STRONG EARTHQUAKES ROCK WESTERN PACIFIC SO OF HONSHU AND IN BANDA SEA

SUMMARY

Strong earthquakes of Mw 6.1 and 5.9 hit the Banda Sea and the region
to the south east of the Island of Honshu, Japan today. Both of these
regions were in the area which was under a seismic watch today -
within 30 degrees longitude from 150E.
Strong events had been considered a possibility today with the
strong geomagnetic storm which occurred yesterday while these
regions were sub-solar.

GLOBAL

In other global activity of Mb>=4, earthquakes were registered
in the South Sandwich Islands (Mb 4.7); Northern Colombia (Mb 4.1);
the Central Philippines (Mb 4.7); Chile and Argentina (Mb 4.5 and 4.3);
Kyushu, Japan (MB 4.2); the Fiji Islands (Mb 4.7) and in the northern
Kermadec Islands, Japan (Mb 4.7).
Local networks recorded events in Taiwan (Mb 4.3); Honshu (Mb 3.8);
and in the Caribbean Sea south of Jamaica (Mb 4.8).

U.S./CANADA

The strongest earthquake in the U.S./Canada region which has been
listed since last report was a Mb 4.5 in the Andreanoff aftershock
zone of the Mb 6.0 earlier this month. Two aftershocks of Ml>=3
occurred in the southern Alaska section following yesterdays
Mb 4.5 in the area.

In California the Central coastal regions were active. This included
a series of earthquakes along the central San Andreas and adjoining
faults. The largest of these was a Ml 3.2 near Pacifica south
of San Francisco. The epicenter of this event and a Ml 2.5
foreshock are near the area where the next large quake is expected
to rupture in this region. However, activity did not stop there.
There were a number events in the Pinnacles and San Juan
Bautista region to the NW of Ml 2.7, 2.4, 2.5, 2.0 and 2.0, the
strongest activity in this region in more than a month. Also
in northern California a Ml 2.8 struck near Markleeville and the
areas north and east of Mammoth Lakes (Hawthorne NV and Lee
Vining, CA) saw a minor swarm of events of Ml 1.5-2.5. This
was an unusual swarm for this region in recent years.
Southern California also saw activity in the upper Ml 2 range
today. The largest event was a Ml 2.9 near Corona about 80 km
east of Los Angeles. There were also events of Ml 2.4 and 2.5
in the Hector Mine region of southeast California. An
unusual Ml 2.2 occurred south of Santa Barbara near Goleto and
one event of Ml>=2 was registered in the the Calexico/Baja
swarm.
No events were listed in the U.S. or Canadian eastern or
central zones. An interesting and rare earthquake did occur
yesterday, however north of Wisconsin in Canada. This Ml 2.0
hit near Thunder Bay, Canada, an are where light seismic
activity has been observed in the past. At one point an attempt
was made to research Indian Legend regarding the Lake to see
if if's name related to noises which occurred during earthquakes.
No evidence for this was found in that study.
A Ml 2.7 hit Central Montana this evening, and the minor
swarm in the Yellowstone area continued with several additional
events of Ml>=2. There were no earthquakes listed today in
the Pacific Northwest of the U.S.

NEW ZEALAND

A Mb 4.7 hit in the northern Kermadec Islands, N.Z. today. No other
moderate or strong seismic activity was evident on the IGNS
on-line seismometer. IGNS did not issue and earthquake reports today.

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 generally quiet today. There was
a light storm which began at about 15:00 when a strong electron
wind cause a strong sudden increase in the Hn geomagnetic field.
The Hn field reached it's maximum value of 2.42e+01 at 15:17 UT
(07:17 PST). One minute later an earthquake of Ml 2.8 occurred
in the Hector Mine aftershocks zone.
For information on minute-to-minute variations in the GOES
geomagnetic field measurements see:

http://sec.noaa.gov/ftpdir/lists/geomag/20020320_G10mag_1m.txt

No M- or X- clas solar flares were observed today.

Flare # START MAX END CLASS

For general space weather conditions see:
http://sec.noaa.gov/today.html
For Solar flare data see:
http://sec.noaa.gov/ftpdir/indices/events/20020320events.txt

TIDAL EFFECTS

March 23 is the tenth day after the beginning of the new 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

Alaska MB>=3.0 6 2.0 0.05
Greece MB>=4.0 8 2.0 0.05
Hawaii MB>=2.0 19 2.7 0.02
Kuriles MB>=4.0 22 1.9 0.05
Mammoth Lakes MB>=3.0 19 2.2 0.05
East Pacific Rise MB>=4.0 38 2.3 0.05
Hindu Kush MB>=4.0 20 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

No Regions

TOMORROW IN EARTHQUAKE HISTORY

The most disastrous earthquake in the recorded history of Spain
occurred on June 21, 1829. This even was felt in province of Murcia,
Spain, but was slightly felt to Madrid. The valley of Segura seems
to have been the center of the disturbance for the shocks were most
violent there. The earthquake was preceded by a slight shock at
noon but about 6 hours later the mainshock came accompanied by
loud underground noises. The earthquake lasted at least a minute
at very severe levels.
The damage done was enormous in very many towns and villages
of Murcia, and in Guradamar, La Mata and Torrevieja in Valencia.
Some places were totally ruined and the destruction of churches,
houses and loss of life were terribel. The precursory noise like
thunder was heard at Torrevieja for more than three-quarters of
an hour. It generally resembled cannon explosion and sometimes
increased gradually and then ceased. It was not heard thereafter
until the following September. At Daja Naeva and Daja Vieja
fissures opened in the earth, and small holes appeared from some
of which large quantities of dey sand and form others of sand and
water were thrown out. In Estremadura, the waster of a lake
suddenly disappeared. On the right bank of the Segura, it was
remarked, the shocks were more numerous and lasted longer than
on the left bank. The course of the river changed and now
enters the sea at different place than it had before the
earthquake.

Southeastern Iran was also struck by a major earthquake on March 21
in 1977. The Mw 7.0 event was centered in the Bandar Abbas area
near the Persian Gulf. The earthquake killed 152 injuring 560 and
causing considerable damage over an area of 550 square km. This shock
was followed by a number of aftershocks, the two strongest of Ms 6.0.
Both aftershocks caused additional damage in the epicenteral area.
About 7000 were left homeless in the Bandar Abbas area. 35 villages
were destroyed in this earthquake.

U.S./CANADA

The strongest earthquake in the U.S./Canada region on March 21
was a Mbl 6.0 in Brittish Colombia in 1986. This event was
felt in many parts of British Colombia and Alberta including
the cities of Prince George, Fort St. John, Dawson Creek
Kamioops, Vancouver, Grande Orairie, Edmonton and Calgary.

The most unusual earthquake on this date occurred in southeastern
Maine in 1904. This strong (Ms 5.8) earthquake overthrew chimneys
in Washington County, in the area of Calais and Eastport ME. and
at St. Stephen, New Brunswick. It was felt throughout most of
New England and the provinces of New Brunswick and Nova Scotia.
It was also observed west to the Hudson River and Montreal, Canada
and south the southern Connecticut.

A swarm of events in 1969 south of Yuma near the Gulf of California
were the only noteworthy events in the California/Western U.S.
region on this date. These events occurred in an unpopulated area
and did not cause damage or casualties although many of Ml>5
occurred.