Offtopic (earthquakes, not taxonomy)

Geoff Read at NIWA.CO.NZ
Sat Jan 1 22:46:21 CST 2005

>       That is what I was wondering---whether even more very large (8.0+)
> earthquakes in the southeastern Asian region might be expected
> during the coming weeks.

I saw a map of recent world quake activity at the USGS site. It seemed to
indicate the  Western Pacific was experiencing more quake activity than
anywhere else in the world over the past month or so. Interesting. But
this may be the status quo for all I know.

The giant quake just north of Macquarie Ridge is of course on the plate
boundary that runs north through New Zealand (where I am). It is rather a
long, indirect way from Sumatra (& see below).

Check out the USGS Sumatra quake page & assoc links:

Quote from the faq:

  Question: How has the occurrence of this earthquake affected the
probability of another great earthquake?

  Answer: The occurrence of this earthquake will have produced a
redistribution of tectonic stresses along and near the boundary between
the India plate and the Burma plate.  In some areas, this redistribution
of stresses will be such as to shorten the time to the next big
earthquake compared to what would have been the case if the earthquake
had not happened.  In other areas, the redistribution of stresses will
be such as to increase the time to the next big earthquake.  Once the
distribution of slip along the earthquake fault has been mapped, it will
be possible to estimate the areas that were moved closer to future
failure and those that were moved farther from future failure. It is not
yet possible, however, to reliably estimate when the future failure will
occur in a given area or how large will be the resulting earthquake.

  Question: This earthquake occurred within three days of a magnitude 8.1
earthquake in the Macquarie Islands.  Is there any relation between the
two earthquakes?

 Answer: The occurrence of two great earthquakes within such a short space
of time is indeed striking. However, even in retrospect, we do not yet
see evidence for a strong causal relationship between the two
[...]The Macquarie Ridge earthquake was very far from the site of the
yet-to-occur Sumatra-Andaman Islands earthquake, and occurred on a
different plate boundary. The hypothesis that long-term stress changes
associated with the Macquarie Ridge earthquake triggered the
Sumatra-Andaman Islands earthquake therefore does not seem compelling.

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