In a message dated 2006/11/17, ian@........... writes:

I>  got my nanos and micros mixed up! The back of envelope calculation 
> concluded a movement of 100 micro meters. So no diffraction patterns involved, 
> phew!  
> 
> The email with the formula is in the 2001 archive, Wed, 7 Feb 2001, subject: 
> "tiltmeter sensitivity". The assumed distance from the epicentre was 90 
> degrees.

Hi Ian,

       Thanks for the reference.

       Sorry to be a bit doubtful, but are you using the formula for the 
vertical response? Are your formulae mixed up?

       The note seems to give the oscillatory response of the pendulum to the 
lateral seismic movement. Has the actual ground tilt been considered?

> No problem with folded pendulums! (or is it pendula?) 
> 
       Either are acceptable.

       Regards,

       Chris Chapman
In a me=
ssage dated 2006/11/17, ian@........... writes:



I
 got my nanos and micros mixed=
 up! The back of envelope calculation concluded a movement of 100 micro mete=
rs. So no diffraction patterns involved, phew!  



The email with the formula is in the 2001 archive, Wed, 7 Feb 2001, subject:=
 "tiltmeter sensitivity". The assumed distance from the epicentre was 90 deg=
rees.




Hi Ian,



       Thanks for the reference.



       Sorry to be a bit doubtful, but are you=
 using the formula for the vertical response? Are your formulae mixed up?


       The note seems to give the oscillatory=20=
response of the pendulum to the lateral seismic movement. Has the actual gro=
und tilt been considered?



No problem with folded pendulum=
s! (or is it pendula?) 



       Either are acceptable.



       Regards,



       Chris Chapman