Hi
   If your sensor isn't in non-stable equibrilium (returns to zero when offset)
then you may be experiencing slab tilting due to moisture gradients of the soil
due to winter weather. Is your sensor on a slab?  It happens to my Lehman this
time of year in my garage. Just another possibility. See which way it moves
relative to the exterior, considering the fact that soil swells when wet,more or
less depending on the soil type. Mine usually stabilizes
once the first several rains finish. It goes the other way in the spring time.
Barry




_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)