On 06/11/10 06:28, Andrew Little wrote:
> Hi PSN list,
> I have a copy of The Amateur Scientist by C.L. Strong 1960. It is a collection
> of projects and articles from The Scientific American. In the Earth Science
> section are several articles on seismology. It was this book that first got me
> interested in the subject. One article by Elmer Rexin describes using a float
> in a well to detect seismic events.
> I happen to have a well under my house, it is cut into the limestone, the water
> surface is 10 Metres below the floor of the cellar. I know of one sink-hole on
> the plateau above the village so It is possible that the well could be
> connected to an aquifer in the limestone hillside. The well in the article did
> have a connection to lake Michigan and so acted as part of a giant "U-tube".
> Anyway, the point of all this is to ask if anyone thinks there could be an
> advantage in setting up some form of sensor in the well, and if so, have you
> any ideas?
> Regards,
> Andy

I've done something similar.

There was a pressure sensor below the lowest water level.

It was intended to measure drawdown when water was drawn from the well.

The refresh rate was too slow for local seismic events but I could see noise 
from large teleseismic events.

It did make a very good tide meter and was also confounded by changes in 
atmospheric pressure. With compensation for these factors you would be on the 
way and get a sensor with extraordinary low frequency response.

Borehole seismometers, which sit at the bottom of wells, are common practice 
and provide excellent isolation from local environmental noise.

regards
Mark

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