MODERATE SEISMICITY CONTINUES IN MOST AREAS - GLOBAL/CALIFORNIA/NEW ZEALAND

SUMMARY

Moderately high levels of seismicity continued today in most of the
study areas of this project. The largest events occurred as regional
aftershocks of the great Kunlun Mts. earthquake. The largest of these
(Mb 5.3-5.7) occurred about 300 km to the east of the mainshock epicenter.
Many of the stronger regional aftershocks have been occurring near
today's epicenter suggesting a concentration of stress in that area
following the great quake of Nov. 14. This relationship had been
noted also in the FFA forecast and in the daily report of November 14.
After a relative lull in seismicity of several weeks, and following
the Ml 3.1 near Aptos, CA three days ago (Nov. 16); seismicity in the
northern California region reached moderately high levels over the
past 24 hours. Events of Ml>=3 were recorded off the northern Coast
of Trinidad (Ml 3.8); in the Geysers region (Ml 3.3) and about 15 km
northwest of Aptos near Saratoga, CA (Ml 3.3). Southern California,
however, was quiet over the last 24 hours.
New Zealand also saw a swarm of (at this time unlocated) earthquake
over the past 24 hours following a Ml 4.4 on South Island near the
northwestern Coast.
The New Zealand, Aptos and Saratoga earthquakes all lie near or within
the S- and p-wave shadow zone boundary, an area where strong FFA triggering
is expected after great global earthquakes such as Kunlun (Mw 8.1).

GLOBAL

Because of a computer error at EMSC which might be related to a Y2K
problem (the lastest listing is for the last week of December, 1999
instead of 2001), and the shutdown of NEIS for the weekend, teleseismic
epicenters for the past two days are not well known at this time. Some
data is available from local networks, however, and on-line seismograms
do show a number of events today in the Mb>=5 range around the world.
Tomorrow's report should provide the appropriate epicenters for these
events.
Local networks in the western Hemisphere show moderate events in
Chiapas, Mexico (Ml 4.7); in Venezuela near Trinidad (Ml 4.4); and in
Central Chile (Mb 4.3) over the past 24 hours.
In Asia, an SR 6.0 was recorded south of Sumatera by AEIC;
and ISR reported a Ml 4.5 in the eastern Mediterranean Sea. GSR (via
Red Puma (Zurich)) has also reported a series of moderate regional
aftershocks in Qinghai, China (Ms 5.2, 3.9) and a Ms 3.5 in SW
Siberia since our last report.

U.S./CANADA

The most active area, by far, in the U.S./Canada today was the
region of Northern California where all three events of Ml>3 in
the U.S. occurred today. These were a Ml 3.3 near Saratoga CA;
a Ml 3.3 near the Geysers, CA and a Ml 3.8 off the Coast of
Trinidad, CA. A number of events of Ml>=2 also occurred in
northern and Central California today. These were near Napa (Md 2.5);
Eureka (Md 2.5); Chester (Md 2.5); Parkfield (Ml 2.0); San Ramon (Ml 2.0)
and Tres Pinos (the Pinnacles) (Ml 2.7). The only event of Ml>=2
in the region which did not occur in northern or Central California
was a Ml 2.2 near Lake Isabella.
In Alaska on event (Ml 3.0) has been recorded in the south-central
area near Anchorage. No events have been reported from Hawaii
over the past three days.
Canada also closes observatory doors over the weekend, reporting
only the strongest earthquakes. Seismograms can be examined for
evidence of mild quakes. In the past 24 hours, the only events
which may have surpassed Ml>=3 were registered in the Yukon/Alaska
region. No reports from eastern Canada were available.
In the eastern U.S., the Ml 1.4 event near Caruthersville, TN
yesterday (in the New Madrid fault zone area) has been recomputed

as a Ml 2.2. This event could be a FFA from the Kunlun Mts. as
it lies at 108 degrees from that great shock. On-line seismograms
for the eastern U.S. do not show any significant events over the
past several days.

DATA ACCESS WHEN LOCAL OBSERVATORIES ARE CLOSED:

SEISMOGRAM ACCESS:

Most areas of the U.S. and Canada were closed today for the weekend.
From automatic epicenter servers, however, a reasonable picture
of the current seismicity can be gained.
Worldwide activity can be followed at the following USGS on-line
seismogram site:

WORLD-WIDE SEISMOGRAMS:

http://aslwww.cr.usgs.gov/Seismic_Data/heli2.htm

Following are also links to some of the available on-line seismograms
for North American events:

CANADIAN SEISMOGRAMS:

Western Canada Seismograms are available at:

http://www.pgc.nrcan.gc.ca/seismo/seismos/24hr-stns.shtml

Hourly plots for the whole of Canada are found at:

http://www.seismo.nrcan.gc.ca/cgi-bin/hplot_e.html

EASTERN U.S. SEISMOGRAMS:

These seismograms are available at:

http://folkworm.ceri.memphis.edu/heli2/welcome.html

NORTHEAST U.S. SEISMOGRAMS:

Seismicity in the northeastern U.S. can be monitored on the
LDGO on-line seismograms at:

http://www.ldeo.columbia.edu/cgi-bin/LCSN/WebSeis/24hr_heli.pl

MONTANA/UTAH/WYOMING SEISMOGRAMS:

Seismograms from the Montana/Utah/Wyoming region also show
several local events, but no significant activity this weekend.
These are available for viewing at:

http://mbmgquake.mtech.edu/earthworm/wavef_disp/welcome.html

UTAH SEISMOGRAMS:

One event of Ml 2.6 was recorded in Utah today near Emery.
Otherwise the region appeared relatively quiet today.
Seismograms covering local events in the Utah region can be
found at:

http://www.seis.utah.edu/helicorder/heli/utah/index.html

YELLOWSTONE/WYOMING SEISMOGRAMS:

Daily seismograms from Yellowstone stations are available at:

http://www.seis.utah.edu/helicorder/heli/yellowstone/index.html

SOUTHWESTERN U.S. SEISMOGRAMS:

The southwestern U.S. is covered by seismograms found at:

http://www.ees.nmt.edu/Eworm/welcome.html

These show a moderate regional event at 14:23 UT today (see
the Barrett or Carthage seismograms for example). This appears
to be a regional event of Ml>=3. Unfortunately, there is power
loss at most seismograms at the time of this event, so it is
difficult to locate an epicenter at this time.

NORTHERN CALIFORNIA SEISMOGRAMS:

Northern California seismograms can be seen at:

http://quake.usgs.gov/cgi-bin/heliLV.pl?2&0&latest

PACIFIC NORTHWEST SEISMOGRAMS:

Seismograms from the Pacific Northwest are available at:

http://www.geophys.washington.edu/SEIS/PNSN/WEBICORDER/welcome.html

These also show no significant activity over the past 24 hours.

NEW ZEALAND

IGNS reported an Ml 4.4 near the coast of South Island near Hokitaka
today. This event was reportedly felt along the NW coastline of South
Island. Also over the past ten hours more than 10 moderate to light regional
earthquakes have been registered on the IGNS on-line seismogram. These appear
to be occurring north of North Island in the Ml 3.0-4.5 range, although
they may also be occurring near the Hokitaka epicenter.

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 today. There
were no M- or X-class solar flares observed. A sharp decline in the
intensity of the geomagnetic field (Hp) occurred with the maximum
reduction at about 00 UT on Nov. 19. This appears to have been related
to an enhancement in proton flux which has been increasing gradually
throughout the day. High proton flux conditions are often associated
with subdued global seismicity, however shortly after the decline
and subsequent return to normal a series of mild earthquake occurred
in Northern and Central California beginning with a Ml 3.3 near the
Geysers.
The largest solar flare of the day was a class C7.4, and was
not associated with any listed seismicity.

For general space weather conditions see:
http://sec.noaa.gov/today.html
For Solar flare data see:
http://sec.noaa.gov/ftpdir/indices/events/20011118events.txt

TROPICAL STORMS

No tropical storms were located in the Atlantic, eastern Pacific
or Indian oceans today.

Tropical depression 28w formed near the Island of Guam this
morning, and is moving to the NNW at about 12 knots. Some localized
associated seismicity in the region of Guam or the southern
Mariana Islands may occur over the next 24-48 hours. For a
public advisory see:

http://www.wunderground.com/auto/HurricaneSite/tropical/wp200101.public.html

TIDAL TRIGGERING (LUNAR)

Statistics have been done on many regions of the world in terms of
relationship of significant regional earthquakes with respect to lunar cycle.
Each report will summarize the most likely areas for tidal triggering
for the next day based on these statistics. It is expected
that tidal triggering will add an additional 0.5 - 1.0 units of
magnitude to events which are about to occur or will move these
events forward in time by up to seven days in the regions where
there is a statistical correlation between lunar phase and
earthquakes.

November 19 is the fifth day after the beginning of the lunar month.
Regions most likely to experience tidal triggering
on this day (With associated magnitude ranges; the percent change in
seismicity rate over background seismicity rate on this
day of the lunar month; statistical z-value and
significance level) are:

Region Magnitude range %change z-value Significance level

JMA MB>=4.0 14 2.0 0.05
Kamchatka MB>=4.0 58 4.3 0.01
Kanto MB>=4.0 42 2.6 0.03
So. California MB>=3.0 60 2.0 0.05
Washington MB>=2.0 36 3.3 0.01
Washington MB>=3.0 11 1.9 0.05
West Pacific MB>=4.0 22 2.2 0.05

Regions expected to experience reverse triggering (i.e. they are
unlikely to experience a significant event at this period of the
lunar cycle) are:

Region Magnitude range %change z-value Significance level

Pacific-Antarctic Ridge MB>=4.0 -59 -2.1 0.05
Caribbean MB>=4.0 -20 -2.2 0.05
N Indonesia MB>=4.0 -41 -2.2 0.05

EARTHQUAKE LISTINGS

GLOBAL

NEW ZEALAND

O: 18Nov2001 05:04 43.0S 170.8E ML=4.4 IGNS So of Ross, N.Z.
Note: (IGNS) Likely to have been felt on the West Coast south of Hokitika
Note: This is probably a FFA from the Kunlun earthquake. It lies at
107 degrees from that event at the p- and s- wave shadow zone boundary
a distance at which strong FFA triggering is expected.

ASIA

O: 18NOV2001 03:55:00 5.5S 103.2E SR=6.0 AEIC1 S MANNA, INDONESIA

O: 17NOV2001 21:11:00 8.3S 116.8E SR=4.9 AEIC1 NE SELONG, INDONESIA

O: 17NOV2001 20:49:20 9.4S 109.8E SR=5.4 AEIC1 S WATES, INDONESIA

O: 17NOV2001 18:54:50 10.4S 113.2E SR=4.9 AEIC1 S LUMAJANG, INDONESIA

O: 16NOV2001 15:48:40 0.9N 98.2E SR=5.2 AEIC1 GUNUNG SITOLI, INDONESIA
O: 16NOV2001 07:00:20 1.4N 98.5E SR=5.0 AEIC1 SW SIBOLGA, INDONESIA

CENTRAL/SOUTH AMERICA

O: 18NOV2001 10:08:19 31.9S 71.3W ML=4.3 DGF E of LOS VILOS, CHILE

O: 18NOV2001 03:29:03 17.1N 100.0W ML=3.9 SSN GUERRERO , MX
O: 18NOV2001 00:19:01 16.9N 100.2W ML=4.1 SSN COSTA DE GUERRERO , MX

O: 17NOV2001 20:41:19 13.6N 91.2W ML=4.7 SSN COSTA GUATEMALA , MX

O: 17NOV2001 13:59:47 16.2N 97.5W ML=3.8 SSN OAXACA , MX

O: 17NOV2001 10:11:58 16.4N 98.1W ML=3.9 SSN COSTA GUERRERO-OAXACA , MX

O: 18NOV2001 07:01:05 10.4N 86.4W MC=3.6 SIS COSTA RICA, C.A.

EUROPE

O: 18NOV2001 5:16:21 39.7N 39.3E ML=3.1 KAN ERZINCAN,TURKEY

O: 18Nov2001 01:01:47 35.0N 29.0E ML=4.5 ISR EASTERN MEDITERRANEAN SEA

U.S/CANADA

CALIFORNIA/NEVADA

O: 18NOV2001 9:57:57 37.8N 122.0W ML=2.0 NCSN SE of San Ramon, CA

O: 18NOV2001 8:47:58 36.1N 117.9W ML=1.9 NCSN NNE of Coso Junction, CA

O: 18NOV2001 14:54:46 35.8N 118.4W ML=2.2 SCSN N of town of Lake Isabella, CA

O: 18NOV2001 19:47:21 37.2N 122.0W ML=3.3 NCSN SSW of Saratoga, CA
O: 18NOV2001 19:49:58 37.2N 122.1W ML=1.5 NCSN SSW of Saratoga, CA
O: 18NOV2001 19:52:03 37.2N 122.0W ML=1.5 NCSN SSW of Saratoga, CA
O: 18NOV2001 19:58:24 37.2N 122.0W ML=0.9 NCSN SW of Saratoga, CA

O: 19NOV2001 2:05:30 36.6N 121.2W ML=2.7 NCSN NW of Pinnacles, CA

O: 19NOV2001 1:54:02 39.9N 123.4W ML=1.7 NCSN NW of Covelo, CA

O: 19NOV2001 1:18:31 40.3N 121.3W ML=2.5 NCSN W of Chester, CA

O: 19NOV2001 1:15:34 36.0N 120.6W ML=2.0 NCSN NW of Parkfield, CA

O: 19NOV2001 0:43:52 38.8N 122.8W ML=3.3 NCSN NNE of The Geysers, CA

O: 18NOV2001 15:08:42 38.3N 122.4W ML=2.5 NCSN SSW of Yountville, CA

O: 18NOV2001 20:08:38 40.9N 124.1W ML=2.5 NCSN WNW of Arcata, CA

O: 19NOV2001 2:36:15 38.7N 119.5W ML=1.6 NCSN SW of Smith, NV
O: 19NOV2001 2:27:38 38.7N 119.5W ML=1.4 NCSN SW of Smith, NV

ROCKY MOUNTAIN AREA

O: 18NOV2001 9:56:18 38.9N 111.4W ML=2.6 UUSN W of Emery, UT

EASTERN U.S./CANADA

O: 18NOV2001 4:25:59 36.1N 89.7W ML=2.2 CERI SSW of Caruthersville, TN

ALASKA

O: 18NOV2001 09:48:07 62.0N 150.4W ML=3.0 AEIC SSW of Talkeetna, Alaska