PSN-L Email List Message

Subject: Re: the warning of earthquakes
From: ChrisAtUpw@.......
Date: Sun, 3 Apr 2005 23:35:25 EDT


In a message dated 03/04/2005, mark.robinson@............... writes:

> Speaking of warning of earthquakes, I made an offhand prediction that 
> there was going to be a significant earthquake six hours or so before 
> the 8.7 in Indonesia.
> 
> This was based this on unusual long period activity on the USGS 
> instrument in Wellington which I have associated with the run up to 
> large quakes in the past. Strange patterns of waves of similar period to 
> the global ringing which happens after a large quake.
> 
> Perhaps some of the learned people here could tell me if this is a known 
> phenomenon and if so point me at some reading material.

Hi Mark,

       I was certainly aware of these eigenmode signals, which are a bit 
difficult to see on 'ordinary' seismometers, but I do not offhand know of any 
reports. There certainly should be some about. You can also see these effects with 
a really sensitive tiltmeter.

       Regards,

       Chris Chapman
In a message dated 03/04/2005, mark=
..robinson@............... writes:

Speaking of warning of earthqua= kes, I made an offhand prediction that
there was going to be a significant earthquake six hours or so before
the 8.7 in Indonesia.

This was based this on unusual long period activity on the USGS
instrument in Wellington which I have associated with the run up to
large quakes in the past. Strange patterns of waves of similar period to the global ringing which happens after a large quake.

Perhaps some of the learned people here could tell me if this is a known phenomenon and if so point me at some reading material.


Hi Mark,

       I was certainly aware of these eigenmod= e signals, which are a bit difficult to see on 'ordinary' seismometers, but=20= I do not offhand know of any reports. There certainly should be some about.=20= You can also see these effects with a really sensitive tiltmeter.

       Regards,

       Chris Chapman

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