PSN-L Email List Message

Subject: Re: Analog Devices & Strong Motion Arrays
From: Doug Crice dcrice@............
Date: Mon, 23 Aug 1999 12:03:17 -0700


jmhannon@.................... wrote:
> 
> >    Please share your opinions on the Analog Devices
> >    accellerometers. Are these good enough to provide
> >    useful srong motion data in large arrays? Or are
> >    they really only suited to emergency switching?
> 
> 

Back in my youth, there was a maximum theoretical acceleration from an
earthquake of a fraction of a g.  Then the Piocama (sp?) Dam earthquake
recorded 1.01 g on bedrock.  This was a good sized earthquake, but not
big enough to inspire memories like the 1972 or Loma Prieta
earthquakes.  I would think that sitting up on the fault you could get
some stuff well within the range of sensitivity of that accelerometer. 
You'll have to wait a while, but your geophones are going to be useless
when it happens and you'll feel bad if you don't get a decent recording
of your own personal event.

Regarding that fish tank, it's going to have serious problems.  Down
here in Saratoga (10 miles North) we had waves over 6 feet in my
swimming pool and lost about two feet of water from the last Loma Prieta
earthquake.  I'm not sure of the solution, maybe suspend it from rubber
bands from the ceiling and put on a cover.

Don't forget that most strong-motion seismographs fail because the
batteries are dead, you will not have any power when it hits, so maybe
one of those computer power supplies is in order.

-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900

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Larry Cochrane <cochrane@..............>