PSN-L Email List Message

Subject: Strange geophone pattern
From: Steinar Midtskogen steinar@.............
Date: Thu, 11 Sep 2008 10:36:05 +0200

I have a Mark Products 4.5 Hz 3 component L15B geophone, and since the
two major earthquakes in Indonesia and Hokkaido happened during the
night here when the local noise is low, I thought it would be
interesting to see whether such quakes show up at all on a geophone.

Apparently, they didn't, but I found a strange pattern repeating every
25 minutes:

Does anyone have any ideas what could cause this?

Perhaps an airconditioner two floors above?  Then it seems to run
through some kind of program that I wasn't aware of.  Or perhaps a
neighbour runnings some kind of machinery going through cycles?

The datalogger is fanless and diskless, so it shouldn't cause any


Public Seismic Network Mailing List (PSN-L)

[ Top ] [ Back ] [ Home Page ]