STRONG (MW 7.2) EARTHQUAKE ROCKS GUAM, MARIANA ISLANDS
DEADLY QUAKES STRIKE GEORGIA, IRAN

SUMMARY

A strong earthquake occurred today in the Southern Mariana Islands
about 50 km southwest of Guam (Guam is at 13.5N 144.8E). Preliminary
estimates place the magnitude at 7.2 or greater (NEIS).

The parameters of this earthquake (NEIS) are given as:

O: 26Apr2002 16:06:06 13.1N 144.5E MW=7.2 NEIS MARIANA ISLANDS

There have been 8 earthquakes of Mw>=7 recorded in the are 12-15N 140-150E
in the past century. The largest occurred last year on October 12, 2001
as a Mw 7.0. The epicenter of this earthquake was very near
the same as today's (12.8N 144.9E) so this may be considered an
aftershock of that event. It is likely to have occurred on the same
asperity and ruptured in a different direction. The event of 2001 had
a depth of 60 km, today's depth was nearly the same (50-70 km).
Other earthquakes of Mw>=7 in the region occurred on Aug 8, 1993 (Mw 8.3);
Nov 1, 1975 (Mw 7.1); May 25, 1950 (MB 7.3); June 14, 1942 (MW 7.0);
Jan 28, 1931 (Ms 7.2); and a series of three between 1909 and 1913
(Mw 8.0 - Dec. 9, 1909; Mw 7.0 - Oct 26, 1912; and Mw 7.1 - July 18, 1913))

A Far-Field Forecast has been published. The FFA forecast for the
previous Guam earthquake on Oct. 12, 2001 was published on Oct. 12.

News reports say that the Island of Guam suffered a island-wide
power black-out. It is expected that a small tsunami may have been
generated, although no reports of such are available at this time.
A News story can be found at:
http://webcenter.newssearch.netscape.com/aolns_display.adp?key=200204261348000109061_aolns.src

The earthquake fell in an area where strong FFA effects from Chile,
Kamchatka and Mexico had been expected. The region was also under
a seismic watch condition at the time of the earthquake from a X1.5
solar flare which had occurred while the region was sub-solar on
April 21.

GLOBAL

A moderately strong earthquake also occurred last night (Mw 5.8)
in the region of Kamchatka. This area had also been under seismic
watch from the recent X-flare. This is the largest event in Kamchatka
since Oct 8, 2001 when a Ms 6.8 preceded the last strong Guam event
by several days. Seismic waves from this earthquake may be the
immediate triggering cause of the Guam earthquake.

A moderate earthquake also hit eastern Turkey/Georgia last night.
Initial reports identifiy 6 deaths associated with this event. A news
Story is found at:

http://webcenter.newssearch.netscape.com/aolns_display.adp?key=200204262003000117577_aolns.src

and

http://webcenter.newssearch.netscape.com/aolns_display.adp?key=200204252119000287892_aolns.src

Experts are calling this the worst earthquake in Georgia in the past 40 years.

Another deadly earthquake hit western Iran yesterday leveling 10 villages
And killing at least two. The news account of this event is found at:

http://webcenter.newssearch.netscape.com/aolns_display.adp?key=200204260808000200533_aolns.src

A moderate quake was felt on Taiwan overnight. No injuries or deaths were
Associated with this event. More at:

http://webcenter.newssearch.netscape.com/aolns_display.adp?key=200204260047000192529_aolns.src

It is not uncommon for damaging and deadly earthquakes to strike between
3 and 5 days following X-class solar flares. This has been noted on many
occasions in this daily report. The latest notification posted on
April 24 had stated:

" Delayed effects from the recent strong geomagnetic storms were
probably important in the timing of the Balkans and the Andreanoff
Islands earthquakes today. STRONG EVENTS OFTEN FOLLOW X-CLASS SOLAR
FLARES 3-5 DAYS LATER IN SUB- AND ANTI-SOLAR REGIONS."

(Emphasis added)

Two earthquakes also occurred in the northern Kermadec Islands region
(Mb 5.2, 5.3). These were expected from geomagnetic and FFA considerations
as well.
The other event of Mb>=5 occurred in northern Colombia at 7N 73W
as a Mb 5.1. The FFA forecast from Chile/Mexico had noted this as
a region where a strong FFA might occur. There had been several light
foreshocks noted in this daily summary over the past several days. The
forecast had said:

"From the combination effects of these events several areas seem
likely to see events of Ms>=5.5 in the next 10 days. These include

Colombia around 7N 73W"

U.S./CANADA

The largest earthquake in the U.S/Canada and posessions was the
Ml 7.2 in Guam. This was the largest earthquake within the U.S. since
a Ms 7.6 Hector Mine earthquake in southern California on Oct. 16, 1999.
It is the largest event near Guam since August 8, 1993 when a great
Mw 8.3 earthquake occurred slightly north of today's epicenter. Several
people were injured in the quake and power was lost throughout the
island of Guam.
Alaska saw a Ml 4.5 earthquake in the Central portion north of
Anchorage and ENE of Talkeetna this afternoon. It was followed by
a minor Ml 3.1 aftershock.
No earthquakes have been located of Ml>=3 in the Hawaii area in the
past five days since an unusual Ml 3.5 on 21 of April, which is still
listed. However, two small (Ml 2.0) earthquakes have been reported
from the Loihi seamount SE of Hawaii in the past three days. These
may reflect a new volcanic phase at this seamount beginning or may
be reactions to the recent geomagnetic storms.
The largest earthquake in the California/Nevada region was a Mb 3.8
(NEIS) in the Ukiah area of northern California. This was the largest
earthquake in Northern California since a Ml 4.1 near Redding on
Jan 27, 2002. It is the second light earthquake in the Central/Northern
California region in the past three days. Of four earthquakes of Ml>=3.5
in the northern and Central California (NCSN) region since Jan 1, 2002,
three have occurred in the past 8 days (since April 18). The fourth was the
4.1 on Jan 27, 2002. NCSN also lists three events of Ml>=3.5 off the
coast of Northern California under the Pacific Ocean and one in the
Mammoth Lakes region. So the past 8 days have represented a substantial
increase in seismic energy release in the region over the rest of 2002.
Events of M>=2 also occurred at NNW of Redding (Md 2.6); San Juan
Bautista (Md 2.4); Lakeport (Md 2.0), San Benito (Md 2.6) today in the
NCSN coverage area.
Four earthquakes of Ml>=2 were also listed in southern California
(SCSN area) today. Three occurred in the Westmorland/Calexico area
of Ml 2.6, 2.2, 2.3. The other was SW of Idyllwild (Ml 2.6).
No events of Ml>=2 were listed in the Pacific northwest or
Rocky Mountain states, although PGC did locate three such earthquakes -
a Ml 3.0 near Haines, Alaska; a Ml 2.6 on western Vancouver Island
and a Ml 2.4 NW of Vancouver, B.C. The largest earthquake located
in the eastern U.S./Canada was a Ml 2.3 north of Maine in Quebec.
A Ml 2.2 aftershock of the Plattsburg N.Y. earthquake occurred
yesterday.

NEW ZEALAND

The largest events in the New Zealand region today were the
Mb 5.2 and 5.3 in the northern Kermadec Islands. IGNS has not
identified any felt events on either North or South Island 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. No
X- or M- class solar flares were 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/20020426events.txt

TIDAL EFFECTS

April 28 is the fifteenth 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

NE Europe MB>=4.0 11 2.5 0.04
Solomon Islands MB>=4.0 26 2.6 0.03
Japan MB>=4.0 16 2.4 0.04
Spain MB>=4.0 30 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

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 27 12 44 0 1909 0.000 147.000 60 7.3 Caroline Islands
4 27 2 36 4 1933 61.250 -150.750 25 7.1 Central Alaska
Northwest of Anchorage, Alaska. Telegraph lines were broken for
a distance of 50 miles from Anchorage. Plate glass windows broke.
Felt in the Aleutian Islands and at Fairbanks and Valdez. Intensity
VII at Big Susitna River District and at Old Tyonek where houses
were sahken off foundations.

4 27 14 38 9 1944 -0.500 133.500 50 7.4 West Irian, PNG

U.S./CANADA

The following events of Mw>=5 have occurred on this date in
recorded history:

MO DA HR MN SC YEAR LATIT LONGIT DEP MW LOCATION

4 27 5 53 0 1914 39.000 -120.000 0 5.0 California/Nevada area
4 27 4 5 0 1925 38.300 -87.600 0 5.0 Indiana area
Intensity V at Brownstown, Evansville and Terre Haute, Ind. and
at Colverport and Louisville, KY. Many persons were awakened and
rumbling sounds were heard. Some dishes brock. Felt areas from
Illinois to Ohio.

4 27 2 36 4 1933 61.250 -150.750 25 7.1 Central Alaska
See description above

4 27 11 55 38 1933 52.500 -167.000 25 6.0 Fox Islands, Aleutians
4 27 8 0 33 1947 56.000 -140.500 0 5.0 Southeast Alaska
4 27 11 8 56 1947 55.320 -137.800 0 5.0 Southeast Alaska
4 27 19 3 53 1958 52.900 -169.500 33 5.9 Fox Islands, Aleutians
4 27 20 24 4 1985 51.900 -172.700 0 5.2 Andreanoff Islands, Aleutians
4 27 22 0 29 1986 52.600 -168.800 0 5.4 Fox Islands, Aleutians
4 27 18 39 53 1989 66.981 -156.303 5 5.0 Northern Alaska
4 27 2 47 20 1992 40.150 -124.050 15 5.2 Off Coast of No. California
4 27 11 53 17 1998 51.112 -169.503 33 5.0 Fox Islands, Aleutians

EARTHQUAKE LISTINGS

ASIA

O: 26APR2002 16:06:06 13.1N 144.5E MB=7.2 NEI MARIANA ISLANDS
Note: This earthquake lies at 43 degrees from Kamchatka, 108 from
Mexico and at 144 degrees from Northern Chile (Mw 6.8, 4-18-02). It is
most likely affected by FFA activity from all three of these events.
It was also located in a region under seismic watch from geomagnetic
effects at the time of the event.

O: 26APR2002 07:15:10 53.7N 160.5E MB=5.8 NEI NEAR EAST COAST OF KAMCHATKA
Note: This event is located in an area which was under seismic watch
at the time of the earthquake. It is a highly volcanic region. Large
events had been expected in highly volcanic zones 3-5 days after the
recent X1.5 solar flare on April 21.

O: 25APR2002 06:01:05 28.5N 52.1E MB=4.0 NEI SOUTHERN IRAN

O: 25APR2002 04:03:40 34.2N 47.2E MB=4.2 NEI WESTERN IRAN

O: 26APR2002 11:28:40 2.4S 123.6E MB=4.9 GSSC SULAWESI, INDONESIA

O: 24APR2002 07:01 42.5N 145.5E Mj=4.5 NIED OFF_NEMURO_PENINSULA, Japan

O: 26APR2002 09:42:20 24.3N 121.7E ML=4.3 TAI Ilan, Taiwan

SOUTH PACIFIC ISLANDS

O: 25APR2002 04:19:58 5.8S 152.1E MB=4.9 NEI NEW BRITAIN REGION, P.N.G.
Note: The Chile FFA forecast had stated:
"From the combination effects of these events several areas seem
likely to see events of Ms>=5.5 in the next 10 days. These include

...New Britain/New Ireland 5S 153E"

O: 25APR2002 09:31:57 10.2S 160.9E MB=4.2 NEI SOLOMON ISLANDS

O: 25APR2002 12:56:31 7.7S 156.3E MB=4.3 NEI SOLOMON ISLANDS

CARIBBEAN/CENTRAL/SOUTH AMERICA

O: 25APR2002 11:50:12 6.2N 73.4W Mc=3.7 ULA Dpto. Santander, Colombia.

O: 26APR2002 01:36:25 6.7N 73.6W MB=5.1 NEI NORTHERN COLOMBIA
O: 26APR2002 01:36:19 6.1N 74.4W Mc=5.2 ULA Dpto. de Cundinamarca, Colombi
Note: The Chile aftershock forecast had stated:

"From the combination effects of these events several areas seem
likely to see events of Ms>=5.5 in the next 10 days. These include

Colombia around 7N 73W"

O: 24APR2002 01:55:25 18.3N 67.2W ML=2.6 PRSN Western Puerto Rico
O: 23APR2002 06:09:05 18.6N 67.1W ML=2.8 PRSN North of Puerto Rico

O: 26APR2002 00:32:15 16.7N 101.0W ML=3.9 SSN COSTA DE GUERRERO, MEXICO
O: 25APR2002 14:50:11 16.8N 101.7W ML=4.1 SSN COSTA DE GUERRERO, MEXICO

O: 25APR2002 22:29:45 14.4N 91.2W ML=4.2 SSN GUATEMALA, MEXICO

O: 25APR2002 01:03:10 16.6N 95.0W ML=4.4 SSN ISTMO DE TEHUANTEPEC, MEXICO

O: 25APR2002 00:55:23 16.7N 93.8W ML=4.2 SSN CHIAPAS, MEXICO

NEW ZEALAND/AUSTRALIA

O: 26APR2002 02:12:56 27.4S 176.7W MB=5.2 NEI KERMADEC ISLANDS REGION

O: 26APR2002 15:06:38 27.8S 176.1W Ms=5.3 GSSC KERMADEC ISLANDS REGION
O: 26APR2002 15:06:39 27.3S 176.9W MB=5.3 NEI KERMADEC ISLANDS REGION

OCEANIA

EUROPE/MIDDLE EAST/AFRICA

O: 25APR2002 17:41:24 41.8N 44.8E MB=4.8 NEI NORTHWESTERN CAUCASUS

O: 26APR2002 16:19:45 44.7N 10.0E Ml=3.1 MIX NORTHERN ITALY

O: 25APR2002 07:28:08 40.5N 21.4E MB=3.9 NEI GREECE

U.S/CANADA

CALIFORNIA/NEVADA

O: 26APR2002 04:23:39 36.5N 120.7W ML=2.6 NCSN NNW of New Idria, CA

O: 25APR2002 22:29:58 39.3N 122.8W ML=2.0 NCSN SE of Lake Pillsbury, CA

O: 26APR2002 11:01:26 39.0N 123.1W MB=3.8 NEI NEAR COAST OF N CALIF.
O: 26APR2002 11:01:26 39.0N 123.1W MB=3.6 NCSN Ukiah, CA

O: 26APR2002 08:13:18 40.7N 122.5W ML=2.6 NCSN NNW of Redding, CA

O: 26APR2002 08:49:13 33.0N 115.9W ML=2.6 SCSN W of Westmorland, CA

O: 26APR2002 08:22:15 32.3N 115.1W ML=2.3 SCSN SE of Calexico, CA

O: 26APR2002 20:31:23 36.9N 121.6W Md=2.4 NCSN NW of San Juan Bautista, CA

PACIFIC NORTHWEST/CANADA

O: 26APR2002 11:08:08 52.5N 132.2W ML=2.4 PGC SSW Sandspit BC

O: 26APR2002 04:46:50 51.1N 130.9W ML=2.6 PGC WSW Bella Bella BC

O: 26APR2002 02:31:40 59.3N 136.6W ML=3.0 PGC WNW Haines AK

O: 26APR2002 02:25:49 49.7N 127.0W ML=0.8 PGC W Gold R. BC

O: 25APR2002 07:10:53 46.2N 123.0W ML=1.0 PNSN N of Longview, WA

O: 26APR2002 12:44:17 47.7N 122.0W ML=1.9 PNSN SSW of Duvall, WA

ROCKY MOUNTAIN AREA

O: 24APR2002 15:16:11 42.5N 111.0W ML=2.1 UUSN ENE of Montpelier, ID
O: 24APR2002 16:46:29 42.5N 111.0W ML=2.0 UUSN S of Afton, WY

O: 25APR2002 11:23:24 41.1N 111.6W ML=1.6 UUSN NNW of Henefer, UT

EASTERN U.S./CANADA

O: 25APR2002 13:39:55 44.5N 73.7W MN=2.2 GSC PLATTSBURGH, N.Y. AFTERSHOCK.

ALASKA

O: 26APR2002 16:16:27 62.7N 148.8W ML=4.5 AEIC Talkeetna, Alaska
O: 26APR2002 20:57:22 62.1N 148.8W ML=3.1 AEIC Palmer, Alaska

HAWAII