Steinar Midtskogen steinar@.............
Subject: Re: Lehman seismometer movement


audun@........... writes:
> My SEP is fairly close to yours, and I got 9mm of movement according to m=
y
 current calibration. Theoretical movement @20sec is 6mm.
Wouldn't actual movement depend a lot on the damping magnet being
sed?
Hi Steinar,
   Seismometers should be set up to 0.7 critical damping, so the=20
deflection should not depend on the magnet used. The SEPs are=20
nominally set to about a 20 second period, but you can set them =20
to far longer periods, if the site drift is small. This will=20
effect the movement of the beam at the longer periods.
   Let me know if you have any difficulties in setting up either
the period or the damping?
    Regards,
    Chris Chapman=20





=
Steinar Midtskogen steinar@latinit=
as.org

Subject: Re: Lehman seismometer movement





audun@........... writes:

> My SEP is fairly close to yours, and I got 9mm of movement according t=
o my
> current calibration. Theoretical movement @20sec=
 is 6mm.

Wouldn't actual movement depend a lot on the damping magnet =
being
used?
Hi Steinar=
,
   Seis=
mometers should be set up to 0.7 critical damping, so the 
deflection should not dep=
end on the magnet used. The SEPs are 
nominally set to about a 20 second period, but=
 you can set them  
to far longer periods, if the site drift is small. This will 
effect the =
movement of the beam at the longer periods.
   Let me know if you have any difficult=
ies in setting up either
the period or the damping?
    Regards,
    Chris Chapman 
=