Barry,

What you are suggesting sounds slightly like Dave Nelson's (CA) FMES 
sensors.  N & E are not combined in a single assembly, but it works very 
roughly along the lines you were mentioning--and from the results he is 
getting, it appears that it makes a very good (and also very simple) 
horizontal.

Brett.

At 08:07 PM 9/28/2009 -0700, you wrote:
>Geoff
>Along that line, a P wave being a pressure wave and a s wave being a shear 
>wave. It seems that if one could see two directions simultaneously during 
>an event one be able to combine the p wave vectors and obtain the 
>direction of max and min p wave contribution and thus the approx direction 
>of the event. I thought one could make a liquid filled cube sensor with a 
>piezoelectric disk in each face. Opposing faces would go into an 
>instrumentation amp to measure the seismic forces on the liquid inside. To 
>increase the mass in each face the center of each face could have a 
>perpendicular tube with the piezo disk at the end of the tube. It would 
>look like a kids "jack". I build one but didn't get the electronics 
>complete. Since a peizo measures velocity, there may be a better way to 
>measure pressure on each face  (diaphram with displacement sensor?).
>Regards
>Barry

Watch our wiggles
http://bnordgren.org/seismo/gif_images.htm

or watch some very very good wiggles
http://aslwww.cr.usgs.gov/Seismic_Data/telemetry_data/ANMO_24hr.html


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