PSN-L Email List Message

Subject: Re: Question on seting up a seismograph
From: George Bush ke6pxp@.......
Date: Sun, 31 Aug 2008 10:18:45 -0700


I have four instruments located in my garsge and am pleased with their
performance there. I have two fine old Geotech model 8700 long-period
horiz seismometers (N-S and E-W), a Teledyne Geotech BB-13 broadband
vertical seismometer and an experimental Hg-pool tiltmeter. They are all
located directly on the concrete slab in a quiet, back corner and the
vertical and the tiltmeter are enclosed by 3" solid-foam enclosures to
minimize temp variations. The vertical picks-up trafic on the nearby
street and the horizontals pick up wave noise and swells from the Ocean
which is about a block away. My instruments trigger anytime the the
garage door opens/closes and when a car enters or leaves the garage. But
their signatures are easy to distinguish and ignore. The nearby traffic
noise is mostly high-frequency on the vertical and doing a .1Hz low pass
filter in WinQuake removes that noise. The recent Vancouver quake came in
right as I was driving out of the garage. If you go to the PSN website,
and look at my recordings for 8/27 19:59:22.0 UT, you can easily see the
car/garage door signature situated just after the P and S wave arrival
and before the surface waves.

I haven't found any need to isolate the seismometers from 'some of the
noise', other than temperature effects, as isolation from noise may
isolate from seismic signals also. I ignore cars going in/out, filter the
nearby street, and simply accept that during storms when the ocean is all
riled-up, my seismic system is simply off of the air.

Hope this helps and congratulations on getting a seismograph set-up!


At 05:09 PM 8/30/2008 -0700, you wrote:=20


I am a long time lurker on this list and am finally getting around to
setting up my seismograph, however the only place I will have available
to set it up will be in my garage.  I know that this will not be the most
advantageous place to do so.  Has anyone set one up in their garage and
what would be the best way of isolating the seismograph from some of the
noise?  I know I will have a fair amount of background noise and was
hoping that I can isolate it so that I can get  meaningful event
recordings.  I am at this time leaning toward a Lehman type sensor with
Larry's Hardware.  Any help or directions to websites would be




Rudy Norvelle


George Bush

Sea Ranch, CA, USA

38.73775N, 123.48882W

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