PSN-L Email List Message

Subject: Re: 8 second Microseisms
From: Karl Cunningham karlc@..........
Date: Thu, 30 May 2002 20:28:22 -0700

Stephen --

I'm seeing the same thing in Southern California, and it has increased
substantially this afternoon.  See

The amplitude is quite large too.  There are two storm systems off Baja
California (one off northern Baja and the other southwest of the tip) that
I suspect are responsible.  Tropical storms and hurricanes (usually later
in the season) are often responsible for large background noise, even when
they are 1500 miles away.

Karl Cunningham

--On Thursday, May 30, 2002 09:08 -0700 Stephen & Kathy 

> FYI,,   I noticed a strangeness in the background noise today as I was
> checking my traces, so I did an FFT and discovered that they had a period
> of about 8 seconds,,   as compared to the normal 4.5 to 5.5 that I've
> noticed over the years for Northern California!    Anyone have any idea
> why????    Could this be caused by the hurricane,, or is something else
> going on???   I verified that it was not my machine by checking with the
> Berkeley "make your own seismogram" link!!
> I haven't noticed such long period microseisms before,,,   perhaps I just
> wasn't looking??


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