VIRGIN ISLANDS EARTHQUAKE (MW6.0) COINCIDES WITH 1ST M-CLASS FLARE SINCE OCT 9

SUMMARY

The Caribbean region continued active today with a Mw 6.0 earthquake
in the Virgin Islands. This was followed about 9 hours later by a Mb 4.6
in the Mona Passage near Puerto Rico. The Mw 6.0 is the largest earthquake
in the Virgin Islands region since a Ms 6.3 on October 12, 1961 more
than 40 years ago. For further details see yesterday's report.
The Virgin Islands earthquake occurred at the end of a M1.1 class
solar flare which occurred from 11:16 UT to 11:28 UT - the Virgin
Islands earthquake occurred at 11:29 UT. This was the first M- or
X-class solar flare since an M1.4 flare which began at 10:46 UT on
October 9, more than 8 days ago.
Since there may be a relation between radio EM from large solar
flares and earthquake occurrence, this coincidence should not
automatically be considered non-causal. It is difficult to confirm
an relationship, however, since all but one of the events in this
region have occurred before available solar flare records begin.
Checking for geomagnetic relations, however, all events of Mb>=5.5
in the Virgin Islands have occurred either during a geomagnetic
storm (1927, 1935, 1955, 1985) or three to four days before such
a storm (1930, 1959, 1961, 1965). This delay is important as it could
indicate a relation with strong flares which typically impact the
earth with a geomagnetic storm 3-5 days later as the solar wind
from the solar flare arrives in the earth's vicinity.
Also of some interest in terms of triggering, this is the latest
in the year that any event of Ml>=5.5 has occurred within 100 km
of today's earthquake, however ALL have occurred during the months
from May to October, typically the strong tropical storm season
in the Caribbean.

GLOBAL

It was a moderately active day in terms of global seismicity.
In Europe, the most interesting and largest event was a Mb 4.3/Ms 3.7
in Romania. The last light earthquake in Romania had occurred on
August 1, 2001.
One other earthquake of Mb>=5 was listed by NEIS a Mb 5.4 in
Argentina. Also in the western Hemisphere a Mb 4.3 was recorded
in Northern Colombia. The Fiji/Tonga region continued active with events
of Mb 4.1 and 4.8.
Activity also continued, but at a reduced rate on the mid-ocean
ridge systems witha Mb 4.2 in the Northern Mid-Atlantic Ridge.
Southern Indonesia, near the antipode of the Virgin Islands
also saw activity today - in the Flores/Timor Islands (ML 4.9. 5.4)
and south of Sumatera (Ml 5.4). An Mj 4.4 was registered off the
east Coast of Honshu, Japan near Toyko this evening.

U.S./CANADA

The largest event in the U.S./Canada region today occurred in Alaska
as a Ml 3.4 in the Kodiak, AL region. No events of Ml>=3 were recorded
in Hawaii or Canada today.
Southern California began to show signs of renewed activity today
after very light activity from the 11th to the 16th of October. SCSN
recorded 9 earthquakes of Ml>=2 on UT day 17 October. The largest was
a Ml 3.3 in the Hector Mine aftershock zone which was followed by
two aftershocks of Ml 2.1 and 2.3. Other events were recorded as
occurring near Catalina Island (Ml 2.0); Anza (Ml 2.8); Wheeler Ridge
(Ml 2.1); Julian (Ml 2.3); Isla Vista (Ml 2.4) and Ocotillo (Ml 2.3).
Last night a Ml 2.5 occurred near San Clemente.
In Northern California, the only region having events of Ml>=2 was the
Geysers which experienced two events of Ml 2.4 and 2.1.
No earthquakes of Ml>=2 were reported outside Alaska or California
today in the U.S/Canada region.

NEW ZEALAND

The IGNS on-line seismometer showed little activity other than
a few minor local events. NEIS reported a Mb 4.4 in the Kermadec
Islands on 15 October in the region.

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 relatively quiet conditions
today. One minor flare was registered at M1.1 class. This flare
lasted from about 11:16 to 11:29 UT. At the end of the flare
the largest event of the day, a Mw 6.0 in the Virgin Islands
occurred. The Virgin Islands would have been at 7:29 a.m. Local
time at the time of the flare, not ideal for triggering effects,
but perhaps given the Ms 5.7 at this location, enough to trigger
the occurrence of this second event.
The parameters of this flare were:

Flare # START MAX END CLASS

3800 + 1116 1123 1128 M1.1

For general space weather conditions see:
http://sec.noaa.gov/today.html
For Solar flare data see:
http://sec.noaa.gov/ftpdir/indices/events/20011017events.txt

TROPICAL STORMS

No tropical storms were affecting Asia or North America today.

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.

October 18 is two 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

Idaho MB>=1.0 15 1.9 0.05
New Zealand MB>=4.0 17 2.0 0.05
NW Europe MB>=4.0 9 2.0 0.05
So South America MB>=4.0 36 4.0 0.01
Central California MB>=2.0 7 1.9 0.05
Mammoth Lakes MB>=2.0 48 2.4 0.04
Mammoth Lakes MB>=3.0 26 2.9 0.01

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
Global MB>=6.0 -14 -2.3 0.04
Siberia MB>=4.0 -45 -2.4 0.04

EARTHQUAKE LISTINGS

GLOBAL

CARIBBEAN

O: 17Oct2001 11:29:09 19.3N 64.9W MW=6.0 NEIS VIRGIN ISLANDS

O: 17Oct2001 20:45:58 18.4N 67.4W MB=4.6 NEIS MONA PASSAGE

NEW ZEALAND

O: 15Oct2001 23:12:01 32.3S 179.6E MB=4.3 NEIS SOUTH OF KERMADEC ISLANDS

SOUTH PACIFIC ISLANDS

O: 17Oct2001 20:25:14 20.7S 179.4W MB=4.8 NEIS FIJI ISLANDS REGION

O: 17Oct2001 20:18:32 16.5S 177.7W MB=4.1 NEIS FIJI ISLANDS REGION

O: 16Oct2001 19:24:47 24.0S 179.9W MB=3.5 NEIS SOUTH OF FIJI ISLANDS

O: 14Oct2001 15:12:44 19.5S 173.6W MB=4.2 NEIS TONGA ISLANDS

O: 14Oct2001 13:55:54 18.6S 177.7W MB=4.0 NEIS FIJI ISLANDS REGION

O: 16Oct2001 22:29:30 18.9S 177.5W MB=3.7 NEIS FIJI ISLANDS REGION

ASIA

O: 16Oct2001 16:37:06 48.3N 155.3E MB=4.6 NEIS KURIL ISLANDS

O: 16Oct2001 19:52:38 4.2N 126.5E MB=5.2 NEIS TALAUD ISLANDS, INDONESIA
O: 16OCT2001 19:52:40 4.4N 126.9E Ms=4.5 GSSC TALAUD ISLANDS, INDONESIA

O: 17OCT2001 12:52:32 9.3S 123.5E MS=4.9 GSSC TIMOR, INDONESIA, REG
O: 17OCT2001 12:52:40 8.7S 123.8E SR=5.3 AEIC1 PANTAIMAKASAR, INDONESIA

O: 17OCT2001 04:54:20 7.6S 121.1E SR=5.0 AEIC1 N BAJAWA, INDONESIA

O: 17OCT2001 04:04:20 7.9S 107.0E SR=5.4 AEIC1 PELABUHAN RATU, INDONESIA

O: 16Oct2001 17:17:55 2.0N 99.3E MB=4.7 NEIS N SUMATERA, INDONESIA
O: 16oct2001 17:17:55 02.0N 099.3E Mb=4.7 ASC W of Airbangis Sumatera

O: 16oct2001 04:46:29 00.1S 098.5E Mb=4.7 ASC ESE of Balari N. Sumatera

O: 17OCT2001 21:30 36.1N 139.8E Mj=4.4 NIED SW_IBARAKI_PREF, JAPAN

O: 14OCT2001 16:53 33.8N 135.4E Mj=4.4 NIED CENTRAL_WAKAYAMA_PREF, JAPAN

O: 13OCT2001 20:02 40.0N 143.0E Mj=4.2 NIED FAR_E_OFF_SANRIKU, JAPAN

O: 13OCT2001 20:27 29.1N 130.6E Mj=3.9 NIED NEAR_AMAMI-OSHIMA_ISLAND, JAPAN
O: 13OCT2001 19:15 29.1N 130.6E Mj=3.8 NIED NEAR_AMAMI-OSHIMA_ISLAND, JAPAN

O: 13OCT2001 04:25 33.9N 141.7E Mj=3.7 NIED FAR_SE_OFF_BOSO_PEN, JAPAN

O: 15Oct2001 17:40 13.7N 122.6E Ms=3.1 PHILV Luzon, Philippines

O: 14Oct2001 13:51:00 28.9N 103.8E ML>4.0 NEIS SICHUAN, CHINA

O: 14Oct2001 02:19:44 52.8N 161.1E MB=4.5 NEIS OFF E COAST OF KAMCHATKA

O: 16Oct2001 17:33:35 30.2N 142.1E MB=4.4 NEIS SOUTHEAST OF HONSHU, JAPAN

CENTRAL/SOUTH AMERICA

O: 16Oct2001 06:48:55 13.1N 89.8W MB=4.2 NEIS EL SALVADOR

O: 16OCT2001 06:49:05 13.5N 88.7W MC=4.6 CASC OFF COAST OF C.A.
O: 15OCT2001 09:12:55 12.6N 88.0W MC=4.0 CASC OFF COAST OF C.A.
O: 15OCT2001 00:22:33 12.8N 88.5W MC=4.5 CASC OFF COAST OF C.A.

O: 16OCT2001 08:30:21 10.3N 86.0W MC=3.8 CASC COSTA RICA, C.A.
O: 15OCT2001 01:43:26 11.7N 86.5W MC=3.9 CASC NICARAGUA, C.A.

O: 16Oct2001 12:27:09 21.4S 66.6W MB=4.2 NEIS SOUTHERN BOLIVIA
O: 16Oct2001 11:58:44 21.4S 67.3W MB=4.1 NEIS CHILE-BOLIVIA BORDER REG

O: 16OCT2001 06:47:23 15.4N 96.6W MC=4.8 CASC OAXACA, MEXICO

O: 16OCT2001 11:05:37 9.9N 84.4W MC=3.8 CASC COSTA RICA, C.A.

O: 17Oct2001 02:34:37 28.3S 68.7W MB=5.3 NEIS LA RIOJA PROV, ARGENTINA
O: 17OCT2001 02:34:40 28.4S 70.1W ML=5.3 DGF ENE of VALLENAR, CHILE

O: 16Oct2001 17:28:19 15.1S 71.7W MB=4.2 NEIS SOUTHERN PERU

O: 17Oct2001 04:49:54 7.2N 72.6W MB=4.3 NEIS NORTHERN COLOMBIA

EUROPE

O: 17OCT2001 13:01:35 46.0N 26.9E Ms=3.7 GSSC ROMANIA
O: 17OCT2001 13:01:32 45.9N 26.7E Mb=4.3 MIX ROMANIA

O: 15OCT2001 00:27:25 34.6N 33.1E ML=2.5 ISR Cyprus

O: 17OCT2001 01:39:55 39.0N 26.2E ML=3.0 KAN AEGEAN SEA TURKEY
O: 17OCT2001 20:53:46 39.5N 26.4E ML=3.2 KAN AYVACIK, TURKEY
O: 17OCT2001 08:56:20 38.8N 26.2E ML=3.7 KAN AEGEAN SEA TURKEY
O: 17OCT2001 05:27:13 39.9N 26.8E ML=3.3 KAN BAYRAMYC, TURKEY

O: 16OCT2001 14:02:14 38.2N 42.6E ML=3.1 KAN HYZAN, TURKEY

O: 17OCT2001 02:27:15 39.9N 26.9E ML=3.9 NOA AEGEAN SEA, GREECE

O: 17OCT2001 05:02:37 45.2N 6.4E Ml=2.5 LDG FRANCE
O: 17OCT2001 04:57:43 45.2N 6.5E Ml=2.7 LDG FRANCE
O: 17OCT2001 04:57:43 45.1N 6.4E ML=2.6 STR SSE SAINT-JEAN-DE-MAURIEN
O: 17OCT2001 05:02:38 45.1N 6.3E ML=2.4 STR S SAINT-JEAN-DE-MAURIENNE

OCEANIA

O: 16Oct2001 05:43:31 47.9N 27.7W MB=4.8 NEIS N MID-ATLANTIC RIDGE

O: 14Oct2001 17:24:49 22.8S 69.7E MB=4.7 NEIS MID-INDIAN RIDGE

O: 17Oct2001 03:56:52 27.1N 45.0W MB=4.2 NEIS N MID-ATLANTIC RIDGE

U.S/CANADA

CALIFORNIA/NEVADA

O: 17OCT2001 6:19:23 34.6N 116.2W ML=2.1 SCSN SW of Ludlow, CA
O: 17OCT2001 6:21:49 34.6N 116.2W ML=2.3 SCSN SW of Ludlow, CA
O: 17OCT2001 5:53:58 34.6N 116.2W ML=3.3 SCSN SW of Ludlow, CA
O: 17Oct2001 05:53:58 34.6N 116.2W ML=3.3 NEIS SOUTHERN CALIFORNIA

O: 17OCT2001 13:01:29 32.9N 116.6W ML=2.3 SCSN S of Julian, CA

O: 16OCT2001 23:13:38 33.0N 117.8W ML=2.5 SCSN WSW of Oceanside, CA

O: 16OCT2001 20:53:59 33.5N 116.6W ML=1.9 SCSN SSE of Anza, CA
O: 17OCT2001 20:02:51 33.5N 116.5W ML=2.8 SCSN ESE of Anza, CA

O: 17OCT2001 4:35:58 34.0N 117.2W ML=1.7 SCSN N of Loma Linda, CA

O: 16OCT2001 22:34:46 34.4N 118.4W ML=1.5 SCSN ENE of Newhall, CA

O: 17OCT2001 7:01:03 34.4N 119.9W ML=2.4 SCSN WNW of Isla Vista, CA

O: 17OCT2001 3:45:46 36.0N 120.5W ML=1.8 SCSN NW of Parkfield, CA
O: 17OCT2001 17:57:44 36.3N 120.7W ML=1.5 NCSN SSW of New Idria, CA
O: 17OCT2001 16:04:23 36.5N 120.7W ML=1.2 NCSN NNW of New Idria, CA

O: 17OCT2001 1:37:09 38.2N 116.9W ML=2.0 NCSN ENE of Tonopah, NV

O: 17OCT2001 13:33:27 38.8N 122.7W ML=2.1 NCSN ESE of The Geysers, CA
O: 18OCT2001 1:53:22 38.8N 122.8W ML=2.4 NCSN E of The Geysers, CA

O: 17OCT2001 05:16:22 31.8N 115.9W ML=2.3 SCSN S of Ocotillo, CA

O: 17OCT2001 19:09:31 35.1N 119.0W MC=2.1 SCSN NW of Wheeler Ridge, CA

O: 17OCT2001 23:04:37 33.4N 118.2W ML=2.0 SCSN NE of Avalon, Catalina Is, CA

PACIFIC NORTHWEST/CANADA

O: 16Oct2001 05:13:51 43.6N 127.5W ML>3.5 NEIS OFF COAST OF OREGON

O: 17OCT2001 17:10:52 47.8N 121.9W ML=1.9 PNSN SE of Monroe, WA

ROCKY MOUNTAIN AREA

O: 18OCT2001 00:37:33 45.7N 112.1W MD=0.7 MBMG MONTANA
O: 17OCT2001 09:02:49 45.7N 112.1W MD=2.1 MBMG MONTANA
O: 16OCT2001 13:51:55 45.7N 112.1W MD=0.7 MBMG MONTANA
O: 16OCT2001 12:37:28 45.6N 112.1W MD=0.9 MBMG MONTANA
O: 16OCT2001 12:32:45 45.7N 112.1W MD=2.2 MBMG MONTANA

O: 18OCT2001 01:12:35 44.7N 111.2W MD=0.3 MBMG MONTANA
O: 17OCT2001 07:10:29 44.7N 111.0W MD=0.0 MBMG MONTANA
O: 17OCT2001 07:10:29 44.7N 111.0W MD=0.0 MBMG MONTANA
O: 17OCT2001 02:08:32 44.7N 111.0W MD=0.1 MBMG MONTANA
O: 16OCT2001 22:35:42 44.7N 111.0W MD=0.0 MBMG MONTANA

O: 16OCT2001 15:53:37 45.8N 113.9W MD=0.0 MBMG MONTANA

O: 16OCT2001 15:52:19 47.5N 114.0W MD=0.0 MBMG MONTANA

O: 16OCT2001 15:50:53 46.5N 113.7W MD=0.0 MBMG MONTANA
O: 16OCT2001 15:44:01 46.8N 113.5W MD=0.0 MBMG MONTANA
O: 16OCT2001 15:25:36 46.6N 113.5W MD=0.4 MBMG MONTANA

O: 16OCT2001 15:05:25 48.0N 112.4W MD=1.8 MBMG MONTANA

O: 16OCT2001 15:02:52 46.5N 113.7W MD=0.0 MBMG MONTANA

O: 16OCT2001 14:57:00 46.4N 112.4W MD=0.9 MBMG MONTANA

O: 15OCT2001 21:30:18 39.0N 113.0W ML=1.9 UUSN SSW of Hinckley, UT

ALASKA

O: 18OCT2001 00:23:26 57.0N 153.3W ML=3.5 AEIC SSW of Kodiak, Alaska