PSN-L Email List Message

Subject: Re: My Kermadec Islands Region earthquake recording
From: Mark Robinson mark.robinson@...............
Date: Wed, 17 May 2006 12:45:59 +1200


Jón Frímann wrote:
> Hi all
> 
> Sorry for the repost, but I probably was not clear enough on the
> strangeness in the Kermadec Islands. But here is the problem. The
> earthquake wave that I did record does not fit predicted P and S arrival
> time. I find it to be really strange, I can't explain this. I was
> hoping that somebody on the PSN mail list might. The trace is here.

The time on the computer you used to send the email appears to be about 27 
seconds fast but that is not enough of an error to explain the displacement. 
The arrivals on USGS sensors in your area seem to be roughly in line with the 
predicted P and S times on your traces. Is the time on your recording computer 
correct ?

> http://seismicnet.com/cgi-dos/event.exe

That URL gives me The Fear.
I tell every windows user to never click on anything ending on .exe.

> The station name is Hvammstangi.
There is a place a little way up the road called Himitangi.

This event was well felt in Wellington New Zealand about 1500km from the 
epicentre. Water (and other liquids) sloshed about in glasses and we 
experienced several minutes of gentle rolling and log period shudder:
     http://zl2tod.net/~mark/200605161250gmt-geonet-drums.html

There were a number of interesting frequency ramp signals on the proximate USGS 
Rarotonga sensor in the 24 hours leading up to the event:
     http://zl2tod.net/~mark/200605161250gmt-RAR_24hr.html
And considerable background activity at various frequencies on the USGS Raoul 
Island Kermadec sensor:
     http://zl2tod.net/~mark/200605161250gmt-RAO_24hr.html
This is not unusual for this location.
These sensors and a number of others seem to have gone offline an hour or so 
after the event.

Coincidentally this event comes almost exactly one year after some eigenmode 
activity around the planet:
     http://zl2tod.net/~mark/200505151251-liss-eigenmode-heli2.shtml
which was followed by this event in the Kermadecs:
     http://zl2tod.net/~mark/20050516-kermadecs-and%20eigenmode-SNZO_24hr.gif

Any comments from the learned appreciated.

Cheers
Mark
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