[Dave Nelson]

> Steinar,
>               I agree with Gary,   mounting you system on a wooden
> floor is just a total
>  no no ... you are reaslly asking for problems

No, it's a vinyl floor, just 1-2 mm thick on concrete in the basement.
The house itself is built on bedrock (with some gravel between, I
suppose).  I can cut holes in the floor so the seismometer becomes
mounted directly on concrete, but I'll not consider that before I know
that the current location is the best I can use.

I don't think water underneath the house causing the ground to swell
can explain why the seismometer tilted.  There had not been any rain
for a while.  Also, I log radon levels in the basement (in the same
room) and the radon levels are a pretty good indication of movements
in the ground due to water.  The radon levels indicate no such ground
movements.


-- 
Steinar
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