PSN-L Email List Message

Subject: NEIS quake reporting
From: S-T Morrissey sean@...........
Date: Mon, 20 Dec 1999 13:19:47 -0600 (CST)


Regarding the timeliness of earthquake reporting by NEIS:

I would like to step in on their side and suggest that they do
a good job (who doesn't make mistakes now and then?) with their
limited resources.

The days of having a funded "duty seismologist" just for the sake
of the science are long past. With the great automation of the
data retrieval and access, the usual scientific concern after a 
quake is how well it was recorded by the stations that are key to
the event's contribution to understanding the earth. This is, of
course, an after-the-fact assessment; the data are or are not.

The funding for NEIS is strongly related to earthquake hazard 
assessment and the task of informing emergency management agencies
worldwide about the human response required after a damaging quake.
So they do have someone to respond with an official notice to
anything that might be considered a risk. I don't know the details,
but I am sometimes surprised as to whose name is on the report;
it looks like everyone helps out.

Regarding the "missing" event at 03:36 19 Dec: NEIS did report the
previous IRIAN JAVA event at 17:44Z 18 December, and an event at 0048Z
19 December in the Marianas (Mb 6.1), with a Mb 5.2 aftershock at
04:42., and A 5.0 in Peru at 09:35. So they were on the job. Why
the 5.6 was not listed is unknown.  Maybe the data was poor, since
other agencies also omitted it. Not all earthquakes have a definitive
P phase (usually required for teleseismic locations) with a radiation 
pattern that arrives at quality seismic stations; they just announce 
themselves (especially SW Pacific events) with a long rippling surface wave.
NEIS  did list another mysterious event, a Ms 4.4 at Hokkaido, Japan ,
at 13:30, 18 December, at an unusual depth of 124 km.

Regards,
Sean-Thomas



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Larry Cochrane <cochrane@..............>