EXTREME QUIET CONDITIONS CONTINUE IN CALIFORNIA, MOST OTHER AREAS

SUMMARY

Since last we met, little has been happening in most study areas
in terms of seismic activity. The earthquake drought continues in
Southern California and in the world at large.
In the world there have been only 3 moderate events of Mb between
5.0 and 5.5 since the Mw 7.1 early on April 27 (UT) near Guam (four
days ago). These have occurred in Taiwan (Mb 5.4 on Apr. 28); the
Galapagos Islands (Mb 5.0, April 28); and in the Kermadec Islands
(Mb 5.2, April 30). Since an average of 4-5 events of Mb>=5 occur
on average per day, this is a substantial reduction in seismic rate.
Likewise in southern California, this is the 26th day without
an earthquake of Ml>=3 in the region. This is the longest such
spell in at least 35 years. Only three periods have seen longer
quiet spells in Southern California in the last half century -

Sept. 5 to Oct 5, 1960 - 30 days
Nov. 21 to Dec 20, 1966 - 29 days
Mar. 16 to Apr. 11 1965 - 27 days

It seems possible that most of the available seismic energy
was used up during and after the strong geomagnetic storms of
April 17 - 20, The X1.6 solar flare may have finished the job.
There is often a lull in activity about 8-15 days after strong
geomagnetic storms and large earthquakes. Apparently it takes
about this much time to regenerate the conditions required for
significant seismic activity.

GLOBAL

Global seismicity was relatively quiet today. An earthquake of
Ms 5.2 in the Kermadec Islands was the largest recorded. The only
other event of Mb>=4.5 listed was in the Santa Cruz Islands (Mb 4.9).
Smaller events occurred in the Iran-Iraq border (Mb 3.4); southern
Iran (Ml 3.7); Italy (ml 3.6); and the Minahassa Peninsula (Mb 4.1).

U.S./CANADA

As noted above the news in the U.S. was the continuing seismic
quiet in southern California which has now lasted nearly 26 days.
In California/Nevada only two earthquakes of Ml>=2 have occurred
since last report (a Ml 2.4 near Lower Lake and a Ml 2.1 aftershock
near Gilroy in Central California). A Ml 1.9 occurred near New
Idria west of Parkfield tonight.
Not all areas of the U.S. were as quiet. A swarm of microearthquakes
including three of Ml>=2 was occurring in the Yellowstone Park area
starting on April 29.
Alaska and Hawaii saw no earthquakes of Ml>=3 today.
Other areas of the U.S. and Canada also recorded no events of
Ml>=2 or unusual activity on this date.

NEW ZEALAND

A Ml 4.9 was recorded near Te Anau, South Island, New Zealand.
This area is still under seismic watch from the Guam earthquake
of April 26 and has seen several felt events on North and South
Island since that time.
A Ml 5.2 was also recorded in the northern Kermadec Islands
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 conditions today. There
were no X- or M- class solar flares observed. SEC expects quiet
conditions to continue, however a mild proton storm appeared to
be occurring early on the morning (UT) of May 1, 2002.

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/20020430events.txt

TIDAL EFFECTS

May 02 is the nineteenth 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

Arctic MB>=4.0 30 1.9 0.05
India MB>=4.0 68 2.9 0.02
Hindu Kush MB>=4.0 14 2.0 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

Mammoth lakes MB>=3.0 -18 -2.1 0.05

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

5 1 0 0 0 1839 42.700 144.900 40 7.0 Hokkaido, Japan
5 1 18 30 36 1910 -20.000 169.000 80 7.1 Vanuatu Islands
5 1 5 0 0 1915 47.000 155.000 25 8.1 NE Pacific
5 1 18 26 30 1917 -29.000 -177.000 60 8.6 No. Kermadec Islands
5 1 15 37 27 1929 37.850 57.750 21 7.2 No. Iran
Iran. 5803 killed. Damage was extreme in the Kopet-Dagh and Baghran-
Germab regions of Iran

5 1 7 4 56 1934 3.500 97.500 145 7.0 Nicobar Islands
5 1 5 58 0 1939 40.133 139.517 60 7.0 Hokkaido, Japan
5 1 5 2 41 1951 -50.500 149.000 0 7.0 Macquarie Islands
5 1 10 3 20 1963 -19.000 168.900 142 7.0 Vanuatu Islands
5 1 13 3 37 1979 -21.244 169.798 79 7.2 Loyalty Islands
5 1 16 11 42 1990 56.100 -156.400 0 7.1 Alaska Peninsula
Felt V at Sterling, IV at Anchorage, Alaska.
5 1 11 37 36 1997 18.993 -107.350 33 7.3 Coast of Jalisco, Mexico
Felt along the coast of Jalisco.

U.S./CANADA

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

MO DA HR MN SC YEAR LATIT LONGIT DEP MW LOCATION

5 1 4 32 0 1918 32.670 -115.500 0 5.0 So. California
Calexico, Plate glass broken. Felt over an area of about
100 miles radius.

5 1 18 54 41 1928 67.000 -172.000 25 6.2 Northern Alaska
5 1 18 49 47 1933 51.700 -173.000 25 6.5 Andreanoff Islands, Aleutians
5 1 21 53 18 1939 40.200 -124.700 0 6.5 Off Coast of No. California
Light shock felt at Aracata. About 20 miles off Punta Gorda.

5 1 23 53 0 1939 32.000 -117.500 0 5.0 So. California
The earthquake was felt over an area of about 1400 square miles in the SW
section of San Diego County CA. The shock was felt along the coast from
the Mexican border to Oceanside on the north. No structural damage
was reported.

5 1 23 28 5 1957 52.500 -171.000 0 5.3 Andreanoff Islands, Aleutians
5 1 1 5 11 1963 51.900 -174.500 0 5.7 Andreanoff Islands, Aleutians
5 1 3 13 4 1964 57.400 -150.000 30 5.3 Southern Alaska
5 1 6 1 55 1964 60.380 -145.860 20 5.5 Central Alaska
5 1 21 27 52 1965 60.330 -145.950 13 5.3 Central Alaska
5 1 20 58 11 1970 63.500 -148.900 0 5.0 Central Alaska
5 1 18 47 54 1975 52.670 -167.050 3 5.1 Fox Islands, Aleutians
5 1 0 59 2 1985 54.343 -161.278 0 5.2 Unimak Islands, Aleutians
5 1 16 12 21 1990 58.760 -156.720 213 6.5 Alaska Peninsula
5 1 7 18 42 1991 62.590 -151.560 108 6.6 Central Alaska

EARTHQUAKE/FORECAST COMPARISONS

ASIA

O: 30APR2002 07:10:30 32.2N 46.8E MS=3.4 GSR IRAN-IRAQ BORDER REGION

O: 29APR2002 02:43:47 7.0S 108.7E MB=4.3 NEI JAWA, INDONESIA

O: 28APR2002 16:58:07 27.6N 144.5E MB=4.0 NEI BONIN ISL, JAPAN REGION

O: 30APR2002 19:06:10 7.5S 112.7E MR=5.6 AEIC1 SW SIDOARDJO

SOUTH PACIFIC ISLANDS

O: 30APR2002 13:52:39 11.0S 166.0E MB=4.9 NEI SANTA CRUZ ISLANDS

O: 28APR2002 07:11:46 21.3S 174.3W MB=4.8 NEI TONGA ISLANDS

O: 28APR2002 17:52:00 14.3S 167.5E MB=4.0 NEI VANUATU ISLANDS

O: 29APR2002 03:24:36 5.9S 153.3E MB=4.3 NEI NEW IRELAND REGION, P.N.G

CARIBBEAN/CENTRAL/SOUTH AMERICA

O: 28APR2002 07:17:03 19.5N 66.8W ML=4.1 PRSN Puerto Rico Trench

O: 28APR2002 00:42:41 18.7N 69.5W MB=4.2 NEI DOMINICAN REPUBLIC REGION

O: 28APR2002 19:56:42 17.2N 100.7W MB=4.7 NEI GUERRERO, MEXICO

O: 29APR2002 07:06:50 18.4N 104.0W MB=3.9 NEI NEAR COAST MICHOACAN, MEX

O: 30APR2002 12:16:28 23.7S 70.4W MB=4.5 DGF Antofagasta, Chile

O: 30APR2002 12:20:05 9.0N 77.1W Mc=5.0 ULA Mar Caribe, Norte del Golfo de
O: 30APR2002 10:48:45 9.4N 78.2W MC=3.9 CASC Colombia, Central America

NEW ZEALAND/AUSTRALIA

O: 30APR2002 22:04 45.0S 167.2E ML=4.9 IGNS NW of Te Anau, N.Z.

O: 30APR2002 06:25:45 29.5S 177.1W MS=5.0 GSR KERMADEC ISLANDS, NEW ZEA

O: 28APR2002 05:53:18 31.6S 179.7W MB>4.0 NEI KERMADEC ISLANDS REGION

OCEANIA

O: 28APR2002 20:16:59 1.8N 102.1W MS=5.0 NEI GALAPAGOS TRIPLE JUNCTION
O: 28APR2002 20:17:03 1.9N 102.0W MB=5.0 NEI EAST CENTRAL PACIFIC OCEA

O: 28APR2002 01:20:50 2.9N 31.1W MB=4.5 NEI CENTRAL MID-ATLANTIC RIDG

O: 28APR2002 17:00:35 31.6N 41.1W MB=4.8 NEI N MID-ATLANTIC RIDGE

O: 29APR2002 12:33:10 54.0N 35.2W MB=4.2 NEI REYKJANES RIDGE

EUROPE/MIDDLE EAST/AFRICA

O: 29APR2002 15:14:09 46.1N 8.6E ML=3.9 LDG C DELLA LAURASCA / ITALY

U.S/CANADA

CALIFORNIA/NEVADA

O: 29APR2002 12:24:41 32.1N 115.0W ML=4.1 SCSN SSW of Yuma, AZ
O: 29APR2002 22:27:43 32.1N 115.0W ML=2.1 SCSN SSW of Yuma, AZ
O: 30APR2002 05:30:18 32.1N 115.0W ML=2.0 SCSN SSW of Yuma, AZ
O: 29APR2002 12:24:41 32.0N 115.0W MB=4.1 NEI W. ARIZONA-SONORA BORDER

O: 30APR2002 05:44:24 37.0N 121.6W ML=2.1 NCSN SSW of Gilroy, CA
O: 30APR2002 05:36:57 37.0N 121.6W ML=3.0 NEI CENTRAL CALIFORNIA

O: 30APR2002 03:14:27 32.3N 116.3W ML=2.0 SCSN SSW of Ocotillo, CA

O: 30APR2002 05:18:42 38.9N 122.5W ML=2.4 NCSN E of Lower Lake, CA

O: 30APR2002 04:05:43 34.4N 116.5W ML=2.3 SCSN N of Yucca Valley, CA

O: 30APR2002 05:20:20 34.1N 117.3W ML=2.0 SCSN WSW of San Bernardino, CA

PACIFIC NORTHWEST/CANADA

O: 30APR2002 04:17:09 50.2N 127.8W ML=1.9 PGC SSW Pt. Hardy BC

O: 29APR2002 13:48:57 45.7N 123.0W ML=1.0 PNSN N of Newberg, OR

ROCKY MOUNTAIN AREA

O: 29APR2002 04:48:01 43.4N 110.8W MD=2.0 USBR NW of Hoback Jct, WY

O: 30APR2002 10:20:02 43.3N 110.5W MD=2.4 USBR E of Hoback Jct, WY

O: 29APR2002 07:43:28 44.8N 111.1W ML=2.6 UUSN N of W. Yellowstone, MT
O: 29APR2002 13:06:43 44.8N 111.1W ML=2.1 UUSN NNE of W. Yellowstone, MT
O: 29APR2002 16:21:21 44.8N 111.1W ML=2.0 UUSN NNE of W. Yellowstone, MT
Note: A strong swarm began in the Yellowstone area on April 29 including
several dozen small events beside these.

EASTERN U.S./CANADA

ALASKA

O: 28APR2002 18:26:00 63.3N 151.5W HB>3.0 NEI CENTRAL ALASKA

HAWAII