MW 7.0 EARTHQUAKE HITS NEW BRITAIN; MODERATE QUAKE (ML5.1) IN SO. CALIFORNIA

SUMMARY

A large. Mw 7.0 earthquake hit the western edge of the New Britain
region last night. This earthquake was the largest within 200 km
of this epicenter since May 10, 1999 (Mw 7.1).
Twenty-two earthquakes of Mw>=7 have occurred in the last century
within 200 km of today's epicenter. The largest was a Mw 8.4 on
September 14, 1906 followed by a Mw 7.7 aftershock on Oct. 2, 1906.
Large events in this area often occur in pairs or groups with the first
event small, leading to larger event(s). For example see events in
1905, 1906, 1945, 1949, and 1999 in Table 1. Of 14 groupings, five
have had multiple events of Mw>=7, so the chance of a second event
in this magnitude range in this area is about one-third. Odds of
one in three. The region is sparsely populated, so only minor
damage is expected. Tsunamis often occur with earthquakes of this size
in this region, but will probably be less than 1 m runup if they occurs.
The region was in the cross-hairs of tidal, far-field and geomagnetic
triggering at this time. A far-field forecast was published with more
details.

NEIS and GSSR give the event parameters as:

O: 31Oct2001 09:10:19 4.9S 149.8E MW=7.0 NEIS NEW BRITAIN REGION, P.N.G
O: 31Oct2001 09:10:15 6.5S 150.6E MS=6.5 GSSR NEW BRITAIN REGION, P.N.G

A moderate earthquake also hit the region near Anza, Southern
California about an hour before the New Britain earthquake. Large
earthquakes in this area of Southern California and New Britain
commonly occur about the same time. Usually, the So. Cal. events
occur after the New Britain shocks, but not always. Table 1
shows the parameters of the 14 events of M>=5 within 50 km of the Anza
mainshock which have been recorded in the past:

Table 1: Events of Ml>=5 within 50 km of the Anza mainshock epicenter

MO DA HR MN SC YEAR N LATI W LONG DEP MAG

2 9 12 6 0 1890 33.500 -116.500 0 6.0
5 28 11 15 0 1892 33.500 -116.000 0 6.0
3 25 16 49 2 1937 33.400 -116.250 10 6.0
6 4 10 35 8 1940 33.000 -116.433 16 5.1
8 15 17 56 24 1945 33.216 -116.133 16 5.7
3 19 9 54 29 1954 33.283 -116.183 16 6.2
3 19 10 21 17 1954 33.283 -116.183 16 5.5
3 23 4 14 50 1954 33.283 -116.183 16 5.1
5 26 15 59 34 1957 33.216 -116.000 15 5.0
9 23 14 41 53 1963 33.700 -116.916 17 5.3
12 30 16 30 35 1965 33.566 -116.550 8 5.9
4 9 2 28 59 1968 33.183 -116.116 11 7.1
4 28 23 20 43 1969 33.333 -116.333 20 6.1
2 25 10 47 39 1980 33.517 -116.550 6 5.6

The parameters of today's earthquake (NEIS) are:
O: 31Oct2001 07:56:16 33.5N 116.5W ML=5.1 NEIS SOUTHERN CALIFORNIA

This earthquake occurred as a strong solar flare was approaching
it's maximum output and also at very near midnight local solar time.
It seems possible that the flare was the immediate triggering
factor for this event.

GLOBAL

Additionally to the New Britain (Mw 7.0) and the Ml 5.1 near
Anza, California other events were also occurring around the world.
The largest was an Ms 6.1 (GSSR) south of the Fiji Islands last night
(NEIS says it was a Mb 5.0). Other events of M>=5 occurred in Turkey
(Mb 5.3) in an event which was probably locally damaging and
north of Iceland (Mb 5.4 IMO).
Earthquake of lesser magnitude were also recorded south of Greece
(Mb 4.8); in Argentina (Mb 4.5) and Central Chile (Mb 4.7); in
Azerbaijan (Mb 4.6) and Hindu Kush/Afghanistan (Mb 4.1). Two
additional events on mid-ocean ridges were reported today which
occurred yesterday on the Reykjanes Ridge (south of Iceland, Mb 4.2)
and in the South Sandwich Islands (Mb 4.1).

U.S./CANADA

The largest event of the past 24 hours occurred near Anza and
is reported on in the summary above. An earthquake near Parkfield
was registered with Ml 2.9 last night as well. Other events occurred
in the Ocotillo region of southern California the largest of which
was a Ml 3.1. This region and the Anza area are often active following
strong geomagnetic storms. In northern California, earthquakes of
Ml 2.0 and 2.2 were recorded near San Juan Bautista and Los Gatos
respectively.
An additional event of Ml 3.0 occurred this morning in Hawaii. This
area is likely to see increased activity over the next several
days from FFA of the New Britain region.
In Alaska three events were recorded of Ml>=3. The largest occurred
in the Unimak/Alaska Peninsula region with Ml 3.6. This is an
area where FFA are also expected.
After a lull of 2 weeks a second earthquake of Ml 2.2 occurred
in the New Madrid region in as many days. Other areas of the U.S.
and Canada have not reported events for today at this time.

NEW ZEALAND

The on-line seismogram from IGNS shows very active conditions
in that nation over the past 24 hours, although IGNS has not
reported any seismic parameters. At least three local events
of Ml>=3.5 can be seen on the seismogram. The North Island
region may see additional FFA from the earthquake in New Britain.

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 despite
a moderate increase in variability towards the end of the day. There
were two M-Class flares observed on the sun with the following
parameters:

Flare # START MAX END CLASS

9180 + 0734 0809 0819 M3.2
9200 + 1039 1051 1100 M1.5

Flare #9180 was the second largest in more than a week, the other
occurred on October 28 - M3.6. About an hour after flare 9180
several significant earthquakes occurred including the Ms 7.0 in
New Britain and the Anza earthquake in southern California. The
Anza event occurred at 07:54 UT near the maxima of flare #9180
and occurred while the epicenter was exactly anti-solar. It is
likely that this flare was responsible at least in part for the
timing of this rupture.

For general space weather conditions see:
http://sec.noaa.gov/today.html
For Solar flare data see:
http://sec.noaa.gov/ftpdir/indices/events/20011031events.txt

TROPICAL STORMS

Tropical Depression fifteen continued to hover over Nicaragua
today and is tracking slowly northward towards Cuba and the
Gulf of Mexico. TD 15 is producing wide-spread flooding
in Honduras and Nicaragua and may intensify as it moves into
the NW Caribbean. All interests in the area are advised to
watch this storm carefully. It is now expected that TD15
will reach hurricane category 1 status by Saturday.

For tracking information see:
http://www.wunderground.com/auto/HurricaneSite/tropical/tracking/at200115.html

Tropical Storm Lorenzo continues to track in the north Atlantic posing
no immediate threat to land at this time. For tracking information see:
http://www.wunderground.com/auto/HurricaneSite/tropical/tracking/at200114.html

A new tropical storm formed south of Mexico today, titled
Tropical Storm Octave, this storm is expected to turn to the
north tonight and move into the region far off the coast of
Baja and southern California. No associated seismicity is
anticipated at this time. For tracking details see:
http://www.wunderground.com/auto/HurricaneSite/tropical/tracking/ep200117.html

Tropical Cyclone Alex-Andre is south of India is back on course
moving SW. It is becoming disorganized and will likely dissipate
in the next few hours. No associated seismicity is expected.

For public advisory see:
http://www.wunderground.com/auto/HurricaneSite/tropical/sp200101.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 1 is sixteen days after the beginning 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

Kermadec MB>=4.0 14 2.0 0.05
Nevada MB>=2.0 22 3.3 0.01
Spain MB>=4.0 35 2.5 0.03
Puerto Rico MB>=4.0 18 2.0 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

So.California MB>=0.0 -8 -2.1 0.05

EARTHQUAKE LISTINGS

GLOBAL

OCEANIA

O: 30Oct2001 07:21:59 52.7N 32.3W MB=4.2 NEIS REYKJANES RIDGE

O: 30Oct2001 11:53:02 60.2S 27.1W MB=4.1 NEIS SOUTH SANDWICH ISL REGION

SOUTH PACIFIC ISLANDS

O: 31Oct2001 09:10:19 5.9S 149.8E MW=7.0 NEIS NEW BRITAIN REGION, P.N.G.

O: 30Oct2001 08:50:15 19.2S 177.5W MB=3.6 NEIS FIJI ISLANDS REGION

O: 31Oct2001 04:31:03 24.5S 177.5W MB=5.0 NEIS SOUTH OF FIJI ISLANDS
O: 31Oct2001 04:31:22 24.5S 177.3W mb=6.1 GSR SOUTH OF FIJI ISLANDS

ASIA

O: 31OCT2001 17:07:37 36.8N 69.5E Ms=4.1 GSSC HINDU KUSH, AFGHANISTAN

O: 30OCT2001 19:41:00 9.5S 115.2E SR=4.9 AEIC1 S DENPASAR , INDONESIA
O: 30OCT2001 19:44:30 10.4S 114.0E SR=4.9 AEIC1 SW DENPASAR , INDONESIA

O: 30OCT2001 17:06:00 10.2S 118.7E SR=4.7 AEIC1 W WAIKABUBAK , INDONESIA
O: 30OCT2001 14:34:40 8.8S 118.9E SR=5.5 AEIC1 m S RABA , INDONESIA

O: 29Oct2001 10:04:50 39.3N 48.7E MB=4.6 NEIS ARMENIA-AZERBAIJAN-IRAN

CENTRAL/SOUTH AMERICA

O: 31Oct2001 04:59:22 31.8S 71.0W MB=4.7 NEIS NEAR COAST OF CEN CHILE
O: 31OCT2001 04:59:25 31.8S 71.2W ML=4.7 DGF W of SALAMANCA, CHILE

O: 31Oct2001 04:29:29 23.9S 67.0W MB=4.5 NEIS JUJUY PROVINCE, ARGENTINA

EUROPE

O: 30Oct2001 06:10:20 36.2N 24.6E MB=4.8 NEIS SOUTHERN GREECE

O: 31Oct2001 12:33:56 37.3N 36.3E MB=5.3 NEIS TURKEY
O: 31OCT2001 12:33:59 37.7N 36.3E Ms=4.4 GSSC TURKEY
O: 31OCT2001 14:33:54 37.2N 36.1E ML=5.2 KAN OSMANYE,TURKEY

O: 31OCT2001 00:48:32 38.7N 28.0E ML=3.1 KAN MANYSA, TURKEY

O: 31OCT2001 07:42:15 63.6N 19.4W Ml=5.4 IMO ICELAND

U.S/CANADA

CALIFORNIA/NEVADA

O: 31OCT2001 01:46:02 35.7N 120.3W ML=2.8 SCSN NW of Cholame, CA

O: 31Oct2001 02:17:06 32.6N 116.1W ML=3.1 NEIS CALIF.-BAJA CALIF. BORDER

O: 31OCT2001 06:26:23 32.1N 115.5W ML=2.3 SCSN S of Calexico, CA

O: 31Oct2001 07:56:16 33.5N 116.5W ML=5.1 NEIS SOUTHERN CALIFORNIA
O: 31Oct2001 10:27:25 33.5N 116.5W ML=2.9 NEIS SOUTHERN CALIFORNIA
O: 31OCT2001 07:56:16 33.5N 116.5W ML=5.1 SCSN ESE of Anza, CA
O: 31OCT2001 08:00:45 33.5N 116.5W ML=2.5 SCSN ESE of Anza, CA
O: 31OCT2001 08:02:20 33.5N 116.5W ML=2.3 SCSN ESE of Anza, CA
O: 31OCT2001 08:03:30 33.5N 116.4W ML=2.1 SCSN ESE of Anza, CA
O: 31OCT2001 08:08:49 33.5N 116.5W ML=2.0 SCSN ESE of Anza, CA
O: 31OCT2001 08:09:02 33.5N 116.5W ML=2.1 SCSN ESE of Anza, CA
O: 31OCT2001 09:09:39 33.5N 116.5W ML=2.2 SCSN ESE of Anza, CA
O: 31OCT2001 09:11:24 33.4N 116.5W ML=2.0 SCSN SE of Anza, CA
O: 31OCT2001 09:12:32 33.5N 116.5W ML=2.0 SCSN ESE of Anza, CA
O: 31OCT2001 09:32:14 33.5N 116.5W ML=2.0 SCSN ESE of Anza, CA
O: 31OCT2001 09:41:00 33.5N 116.5W ML=2.8 SCSN ESE of Anza, CA
O: 31OCT2001 09:41:05 33.4N 116.5W ML=2.7 SCSN ESE of Anza, CA
O: 31OCT2001 10:27:25 33.5N 116.5W ML=2.9 SCSN ESE of Anza, CA
O: 31OCT2001 18:09:37 33.5N 116.4W ML=2.3 SCSN SSW of Palm Desert, CA

O: 31OCT2001 12:50:10 33.1N 115.6W ML=2.1 SCSN W of Obsidian Butte, CA

O: 31OCT2001 2:17:06 32.6N 116.2W ML=3.0 SCSN WSW of Ocotillo, CA
O: 31OCT2001 2:27:50 33.2N 116.1W ML=1.5 SCSN N of Ocotillo Wells, CA
O: 31OCT2001 4:12:18 33.2N 116.1W ML=2.4 SCSN N of Ocotillo Wells, CA

O: 31OCT2001 01:46:01 35.8N 120.3W Md=2.9 NCSN SE of Parkfield, CA

O: 31OCT2001 12:10:59 36.8N 121.5W Md=2.2 NCSN S of San Juan Bautista, CA

O: 31OCT2001 19:57:54 37.3N 122.1W Md=2.0 NCSN NW of Los Gatos, CA

ROCKY MOUNTAIN AREA

O: 30OCT2001 0:39:14 44.7N 111.0W ML=1.0 UUSN NE of W. Yellowstone, MT

O: 29OCT2001 16:30:40 41.1N 111.6W ML=1.7 UUSN NW of Henefer, UT

O: 29OCT2001 16:13:18 38.1N 112.4W ML=1.9 UUSN WSW of Circleville, UT

EASTERN U.S./CANADA

O: 31OCT2001 7:59:44 36.0N 89.9W ML=2.2 CERI Blytheville, MO

ALASKA

O: 31OCT2001 08:18:11 55.2N 161.0W ML=3.6 AEIC WSW of Sand Point, Alaska

O: 31OCT2001 13:06:38 61.2N 150.8W ML=3.2 AEIC W of Anchorage, Alaska

HAWAII

O: 31OCT2001 10:23:51 19.2N 155.5W ML=3.0 HVO SW of Pahala, Hawaii