VOLCANIC EARTHQUAKES/ERUPTIONS FADE AWAY

SUMMARY

The swarms of earthquakes which began within an hour of the Honshu
Mw 6.4 mainshock on Dec. 2 at Yellowstone, Mt. Hood, Mammoth Lakes, CA;
Kick-'em-Jenny volcano, West Indies and Mt. St. Helen's. An increase
in seismicity was also observed from Dec. 2 to Dec. 4 at Iceland
and in the vicinity of Mauna Loa, Hawaii.
All of these volcanically-related earthquake swarms which have
been reported on in the past three days here, are now returning
to background seismicity, including the very strong swarm at
Yellowstone, WY.

The following table shows the number of events recorded in each region
per 24-hour period following the Honshu earthquake which occurred at 13:04 UT
on Dec 6 in these various regions. The number listed under the hours
in the row assigned to a particular center is the number of recorded
earthquakes in that region within the period of time listed at the
top from the Honshu earthquake. For example in the period -24 to 0 hours
before Honshu (the prior day) 14 events were located in the Yellowstone
Park area, whereas during the 0-24 hours after Honshu 74 such events
were located and during the 3rd day the number of recorded events
at Yellowston had dropped to 46.

TIME FROM HONSHU -48to-24hrs -24to0hrs. 0-24hrs 24-48hrs 48-72hrs 73-96hrs
REGION
Yellowstone 3 14 74 52 46 11

Mammoth Lakes 0 1 26 16 4 7

The Geysers 5 3 7 11 3 7

Mt. Hood OR 0 0 6 1 3 1

Mt. St. Helens 0 0 1 3 1 4

Iceland 8 9 17 14 12 14
(Ml>=1)
Kick-'em-Jenny 0 0 3 200 400 <10

Each of these areas shows the same general pattern - background seismicity
up to the Honshu earthquake followed be strong activity in the first
two days following the Honshu event and declining activity back to near
background during the next two days. This is the same pattern that
Hill et al. described in 1992 following the Lander's earthquake. The
difference here is that these centers of activity are spread around
the world and the Honshu event was much smaller (Mw 6.5 vs Mw 7.5
for Landers).
A contributing factor may be the strong geomagnetic storms that occurred
at the end of November. Strong volcanic activity often appears to
follow such storms between 4 and 7 days after the storm occurs. In
this case, that volcanism would have been expected on Dec 1-3. The
Honshu event occurred in the middle of this expected volcanism time
window and may only be the immediate trigger for these earthquake
swarms.

GLOBAL

Global seismicity today was relatively quiet. There were no events
of Mb>=5 recorded since last report. Additional events were recorded
on Mid-Ocean ridges in the Reykjanes Ridge region (Mb 4.3) (North Atlantic
Ocean) and the area southwest of Africa (Mb 4.3). On December 5 the
ridge systems were especially active with seismicity recorded in the
Southern East Pacific Rise (Mb 4.4); Southwest of Africa (Mb 5.5, 4.3)
the Greenland Sea (Mb 4.9) and the Reykjanes Ridge (Mb 4.3).

Global activity also continued near 45 degrees from the Honshu mainshock
of Dec. 2 (Mw 6.5). Additional events in this FFA ring were listed today
in the Solomon Islands (Mb 4.3); New Britain (Mb 5.5) an Sulawesi (Mb 5.0).

U.S./CANADA

The region near San Francisco, CA at 72 degrees from Honshu was the
most active area in the U.S./Canada region today. Earthquakes of
Ml 3.2 and 2.9 occurred near Morgan Hill and Napa, Central California
today. The Ml 2.9 near Napa was followed by a Ml 1.3 aftershock S.
of Portola Valley this evening. A Ml 2.2 also occurred near San Juan
Bautista this about the same time as the Portola Valley quake.
This area has been surprisingly quiet over the past week.
The increase in seismicity throughout the region of Central California
today suggest some sort of regional triggering effect in addition to
FFA effects from Honshu. We can only speculate what this might be,
but a strong geomagnetic storm at this time might help release significant
energy in the region under these conditions.
Smaller earthquakes also occurred in the same general area of
California at Gustine (Ml 1.7) and Morgan Hill (aftershock Ml 1.5). In
Southern California two earthquake of Ml 2.6 and 2.4 occurred SE of
Taft (NW of Los Angeles).
Other events in the California/Nevada region of Ml>=2 were listed
in the Coso Junction area (Ml 2.6, 2.0); Anza (Ml 2.0; Lake Isabella (Ml 2.3);
Indio (Ml 2.5); the Geysers (Ml 2.2) and Mammoth Lakes (Ml 2.6).
Two earthquakes of Ml>=2 were identified as occurring yesterday
(Dec. 5) in the eastern U.S/Canada - in eastern Tennessee (Ml 2.5)
and in the Charlevoix Fault zone, Quebec (Ml 2.5).
The swarm of microearthquakes in the Yellowstone Park area declined
to near background levels today. No new centers of activity have
appeared in the Rocky Mountains since this swarm began.
In the northwest U.S and western Canada a Ml 2.4 was recorded near
Eatonville, WA this afternoon. No other events of Ml>=2 were
listed in earthquake catalogs today.
Seismicity in Alaska and Hawaii was also relatively quiet, as no
events of Ml>=3 were found in either state today.

NEW ZEALAND

Three red-line events were visible on the Cannon Point (IGNS)
seismogram during the past 24 hours. IGNS has located one of these
events as a relatively minor Ml 3.2 NW of Paraparaumu. The other
two such events were probably close to this one.

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 was
one M-class solar flare observed with the following parameters:

Flare # START MAX END CLASS

9620 + 0813 0826 0839 M1.0

The only seismic event known to have been associated with this flare was
a Ml 2.4 which occurred in Austria at 08:37 UT.

For general space weather conditions see:
http://sec.noaa.gov/today.html
For Solar flare data see:
http://sec.noaa.gov/ftpdir/indices/events/20011206events.txt

TROPICAL STORMS

TROPICAL STORM KAJIKI

No tropical storms were currently active in the North Atlantic,
east Pacific or Indian Oceans today.

Tropical Storm Kajiki is currently located over the west-central
Philippine Islands. Associated seismicity in Luzon and Samar is still
possible in the next 2 days.

For more details see:

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

A Satellite View of Kajik can be found at:

http://www.osei.noaa.gov/Events/Current/TRCkajiki339_GML.jpg

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.

December 07 is the twenty-third 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

Caribbean MB>=4.0 22 2.4 0.04
Central California MB>=0.0 32 2.1 0.05
Central California MB>=2.0 11 2.9 0.02
Central California MB>=3.0 23 2.9 0.02
Mammoth Lakes MB>=0.0 56 2.5 0.04
San Andreas MB>=0.0 14 2.4 0.04
San Andreas MB>=3.0 38 2.7 0.02
So Asia MB>=4.0 50 3.6 0.01
Canada MB>=2.0 26 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

No Regions

EARTHQUAKE LISTINGS

GLOBAL

NEW ZEALAND/AUSTRALIA

O: 6Dec2001 08:24 40.8S 174.8E ML=3.2 IGNS NW of Paraparaumu, N.Z.
Note: (IGNS) Probably felt on the Kapiti Coast, because of its extremely
shallow depth.

SOUTH PACIFIC ISLANDS

O: 05Dec2001 19:29:49 6.3S 155.1E MB=4.3 NEIS SOLOMON ISLANDS

O: 05Dec2001 13:49:40 17.8S 167.7E MB=4.7 NEIS VANUATU ISLANDS
Not Forecast

ASIA

O: 05Dec2001 02:35:13 3.6S 129.4E MB=4.7 NEIS SERAM, INDONESIA

O: 05Dec2001 01:22:00 5.6N 126.7E MB=4.2 NEIS MINDANAO, PHILIPPINES

O: 05Dec2001 17:18:58 23.6N 121.7E MB=4.4 NEIS TAIWAN

O: 04DEC2001 05:38 26.6N 128.0E Mj=4.3 NIED NEAR_OKINAWAJIMA_ISLAND, JAPAN
O: 03DEC2001 18:44 27.1N 129.9E Mj=3.6 NIED NEAR_AMAMI-OSHIMA_ISLAND, JAPAN

O: 05DEC2001 20:24:51 1.4S 123.5E M =5.1 GSSC MINAHASSA PENINSULA,

O: 06DEC2001 07:03:12 56.4N 112.5E Ms=3.6 GSSA LAKE BAYKAL, RUSSIA,

CENTRAL/SOUTH AMERICA

O: 06DEC2001 14:12:20 20.2S 69.4W ML>4.0 DGF E of IQUIQUE, CHILE

O: 06DEC2001 14:40:19 15.5S 73.1W MB=4.0 IGP SW of Cotahuasi, Peru (III)

O: 05DEC2001 18:13:33 16.9N 100.1W ML=3.4 SSN COSTA DE GUERRERO , MEXICO
O: 05DEC2001 16:49:23 16.9N 100.2W ML=3.5 SSN COSTA DE GUERRERO , MEXICO

O: 06DEC2001 18:13:18 10.0N 86.3W MC=3.8 CASC COSTA RICA, C.A.

O: 07DEC2001 00:35:41 11.0N 87.0W ML=3.4 SIS NICARAGUA, C.A.

O: 05DEC2001 21:09:31 8.9N 71.2W Mb=3.7 ULA Tulio Febres Cordero, Venezuela

EUROPE/AFRICA/MIDDLE EAST

O: 6DEC2001 5:44:18 40.1N 25.8E ML=3.2 KAN AEGEAN SEA, TURKEY

O: 6DEC2001 5:38:18 40.2N 30.8E ML=3.1 KAN BOLU, TURKEY

O: 6DEC2001 10:36:21 38.7N 43.4E ML=3.2 KAN VAN, TURKEY

O: 05DEC2001 19:26:56 35.7N 26.8E ML=3.7 NOA GREECE

O: 05DEC2001 18:24:13 57.2N 5.4W ML>1.0 BGS GLEN SHEIL,HIGHLAND, ENGLAND

O: 05DEC2001 09:50:50 43.5N 0.5W ML=2.4 STR NNW PAU, FRANCE
O: 05DEC2001 14:28:56 42.9N 0.8W ML=2.3 STR WSW ACCOUS, FRANCE

O: 05DEC2001 21:21:02 44.8N 2.9E Ml=2.4 LDG FRANCE

O: 06DEC2001 13:24:30 39.0N 0.8E Ml=3.3 LDG SPAIN

O: 05DEC2001 16:33:20 63.6N 19.3W ML=3.2 ISO Iceland
O: 05DEC2001 08:39:34 63.6N 19.3W ML=3.2 ISO Iceland

O: 06DEC2001 20:47:25 42.8N 7.2W Ml=2.8 IMP SPAIN

O: 06DEC2001 20:30:25 40.4N 23.9E Ml=3.5 THE GREECE

O: 06DEC2001 17:44:56 44.5N 11.2E Ml=3.3 SED NORTHERN ITALY

OCEANIA

O: 05Dec2001 10:07:29 52.8S 18.7E MB=4.3 NEIS SOUTHWEST OF AFRICA
O: 05Dec2001 07:46:38 52.6S 18.1E MS=5.5 NEIS SOUTHWEST OF AFRICA

O: 05Dec2001 15:29:31 57.7N 33.3W MB=4.3 NEIS REYKJANES RIDGE

U.S/CANADA

CALIFORNIA/NEVADA

O: 6DEC2001 7:17:00 34.9N 119.3W ML=2.4 SCSN SE of Taft, CA
O: 6DEC2001 3:38:12 35.0N 119.3W ML=2.6 SCSN SE of Taft, CA

O: 06DEC2001 16:08:00 37.5N 118.8W ML=2.6 NCSN WSW of Toms Place, CA

O: 06DEC2001 15:26:40 35.8N 118.4W ML=1.8 SCSN N of Lake Isabella, CA

O: 06DEC2001 13:55:17 34.1N 118.4W ML=1.6 SCSN E of Beverly Hills, CA

O: 7DEC2001 2:08:58 36.9N 121.6W ML=2.2 NCSN WNW of San Juan Bautista, CA

O: 06DEC2001 10:41:49 37.2N 121.6W ML=3.2 NCSN N of Morgan Hill, CA
O: 06DEC2001 22:26:54 37.3N 121.6W ML=1.5 NCSN N of Morgan Hill, CA

O: 7DEC2001 1:30:36 38.8N 122.8W ML=2.2 NCSN NNE of The Geysers, CA

O: 7DEC2001 1:02:22 38.3N 122.3W ML=2.9 NCSN SW of Napa, CA

O: 06DEC2001 22:03:59 37.1N 121.2W ML=1.7 NCSN SW of Gustine, CA

O: 06DEC2001 20:18:00 36.0N 117.7W ML=2.6 NCSN E of Coso Junction, CA

O: 07DEC2001 00:58:09 35.6N 118.3W ML=2.3 SCSN ESE of Lake Isabella, CA

O: 07DEC2001 03:00:22 33.9N 116.2W ML=2.5 SCSN N of Indio, CA

PACIFIC NORTHWEST/CANADA

O: 06DEC2001 23:24:08 46.9N 122.4W ML=2.4 PNSN WNW of Eatonville, WA

ROCKY MOUNTAIN AREA

O: 6DEC2001 3:59:34 42.2N 111.5W ML=1.3 UUSN WSW of Paris, ID

O: 06DEC2001 17:51:04 44.7N 110.8W ML=1.1 UUSN W of Norris Junc., WY
O: 06DEC2001 12:46:32 44.6N 110.8W ML=2.3 UUSN ESE of Madison Junc., WY
O: 06DEC2001 9:57:41 44.8N 111.0W ML=1.5 UUSN NNE of W. Yellowstone, MT
O: 6DEC2001 4:23:33 44.8N 111.0W ML=1.4 UUSN NNE of W. Yellowstone, MT
O: 6DEC2001 4:07:29 39.5N 111.2W ML=2.2 UUSN ESE of Mount Pleasant, UT
O: 6DEC2001 3:50:13 44.8N 111.0W ML=1.2 UUSN NNE of W. Yellowstone, MT
O: 6DEC2001 1:05:09 44.9N 111.0W ML=1.0 UUSN NNE of W. Yellowstone, MT
O: 05DEC2001 23:35:43 44.8N 111.0W ML=1.5 UUSN NNE of W. Yellowstone, MT
O: 05DEC2001 21:28:30 44.8N 111.0W ML=1.2 UUSN NNE of W. Yellowstone, MT
O: 05DEC2001 21:05:02 44.8N 111.0W ML=0.8 UUSN NNE of W. Yellowstone, MT
O: 05DEC2001 18:46:26 44.8N 111.0W ML=2.0 UUSN NNE of W. Yellowstone, MT
O: 05DEC2001 17:59:13 44.8N 111.0W ML=1.3 UUSN NNE of W. Yellowstone, MT
O: 05DEC2001 17:23:35 44.8N 111.0W ML=1.7 UUSN NNE of W. Yellowstone, MT

EASTERN U.S./CANADA

O: 05DEC2001 04:57:56 47.6N 70.0W ML=1.7 PGC CHARLEVOIX SEISMIC ZONE, QUE.
O: 05DEC2001 18:48:27 47.5N 70.2W ML=2.4 PGC CHARLEVOIX SEISMIC ZONE, QUE.

O: 05DEC2001 13:07:40 35.6N 84.0W ML=2.2 JIEE 9 km SW of Maryville, TN

ALASKA

O: 06DEC2001 02:58:54 59.2N 147.9W ML=3.3 AEIC SE of Seward, Alaska

O: 05Dec2001 08:20:05 60.1N 152.9W HN=4.2 NEIS SOUTHERN ALASKA