In a message dated 17/05/06, jonfr500@......... writes:

> But what surprices me the most is the fact i did actually detect this
> earthquake, at this range. Even if the p and s waves are strange. I
> didn't think this was possible with my geophone.

Hi Jon,

       With large quakes you can also pick up locally generated noise. The 
geophone response falls off below 4.5 Hz as f^2 - it does not go to zero. Do a 
FFT and see what the signal peak frequencies were?

       Regards,

       Chris Chapman
In a message=20=
dated 17/05/06, jonfr500@......... writes:



But what surprices me the m=
ost is the fact i did actually detect this

earthquake, at this range. Even if the p and s waves are strange. I

didn't think this was possible with my geophone.




Hi Jon,



       With large quakes you can also pick=
 up locally generated noise. The geophone response falls off below 4.5 Hz as=
 f^2 - it does not go to zero. Do a FFT and see what the signal peak frequen=
cies were?



       Regards,



       Chris Chapman