PSN-L Email List Message

Subject: Re: 8 second Microseisms
From: "Jan D. Marshall" jandmarshall@............
Date: Thu, 30 May 2002 21:35:52 -0600

Jan D. Marshall
Nampa, Idaho

----- Original Message -----
From: "Karl Cunningham" 
Sent: Thursday, May 30, 2002 9:28 PM
Subject: Re: 8 second Microseisms

Stephen --

I'm seeing the same thing in Southern California, and it has
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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