[irised] Annoying Spikes

[Jerry Cook]

Dear Dr. Jones,
You rock! When I turned off all filtering the active trace was 21 hours off. Now that I have it centered on the correct hour the spikes are gone. I have no Idea how the trace got so far off. I will add this little gem of knowledge to my list of trouble shooting fixes.
Cheers,
J. Bob

________________________________

From: Alan Jones [mailto:AlanJones at stny.rr.com]
Sent: Mon 1/28/2008 2:57 PM
To: Jerry Cook
Cc: John Lahr; IRISED
Subject: Re: [irised] Annoying Spikes


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 <mailto:jerry.cook at pcds.org>  
	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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