QUIET DAYS AND SILENT NIGHTS

SUMMARY AND GLOBAL

Global seismicity was at quiet levels today. The few events that
did occur were apparently FFA, however.
Two events occurred in the Samoa/Tonga region of Mb 5.5 and 4.9.
These had been expected FFA from the Ryukyu shock at 72 degrees
from that event as noted in the FFA forecast:

"71-73 degrees: South-Central Alaska, Eastern Turkey/Caucasus, Fiji Isl."

and

"The most likely events of Mw>=6 in the next 10 days appear to be:
(Number in paranthesis indicated number of times and event of M>=6
has followed a Ryukyu mainshock within 2-3 weeks).

Tonga - around 20S (3)"

Events of Ml 3.4 occurred in Eastern Turkey today and of 4.2 in
south-Central Alaska, but were not in this distance range from Ryukyu.

An earthquake of Mb 4.8 also occurred in Southern Ecuador. This
was a region where FFA had been expected from the northern Chile
earthquake as noted:

"17-19 degrees: So. Ecuador..."

An earthquake in the Revillo Gigedo Islands, Mexico occurred at
61 degrees from the Central Chile mainshock and had also been
an expected FFA:

"59-61 degrees: ... Revillo Gigedo Islands"

Earthquakes of Ml 3.4 and 3.1 continued to be registered in the
Sicily/So. Italy region (see yesterday's summary for more details).

GLOBAL

In addition, two aftershocks (Ml 4.1 and 4.7) were registered
in Taiwan. Mexico recorded events of Ml 4.0 in Oaxaca and 3.7
in the Gulf of Tehuantepec regions.

U.S./CANADA

It was apparently a quiet day in the U.S./Canada area today.
The largest event registered was a Ml 4.2 in south-Central Alaska.
The Alaska earthquake occurred at 106 degrees from the North
Chile earthquake, at the CM- shadow zone boundary and had been
an expected FFA as noted in the FFA forecast.

"103-106 degrees***: Southern, Gulf of Alaska"

In the California/Nevada area, only 4 events of Ml>=2 have been
listed since the last summary. Two of these occurred as Ml 2.0 and 2.1
in the Geysers, California area. The other two were in Southern California
in the Yucca Valley area (Ml 2.1 ) and near Mission Beach, CA (Ml 2.4).

Due to the weekend, other areas of the U.S./Canada area not
reporting local events today, but appear from seismograms
to be quiet.

NEW ZEALAND

No events were reported by IGNS from New Zealand 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 at quiet levels today. There were
no X- or M- class flares observed.

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/20020406events.txt

TIDAL EFFECTS

April 08 is the twenty-sixth 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

Australia MB>=4.0 39 3.1 0.01
Nevada MB>=2.0 16 2.5 0.03
So Indonesia MB>=4.0 32 2.4 0.04
Turkey MB>=4.0 10 1.9 0.05
Washington MB>=0.0 68 2.3 0.05
NW Europe MB>=4.0 11 2.5 0.04
So. California MB>=3.0 63 2.1 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

TOMORROW IN EARTHQUAKE HISTORY

GLOBAL:

The following events of Mw>=7 have occurred on this date in
recorded history:

MO DA HR MN SC YEAR LATIT LONGIT DEP MW LOCATION

4 7 23 29 17 1941 17.750 -78.500 0 7.1 Jamaica
4 7 15 30 40 1958 66.030 -156.590 0 7.3 Northern Alaska
4 7 5 34 6 1970 15.761 121.717 37 7.5 Luzon, Philippines
A strong earthquake shock the whole of Luzon and Northern Visayas.
Damage was done to schools in Manila. Buildings in Central Manila
suffered slight damage. Manila International Airport suffered cracked
walls and broken Windows. 14 were killed and hundreds injured.
The dealtsh all resulted from the mainshock. Dozens of injuries, however
resulted from the most sever aftershock on April 12. Considerable
damage occurred to buildings on Alluvial ground in Manilla. Severe
damage was done to roads and bridges in the epicentral areas. Estimated
cost to injured coconut trees - $2 million. The earthquake was
characterized by "short rapid jerks, zigzags rather than arches". This
quake radiated from the point of the fault-line that runs along the
Philippine Pacific coast. People at the shore twons "saw the sea
pushed back, saw the water tripped off like a carpet from the
shoreline and folded up into the horizon. But the next moment
the folded sea unrollwed and came rushing back as a wall of
water, sort of tide, a mile-wide torrent that flloed and crashed
past the shoreline, engulfing trees, boats, huts and beach". Roads
split was was as two feet, water fountained from the deep chasms
created, bridges collapsed.

4 7 22 6 57 1995 -15.199 -173.529 21 8.1 Tonga Islands

U.S./CANADA

Following are events of Mb>=5 which have occurred in this region on
this date.

4 7 2 16 0 1934 41.500 -111.500 0 5.5 Utah
Felt at Salt Lake City (III). Also felt at Pocotello, Idaho.

4 7 15 27 50 1963 52.600 -169.500 150 5.4 Fox Islands, Aleutians
4 7 15 28 4 1963 53.710 -169.960 224 6.0 Fox Islands, Aleutians
4 7 1 43 25 1964 58.530 -154.460 2 5.0 Southern Alaska
4 7 19 28 25 1964 55.700 -151.830 20 5.5 Southern Alaska
4 7 3 16 23 1972 60.129 -152.754 98 5.1 Central Alaska
4 7 6 18 31 1979 41.982 -126.885 3 5.4 Off Coast of No. California
4 7 20 7 30 1989 33.620 -117.900 13 5.0 So. California
Near Newport Beach, Orange county, slight damage reported
at Corona Del Mar, and Newport Beach. Typical damage consisted of
broken chimneys, walls, plaster and windows and merchandise damaged
while falling from shelves in stores. Ceiling tiles also fell from
some stores in Newport Beach, and a brick wall toppled.

4 7 6 4 2 1990 56.406 -153.971 33 5.0 Southern Alaska
4 7 20 10 54 1990 55.000 -152.900 0 5.4 Southern Alaska
4 7 0 42 16 1992 50.910 -130.720 10 5.0 British Colombia
4 7 16 16 45 1994 42.561 -111.032 5 5.2 Yellowstone/Wyoming
Felt at Afton, Smoot and Thayne and at Auburn, eastern Idaho.

4 7 4 31 7 1996 51.000 -32.000 0 5.2 North Mid-Atlantic Ridge
4 7 16 43 23 2000 51.821 -170.473 33 5.0 Andreanoff Islands, Aleutians

EARTHQUAKE LISTINGS

ASIA

O: 3APR2002 18:43:26 14.4N 145.0E MB=4.4 NEI MARIANA ISLANDS

O: 6APR2002 05:54:25 24.4N 122.0E ML=4.7 TAI Ilan, Taiwan
O: 6APR2002 13:09:55 24.3N 121.8E ML=4.2 TAI Ilan, Taiwan

SOUTH PACIFIC ISLANDS

O: 4APR2002 17:00:34 26.6S 178.2W MB=4.1 NEI SOUTH OF FIJI ISLANDS

O: 5APR2002 23:02:29 15.2S 173.5W MS=5.5 NEI TONGA ISLANDS
O: 6APR2002 01:45:17 15.1S 173.5W MS=4.8 NEI TONGA ISLANDS

CARIBBEAN/CENTRAL/SOUTH AMERICA

O: 6APR2002 14:41:25 2.9S 79.8W MB=4.5 NEI NEAR COAST OF ECUADOR

O: 6APR2002 06:51:11 17.0N 100.2W ML=3.5 SSN COSTA DE GUERRERO, MEXICO

O: 6APR2002 00:51:44 15.1N 96.5W ML=4.0 SSN COSTA DE OAXACA, MEXICO
O: 5APR2002 14:49:35 15.6N 95.9W ML=4.2 SSN GOLFO DE TEHUANTEPEC, MEXICO

O: 5APR2002 14:45:00 7.1N 82.8W MC=4.2 CASC So. of Panama, Central America

NEW ZEALAND

OCEANIA

O: 4APR2002 22:50:32 54.7S 128.6W HN>4.0 NEI PACIFIC-ANTARCTIC RIDGE

EUROPE/MIDDLE EAST/AFRICA

O: 6APR2002 22:17:28 38.7N 30.8E ML=3.1 KAN BOLVADIN, TURKEY

O: 6APR2002 17:54:53 40.7N 29.1E ML=3.0 KAN YALOVA, TURKEY

O: 6APR2002 15:48:12 39.7N 39.3E ML=3.4 KAN ERZINCAN, TURKEY

U.S/CANADA

CALIFORNIA/NEVADA

O: 5APR2002 08:02:55 34.5N 116.3W ML=4.2 NEI SOUTHERN CALIFORNIA

O: 5APR2002 20:26:03 34.0N 116.7W ML=2.1 SCSN NE of Cabazon, CA

O: 6APR2002 11:30:32 38.8N 122.8W ML=2.1 NCSN NE of The Geysers, CA
O: 6APR2002 13:33:59 38.8N 122.8W ML=2.0 NCSN NNE of The Geysers, CA

O: 6APR2002 14:42:57 32.6N 117.5W ML=2.4 SCSN WSW of Mission Beach, CA

PACIFIC NORTHWEST/CANADA

ROCKY MOUNTAIN AREA

O: 5APR2002 06:36:10 37.1N 112.9W ML=2.8 NEI UTAH
O: 5APR2002 11:55:34 37.2N 112.8W ML=2.8 NEI UTAH

O: 5APR2002 03:15:11 5.3S 150.3E MB=4.7 NEI NEW BRITAIN REGION, P.N.G

EASTERN U.S./CANADA

ALASKA

O: 6APR2002 15:07:09 64.1N 150.1W ML=4.2 AEIC Healy, Alaska

HAWAII