In a message dated 2008/10/02, tchannel1@............ writes:

> I have seen something similar somewhere on the web, but I can't find it.   
> This is all I could find.   If someone has tried this please email me.   
> Thanks, Ted
>  Torsion Seismometer Wood Anderson
>  http://www.data.scec.org/Module/s3inset3.html

Hi Ted,

       The Wood-Anderson was a horizontal system with a torsion suspension, 
magnetic damping, optical + photographic recording and a period of about a se
cond. There is no reason why you could not fit a dual Si photocell readout 
system. 

       To increase the period you can reduce the wire diameter / increase the 
wire length / mount the mass on an extended side boom to increase the 
inertia.

       Check out
       http://doga.ogs.trieste.it/doga/risk/woodanderson/index.html
       http://www.eas.slu.edu/Earthquake_Center/Instruments/

       Randall Peters has a vertical torsion device on this website.
       http://physics.mercer.edu/hpage/peters.html

       Regards,

       Chris Chapman   
In a me=
ssage dated 2008/10/02, tchannel1@............ writes:



I have seen something similar s=
omewhere on the web, but I can't find it.   This is all I could fi=
nd.   If someone has tried this please email me.   Thank=
s, Ted

 Torsion Seismometer Wood Anderson

 http://www.data.=
scec.org/Module/s3inset3.html




Hi Ted,



       The Wood-Anderson was a horizontal syst=
em with a torsion suspension, magnetic damping, optical + photographic recor=
ding and a period of about a second. There is no reason why you could not fi=
t a dual Si photocell readout system. 



       To increase the period you can reduce t=
he wire diameter / increase the wire length / mount the mass on an extended=20=
side boom to increase the inertia.



       Check out

       http://doga.ogs.trieste.it/doga/risk/wo=
odanderson/index.html

       http://www.eas.slu.edu/Earthquake_Cente=
r/Instruments/



       Randall Peters has a vertical torsion d=
evice on this website.

       http://physics.mercer.edu/hpage/peters.=
html



       Regards,



       Chris Chapman