[irised] Annoying Spikes

Alan Jones AlanJones at stny.rr.com
Mon Jan 28 13:57:35 PST 2008


Jerry,

This could be because you don't have the seismometer zeroed out. A constant offset can cause this.

Turn off all filtering and make sure the active trace is right on the blue line. With the filtering turned off, do you still get the spiles?

Are you sure the data shows up as a spike when you extract? It doesn't with me. It's just that each line is filtered separately and there is some start-up problems at the beginning of the line.

I'm copying John Lahr and the IRIS listserv to see if others have ideas.

Let us know if this helps.

Alan

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  ----- Original Message ----- 
  From: Jerry Cook 
  To: irised at iris.washington.edu 
  Sent: Monday, January 28, 2008 3:47 PM
  Subject: [irised] Annoying Spikes


  Hi All,
  I have a problem with my display that is driving me nuts. Every time the
  display goes to a new line at the end of the hour there is a spike on the
  new line. Check it out at this link;
  http://www.pcds.org/share/earthquake/

  This a real problem if an earthquake happens to span two lines. When I
  extract the event all I get is the spike and the seismic waves are about 1mm
  high. Any suggestions?
  J. Bob



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