GLOBAL QUIET OF LARGE QUAKES BROKEN WITH VANUATU MS 6.4

SUMMARY

As suggested in yesterday's report, the global quiet in large
quakes (Ms>6) which has persisted since September 11-12 was broken
this morning (UT) with the conclusion of the proton storm. As the proton
flux returned to background, a Ms 6.4 occurred in the region of
the southern Vanuatu Islands. The Vanuatu Islands was within
20 degrees of the sub-solar point of the geomagnetic storm on
24 September as noted in the report from that date:

"...yesterday's geomagnetic storm which began about 06:00 UT and
reintensified about 12:00 UT. In addition to the areas identified
the reintensification of that storm at 12:00 UT should enhance
seismicity in regions within 10 degrees of 180E and 0E, an area
that would also include Europe and New Zealand.
Strong earthquakes are most likely to occur in these areas
and high latitudes between September 27 and September 29."

The Vanuatu event occurred within 30 km of an area which had
been forecast to see strong activity today. Comparison of the
forecast for this event (as of 23 September, 2001 and the event
parameters as given by NEIS follows:

O: 29SEP2001 02:40:07 18.6S 168.2E Ms=6.4 NEIR VANUATU ISLANDS

The forecast had been:

29SEP2001 19.3S 167.6E 4.5-5.5 Vanuatu Islands (received 9-22)
30SEP2001 19.4S 167.8E 5.0-6.0 Vanuatu Islands (received 9-23)
1OCT2001 18.4S 167.9E 5.0-6.0 Vanuatu Islands (received 9-24)

Note how the forecast location got closer to the observed with each subsequent
update to this forecast.

GLOBAL

Most teleseismic networks were closed today for the weekend. Earthquakes
of of Mb>=4 were recorded as a Ml 4.8 in Mexico; Ml 4.5 (Taiwan);
MB 4.9 (Ryukyu Islands); and MB 4.1 (Libya) have been listed since the
last report.

U.S./CANADA

One earthquake of Ml 3.0 was observed in the California-Nevada region
today (near Big Bear, Ml 3.0). However, it was an active day with
earthquakes of Ml 2.9 reported near Taft and Obsidian Butte, CA and other
events of Ml>=2 at The Geysers CA (Ml 2.2); Mt. San Gorgonio, CA (Ml 2.7);
Bodie, CA (Ml 2.6); Midway NV (Ml 2.1) and two near the coast of Northern
California of Ml 2.8 (Weitchpec, CA) and Ml 2.1 (Blue Lake CA) since
last report.
The only other event in the U.S. (excluding Alaska and Hawaii) of Ml>=2
reported today occurred north of Mt. St. Helens, WA (Ml 2.1). A swarm
has been occurring in this region over the past week, but this event
is slightly north of those previous events. It occurs in an area
where recent activity has been quiet. It is only the second event
of Ml>=2 in a 50-km radius since May 8, 2001.

NEW ZEALAND

No reports were received from IGNS today, however the on-line
seismometer shows many light to moderate earthquakes in the region
in the past 24 hours.

The IGNS on-line Seismometer can be found at:
http://www.gns.cri.nz/news/earthquakes/latest_drum.html

GEOMAGNETIC/SOLAR FIELDS

The geomagnetic field remained at quiet conditions throughout
Sept. 28 and began to experience minor disturbances during Sept.
29. A strong geomagnetic storm began at about 21:00 U.T. If this
storm continues for an additional 9 hours, a seismic watch will
be in effect for the next day for high latitudes, areas near the
geomagnetic equator and regions within 20 degrees longitude of 135W and 55E.
These areas include Alaska and much of the Pacific Coast of the
U.S. and regions of Turkey to Iran and Afghanistan to Xinjiang, China.
Moderate events could occur in southeastern Iran or eastern Turkey, among
other locales. A seismic watch due to geomagnetic activity means
that maximum magnitude of events could increase by up to 0.5 units
above that previously anticipated.
One minor M-Class solar flare occurred today with the following parameters:

Flare # START MAX END CLASS

9680 1019 1106 1148 M1.8

No seismic activity could be directly linked to this flare.

For general space weather conditions see:
http://sec.noaa.gov/today.html
For Solar flare data see:
http://sec.noaa.gov/ftpdir/indices/events/20010929events.txt

TROPICAL STORMS

Typhoon Lekima has moved slowly over the region of Taiwan and
the Ryukyu Islands over the past three days. It is currently located
at 27N 123E nd has weakened considerably. A swarm of earthquakes
in Taiwan accompanied this typhoon. These events were of Ml
4.1, 4.3, 4.3, 4.0 and 4.5. For data on earthquakes in Taiwan see:
http://www.cwb.gov.tw/V3.0e/index-e.htm
A Mb 4.9 earthquake also occurred in the Ryukyu Islands this
afternoon in association with this hurricane. This area has been
relatively quiet seismically in recent months. Only three events
of Mb>=4.9 have occurred in the area 29N-25N 125-130E since October,
2000, the last being on May 13, 2001 (Mb 5.0), so the association
with the passage of Lekima may be significant.

For Information on Typhoon Lekima see:
http://www.wunderground.com/auto/HurricaneSite/tropical/wp200101.public.html

Juliette was downgraded from a Hurricane to a tropical storm
as it stalled over the southern tip of the Baja peninsula today.
It is expected to further diminish to a tropical depression over
the next 72 hours while tracking northward towards California.
The only seismicity associated with Juliette today was a
Ml 3.7 off he coast of Jalisco, although seismic activity throughout
the region of Mexico has been very active throughout the passage
of Juliette through the region. For listing of recent Mexican
earthquakes see:
http://www.ssn.unam.mx/~yi/SSN/ssn-ultimos.html

For tracking information on Juliette see:

http://www.wunderground.com/auto/HurricaneSite/tropical/tracking/ep200111.html

The Atlantic Ocean remained free of tropical storms today.