This is just a guess, but I wonder if this was done for thermal =
stabilization of the instrument.  The instrument was not covered and it =
would be susceptible to thermal air currents as the temperatures rise =
and descend over a 24 hour period.

I have a similar installation and initially covered my instrument with =
sand bags, but they were very heavy to remove each time I needed access =
to the instrument.  I then covered my instrument with a 10 gallon barrel =
lined with fiberglass.  This has killed all of the thermal variations =
that I used to received.  Thermal variations are very noticeable and are =
one reason the instruments are always covered.=20

Bob Hancock=20

On May 13, 2010, at 5:53 AM, GPayton wrote:

> Looking at the photographs at  =
http://www.eas.slu.edu/Earthquake_Center/NM/UALR/ualr.pict.html  I =
couldn't help but be surprised at the last photograph.  Water put in the =
vault?  I've never see this before; why?  Anyone explain?
> =20
> Thanks,
> Jerry

This is just a guess, but I wonder if this was =
done for thermal stabilization of the instrument.  The instrument =
was not covered and it would be susceptible to thermal air currents as =
the temperatures rise and descend over a 24 hour =
period.

I have a similar installation and =
initially covered my instrument with sand bags, but they were very heavy =
to remove each time I needed access to the instrument.  I then =
covered my instrument with a 10 gallon barrel lined with fiberglass. =
 This has killed all of the thermal variations that I used to =
received.  Thermal variations are very noticeable and are one =
reason the instruments are always =
covered. 

Bob =
Hancock 

On May 13, 2010, at 5:53 AM, GPayton =
wrote:

Looking at the photographs =
at  h=
ttp://www.eas.slu.edu/Earthquake_Center/NM/UALR/ualr.pict.html  =
I couldn't help but be surprised at the last photograph.  Water put =
in the vault?  I've never see this before; why?  Anyone =
explain?
 
Thanks,
Jerry

=