In a message dated 2006/12/10, jonfr500@......... writes:

> This low period noise is so low that it registers from 0.1Hz and to 1Hz, 
> but the main peak is around 0.2Hz. This would not have been interesting except 
> for the fact that this low period noise also appears on the sensors that IMO 
> is running.

Hi Jon,

       This sounds like ocean microseismic noise. It varies in amplitude 
between quiet periods at about 0.5 micron and ocean storm conditions at maybe 15 
microns, mostly at around 6 secs period. The generating centre may be S / SE of 
Greenland - relatively close to you! 

       Go to http://www.earthquakes.bgs.ac.uk/helicorder/heli.html and look 
at the Very Long Period traces for Lerwick in the Shetland Islands north of 
Scotland.

       Regards,

       Chris Chapman
In a me=
ssage dated 2006/12/10, jonfr500@......... writes:



This low period noise is so low=
 that it registers from 0.1Hz and to 1Hz, but the main peak is around 0.2Hz.=
 This would not have been interesting except for the fact that this low peri=
od noise also appears on the sensors that IMO is running.




Hi Jon,



       This sounds like ocean microseismic noi=
se. It varies in amplitude between quiet periods at about 0.5 micron and oce=
an storm conditions at maybe 15 microns, mostly at around 6 secs period. The=
 generating centre may be S / SE of Greenland - relatively close to you! 


       Go to http://www.earthquakes.bgs.ac.uk/=
helicorder/heli.html and look at the Very Long Period traces for Lerwick in=20=
the Shetland Islands north of Scotland.



       Regards,



       Chris Chapman