PSN-L Email List Message

Subject: Re: tornados
From: ChrisAtUpw@.......
Date: Wed, 9 Nov 2005 19:47:00 EST


In a message dated 10/11/05, dickthomas01@............. writes:

> Has anyway recorded any "strange"/"distinct" effects when tornadoes came 
> close to their seismic detectors?

Hi Tom,

       I have seen reports of seismic signals, but how are you defining 
'strange' and 'distinct'?
       Extreme weather conditions, passing fronts, wave systems, rotors and 
tornadoes can all be expected to be capable of producing direct seismic signals.
       However, since you use a vertical sensor without a hermetic case, it 
will also sense the changes in air density which these systems generate. This 
is a well documented source of atmospheric 'noise' in vertical instruments. Put 
the sensor in a hermetic chamber and you reduce the noise by up to x100. 

       Regards,

       Chris

       
In a message=20=
dated 10/11/05, dickthomas01@............. writes:


Has anyway recorded any "st= range"/"distinct" effects when tornadoes came=20
close to their seismic detectors?


Hi Tom,

      I have seen reports of seismic sign= als, but how are you defining 'strange' and 'distinct'?
      Extreme weather conditions, passing= fronts, wave systems, rotors and tornadoes can all be expected to be capabl= e of producing direct seismic signals.
      However, since you use a vertical s= ensor without a hermetic case, it will also sense the changes in air density= which these systems generate. This is a well documented source of atmospher= ic 'noise' in vertical instruments. Put the sensor in a hermetic chamber and= you reduce the noise by up to x100.=20

      Regards,

      Chris

      

[ Top ] [ Back ] [ Home Page ]