PSN-L Email List Message

Subject: Re: Instrument quality - microseisms
From: Stephen & Kathy skmort@............
Date: Wed, 21 Oct 2009 20:53:13 -0700


Hi Barry, I'm a little south of you...   I also
have increased noise.  Whenever I see this kind of noise, I check with
Berkeley at:

If you just create plot without setting time, it will create todays seismogram for CMB... I use 4 for compression to get an hour per line;  and pixels at 25 to get a little separation.  Sorry if I am sharing old info...   if so, maybe it will help others?

If you check the following ocean weather link you will see why...  there are 20 to 25 foot waves off the NW USA coast.   Earlier, they were showing up to 30 foot waves. You can click on any box to see the conditions in the box...  I click on the box that shows Alaska to below Baja...   and yes, the energy is apparently coming from 200 to 400 miles away:

At one time I had my gain so high that noise like this would set off my alarm, (I have a separate alarm, which I built before I had a computer and recording capability).
  PSN Station #55
  38.828N  120.979W
  near Pilot Hill Calif  

Barry Lotz wrote:

To all
Related to instrument quality- maybe. I have noticed a lot more microseismic activity the last few days. The background noise on my vertical is around +/- 300 counts @  8.7 sec  and 6.6 sec  (two narrow peaks). I don't remember this magnitude in years past. I'm sure it is weather related. I live about 200 miles east of the west coast of northern California. Anyone else noticed an increase in background lately? Every time I look at the output I think I'm looking at surface waves after an event.

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