In a message dated 30/05/2009, gmvoeth@........... writes:

Just out  of curiosity has any of you guys with those garden gate 
seismometers ever put  one of these little plastic levels on the lever to see just 
how far off level  it is at 10 or 20 seconds. I mean ere like 1/2, 1/4 or so a 
bubble across the  line if you understand what I mean here ?
Hi Geoff,
 
    My 9" spirit level shows ~1.5 deg change when the  bubble moves by it's 
own length. 
    The tilt angle of a 1.5 second arm extended to 20  seconds is 0.32 
Degrees.
 
    Regards,
 
    Chris Chapman









In a message dated 30/05/2009, gmvoeth@........... writes:
Just out 
  of curiosity has any of you guys with those garden gate seismometers eve=
r put 
  one of these little plastic levels on the lever to see just how far off=
 level 
  it is at 10 or 20 seconds. I mean ere like 1/2, 1/4 or so a bubble acros=
s the 
  line if you understand what I mean here ?
Hi Geoff,
 
    My 9" spirit level shows ~1.5 deg change=
 when the 
bubble moves by it's own length. 
    The tilt angle of a 1.5 second arm extend=
ed to 20 
seconds is 0.32 Degrees.
 
    Regards,
 
    Chris Chapman