SEISMIC ACTIVITY ALIVE AND WELL - ESPECIALLY IN SOUTH PACIFIC

SUMMARY

Although most teleseismic and local seismic networks were taking
a break for the weekend, the earth chose to be in active motion
throughout the day. Much of the activity centered in the South
Pacific Ocean where moderately large earthquakes occurred near
New Zealand, the Kermadec Islands, Tonga and Fiji. All of these
areas lie near 180E an area where seismicity was expected to be
high at this time due to the two recent M- class solar flares.

GLOBAL

As this summary was being written a Ms 5.6+ earthquake (NEIC) occurred
In the northern Chile region. This is the largest earthquake today, and
had been anticipated several days ago in this report in view of a series
of small earthquakes that were occurring in the Central U.S. at 60
degrees from the location of tonight's (PST) event. This earthquake
occurred at 20S 68W. The daily summary had noted on March 13, regarding
this possibility:

"There have been occasions in the past, most notably prior to the
great Alaska earthquake of March 28, 1964, when a series of aligned
earthquakes occurred prior to a great earthquake at an FFA distance
to that event. These events all lie approximately 60 degrees from
a location in Northern Chile at about 20N 68W.."

Moderate earthquakes were recorded by GSSC (Geological Survey
of Russia) off New Zealand (Ms 5.1); in Fiji (Mb 5.6) and south
of the Fiji Islands in Tonga (Mb 5.3); in Samoa (Mb 4.6); and
south of the Kermadec Islands (Mb 5.1). Except for Samoa all
of these events lie within 2 degrees of the international Date
line (180E). The Samoa earthquake occurred at 173W, the same
longitude as the current swarm in the Andreanoff Islands.
Other seismic activity of Mb>=4.0 was recorded today in
Nicaragua (Ml 5.8) and Costa Rica (Ml 4.5); in Mexico (Mb 4.5, 4.3);
and in Minahassa Peninsula, Indonesia (Mb 5.0).

U.S./CANADA

Seismicity in the U.S. and Canada was relatively quiet today
after a flurry of light to moderate seisms yesterday.
No earthquakes of Ml>=3 have been listed since the last daily
report. The largest event occurred as a Ml 2.9 in the Calexico
swarm (the only listed event Ml>=2 in that region today).
The most active area was Nevada and the California/Nevada
border. Earthquakes of Ml>=2 occurred in Nevada at four separate
epicenters - SE of Bodie (Ml 2.4); ESE of Yankee Blade (Ml 2.2);
Tokop (Ml 2.0); and a light swarm in Mammoth Lakes (Ml 1.8, 1.5, 0.8).
No events of Ml>=3 were listed from Alaska or Hawaii today
from reporting local or teleseismic networks.
No events were noted from the rest of the U.S. or Canada either
because of non-manned networks on weekends.

NEW ZEALAND

At least two events - both Mb 5.0-5.5 occurred in the New
Zealand region today. Although both are currently listed at
Mb 5.1 by GSSC, it is likely the final magnitudes will be
higher. These occurred off the NE coast of North Islands and
in the southern Kermadec Islands.

New Zealand was in the region of possible geomagnetic/solar flare-
Related triggering from two M-class flares over the past two days.

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, however
SEC (see link below "today.html") has issued the following
alert for tomorrow:

"Geophysical Activity Forecast: The geomagnetic field is expected to reach active to minor storm
levels tomorrow in response to the halo CME event of 15/2310 UTC. A decrease to active is
expected on the second day and a further decline to unsettled is expected by the third day. The
current trend of the 10 MeV protons and the likely arrival of a shock in the next 12 hours all
suggest that the proton fluxes should once again cross threshold. "

Geomagnetic storms appear to be capable of affecting seismic activity
in regions of high latitudes, the geomagnetic equator and areas sub-solar
and anti-solar at the time of sudden commencement.

There were two M-class solar flares observed today.
The maximum of the first of these (#2170) occurred within a minute of
a Mb 4.6 in Samoa (at 10:18 UT). The second was followed by a Ml 4.0
In the Aegean Sea and within two hours by events of of M>5 in the
South Kermadec Island and north of North Island, New Zealand. Following
Are the parameters for these solar flares:

Flare # START MAX END CLASS

2170 + 1011 1019 1024 M1.3
2380 + 1924 1931 1934 M4.0
0216 0231 0330 M1.0

A third M1.0 solar flare occurred this evening (PST) at 02:16 UT maximizing
at 02:31 UT and is continuing at this writing. A mb 5.6+ earthquake occurred
In the region of Northern Chile during the course of this flare.

For general space weather conditions see:
http://sec.noaa.gov/today.html
For Solar flare data see:
http://sec.noaa.gov/ftpdir/indices/events/20020317events.txt

TIDAL EFFECTS

March 20 is the sixth 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

Indian Ocean MB>=4.0 17 2.1 0.05
Kamchatka MB>=4.0 35 2.6 0.03

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

Global MB>=6.0 -17 -2.8 0.02
West Pacific MB>=4.0 -20 -1.9 0.05
Yellowstone MB>=0.0 -19 -2.0 0.05
Puerto Rico MB>=4.0 -17 -1.9 0.05

TOMORROW IN SEISMIC HISTORY

GLOBAL

The most destructive earthquake to occur on March 18 was a Ms 7.4 which
occurred southwest of Istanbul, Turkey in 1953. This event killed 1103
including 998 in Yenice, 50 in Gonen, 20 in Can and 3 in Manyas. Yenice
was destroyed and major damage occurred at Gonena nd Can. It was felt
throughout the Aegean Islands and southern Greece. The felt area
was estimated at about 200,000 square miles with damage more than
$4 million US$.
During the 1950's and 1960's water levels in wells was carefully
monitored at all times for correlation with earthquake activity. The
earthquake in Turkey was registered as fluctuations in water well
levels in many areas of the U.S. (Illinois, Minnesota, Utah, Wisconsin,
Florida, New Jersey, New York). The maximum water level fluctuations after this
earthquake occurred in Wisconsin where water levels fluctuated nearly
2 inches and in southern Florida where the amplitude of fluctuation
was about 2.5 inches. In most cases water returns to it's original
level after being squeezed from the subsurface by the p- s- and
surface waves into high levels. It has been suggested that this might
be a mechanism by which large earthquakes can trigger other earthquakes
at a distance - essentially by lubricating the faults with fluid
squeezed onto them by seismic waves. This would lead to an increase
in seismicity in regions where the amplitude of the waves was greatest
for a period of time before the water dried on the fault surface. Once
the water has dried, it forms a concrete which connects the two sides
of the fault leading to a temporary hardening of the fault and a
reduction in seismicity in these areas. This tends to agree with
the observations of FFA after large earthquakes.

U.S./CANADA

The largest earthquakes in the U.S. and Canada on this date were
both non-destructive and occurred in the same area one year apart.
They occurred On March 18. 1957 (Ms 6.2) and again on March 18, 1958
(Ml 6.2) in the Fox Islands, Aleutians.

The strongest earthquake in California on this date was also on
March 18, 1957 (Mb 5.0). The event was felt over a land area
approximately 3,000 square miles of southern California, principally
in Ventura County. Minor damage occurred at Oxnard, Port Hueneme
and Ventura. At Oxnard extensive damage was done to the old
Masonic Temple where bricks and interior walls cracked and fell.
Windows broke at several locations. Several pipes broke at the
American Crystal Sugar Company and two steel I-beams pulled away
from a brick wall and fell to the floor. A large quantity of
merchandise fell in stores with considerable breakage.
At Port Hueneme, a full-length crack formed in the exterior
wall of the First National Bank Building. At Ventura three schools
were damaged and cracks developed in the buildings.