FAR-FIELD AFTERSHOCK FORECAST FOR NEW BRITAIN MW 7.0 (PRELIMINARY)
(OCTOBER 31, 2001)

A strong Mw 7.0 earthquake occurred in the easatern New Britain
region this morning shortly after a strong M3.4 class solar
flare about half an hour earlier. As this report will show, the
region was in the cross-hairs of tidal, far-field and geomagnetic
triggering at this time, so this event and it's timing should not come as a
surprise to those who follow these phenomena.

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

SEISMIC HISTORY OF AREA:

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.

Table 1 lists the parameters of earthquake of Mw>=7 within 200 km of
today's NEIC epicenter.

Table 1: Seismicity within 200 km of 4.9S 149.8E (Ms>=7)

MO DA HR MN SC YEAR S LATIT E LONG DEPT MW

3 4 16 0 20 1905 4.000S 149.000E 60 7.1
3 4 23 17 30 1905 4.000S 149.000E 60 7.2
5 18 13 45 6 1905 4.000S 149.000E 60 7.5

8 26 5 59 31 1906 4.000S 149.000E 60 7.4
9 14 0 0 0 1906 6.000S 150.000E 0 8.4
9 17 8 38 0 1906 4.000S 149.000E 60 7.1
10 2 2 52 0 1906 4.000S 149.000E 60 7.7

9 7 7 11 18 1910 6.000S 151.000E 80 7.3

11 2 21 8 6 1923 4.500S 151.500E 50 7.2

6 11 0 49 35 1930 5.500S 150.000E 60 7.1

2 28 14 21 42 1934 5.000S 150.000E 60 7.2

12 27 4 41 5 1945 6.000S 151.000E 40 7.0
12 28 17 48 45 1945 6.000S 150.000E 60 7.8

3 16 22 15 13 1949 5.500S 151.000E 60 7.0
3 17 21 5 3 1949 5.500S 151.000E 60 7.0

11 17 8 15 39 1964 5.700S 150.700E 45 7.6

5 30 7 49 43 1984 4.700S 151.800E 169 7.1

5 10 15 35 51 1985 5.599S 151.045E 27 7.3

10 16 20 47 58 1987 6.000S 149.100E 24 7.1

9 28 20 26 56 1991 5.814S 150.959E 28 7.1

4 5 11 8 4 1999 5.591S 149.568E 150 7.4
5 10 20 33 2 1999 5.159S 150.880E 138 7.1

FAR-FIELD TRIGGERING:

The area had been identified as a region subject to Far-field
aftershocks (FFA) from the Ms 6.8 in New Zealand on 21 October, 2001 (that
forecast expires tomorrow). The forecast had stated:

From Guam:

"17-19 degrees: ...East Papua New Guinea"

and

"Areas which have had several occurrences of unusual earthquakes
following such events include:
...Papua New Guinea/New Britain/Admiralty Islands"
and

"43-45 degrees: Papua New Guinea, Bismarck Sea, New Ireland,"

This event is 42-43 degrees from the Banda epicenter (depending on
which determination is used).

The epicentral region was probably also affected by the Kamchatka
(October 8) and the Guam earthquakes (October 12). This earthquake
is located at 18 degrees from Guam and 59 degrees from Kamchatka,
both distances where FFA area expected. The far-field forecasts
from those events had stated:

From Guam:

"17-19 degrees: ...East Papua New Guinea"

and

"Secondary location where event tend to occur but are not
as large or as likely . MB>=4.8 considered likely in next
10 days.

....New Britain"

And from Kamchatka:

"The most likely events of M>=5 in the next 10 days on the
basis of history and far-field triggering theory appear to be:

Papua, ... New Guinea"

and

"59-61 degrees: ... Solomon Isl./New Britain/Papua"

TIDAL TRIGGERING

The New Britain/Solomon Islands had been identified in yesterday's
report (October 30, 2001) as an area where seismicity is statistically
correlated with this day of the lunar month. The region has shown a
26% rate increase in events of Mb>=4 on this day of the lunar cycle
over the past 100 years. This is a highly significant (at 0.03 level)
increase in seismicity. That report had given the following statistics
for the area for tidal triggering in the region today (October 31, 2001):

"Region Magnitude range %change z-value Significance level

...
Solomon Islands MB>=4.0 26 2.6 0.03"

SOLAR/GEOMAGNETICS EFFECTS:

The earthquake may have been immediately triggered effects from an
M-Class solar flare which occurred during hour prior to the earthquake.
SEC gives the flare the following parameters:

Flare # START MAX END CLASS

9180 + 0734 0809 0819 M3.2

This is the largest observed flare since an M6.5 on October 22 and
an M3.6 on October 28.

The area was also under a seismic watch for larger events due
to the CME and resulting geomagnetic storm of October 28. A special
warning had been issued on that watch which stated (on Oct. 28):

"The CME arrival was followed quickly by a strong sudden commencement
geomagnetic storm. The storm started at 03:21 UT. Anti-solar areas
are within 20 degrees longitude of 50W; subsolar regions within
20 degrees of 130E. This includes most of the western Pacific
region and the eastern Caribbean Sea. These areas will be under
seismic watch conditions for the next two days. LARGER ASSOCIATED EVENTS
ARE LIKE TO OCCUR FROM OCTOBER 31-NOVEMBER 2" [emphasis added]

This watch/warning was repeated in the daily report from October 28, 2001.

This epicenter lies with 20 degrees longitude of 130 E and therefore
was subject to this seismic watch. New Britain also lies near the
geomagnetic equator, an area where delayed triggering effects from
geomagnetic storms are expected to be enhanced due to the equatorial
electrojets.

The combination of tidal, pulse, geomagnetic and far-field triggering
was probably sufficient to trigger this large earthquake.

Seismicity is expected to increase in areas where seismic energy
from the great shocks is concentrated due to internal reflections
and refractions of waves off internal boundaries. Following are the
locations and distances where this is expected to occur. Triggered
activity in these regions appears likely from 31 October through
10 November. Maximum event size for these regions is expected to
increase by 0.8 magnitude units in this period.

0-5 degrees: Regional triggering- Bismarck Sea, New Britain, New Ireland,
eastern Papua New Guinea, Solomon Islands, Admiralty Islands.
9-10 degrees: West Irian (about 140E), Solomon Islands (about 160E)
17-19 degrees: Santa Cruz Isl, Vanuatu (about 15-16S), Ceram, Guam
34-36 degrees: So. of Bali/Java, Luzon, Philippines, Ryukyu Isl.
SE of Honshu (around 30-32N 141E), Samoa/No. Tonga Islands
43-45 degrees: South of Sumatera (about 5-7S, 103-105E), North of Tokyo
E. Coast of Honshu (36-38N, 140-142E), most of North and South
Island, New Zealand,
59-61 degrees: Andaman Is., Myanmar, Kamchatka, Central Aleutians,
Hawaii
71-73 degrees: Nepal, Alaska Peninsula,
103-107 degrees***: Central, eastern Turkey, Caucasus, Michoacan/Jalisco
Mexico, Central Plains, U.S.
142-146 degrees: Virgin Island, Azores, Puerto Rico
176-180 degrees: Central Mid-Atlantic Ridge (Seismic area 5N 30W-32W)

***: The strongest triggering is always expected to be along the
shadow zone boundary between 103-107 degrees from the epicenter.

Historical following quakes after large events in the Guam region:

MAIN MAR 4 1905 4.0S 149.0E 60 7.1
MAIN MAR 4 1905 4.0S 149.0E 60 7.2

AFTEREVENTS

Mar 04 43N 72W M VI New York State
Mar 05 33N 80W Ml 2.7 South Carolina
Mar 13 45N 87W Ml 4.3 North of Chicago, ILL
Mar 14 40N 76E M 6.2 Xinjiang, China

MAIN MAY 18 1905 4.0S 149.0E 60 7.5

AFTEREVENTS

May 22 0N 79W M 6.2 Ecuador
May 30 46N 16E Ml 5.2 Austria
Jun 01 42N 20E M 6.6 No. Greece/Bulgaria/Albania

MAIN AUG 26 1906 4.0S 149.0E 60 7.4

AFTEREVENTS

Aug 28 44N 19E Ml 4.0 Austria/Hungary
Aug 29 42N 18E Ml 5.2 Albania
Aug 39 21S 70W M 7.2 Northern Chile
Aug 31 27N 97E M 7.0 Southern China
Sep 07 38N 87W M 3.8 Indiana/Kentucky
Sep 07 34N 141E M 7.1 Off E. Coast Honshu

MAIN SEP 14 1906 6.0S 150.0E 0 8.4
MAIN SEP 17 1906 4.0S 149.0E 60 7.1

AFTEREVENTS

Sep 17 41N 20E Ml 4.4 Northern Greece/Albania
Sep 20 45N 18E Ml 4.7 Austria/Hungary
Sep 28 40N 42E M 6.2 Easatern Turkey
Sep 28 2S 79E M 7.9 Ecuador

MAIN OCT 2 1906 4.0S 149.0E 60 7.7

AFTEREVENTS

Oct 02 44N 18E Ml 4.7 Austria/Hungary
Oct 04 37N 68E M 5.7 Afghanistan
Oct 08 53N 155E M 7.0 Kamchatka
Oct 11 40N 140E Ml 5.6 So. of Hokkaido, Japan
Oct 13 39N 76W Ml 2.7 No. Virginia
Oct 12 34N 107E Ml III New Mexico
Oct 16 46N 27E M 5.5 Romania
Oct 18 19N 121E M 7.3 Taiwan
Oct 20 41N 43 M 5.4 Eastern Turkey

MAIN SEP 7 1910 6.0S 151.0E 80 7.3

AFTEREVENTS

Sep 09 51N 179W M 7.3 Central Aleutians
Sep 12 33N 80W Ml 2.7 So. Carolina
Sep 24 17N 96W M 7.1 Oaxaca Mexico

MAIN NOV 2 1923 4.5S 151.5E 50 7.2
MAIN NOV 3 1923 5.0S 152.0E 60 7.2

AFTEREVENTS

Nov 03 19N 73W M 6.0 No. of Haiti
Nov 03 30N 131E M 6.8 Kyushu, Japan (swarm including 7.1 on 11-5)
Nov 04 36N 139E M 6.3 Off E. Coast Honshu
Nov 06 33N 116E M 5.0 Anza, So. California
Nov 07 38S 73W M 6.3 Southern Chile
Nov 07 33N 116E M 6.3 Anza, So. California
Nov 11 40N 90W Ml 4.2 SW of Chicago, Ill
Nov 16 53N 133W Ms 5.0 Queen Charlotte Isl. B.C.
Nov 17 36N 141E Ms 6.3 Off E Coast, Honshu

MAIN JUN 11 1930 5.5S 150.0E 60 7.1

AFTEREVENTS

Jun 11 25N 94E M 5.0 Myanmar
Jun 12 19N 155W Ml 5.0 Hawaii
Jun 12 43N 111W Ml 5.8 Jackson Lake area, Wyoming
Jun 15 46S 116W Ml 6.3 So. East Pacific Rise
Jun 26 19N 64W M 6.3 Virgin Islands

MAIN FEB 28 1934 5.0S 150.0E 60 7.2

AFTEREVENTS

Mar 01 7S 148E M 6.5 Papua New Guinea
Mar 01 40S 71W M 7.1 So. Chile
Mar 02 33N 116E Ml 4.5 Southern California (swarm in Anza area)
Mar 03 34N 118E Ml 3.5 So. California (So. of L.A.)
Mar 04 16S 168E M 6.3 Vanuatu Islands
Mar 04 56N 164E M 6.3 Komandorsky Islands
Mar 05 40S 175E Ms 7.5 North Island N.Z. (near Wellington)
Mar 07 13N 87W Ms 6.3 El Salvador area
Mar 12 41N 113W Ms 6.6 Utah
Mar 13 11S 164E Ms 6.8 Santa Cruz Islands

MAIN DEC 27 1945 6.0S 151.0E 40 7.0
MAIN DEC 28 1945 6.0S 150.0E 60 7.8

AFTEREVENTS

Dec 28 44N 71W Ml 2.3 Eastern New York
Jan 05 15N 91W M 6.0 Guatemala/Chiapas border
Jan 05 16S 167E M 7.3 Central Vanuatu Islands
Jan 08 33N 116W Ml 5.4 Southern California (Anza)
Jan 10 44N 130E Ml 7.2 Sea of Japan
Jan 13 59N 147W M 7.2 South of Alaska
Jan 13 37N 118W Ml 4.7 Mammoth Lakes, California

MAIN MAR 16 1949 5.5S 151.0E 60 7.0
MAIN MAR 17 1949 5.5S 151.0E 60 7.0

AFTEREVENTS

Mar 19 31N 131E M 6.0 Kyushu
Mar 17 33N 116W Ml 3.7 Southern California (Anza)
Mar 20 35N 117E Ml 4.4 China Lake, California
Mar 24 42N 126W M 6.2 Off Coast No. California
Mar 25 42N 126W M 6.2 Off Coast No. California
Mar 27 3N 127W M 7.0 Molucca
Mar 30 49N 128W Ml 4.8 Vancouver, B.C.
Mar 22 44N 129W Ms 6.8 OFf Coast of Oregon

MAIN NOV 17 1964 5.7S 150.7E 45 7.6
MAIN NOV 19 1964 6.0S 150.7E 45 7.0

AFTEREVENTS

Nov 17 44N 111W Ml 3.9 Yellowstone
Nov 17 33N 116W Ml 4.5 Southern California (Anza)
Nov 17 41N 74W Ml 4.3 New York City
Nov 18 20S 174W Ml 6.0 Tonga/Samoa
Nov 20 5S 145E M 6.0 Papua New Guinea
Nov 20 44N 150E Ml 5.5 Kuril Islands
Nov 24 6S 107W Ms 6.0 South of Sumatera
Nov 24 13N 124E Ms 6.7 Luzon, Philippines
Nov 25 4S 122E Ms 6.2 Banda Sea
Nov 26 24S 124E Ms 6.4 Taiwan

MAIN MAY 30 1984 4.7S 151.8E 169 7.1

AFTEREVENTS

Jun 06 4S 125E Ms 5.9 Banda Sea
Jun 07 5S 104E Ms 6.0 South of Sumatera
Jun 11 30S 71W Ml 6.3 Central Chile

MAIN MAY 10 1985 5.5S 151.0E 27 7.3

AFTEREVENTS

May 10 34N 121W Ml 3.8 Southern California (triggered by P-arrival)
May 10 43N 20E Ml 5.2 Yugoslavia
May 11 36N 120E Ml 4.0 Coalinga, Central California
May 11 37N 141E MB 5.5 Off E. Coast Honshu
May 12 16N 120E MB 5.4 Luzon, Philippines
May 13 33N 133E MB 5.7 Shikoku, Japan
May 14 10S 41E Ms 6.4 Madagascar
May 15 56S 25W Ms 6.4 So. Sndwich Islands
May 16 29S 77E Ms 6.1 Mid-Indian Rise
May 19 30S 71W Ms 6.0 Central Chile
May 20 35N 87E Ms 6.0 Tibet

MAIN OCT 16 1987 6.0S 149.1E 24 7.1

AFTEREVENTS

Oct 19 40N 111W Ml 3.9 Utah
Oct 22 37N 122W Ml 4.4 Central California
Oct 25 5N 36E M 6.2 Ethiopia
Oct 25 2S 138E MS 7.0 West Irian
Oct 26 41N 113W Ml 4.8 Utah

MAIN SEP 28 1991 5.8S 150.9E 28 7.1

AFTEREVENTS

Sep 30 20S 178W M 6.3 Tonga/Fiji
Sep 30 43N 71W Ml 2.7 Southern New England
Oct 03 36N 90W Ml 3.0 New Madrid
Oct 03 17S 167E M 5.7 So. Vanuatu Isl.
Oct 05 46N 13E Ml 4.5 Austria

MAIN APR 5 1999 5.5S 149.5E 150 7.4

Apr 05 24N 94E Ml 5.6 Myanmarka
Apr 06 39N 38E M 5.1 Central Turkey
Apr 06 41N 108E Ml 4.3 Wyoming (Rock Springs area)
Apr 06 24N 48W MW 5.9 Northern Mid-Atlantic ridge
Apr 06 6S 147E MW 6.4 Papua New Guinea
Apr 07 33N 116E Ml 4.0 Southern California
Apr 08 43N 130E Ms 7.1 Russia/China border
Apr 09 42S 84E Ms 5.6 Southeast Indian Rise
Apr 09 26S 178E Ms 6.1 South of Fiji Islands
Apr 12 20S 168E Ms 5.7 Loyalty Islands
Apr 13 21S 176W Ms 6.8 Fiji/Tonga area
Apr 13 53N 163W Ms 5.1 Alaska Peninsula/Unimak
Apr 17 19N 155W Ms 5.6 Hawaii

MAIN MAY 10 1999 5.1S 150.8E 138 7.1
MAIN MAY 16 1999 4.8S 152.5E 74 7.1

AFTEREVENTS

May 10 36S 110W Mw 6.0 South east Pacific Rise followed by swarm
May 11 54N 165W M 5.4 Fox Islands
May 12 43N 143E Mw 6.2 Hokkaido, Japan
May 14 34N 116W Ml 4.9 Southern California (Landers area)
May 14 3S 130E Ml 5.5 Seram
May 15 4S 102E Ml 5.2 South of Sumatera
May 15 37N 118W MW 5.6 Mammoth Lakes, California
May 16 3S 138E MW 6.2 Irian Jaya
May 18 39S 175E MW 5.8 North Island, New Zealand
May 21 60S 24W MW 5.7 South Sandwich Islands
May 22 20S 169E MW 6.0 Vanuatu Islands
May 27 15S 120E MW 5.5 Luzon, Philippines
May 27 58N 137W MW 5.6 SE Alaska

Summary of far-field events following New Britain mainshocks:

In general, the events of Mb>=5 tend to fall in the areas
described by the listing of far-field events expected above
from distance considerations.

The most likely events of Mw>=6 in the next 10 days appear to be:

Central Vanuatu Islands
Off East Coast of Honshu, or Hokkaido, Japan
Ecuador
Papua New Guinea/West Irian
Banda Sea
Samoa/Tonga/Foko
Central Chile

The most likely events of M>=5 in the next 10 days on the
basis of history and far-field triggering theory appear to be:

South of Sumatera/Java
Luzon, Philippines
Myanmar
Shikoku/Kyushu Japan
Taiwan
Austria/Hungary/Yugoslavia area
Central Aleutians
South of Alaska
Virgin Islands to Haiti

Secondary location where event tend to occur but are not
as large or as likely . MB>=4.8 considered likely in next
10 days.

South Sandwich Islands
North Island, New Zealand
Central Turkey
Southern Chile
Santa Cruz Islands

Areas of U.S. and Canada where triggering may occur (Ml>=4.0)

Hawaii
Central Andreanoff Islands
Off the Coast of California and Oregon
Southern California - esp. in Anza and area to south
Utah around 41N 111-113W
Vancouver Island
SE Alaska

Areas of U.S. and Canada where triggering may occur (Ml>=3 or unusual events)

New England/esp. Eastern New York State
Area surrounding Chicago Ill./ great plains states
Indiana/Kentucky/Virginia

Unusual events may occur in

Madagascar
Ethiopia

There is a strong relationship between New Britain events and
succeeding earthquake in southern California especially in the
area of Anza to the Salton Sea. This is probably because wave
fronts from New Britain arrive approximately parallel to the
San Andreas in this region, promoting larger events. This area
should remain active for several week. A larger event in this
area often occurs 28-33 or 43-46 days after the event in New
Britain, so the danger is not yet over.