahedral divot for the fixed point ball end to rest in, a tri-angular groove aligned along the line of the fixed point and the screw ball end, and finally a flat plate for the final screw ball end. This constrains the whole fixture so it doesn't slide or twist on the resting base. Charles Patton John Lahr wrote: > Hi Kay, > > The problem with a fixed pin at one end is that to change to level in > the long direction, both of the other screws would need to be turned. > This would probably mess up the tilt in the short direction. > > With three screws, the short-direction tilt and the long-direction tilt > can be adjusted independently. > > Cheers, > John > > At 12:22 PM 4/2/2008, you wrote: >> Folks, >> >> A quick question regarding the leveling screws for a vertical >> seismosmeter... >> >> If you look at the three leveling screws on the AS-1 seismometer at >> http://www.amateurseismologist.com/, >> you see that there are two screws on the end with the vertical support >> and one screw on the end near the coil. It is obvious why only three >> screws are used. But is their a reason for putting the single screw >> near the coil and not near the vertical support. Also, wouldn't there >> be greater stability if the single screw was actually a fixed pin, >> leaving the other two to be adjustable screws? >> >> Just wondering before I drill the base in my next vertical seismometer. >> >> Thanks, >> Kay Wyatt >> >> > > > __________________________________________________________ > > 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: Question regarding leveling of vertical seismometer From: ChrisAtUpw@....... Date: Thu, 3 Apr 2008 14:19:23 EDT In a message dated 2008/04/03, charles.r.patton@........ writes: > The only other trick is to put enough weight on the base > so that the center-of-mass is within the triangle formed by the fixed > point and two screws (or use a long, triangular shaped base where all > the parts are within the triangle. Hi Charles, This is not usually done. The base is always flexible to some extent and having an offset centre of mass / anisotropic flexure may not be exactly helpful. Regards, Chris Chapman In a me= ssage dated 2008/04/03, charles.r.patton@........ writes:

The only other trick is to put=20= enough weight on the base
so that the center-of-mass is within the triangle formed by the fixed
point and two screws (or use a long, triangular shaped base where all
the parts are within the triangle.


Hi Charles,
      
       This is not usually done. The base is a= lways flexible to some extent and having an offset centre of mass / anisotro= pic flexure may not be exactly helpful.

       Regards,

       Chris Chapman Subject: Shake table From: "Kay Wyatt" kwyatt@............. Date: Fri, 4 Apr 2008 09:57:58 -0700 Folks, Thanks for the feedback on the leveling screws for my seismometer. Now here is a question regarding a shake table. =20 I currently have a small shake table that has a 10" base plate which I = use in the public schools to help kids understand the relationship of = building structure and materials to earthquake damage. I divide the = kids up into teams to construct their "buildings" and then individually = set them on the shake table. Because only one building can be tested at = a time it is more time consuming and less "fun" for the kids because = they can't easily see how their building measures up to another team's = building. So, I am constructing a larger shake table with a 30" base that can hold = four buildings. This lets a class divide up into four teams and then = the entire class can watch their buildings shake at once. Say an actual building has a footprint of 100 feet square. Relative to = a model building which has a footprint of 12 inches square, the width is = a factor of 100. I have a variable frequency motor to which I am = attaching off center cams to create the vibration movement. Springs = pull back the base towards the drive shaft with the cams. So, here is my question. Has anybody experimented with a shake table of = this size? What displacements should I design the cams to create? I = could use different size cams to create different "magnitude" = earthquakes. Also, what frequencies should I set the motor to run. Thanks for any help that you might offer. Kay
Folks,
 
Thanks for the feedback on the leveling screws = for my=20 seismometer.
 
Now here is a question regarding a shake=20 table.  
 
I currently have a small shake table that has a = 10" base=20 plate which I use in the public schools to help kids understand the = relationship=20 of building structure and materials to earthquake damage.  I divide = the=20 kids up into teams to construct their "buildings" and then individually = set them=20 on the shake table.  Because only one building can be tested at a = time it=20 is more time consuming and less "fun" for the kids because they can't = easily see=20 how their building measures up to another team's building.
 
So, I am constructing a larger shake table with = a 30" base=20 that can hold four buildings.  This lets a class divide up into = four teams=20 and then the entire class can watch their buildings shake at = once.
 
Say an actual building has a footprint of 100 = feet=20 square.  Relative to a model building which has a footprint of 12 = inches=20 square, the width is a factor of 100.  I have a variable frequency = motor to=20 which I am attaching off center cams to create the vibration = movement. =20 Springs pull back the base towards the drive shaft with the = cams.
 
So, here is my question.  Has anybody = experimented=20 with a shake table of this size?  What displacements should I = design the=20 cams to create?  I could use different size cams to create = different=20 "magnitude" earthquakes.  Also, what frequencies should I set the = motor to=20 run.
 
Thanks for any help that you might = offer.
 
Kay
 
Subject: Re: Shake table From: ChrisAtUpw@....... Date: Fri, 4 Apr 2008 15:56:19 EDT In a message dated 2008/04/04, kwyatt@............. writes: > So, I am constructing a larger shake table with a 30" base that can hold > four buildings. This lets a class divide up into four teams and then the > entire class can watch their buildings shake at once. Hi Kay, Something that size could be quite heavy. Consider foam filled buiilding / wall sheet with an Al L angle surround and four vertical foil flexures? You can also buy metal + rubber vibration isolation mountings.You can get Celotex up to at least 3" thick? This has a thin glass/resin skin. Apart from variable speed motors you can also get 'floor shakers', which are a very heavy magnet + coil driver system. We use them for testing seismometers & geophones. Alternatively, you could use a coil of wire and NdFeB magnets. Maybe drive it with a LF oscillator and an audio amplifier? The professional shake tables may use an electromagnetic drive controlled by a distance transducer. You can vary the frequency and the amplitude. Regards, Chris Chapman In a me= ssage dated 2008/04/04, kwyatt@............. writes:

So, I am constructing a larger=20= shake table with a 30" base that can hold four buildings.  This lets a=20= class divide up into four teams and then the entire class can watch their bu= ildings shake at once.


Hi Kay,

       Something that size could be quite heav= y. Consider foam filled buiilding / wall sheet with an Al L angle surround a= nd four vertical foil flexures? You can also buy metal + rubber vibration is= olation mountings.You can get Celotex up to at least 3" thick? This has a th= in glass/resin skin.
       Apart from variable speed motors you ca= n also get 'floor shakers', which are a very heavy magnet + coil driver syst= em. We use them for testing seismometers & geophones. Alternatively, you= could use a coil of wire and NdFeB magnets. Maybe drive it with a LF oscill= ator and an audio amplifier?
       The professional shake tables may use a= n electromagnetic drive controlled by a distance transducer. You can vary th= e frequency and the amplitude.

       Regards,

       Chris Chapman
 Subject: Re: Shake table From: John Lahr johnjan@........ Date: Sat, 05 Apr 2008 03:01:17 -0700 Hi Kay, This sounds like a great project. I would really like to post some pictures to my web site, along with construction details, when you're done. I've always used variable frequency, rather than amplitude. It's easier to do and let's the resonant period of the model be determined. The best frequency (the one that causes damage!) will depend on the height and construction of each model. It's best if there is a weight requirement, in that each model must carry a considerable weight on the roof. This could be considered an air conditioner unit for the building or some other machinery. One thing to avoid is providing too much time/material so that the buildings are indestructible! A teacher sent me a video of his class testing their models and they were so strong that not much happened on the shake table. One actually fell on the floor and was not damaged! Cheers, John At 09:57 AM 4/4/2008, you wrote: >Folks, > >Thanks for the feedback on the leveling screws for my seismometer. > >Now here is a question regarding a shake table. > >I currently have a small shake table that has a 10" base plate which >I use in the public schools to help kids understand the relationship >of building structure and materials to earthquake damage. I divide >the kids up into teams to construct their "buildings" and then >individually set them on the shake table. Because only one building >can be tested at a time it is more time consuming and less "fun" for >the kids because they can't easily see how their building measures >up to another team's building. > >So, I am constructing a larger shake table with a 30" base that can >hold four buildings. This lets a class divide up into four teams >and then the entire class can watch their buildings shake at once. > >Say an actual building has a footprint of 100 feet square. Relative >to a model building which has a footprint of 12 inches square, the >width is a factor of 100. I have a variable frequency motor to >which I am attaching off center cams to create the vibration >movement. Springs pull back the base towards the drive shaft with the cams. > >So, here is my question. Has anybody experimented with a shake >table of this size? What displacements should I design the cams to >create? I could use different size cams to create different >"magnitude" earthquakes. Also, what frequencies should I set the motor to run. > >Thanks for any help that you might offer. > >Kay > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Electronic components From: tchannel1@............ Date: Sat, 5 Apr 2008 09:35:15 -0600 Hi Folks, Could anyone recommend a wed site where I can purchases = electronic bits and pieces, ic's, relays, etc, and has little or no = minimum order? I did Goggle it but I am not having much luck. Thanks, Ted
Hi Folks,  Could anyone recommend = a wed site=20 where I can purchases electronic bits and pieces, ic's, = relays, etc, and=20 has little or no minimum order?
 
I did Goggle it but I am not having = much=20 luck.
 
 
Thanks, Ted
Subject: Re: Electronic components From: "Jerry Payton" gpayton880@....... Date: Sat, 5 Apr 2008 10:48:31 -0500 Hi Ted, The Mad Scientist at work again, huh. (Just joking) You might try www.mouser.com or www.digikey.com , depending upon what you are looking for. We also used http://www.allelectronics.com/ before too. Regards, Jerry ----- Original Message ----- From: tchannel1@............ To: psn Sent: Saturday, April 05, 2008 10:35 AM Subject: Electronic components Hi Folks, Could anyone recommend a wed site where I can purchases electronic bits and pieces, ic's, relays, etc, and has little or no minimum order? I did Goggle it but I am not having much luck. Thanks, Ted
Hi Ted,
 
The Mad Scientist at work again, huh.  (Just joking)
 
You might try  www.mouser.com  or  www.digikey.com , depending = upon what you=20 are looking for.  We also used  http://www.allelectronics.com/ =20 before too.
 
Regards,
Jerry
 
 
----- Original Message -----=20
From: tchannel1@............
To: psn
Sent: Saturday, April 05, 2008 10:35 AM
Subject: Electronic components

Hi Folks,  Could anyone recommend = a wed site=20 where I can purchases electronic bits and pieces, ic's, = relays, etc, and=20 has little or no minimum order?
 
I did Goggle it but I am not having = much=20 luck.
 
 
Thanks, Ted
Subject: Whip antenna From: tchannel1@............ Date: Sat, 5 Apr 2008 10:01:11 -0600 Hi Folks, If I had a 36" whip antenna, just a piece of spring steel rod, = with a small mass on the tip, how much would the tip move during a = earthquake? I know that is just a general question, and it would depend on many = factors. Let's say the size of the event was 6.0M, 1000 mile away. = This event would be recorded by all three of my sensors. The movement = of sensor's pendulum or vertical spring during this type of event would = probably not be noticeable to the eye. If the event was a large one, = then surely it would be noticeable to the eye, perhaps even 1/8" or = more. I am still trying to come up with a Earthquake Directional Device. I = have seen articles on the Chinese versions, and turn of the century = devices which used a variety of approaches, where a normal pendulum or = even a "Wipe Antenna" / inverted pendulum would be set in motion and = make contact with a circuit. I know such devices would work in = California, but I don't know how small or weak events would work. =20 My thinking is, if I just use the motion of a "Whip Antenna" to close a = contact, it would not record much, unless I could move the two points of = contact to within the thickness of a human hair. I know I could use a magnet/coil and the device would work on most all = earthquakes, presently recordable, but I don't want to dismiss these old = approaches either. Just wanted to get an opinion. Thanks, Ted
Hi Folks, If I had a 36" whip antenna, = just a piece=20 of spring steel rod, with a small mass on the tip, how much would the = tip move=20 during a earthquake?
I know that is just a general question, = and it=20 would depend on many factors.   Let's say the size of the = event was=20 6.0M, 1000 mile away.  This event would be recorded by all three of = my=20 sensors.  The movement of sensor's pendulum or vertical spring = during=20 this type of event would probably not be noticeable to the eye.  If = the=20 event was a large one, then surely it would be noticeable to the eye, = perhaps=20 even 1/8" or more.
 
I am still trying to come up with a = Earthquake=20 Directional Device.   I have seen articles on the Chinese = versions,=20 and turn of the century devices which used a variety of approaches, = where a=20 normal pendulum or even a  "Wipe Antenna" / inverted pendulum = would be=20 set in motion and make contact with a circuit.   I know such = devices=20 would work in California, but I don't know how small or weak events = would=20 work. 
 
My thinking is, if I just use the = motion of a "Whip=20 Antenna" to close a contact, it would not record much, unless I could = move the=20 two points of contact to within the thickness of a human = hair.
 
I know I could use a magnet/coil and = the device=20 would work on most all earthquakes, presently recordable, but I don't = want to=20 dismiss these old approaches either.
 
Just wanted to get an = opinion.
 
Thanks, Ted
 
Subject: Re: Electronic components From: "Erich Kern" efkern@............. Date: Sat, 5 Apr 2008 09:32:17 -0700 Ted, Send me a list (off-list, to my email adress) of what you need and I'll = email you a price quote + postage. All new parts.=20 Erich Kern Murrieta, Calif.=20 ----- Original Message -----=20 From: tchannel1@............... To: psn=20 Sent: Saturday, April 05, 2008 8:35 AM Subject: Electronic components Hi Folks, Could anyone recommend a wed site where I can purchases = electronic bits and pieces, ic's, relays, etc, and has little or no = minimum order? I did Goggle it but I am not having much luck. Thanks, Ted
 
Ted,
 
Send me a list (off-list, to my email adress) of = what you=20 need and I'll email you a price quote + postage. All new parts. =
 
Erich Kern
Murrieta, Calif.
 
 
----- Original Message -----=20
From: tchannel1@............
To: psn
Sent: Saturday, April 05, 2008 8:35 AM
Subject: Electronic components

Hi Folks,  Could anyone recommend = a wed site=20 where I can purchases electronic bits and pieces, ic's, = relays, etc, and=20 has little or no minimum order?
 
I did Goggle it but I am not having = much=20 luck.
 
 
Thanks, Ted
Subject: RE: Electronic components From: "Keith Payea" kpayea@.............. Date: Sat, 5 Apr 2008 09:35:27 -0700 Ted: Others have mentioned DigiKey and Mouser. I also use Jameco www.jameco.com for small orders. Keith _____ From: psn-l-request@.............. [mailto:psn-l-request@............... On Behalf Of tchannel1@............ Sent: Saturday, April 05, 2008 8:35 AM To: psn Subject: Electronic components Hi Folks, Could anyone recommend a wed site where I can purchases electronic bits and pieces, ic's, relays, etc, and has little or no minimum order? I did Goggle it but I am not having much luck. Thanks, Ted
Ted:
 
Others have mentioned DigiKey and Mouser.  = I also use=20 Jameco www.jameco.com for small=20 orders.
 
    Keith

From: psn-l-request@................. [mailto:psn-l-request@............... On Behalf Of=20 tchannel1@............
Sent: Saturday, April 05, 2008 8:35 = AM
To: psn
Subject: Electronic=20 components

Hi Folks,  Could anyone recommend = a wed site=20 where I can purchases electronic bits and pieces, ic's, = relays, etc, and=20 has little or no minimum order?
 
I did Goggle it but I am not having = much=20 luck.
 
 
Thanks, Ted
Subject: RE: Electronic components From: Brad Douglas rez@.................. Date: Sat, 05 Apr 2008 16:58:06 +0000 BTW, if you're in the SF Bay area, Jameco does will-call and walk-ins. Not everything is immediately available (different warehouse), but much of their stock is. DigiKey can be hard on shipping expenses, but they are the "gold standard". Mouser can be cheaper, but does not come close to carrying DigiKey's vast stock. Hope this helps the search for parts. On Sat, 2008-04-05 at 09:35 -0700, Keith Payea wrote: > Ted: > > Others have mentioned DigiKey and Mouser. I also use Jameco > www.jameco.com for small orders. -- 73, de Brad KB8UYR/6 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Whip antenna From: ChrisAtUpw@....... Date: Sat, 5 Apr 2008 16:20:06 EDT In a message dated 2008/04/05, tchannel1@............ writes: > Hi Folks, If I had a 36" whip antenna, just a piece of spring steel rod, > with a small mass on the tip, how much would the tip move during a earthquake? Hi Ted, The mass should ideally NOT move at all ! It is the Earth which moves. See the graphs at http://jclahr.com/science/psn/magnitude.html for actual amplitides of phases. Regards, Chris Chapman In a me= ssage dated 2008/04/05, tchannel1@............ writes:

Hi Folks, If I had a 36" whip a= ntenna, just a piece of spring steel rod, with a small mass on the tip, how=20= much would the tip move during a earthquake?


Hi Ted,

       The mass should ideally NOT move at all= ! It is the Earth which moves. See the graphs at http://jclahr.com/science/= psn/magnitude.html for actual amplitides of phases.

       Regards,

       Chris Chapman Subject: Re: Electronic components From: "Geoff" gmvoeth@........... Date: Sat, 5 Apr 2008 16:51:22 -0700 NOPE...Mad ENGINEER or Technician like ME. Did you know they do not teach law to up and coming engineers at the Universities and that those Engineers are relatively frightened of legal peoples ?? I understand in some countries if you have no degrees in the right field then practicing say like seismology might be technically illegal. I think thats why the Counter Intelligence peoples can get away with murder. They dont even know or care about the laws such as INFERNAL DEVICES. Just care about the moneys they make doing their shady work and raising their equally crooked families. I think seismology is one of the more harmless amateur sciences to be in unless it becomes somehow a real live social event. Possibly a company called Allied or Newark Electronics but its best if you can afford it to go with prebuilt systems. Complete systems unless you want to know all the technical details. The cost of parts are totally outrageous today and you almost need a microscope and surgeon tools to work with them. The EARLY 1980s saw a reduction in general industrial inventories of electronics that drove prices out of sight for little/small quantity parts. USe kits where ever possible. :-) ----- Original Message ----- From: "Jerry Payton" To: Sent: Saturday, April 05, 2008 8:48 AM Subject: Re: Electronic components > Hi Ted, > > The Mad Scientist at work again, huh. (Just joking) > > You might try www.mouser.com or www.digikey.com , depending upon what you > are looking for. We also used http://www.allelectronics.com/ before too. > > Regards, > Jerry > > > ----- Original Message ----- > From: tchannel1@............ > To: psn > Sent: Saturday, April 05, 2008 10:35 AM > Subject: Electronic components > > > Hi Folks, Could anyone recommend a wed site where I can purchases > electronic bits and pieces, ic's, relays, etc, and has little or no minimum > order? > > I did Goggle it but I am not having much luck. > > > Thanks, Ted > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Whip antenna From: "Geoff" gmvoeth@........... Date: Sat, 5 Apr 2008 17:02:21 -0700 Yesireee, The mass serves as a reference point against which the earth moves. But only frequencies at or above the point of resonance as I understand. Below resonance the mass starts to move with the Earth and more so as the frequency lowers. You must somehow lower gravity accelerational effects to the point where you get a 4 second period before you can easily fit the electronics to the sensor wuthout a lot of equalization to get a flat response ove the range of interest. Possibly 1 to 3ft/s^2 instead of 32ft/s^2 . How you do this is the real trick for a spring and a mass. :-) :-| :-O :-( ----- Original Message ----- From: To: Sent: Saturday, April 05, 2008 1:20 PM Subject: Re: Whip antenna > In a message dated 2008/04/05, tchannel1@............ writes: > >> Hi Folks, If I had a 36" whip antenna, just a piece of spring steel rod, >> with a small mass on the tip, how much would the tip move during a earthquake? > > Hi Ted, > > The mass should ideally NOT move at all ! It is the Earth which moves. > See the graphs at http://jclahr.com/science/psn/magnitude.html for actual > amplitides of phases. > > Regards, > > Chris Chapman > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: seismometer mass movement From: Randall Peters PETERS_RD@.......... Date: Mon, 07 Apr 2008 09:41:42 -0400 Geoff, Your understanding is indeed correct. Only for drive frequencies above the natural frequency of the instrument does the mass not move relative to the inertial frame (instrument behaving as a vibrometer). At frequencies below the natural frequency, it is the motion of the mass relative to the inertial frame that limits sensitivity. By making the natural frequency lower, the amplitude of this mass motion decreases, which increases the sensitivity (and is the reason for the low frequency sensitivity to displacement being proportional to the square of the natural period). At very low drive frequency the pendulum aligns itself with the vector sum of the earth's field vector g and the negative of the drive acceleration vector a; i.e., the angle of deflection in radians is given by -a/g (for a small compared to g). If there were no mass motion at low drive frequency, the pendulum would have no acceleration response whatsoever. Instead of the small deflection angle in radians being -a/g, zero inertial mass motion would require the angle to be identically zero. One can demonstrate the difference between high frequency stationary mass and low frequency moving mass very easily with a simple pendulum (a nut and a string). Hold the pendulum with your hand at the top of the string supporting the nut on the other end. Move your hand rapidly back and forth and you will see that the bob doesn't move--being at rest with respect to the room but with a motion relative to your hand that is out of phase by 180 degrees. Now move the string back and forth slowly and you will see the bob is in phase (in a relative sense) with your hand's motion (and it most certainly is not at rest relative to the room). Randall Subject: correction--mass movement From: Randall Peters PETERS_RD@.......... Date: Mon, 07 Apr 2008 09:58:23 -0400 If the mass did not move at very low drive frequencies, the deflection would be non-physically huge instead of my statement that is would be zero. Subject: RE: Shake table From: felipe luevanos luevanos felicaribe5@........... Date: Mon, 7 Apr 2008 20:17:40 +0000 Hi, =20 =20 What you are building is nice; have you tried having inverted pendulums sup= ported by a 2x4 piece of wood all of the pendulums in different lengths wit= h lets say foam balls of equal or different masses, then you shake the tabl= e with your hands at diffrent frequencies and observe the totally different= responses of each (ball/mass/pendulum)? =20 Good luck =20 =20 Felipe Luevanos From: kwyatt@................ psn-l@...................... Shake tableDate:= Fri, 4 Apr 2008 09:57:58 -0700 Folks, =20 Thanks for the feedback on the leveling screws for my seismometer. =20 Now here is a question regarding a shake table. =20 =20 I currently have a small shake table that has a 10" base plate which I use = in the public schools to help kids understand the relationship of building = structure and materials to earthquake damage. I divide the kids up into te= ams to construct their "buildings" and then individually set them on the sh= ake table. Because only one building can be tested at a time it is more ti= me consuming and less "fun" for the kids because they can't easily see how = their building measures up to another team's building. =20 So, I am constructing a larger shake table with a 30" base that can hold fo= ur buildings. This lets a class divide up into four teams and then the ent= ire class can watch their buildings shake at once. =20 Say an actual building has a footprint of 100 feet square. Relative to a m= odel building which has a footprint of 12 inches square, the width is a fac= tor of 100. I have a variable frequency motor to which I am attaching off = center cams to create the vibration movement. Springs pull back the base t= owards the drive shaft with the cams. =20 So, here is my question. Has anybody experimented with a shake table of th= is size? What displacements should I design the cams to create? I could u= se different size cams to create different "magnitude" earthquakes. Also, = what frequencies should I set the motor to run. =20 Thanks for any help that you might offer. =20 Kay =20 _________________________________________________________________ Connect to the next generation of MSN Messenger=A0 http://imagine-msn.com/messenger/launch80/default.aspx?locale=3Den-us&sourc= e=3Dwlmailtagline= Hi,
 
 
What you are building is nice; have you tried having inverted pendulums sup= ported by a 2x4 piece of wood all of the pendulums in different lengths wit= h lets say foam balls of equal or different masses, then you shake the tabl= e with your hands at diffrent frequencies and observe the totally different= responses of each (ball/mass/pendulum)?
 
Good luck
 
 
Felipe Luevanos


From: kwyatt@.............
To: psn-l@..............
Subject: Shake ta= ble
Date: Fri, 4 Apr 2008 09:57:58 -0700

Folks,
 
Thanks for the feedback on the leveling screws for = my seismometer.
 
Now here is a question regarding a shake table.&nbs= p; 
 
I currently have a small shake table that has a 10"= base plate which I use in the public schools to help kids understand the r= elationship of building structure and materials to earthquake damage. = I divide the kids up into teams to construct their "buildings" and then in= dividually set them on the shake table.  Because only one building can= be tested at a time it is more time consuming and less "fun" for the kids = because they can't easily see how their building measures up to another tea= m's building.
 
So, I am constructing a larger shake table with a 3= 0" base that can hold four buildings.  This lets a class divide up int= o four teams and then the entire class can watch their buildings shake at o= nce.
 
Say an actual building has a footprint of 100 feet = square.  Relative to a model building which has a footprint of 12 inch= es square, the width is a factor of 100.  I have a variable frequency = motor to which I am attaching off center cams to create the vibration movem= ent.  Springs pull back the base towards the drive shaft with the cams= ..
 
So, here is my question.  Has anybody experime= nted with a shake table of this size?  What displacements should I des= ign the cams to create?  I could use different size cams to create dif= ferent "magnitude" earthquakes.  Also, what frequencies should I set t= he motor to run.
 
Thanks for any help that you might offer.
 
Kay
 

Connect to the next generation of= MSN Messenger=A0 Get it now= ! = Subject: Re: Shake table From: ChrisAtUpw@....... Date: Mon, 7 Apr 2008 18:23:23 EDT In a message dated 2008/04/07, felicaribe5@........... writes: > What you are building is nice; have you tried having inverted pendulums > supported by a 2x4 piece of wood all of the pendulums in different lengths with > lets say foam balls of equal or different masses, then you shake the table > with your hands at diffrent frequencies and observe the totally different > responses of each (ball/mass/pendulum)? Hi Felipe, This works fine as a simple demonstration, but it doesn't capture the attention of students the way that having them build four model 'buildings' and then see them collapse in sequence can. Most students will not think of a real tall building as something which can and does oscillate and fall to pieces during an Earthquake. Regards, Chris Chapman In a me= ssage dated 2008/04/07, felicaribe5@........... writes:

What you are building is nice;=20= have you tried having inverted pendulums supported by a 2x4 piece of wood al= l of the pendulums in different lengths with lets say foam balls of equal or= different masses, then you shake the table with your hands at diffrent freq= uencies and observe the totally different responses of each (ball/mass/pendu= lum)?


Hi Felipe,

       This works fine as a simple demonstrati= on, but it doesn't capture the attention of students the way that having the= m build four model 'buildings' and then see them collapse in sequence can. <= BR>        Most students will not think of a real=20= tall building as something which can and does oscillate and fall to pieces d= uring an Earthquake.

       Regards,

       Chris Chapman Subject: Article On Microseisms From: Bob Hancock carpediem1@......... Date: Thu, 10 Apr 2008 19:32:06 -0700 The link is to an article on microseisms http://earthobservatory.nasa.gov/Newsroom/NasaNews/2008/2008030726263.html Article On Microseisms The l= ink is to an article on microseisms


    http://earthobservatory.nasa.gov/Newsro= om/NasaNews/2008/2008030726263.html
 


 Subject: Re: Article On Microseisms From: "Geoff" gmvoeth@........... Date: Fri, 11 Apr 2008 05:29:47 -0700 Interesting, I have noticed a significant increase in the magnitude of such Microseisms just hours preceeding a major weather front here in Arizona. I used to think it might relate to winds hitting the mountains but according to this it must be wave interaction in the Pacific Ocean. ----- Original Message ----- From: "Bob Hancock" To: "PSN" Sent: Thursday, April 10, 2008 7:32 PM Subject: Article On Microseisms > The link is to an article on microseisms > > > > http://earthobservatory.nasa.gov/Newsroom/NasaNews/2008/2008030726263.html > > > > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Article On Microseisms From: ChrisAtUpw@....... Date: Fri, 11 Apr 2008 09:46:11 EDT In a message dated 2008/04/11, gmvoeth@........... writes: > I have noticed a significant increase in the magnitude of such Microseisms > just hours preceeding a major weather front here in Arizona. > I used to think it might relate to winds hitting the mountains but according > to this it must be wave interaction in the Pacific Ocean. Hi Geoff, Those were probably due to pressure noise on the weather front. They can be quite noisy. Note that there are several places in the ocean which generate microseisms. The news article referreed to only one. The shelving bottom to the west of Norway is another and there are others in the Pacific. Regards, Chris Chapman In a me= ssage dated 2008/04/11, gmvoeth@........... writes:

I have noticed a significant in= crease in the magnitude of such Microseisms
just hours preceeding a major weather front here in Arizona.
I used to think it might relate to winds hitting the mountains but according= to this it must be wave interaction in the Pacific Ocean.


Hi Geoff,

       Those were probably due to pressure noi= se on the weather front. They can be quite noisy.

       Note that there are several places in t= he ocean which generate microseisms. The news article referreed to only one.= The shelving bottom to the west of Norway is another and there are others i= n the Pacific.

       Regards,

       Chris Chapman Subject: Re: Article On Microseisms From: Bob Hancock carpediem1@......... Date: Fri, 11 Apr 2008 07:12:12 -0700 Hi Chris - As you said, microseisms are generated world wide when ocean waves strike shore. The strength of the microseisms are largely dependent upon the size of the waves that come ashore. The US Navy Fleet Numerical Meteorology and Oceanography Center - https://www.fnmoc.navy.mil/public/ publishes charts with current and projected ocean wave height worldwide and regional. This web site is a good place to start with when you see microseisms. You can often see the microseisms from large oceanic storms at long distances. East Coast USA hurricanes are very visible on West Coast USA seismic stations, and are probably also visible in Europe. Cheers, Bob Hancock On 4/11/08 6:46 AM, "ChrisAtUpw@......." wrote: > In a message dated 2008/04/11, gmvoeth@........... writes: > >> I have noticed a significant increase in the magnitude of such Microseisms >> just hours preceeding a major weather front here in Arizona. >> I used to think it might relate to winds hitting the mountains but according >> to this it must be wave interaction in the Pacific Ocean. > > > Hi Geoff, > > Those were probably due to pressure noise on the weather front. They > can be quite noisy. > > Note that there are several places in the ocean which generate > microseisms. The news article referreed to only one. The shelving bottom to > the west of Norway is another and there are others in the Pacific. > > Regards, > > Chris Chapman Re: Article On Microseisms Hi Ch= ris -

As you said, microseisms are generated world wide when ocean waves strike s= hore.  The strength of the microseisms are largely dependent upon the s= ize of the waves that come ashore.

The US Navy Fleet Numerical Meteorology and Oceanography Center -  htt= ps://www.fnmoc.navy.mil/public/

publishes charts with current and projected ocean wave height worldwide and= regional.  This web site is a good place to start with when you see mi= croseisms.  You can often see the microseisms from large oceanic storms= at long distances.  East Coast USA hurricanes are very visible on West= Coast USA seismic stations, and are probably also visible in Europe.

Cheers,

Bob Hancock

On 4/11/08 6:46 AM, "ChrisAtUpw@......." <ChrisAtUpw@.......&g= t; wrote:

In a message dated 2008/04/11, gmvoeth@........... writes:

I have noticed a significant increase in the magnitude of such Microseisms<= BR> just hours preceeding a major weather front here in Arizona.
I used to think it might relate to winds hitting the mountains but accordin= g to this it must be wave interaction in the Pacific Ocean.


Hi Geoff,

       Those were probably due to pressu= re noise on the weather front. They can be quite noisy.

       Note that there are several place= s in the ocean which generate microseisms. The news article referreed to onl= y one. The shelving bottom to the west of Norway is another and there are ot= hers in the Pacific.

       Regards,

       Chris Chapman   

 Subject: Re: Article On Microseisms From: ChrisAtUpw@....... Date: Fri, 11 Apr 2008 11:06:28 EDT In a message dated 2008/04/11, carpediem1@......... writes: > As you said, microseisms are generated world wide when ocean waves strike > shore. The strength of the microseisms are largely dependent upon the size of > the waves that come ashore. Hi Bob, Not generally I think. There is an ocean area S of Greenland and another on the continental shelf off the NW coast of Norway which dominate the Atlantic systems. You can also get 10 to 12 second stuff from storms directly coming on shore, but that is different. Cold fronts can also have a lot of seismic noise on them, as Geoff observed. Regards, Chris Chapman In a message dated 2008/04/11, carp= ediem1@......... writes:

As you said, microseisms are= generated world wide when ocean waves strike shore.  The strength of t= he microseisms are largely dependent upon the size of the waves that come as= hore.


Hi Bob,

       Not generally I think. There is an ocea= n area S of Greenland and another on the continental shelf off the NW coast=20= of Norway which dominate the Atlantic systems. You can also get 10 to 12 sec= ond stuff from storms directly coming on shore, but that is different.
       Cold fronts can also have a lot of seis= mic noise on them, as Geoff observed.

       Regards,

       Chris Chapman Subject: Re: Article On Microseisms From: Bob Hancock carpediem1@......... Date: Fri, 11 Apr 2008 09:02:47 -0700 Hi Chris - Cold fronts can generate increased wind velocity. This in turn moves trees and buildings, and this is visible on seismometers; however, this does not appear to travel long distances. This is readily visible on the seismometers located in the Long Valley Caldera, Mammoth Lakes, CA, an area subject to high winds. However, ocean storms, particularly when they come ashore can increase seismic background noise that travels for thousands of kilometers. This is observable when major storms or hurricanes and typhoons occur. In addition, low frequency background seismic noise is more pronounced on seismic stations located on small islands =AD such as Pitcairn Island, Wake Island, and many others all around the world. This is at a much lower frequency than is normally associated with microseisms , and I do not know if would be classified as a microseism. Cheers Bob Hancock =20 On 4/11/08 8:06 AM, "ChrisAtUpw@......." wrote: > In a message dated 2008/04/11, carpediem1@......... writes: >=20 >> As you said, microseisms are generated world wide when ocean waves strik= e >> shore. The strength of the microseisms are largely dependent upon the s= ize >> of the waves that come ashore. >=20 >=20 > Hi Bob, >=20 > Not generally I think. There is an ocean area S of Greenland and > another on the continental shelf off the NW coast of Norway which dominat= e the > Atlantic systems. You can also get 10 to 12 second stuff from storms dire= ctly > coming on shore, but that is different. > Cold fronts can also have a lot of seismic noise on them, as Geoff > observed. >=20 > Regards, >=20 > Chris Chapman Re: Article On Microseisms Hi Ch= ris -

Cold fronts can generate increased wind velocity.  This in turn moves = trees and buildings, and this is visible on seismometers; however, this does= not appear to travel long distances.  This is readily visible on the s= eismometers located in the Long Valley Caldera, Mammoth Lakes, CA, an area s= ubject to high winds.

However, ocean storms, particularly when they come ashore can increase seis= mic background noise that travels for thousands of kilometers.  This is= observable when major storms or hurricanes and typhoons occur.

In addition, low frequency background seismic noise is more pronounced on s= eismic stations located on small islands – such as Pitcairn Island, Wa= ke Island, and many others all around the world.  This is at a much low= er frequency than is normally associated with microseisms , and I do not kno= w if would be classified as a microseism.

Cheers

Bob Hancock

  


On 4/11/08 8:06 AM, "ChrisAtUpw@......." <ChrisAtUpw@.......&g= t; wrote:

In a message dated 2008/04/11, carpediem1@......... writes:

As you said, microseisms are generated world wide when = ocean waves strike shore.  The strength of the microseisms are largely = dependent upon the size of the waves that come ashore.


Hi Bob,

       Not generally I think. There is a= n ocean area S of Greenland and another on the continental shelf off the NW = coast of Norway which dominate the Atlantic systems. You can also get 10 to = 12 second stuff from storms directly coming on shore, but that is different.=
       Cold fronts can also have a lot o= f seismic noise on them, as Geoff observed.

       Regards,

       Chris Chapman   

 Subject: Noise From: "Thomas Dick" dickthomas01@............. Date: Sat, 12 Apr 2008 21:45:03 -0500 I have never been satisfied with my setup. I would like some suggestions = on where to look for the noise I still get on my units. Among the things = that I have enjoyed identifying included wind, walnuts falling on the = porch roof, a microwave oven, garbage trucks(empty and full), falling = trees, an assortment of caterpillars and shovels moving dirt and a = seismic truck testing soils in my area for liquifaction. If anybody has = the time, I put a rather large PDF file (~2.5 megs) on this site = http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the = level of the rest of the PSN event submissions. Your suggestions would = be welcomed.
I have never been satisfied with my = setup. I would=20 like some suggestions on where to look for the noise I still get on = my=20 units. Among the things that I have enjoyed identifying included wind, = walnuts=20 falling on the porch roof, a microwave oven, garbage trucks(empty and = full),=20 falling trees, an assortment of caterpillars and shovels moving = dirt and a=20 seismic truck testing soils in my area for liquifaction. If anybody = has the=20 time, I put a rather large PDF file (~2.5 megs) on this site http://bachcottage.com/inquiry.pdf. My eventual goal = is to get=20 to the level of the rest of the PSN event submissions. Your suggestions = would be=20 welcomed.
Subject: Re:Noise From: rsparks rsparks@.......... Date: Sun, 13 Apr 2008 06:26:26 -0700 Hi Dick, I took a look at your posting. Nice job of collecting information and posting. For reference, I collected one hours noise from this morning. http://www.fairpoint.net/~rsparks/080413_090338_ebgz_psn_fft.gif My seismometer is a tilted vertical with a single long spring supporting the sensing coil. The spring is the hinge. I post under the station identifier "EBGZ". The seismometer is in the basement. From looking at your pictures and FFT, I wondered if all of your components are either securely assembled or placed on three point mounts. Four point mounts or components resting on flat surfaces can be unexpected balanced between two semi-stable positions. If so, the microsiems or quakes can move the components between those two positions resulting in high frequency noise. Another source of noise can be the hinges. The AS-1 actually has three hinges if you count the spring attachment points as moving connections. I don't know if lubrication with a light oil would help or not. The problem from hinges is that all hinges have some friction, and the motion in a seismometer hinge starts and stops. Static friction is always greater than moving friction so there is a small "tremble" as the transfer between static and moving occurs. This "tremble" would be recorded as noise. You could test the electronic noise by locking the seismometer. I would not expect much noise from electronics compared to the noise that will come from the seismometer output. Certainly the wind can cause noise but you are probably well aware of the magnitude of wind and other locally generated noise sources. Good luck on your noise hunt. Roger > .------ ------ ------ ------ ------ ------ ------ ------ ------ ------. > | Message 1 | > '------ ------ ------ ------ ------ ------ ------ ------ ------ ------' > Subject: Noise > From: "Thomas Dick" > Date: Sat, 12 Apr 2008 21:45:03 -0500 > > > I have never been satisfied with my setup. I would like some suggestions = > on where to look for the noise I still get on my units. Among the things = > that I have enjoyed identifying included wind, walnuts falling on the = > porch roof, a microwave oven, garbage trucks(empty and full), falling = > trees, an assortment of caterpillars and shovels moving dirt and a = > seismic truck testing soils in my area for liquifaction. If anybody has = > the time, I put a rather large PDF file (~2.5 megs) on this site = > http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the = > level of the rest of the PSN event submissions. Your suggestions would = > be welcomed. > > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Re:Noise From: "Thomas Dick" dickthomas01@............. Date: Sun, 13 Apr 2008 12:30:44 -0500 From looking at your pictures and FFT, I wondered if all of your components are either securely assembled or placed on three point mounts Four point mounts or components resting on flat surfaces can be unexpected balanced between two semi-stable positions. I did use four pivot points on the Lehmans...a mistake I won't make again .... the bases for the Lehmans are 1/4" steel these could be used as boat anchors ... unfortunately I sold the boat! The support of the mental plates that hold the magnets isn't as stable ... this could be an issue. But the peaks at 4 hz is gound on the geophone buried outside! If so, the microsiems or quakes can move the components between those two positions resulting in high frequency noise .. The AS-1 uses a knief edge rather than a hinge. The AS-1 sits in an old refrigerator with the door closed. The pivot point on the booms of the Lehmans is a stainless steel ball bearing. The only issue I haven't addressed is that the Lehmans sit on concrete blocks sitting on the concrete floor. From what you infer, this might be an issue. I raised the Lehmans up off the floor so that I didn't have to bend over as much. . I collected one hours noise from this morning. Mine are one minute but it would help know where you two are....??? Georgia??? Macon ...right? You could test the electronic noise by locking the seismometer. I would not expect much noise from electronics compared to the noise that will come from the seismometer output. suggestion under advisement This issue has been around for some time. I even sent one amp board back to Larry for him to look at. I put an isolation transformer and battery back up to help smooth out the AC. I even had the local electric company come out(firends in the right places) with special equipment and test the incoming AC...nothing serious there. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Noise From: "Dale Hardy" photon1@........... Date: Mon, 14 Apr 2008 11:51:52 +1000 Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is = the link correct ? thanks Dale ----- Original Message -----=20 From: Thomas Dick=20 To: psn-l@................. Sent: Sunday, April 13, 2008 12:45 PM Subject: Noise I have never been satisfied with my setup. I would like some = suggestions on where to look for the noise I still get on my units. = Among the things that I have enjoyed identifying included wind, walnuts = falling on the porch roof, a microwave oven, garbage trucks(empty and = full), falling trees, an assortment of caterpillars and shovels moving = dirt and a seismic truck testing soils in my area for liquifaction. If = anybody has the time, I put a rather large PDF file (~2.5 megs) on this = site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to = the level of the rest of the PSN event submissions. Your suggestions = would be welcomed.
Hi Thomas, tried to open the site in = IE7 and=20 Firefox unsucessfully, is the link correct ?
thanks
Dale
----- Original Message -----
From:=20 Thomas Dick
Sent: Sunday, April 13, 2008 = 12:45=20 PM
Subject: Noise

I have never been satisfied with my = setup. I=20 would like some suggestions on where to look for the noise I = still get on=20 my units. Among the things that I have enjoyed identifying included = wind,=20 walnuts falling on the porch roof, a microwave oven, garbage = trucks(empty and=20 full), falling trees, an assortment of caterpillars and shovels moving = dirt and a seismic truck testing soils in my area for = liquifaction.=20 If anybody has the time, I put a rather large PDF file (~2.5 megs) on = this=20 site http://bachcottage.com/inquiry.pdf. My eventual = goal is to=20 get to the level of the rest of the PSN event submissions. Your = suggestions=20 would be welcomed.
Subject: Re: Noise From: "Thomas Dick" dickthomas01@............. Date: Sun, 13 Apr 2008 21:15:56 -0500 yes, it might be a little slow particularly in the PDF format....sorry ----- Original Message -----=20 From: Dale Hardy=20 To: psn-l@................. Sent: Sunday, April 13, 2008 8:51 PM Subject: Re: Noise Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is = the link correct ? thanks Dale ----- Original Message -----=20 From: Thomas Dick=20 To: psn-l@................. Sent: Sunday, April 13, 2008 12:45 PM Subject: Noise I have never been satisfied with my setup. I would like some = suggestions on where to look for the noise I still get on my units. = Among the things that I have enjoyed identifying included wind, walnuts = falling on the porch roof, a microwave oven, garbage trucks(empty and = full), falling trees, an assortment of caterpillars and shovels moving = dirt and a seismic truck testing soils in my area for liquifaction. If = anybody has the time, I put a rather large PDF file (~2.5 megs) on this = site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to = the level of the rest of the PSN event submissions. Your suggestions = would be welcomed.
yes, it might be a little slow = particularly in the=20 PDF format....sorry
----- Original Message -----
From:=20 Dale Hardy=20
Sent: Sunday, April 13, 2008 = 8:51=20 PM
Subject: Re: Noise

Hi Thomas, tried to open the site in = IE7 and=20 Firefox unsucessfully, is the link correct ?
thanks
Dale
----- Original Message -----
From:=20 Thomas Dick
Sent: Sunday, April 13, 2008 = 12:45=20 PM
Subject: Noise

I have never been satisfied with my = setup. I=20 would like some suggestions on where to look for the noise I = still get=20 on my units. Among the things that I have enjoyed identifying = included wind,=20 walnuts falling on the porch roof, a microwave oven, garbage = trucks(empty=20 and full), falling trees, an assortment of caterpillars and shovels = moving=20 dirt and a seismic truck testing soils in my area for=20 liquifaction. If anybody has the time, I put a rather large PDF file = (~2.5=20 megs) on this site http://bachcottage.com/inquiry.pdf.=20 My eventual goal is to get to the level of the rest of the PSN event = submissions. Your suggestions would be=20 welcomed.
Subject: Re: Noise From: pattilightfoot11@....... Date: Sun, 13 Apr 2008 23:38:55 -0400 Hello, Could you please remove my name from your emailing. I just wanted info if there was anything to be concerned about! Thanks! Patti -----Original Message----- From: Dale Hardy To: psn-l@.............. Sent: Sun, 13 Apr 2008 6:51 pm Subject: Re: Noise Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is the link correct ? thanks Dale ----- Original Message ----- From: Thomas Dick To: psn-l@.............. Sent: Sunday, April 13, 2008 12:45 PM Subject: Noise I have never been satisfied with my setup. I would like some suggestions on where to look for?the noise I still get on my units. Among the things that I have enjoyed identifying included wind, walnuts falling on the porch roof, a microwave oven, garbage trucks(empty and full), falling trees, an assortment of caterpillars and shovels moving dirt?and a seismic truck testing soils in?my area for liquifaction. If anybody has the time, I put a rather large PDF file (~2.5 megs) on this site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the level of the rest of the PSN event submissions. Your suggestions would be welcomed. Hello, Could you please remove my name from your emailing. I just wanted info if there was anything to be concerned about!

Thanks!

Patti



-----Original Message-----
From: Dale Hardy <photon1@...........>
To: psn-l@..............
Sent: Sun, 13 Apr 2008 6:51 pm
Subject: Re: Noise

Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is the link correct ?
thanks
Dale
----- Original Message -----
Sent: Sunday, April 13, 2008 12:45 PM
Subject: Noise

I have never been satisfied with my setup. I would like some suggestions on where to look for the noise I still get on my units. Among the things that I have enjoyed identifying included wind, walnuts falling on the porch roof, a microwave oven, garbage trucks(empty and full), falling trees, an assortment of caterpillars and shovels moving dirt and a seismic truck testing soils in my area for liquifaction. If anybody has the time, I put a rather large PDF file (~2.5 megs) on this site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the level of the rest of the PSN event submissions. Your suggestions would be welcomed.
Subject: Re: Noise From: pattilightfoot11@....... Date: Sun, 13 Apr 2008 23:39:11 -0400 Hello, Could you please remove my name from your emailing. I just wanted info if there was anything to be concerned about! Thanks! Patti -----Original Message----- From: Thomas Dick To: psn-l@.............. Sent: Sun, 13 Apr 2008 7:15 pm Subject: Re: Noise yes, it might be a little slow particularly in the PDF format....sorry ----- Original Message ----- From: Dale Hardy To: psn-l@.............. Sent: Sunday, April 13, 2008 8:51 PM Subject: Re: Noise Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is the link correct ? thanks Dale ----- Original Message ----- From: Thomas Dick To: psn-l@.............. Sent: Sunday, April 13, 2008 12:45 PM Subject: Noise I have never been satisfied with my setup. I would like some suggestions on where to look for?the noise I still get on my units. Among the things that I have enjoyed identifying included wind, walnuts falling on the porch roof, a microwave oven, garbage trucks(empty and full), falling trees, an assortment of caterpillars and shovels moving dirt?and a seismic truck testing soils in?my area for liquifaction. If anybody has the time, I put a rather large PDF file (~2.5 megs) on this site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the level of the rest of the PSN event submissions. Your suggestions would be welcomed. Hello, Could you please remove my name from your emailing. I just wanted info if there was anything to be concerned about!

Thanks!

Patti


-----Original Message-----
From: Thomas Dick <dickthomas01@.............>
To: psn-l@..............
Sent: Sun, 13 Apr 2008 7:15 pm
Subject: Re: Noise

yes, it might be a little slow particularly in the PDF format....sorry
----- Original Message -----
From: Dale Hardy
Sent: Sunday, April 13, 2008 8:51 PM
Subject: Re: Noise

Hi Thomas, tried to open the site in IE7 and Firefox unsucessfully, is the link correct ?
thanks
Dale
----- Original Message -----
Sent: Sunday, April 13, 2008 12:45 PM
Subject: Noise

I have never been satisfied with my setup. I would like some suggestions on where to look for the noise I still get on my units. Among the things that I have enjoyed identifying included wind, walnuts falling on the porch roof, a microwave oven, garbage trucks(empty and full), falling trees, an assortment of caterpillars and shovels moving dirt and a seismic truck testing soils in my area for liquifaction. If anybody has the time, I put a rather large PDF file (~2.5 megs) on this site http://bachcottage.com/inquiry.pdf. My eventual goal is to get to the level of the rest of the PSN event submissions. Your suggestions would be welcomed.
Subject: Re: Noise From: ChrisAtUpw@....... Date: Mon, 14 Apr 2008 00:03:35 EDT In a message dated 2008/04/14, pattilightfoot11@....... writes: > Could you please remove my name from your emailing. Hi Patti, Go to http://psn.quake.net/maillist.html#archives, fill in the form and click the unsubscribe dot. Regards, Chris In a me= ssage dated 2008/04/14, pattilightfoot11@....... writes:

Could you please remove my name= from your emailing.


Hi Patti,

       Go to http://psn.quake.net/maillist.htm= l#archives, fill in the form and click the unsubscribe dot.

       Regards,
      
       Chris Subject: Oregon earthquake swarm From: jonfr@......... Date: Mon, 14 Apr 2008 21:52:43 -0400 (EDT) Hi all Here are news regarding the Oregon earthquakes. The data so far suggests that there might be an eruption happening in that area. If any of you that are close to this area detect low frequancy signal that is not earthquake you might be looking at eruption tremor that is constant. http://www.sciencedaily.com/releases/2008/04/080413184801.htm http://www.ecanadanow.com/news/science/string-of-strange-earthquakes-rock-oregon-20080414.html Regards. Jón Frímann. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Oregon earthquake swarm From: "Thomas Dick" dickthomas01@............. Date: Mon, 14 Apr 2008 21:19:29 -0500 NBC New tonight on this subject http://www.nbc15online.com/news/national/story.aspx?content_id=5b190a5f-b113-46ac-9f6b-4d8df90f4587 __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Oregon earthquake swarm From: "Geoff" gmvoeth@........... Date: Mon, 14 Apr 2008 22:31:46 -0700 I think there are black smokers of volcanic origin in that area and when I was a SONAR tech aboard the USS Bainbridge back in the mid-late 1970s I saw a contact on the TBR (Time Bearing Recorder) that was weak and continuous and was not able to identify that seemed to be coming from that area of the Pacific Ocean. Today it would not surprise me if that contact had been one of those smoker thingys really putting on a show. I pointed the ship right at the contact to try and get closer and louder but the navagational people got upset with me and I turned control back to them so we could all go home. A steady black smoker volcanic thingy would explain the kind of noise I saw but was unable to hear. It was off central Oregon about 280 290 degrees or so as we were headed for the Straights of Juan De Fuca If I remember correctly. The Navagational logs of the ship should have recorded the position and course change of the ship and the ship was pointed by myself directly at the noise source for a few minutes. It was far enough away that the bearing did not change very much as we traveled on and simply lost interest in the target. But also i heard that a Soviet Nuclear Sub liked to do a slow three knot circle in that same area. 100 miles or so off the Coast of Oregon. :-( So you tell me what i saw ??? ----- Original Message ----- From: To: Sent: Monday, April 14, 2008 6:52 PM Subject: Oregon earthquake swarm > Hi all > > Here are news regarding the Oregon earthquakes. The data so far suggests > that there might be an eruption happening in that area. If any of you that > are close to this area detect low frequancy signal that is not earthquake > you might be looking at eruption tremor that is constant. > > http://www.sciencedaily.com/releases/2008/04/080413184801.htm > http://www.ecanadanow.com/news/science/string-of-strange-earthquakes-rock-oregon-20080414.html > > Regards. > Jón Frímann. > > __________________________________________________________ > > 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: Katla volcano preparing eruption From: jonfr@......... Date: Tue, 15 Apr 2008 17:19:40 -0400 (EDT) Hi all It appears that Katla volcano is preparing an eruption. On the 8th April there was a 10 min long tremor detected in the volcano. One of the main glacier rivers from the Myrdalsjokull glacier has been dry since mid January. So the evidence for an coming eruption are mounting. The tremor can be seen here. http://hraun.vedur.is/ja/viku/2008/vika_15/katla.jpg I am going to setup a geophone near Hekla volcano in June, so if there is going to be an eruption in Katla it is going to appear good on that station too. I've post new information on this when I know more. Regards. Jón Frímann. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: quake From: "Thomas Dick" dickthomas01@............. Date: Fri, 18 Apr 2008 04:50:01 -0500 I don't know where but we just had a serious quake here in Evansville = In. Can't get out to some of the networks. It woke me. Lasted for almost = a minute or more. Can anyone tell me where it was?
I don't know where but we just had a = serious quake=20 here in Evansville In. Can't get out to some of the networks. It woke = me. Lasted=20 for almost a minute or more. Can anyone tell me where it = was?
 
Subject: Re: quake From: "Robert Thomasson" rlthomasson@......... Date: Fri, 18 Apr 2008 13:00:25 +0300 It was a magnitude 5.4 about 7 miles from West Salem, Illinois. I picked it up very nicely here in Reno. On Fri, Apr 18, 2008 at 12:50 PM, Thomas Dick wrote: > I don't know where but we just had a serious quake here in Evansville In. > Can't get out to some of the networks. It woke me. Lasted for almost a > minute or more. Can anyone tell me where it was? > > It was a magnitude 5.4 about 7 miles from West Salem, Illinois.  I picked it up very nicely here in Reno.

On Fri, Apr 18, 2008 at 12:50 PM, Thomas Dick <dickthomas01@.............> wrote:
I don't know where but we just had a serious quake here in Evansville In. Can't get out to some of the networks. It woke me. Lasted for almost a minute or more. Can anyone tell me where it was?
 

Subject: Re: quake From: jonfr@......... Date: Fri, 18 Apr 2008 06:05:01 -0400 (EDT) Hi EMSC is reporting Mb5.4 earthquake in Illinois at the depth of 2 km. More details here, http://www.emsc-csem.org/index.php?page=current&sub=detail&id=83987 Regards. Jón Frímann. > It was a magnitude 5.4 about 7 miles from West Salem, Illinois. I picked > it > up very nicely here in Reno. > > On Fri, Apr 18, 2008 at 12:50 PM, Thomas Dick > wrote: > >> I don't know where but we just had a serious quake here in Evansville >> In. >> Can't get out to some of the networks. It woke me. Lasted for almost a >> minute or more. Can anyone tell me where it was? >> >> > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: Mark Robinson mark.robinson@............... Date: Fri, 18 Apr 2008 22:06:29 +1200 Thomas Dick wrote: > > I don't know where but we just had a serious quake here in Evansville > In. Can't get out to some of the networks. It woke me. Lasted for almost > a minute or more. Can anyone tell me where it was? http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008qza6.php 5.4, Illinois -- Mark Robinson ------------- 18 Apr 1906 5am San Francisco devastated by earthquake and ensuing fire. 400 killed. 18 Apr 1954 Nasser becomes Egyptian Premier. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: RE: quake From: "Finke, John" John.Finke@.......... Date: Fri, 18 Apr 2008 05:04:24 -0500 Good thing for the PSN, the EQ woke my whole family and they asked me if = it was an earthquake but I too was unable to get to any networks. Hence rig= ht now, with your response, is the only confirmation we have of it in the Midwest. Earthquake watch.com doesn't even show it. ________________________________ From: psn-l-request@.............. on behalf of Robert Thomasson Sent: Fri 4/18/2008 5:00 AM To: psn-l@.............. Subject: Re: quake It was a magnitude 5.4 about 7 miles from West Salem, Illinois. I picked= it up very nicely here in Reno. On Fri, Apr 18, 2008 at 12:50 PM, Thomas Dick wrote: I don't know where but we just had a serious quake here in Evansville In. Can't get out to some of the networks. It woke me. Lasted for almost = a minute or more. Can anyone tell me where it was? =20 NOTICE - This communication may contain confidential and privileged infor= mation that is for the sole use of the intended recipient. Any viewing, c= opying or distribution of, or reliance on this message by unintended reci= pients is strictly prohibited. If you have received this message in error= , please notify us immediately by replying to the message and deleting it= from your computer. =0A=0A=0A=0A
=0A=
Good thing for= the PSN, the EQ woke my whole family and they asked me if it was an eart= hquake but I too was unable to get to any networks.  Hence right now= , with your response, is the only confirmation we have of it in the Midwe= st.  Earthquake watch.com doesn't even show it.
=0A=

=0A
=0A<= B>From: psn-l-request@.............. on behalf of Robert ThomassonSent: Fri 4/18/2008 5:00 AM
To: psn-l@..............Subject: Re: quake

=0A
It was a magnitude= 5.4 about 7 miles from West Salem, Illinois.  I picked it up very n= icely here in Reno.

=0A
On Fri, Apr 18, 20= 08 at 12:50 PM, Thomas Dick <dickthomas01@.............> wrote:
=0A
=0A
=0A
I don't know where but we just had a serious quake here in Evansvil= le In. Can't get out to some of the networks. It woke me. Lasted for almo= st a minute or more. Can anyone tell me where it was?
=0A 


NOTICE - This communi= cation may contain confidential and privileged information that is for th= e sole use of the intended recipient. Any viewing, copying or distributio= n of, or reliance on this message by unintended recipients is strictly pr= ohibited. If you have received this message in error, please notify us im= mediately by replying to the message and deleting it from your computer.<= /BODY>= Subject: RE: quake From: jonfr@......... Date: Fri, 18 Apr 2008 06:18:12 -0400 (EDT) Hi The earthquake is clearly visable on few plots that are in the U.S. I have a collection of them here, http://www.simnet.is/jonfr500/earthquake/othersten.htm Regards. Jón Frímann. > Good thing for the PSN, the EQ woke my whole family and they asked me if > it > was an earthquake but I too was unable to get to any networks. Hence > right > now, with your response, is the only confirmation we have of it in the > Midwest. Earthquake watch.com doesn't even show it. > > ________________________________ > > From: psn-l-request@.............. on behalf of Robert Thomasson > Sent: Fri 4/18/2008 5:00 AM > To: psn-l@.............. > Subject: Re: quake > > > It was a magnitude 5.4 about 7 miles from West Salem, Illinois. I picked > it > up very nicely here in Reno. > > > On Fri, Apr 18, 2008 at 12:50 PM, Thomas Dick > wrote: > > > I don't know where but we just had a serious quake here in Evansville > In. Can't get out to some of the networks. It woke me. Lasted for almost a > minute or more. Can anyone tell me where it was? > > > > > NOTICE - This communication may contain confidential and privileged > information that is for the sole use of the intended recipient. Any > viewing, copying or distribution of, or reliance on this message by > unintended recipients is strictly prohibited. If you have received this > message in error, please notify us immediately by replying to the message > and deleting it from your computer. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: "Thomas Dick" dickthomas01@............. Date: Fri, 18 Apr 2008 05:54:02 -0500 There are many aftershocks in the area. Quake about 60 (NW) miles away. I am very disappointed at my data -- can't see much. I am sure they will refine data soon. USGS preliminary data seems to be inaccurate. P arrival got here ..05 seconds later than USGS data would indicate. Maybe location (epicenter) is off. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: jonfr@......... Date: Fri, 18 Apr 2008 06:58:09 -0400 (EDT) Hi Low frequency sensors aren't good for local events. You would need something like an 4.5Hz sensor to see this event this close to your location properly. Regards. Jón Frímann. > There are many aftershocks in the area. Quake about 60 (NW) miles away. I > am > very disappointed at my data -- can't see much. I am sure they will refine > data soon. USGS preliminary data seems to be inaccurate. P arrival got > here > .05 seconds later than USGS data would indicate. Maybe location > (epicenter) > is off. > __________________________________________________________ > > 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: quake From: "Thomas Dick" dickthomas01@............. Date: Fri, 18 Apr 2008 06:16:43 -0500 You're right Jon, the geophone displays are better but still amplitudes make it almost impossible to see much -- distortion. .. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: jonfr@......... Date: Fri, 18 Apr 2008 07:31:57 -0400 (EDT) Hi I have my geophone on high amplitude. I haven't noticed any distortion. Noise I see, but no distortion. The biggest earthquake I have recored was a M4.3 at the distance of 85 km, no issues with that recording at all. Regards. Jón Frímann. > You're right Jon, the geophone displays are better but still amplitudes > make > it almost impossible to see much -- distortion. > . > __________________________________________________________ > > 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: quake From: "Thomas Dick" dickthomas01@............. Date: Fri, 18 Apr 2008 08:37:52 -0500 I see they downgraded the quake to 5.2. I describe it as a "serious" quake in my first posting. I suppose I based this on passed quakes in this locality which did not last as long. Certainly this lasted a lot longer. This one lasted at least 45 seconds e.g. felt for that long. We have lights on our desks that are suspended. The quake waves continued to vibrate for over two minutes. I used the word distortion of data. This quake was so strong and so close. If this were audio, I would describe the incoming data as being clipped. I saved six aftershocks out of maybe ten or more I considered significant. At least two were felt and reported by TV listeners as I watched my computer screen. Lehmans and AS-1 showed tendency toward peak in the .1 to .3 Hz range five minutes before quake on a relatively quiet display. And below .1 Hz just seconds before quake. Is that important? __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: jonfr@......... Date: Fri, 18 Apr 2008 11:40:45 -0400 (EDT) Hi all There just was an aftershock now, emsc says it is M 4.5. See here, http://www.emsc-csem.org/index.php?page=current&sub=detail&id=84013 (might be outdated soon) By the looks of it, there is a slight chance of a swarm of mag 4.0 to 5.5 earthquakes, they might even go as high as mag 6.0. But that would be a rare event, but I am not expecting it. I however also don't rule it out. Regards. Jón Frímann. > I see they downgraded the quake to 5.2. I describe it as a "serious" quake > in my first posting. I suppose I based this on passed quakes in this > locality which did not last as long. Certainly this lasted a lot longer. > This one lasted at least 45 seconds e.g. felt for that long. We have > lights > on our desks that are suspended. The quake waves continued to vibrate for > over two minutes. I used the word distortion of data. This quake was so > strong and so close. If this were audio, I would describe the incoming > data > as being clipped. I saved six aftershocks out of maybe ten or more I > considered significant. At least two were felt and reported by TV > listeners > as I watched my computer screen. Lehmans and AS-1 showed tendency toward > peak in the .1 to .3 Hz range five minutes before quake on a relatively > quiet display. And below .1 Hz just seconds before quake. Is that > important? > __________________________________________________________ > > 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: quake From: "Thomas Dick" dickthomas01@............. Date: Fri, 18 Apr 2008 11:08:38 -0500 > There just was an aftershock now, emsc says it is M 4.5. See here, > http://www.emsc-csem.org/index.php?page=current&sub=detail&id=84013 (might > be outdated soon) > >Here in Indiana, before this last quake the FFT for 20 seconds just before >dropped to below one from over 10 before the first quake in the frequencies >of .06 to .3 Hz __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: Pete Rowe ptrowe@......... Date: Fri, 18 Apr 2008 10:21:08 -0700 (PDT) Loud and clear in San Jose, CA. It's on my website right now (www(dot)rowelabs(dot)com Enjoy Pete --- On Fri, 4/18/08, Thomas Dick wrote: > From: Thomas Dick > Subject: Re: quake > To: psn-l@.............. > Date: Friday, April 18, 2008, 9:08 AM > > There just was an aftershock now, emsc says it is M > 4.5. See here, > > > http://www.emsc-csem.org/index.php?page=current&sub=detail&id=84013 > (might > > be outdated soon) > > > >Here in Indiana, before this last quake the FFT for 20 > seconds just before > >dropped to below one from over 10 before the first > quake in the frequencies > >of .06 to .3 Hz > __________________________________________________________ > > 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. ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake From: shammon1@............. Date: Fri, 18 Apr 2008 11:34:01 -0700 (GMT-07:00) Wow after looking at your site Pete I went and checked my long period AT1 in Aptos and can see I also recorded that event... (and I thought my system was not working that well.) I'm at Cabrillo College teaching a Social Justice Research class at the moment but when I get home I'll check and upload my data. I bet that Jan and Larry also recorded these events. Steve Hammond PSN San Jose, Aptos, CA http://pw2.netcom.com/~shammon1/recent.htm >Loud and clear in San Jose, CA. >It's on my website right now (www(dot)rowelabs(dot)com >Enjoy >Pete --- On Fri, 4/18/08, Thomas Dick wrote: > From: Thomas Dick > Subject: Re: quake > To: psn-l@.............. > Date: Friday, April 18, 2008, 9:08 AM > > There just was an aftershock now, emsc says it is M > 4.5. See here, > > > http://www.emsc-csem.org/index.php?page=current&sub=detail&id=84013 > (might > > be outdated soon) > > > >Here in Indiana, before this last quake the FFT for 20 > seconds just before > >dropped to below one from over 10 before the first > quake in the frequencies > >of .06 to .3 Hz > __________________________________________________________ > > 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: Winquake From: "Thomas Dick" dickthomas01@............. Date: Sun, 20 Apr 2008 08:06:29 -0500 An unusual problem that I am sure those of you in California have = solved. These southern Illinois quakes that are ove