In a message dated 31/10/2007, paleoartifact@......... writes:

Quite some time back, their was a reference (text) regarding a rough  
"deflection" test; 
where a small item (feather or something similar), was placed upon the  mass 
of a
vertical seismometer, and that displacement was a rough measure of (I  think) 
of its
crude sensitivity?



Hi Meredith,
 
    Weight lift calibration is used on AS-1  seismometers. See links from  
_http://jclahr.com/science/psn/as1/_ (http://jclahr.com/science/psn/as1/) 
    Far from being crude, it should be accurate at  least to a few%. I favour 
using weights made from known lengths and diameters of  copper wire, bent to 
give three point contacts. You can use fine nylon fishing  line to lift the 
weight. Sewing thread tends to twist.
    You can also calibrate horizontal seismometers  using a wire weight 
suspended on a 90 deg V silk / cotton thread. Having set the  system up, you 
release the mass by burning the thread.  
 
    Regards,
 
    Chris



   






In a message dated 31/10/2007, paleoartifact@......... writes:
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>
  
Quite some time back, their was a reference (text) regarding a rough=20
  "deflection" test; 
  
where a small item (feather or something similar), was placed upon th=
e=20
  mass of a
  
vertical seismometer, and that displacement was a rough measure of (I=
=20
  think) of its
  
crude sensitivity?

Hi Meredith,
 
    Weight lift calibration is used on AS-1=20
seismometers. See links from  http://jclahr.com/science/psn/as=
1/
    Far from being crude, it should be accurate at=20
least to a few%. I favour using weights made from known lengths and diameter=
s of=20
copper wire, bent to give three point contacts. You can use fine nylon fishi=
ng=20
line to lift the weight. Sewing thread tends to twist.
    You can also calibrate horizontal seismometers=20
using a wire weight suspended on a 90 deg V silk / cotton thread. Having set=
 the=20
system up, you release the mass by burning the thread.  
 
    Regards,
 
    Chris