Earthquake Summary for October 27, 2001

Earthquake Summary for October 27, 2001

Posted by Lowell on October 27, 2001 at 20:33:18:

MINOR EARTHQUAKE SHAKES MANHATTAN, NEW YORK NORTH OF TRADE TOWER DEBRIS FIELD
MODERATE, RARE EARTHQUAKE HITS SOUTHEASTERN AUSTRALIA (ML 5.1)

SUMMARY

MANHATTAN EARTHQUAKE

An earthquake occurred in New York City, N.Y and was felt in Manhattan
this morning of Ml 2.6. This is the largest earthquake within
50 km of New York City since a Ml 3.1 in Connecticut on Jan. 9, 1992
and the second largest in this region since Aug 1980 (a Ml 2.4 occurred
about near today's epicenter on Jan 17, 2001). Current NEIS
parameters for this event are:

O: 27Oct2001 05:42:20 40.8N 74.0W LG=2.6 NEIS NEW YORK CITY, NEW YORK

FAR-FIELD EFFECTS

The Mw 7.5 Banda Sea earthquake of October 19 may have helped trigger
this event. The FFA forecast from that event had specifically
noted eastern New York (this earthquake lies in the Hudson River
valley near Yonkers, New York on the eastern border of New York State)
The FFA forecast had said:

"Areas of U.S. and Canada where triggering may occuR (Ml>=3)

New England/Eastern New York"

Recall that two days ago a Ml 3.5 occurred in central Maine, the
largest event in New England in nearly one-and-a-half years.

GEOMAGNETIC STORM EFFECTS

Both of these areas were under seismic watch at the time of
the earthquakes. The report of October 21 had stated:

"A strong sudden commencement storm arrived at about 16:48 UT
today (October 21, 2001). This is the first expected arrival of the
CME from the X-flares of two days ago. Areas which were sub-solar
at the time of the commencement are at 72 +/- 20 degrees W longitude
or anti-solar areas are at 108 +/- 20 degrees E longitude. These
regions are expected to see increased seismic activity for the next
4 days with strong events possible on Oct. 25-27."

A Mb 5.6 also occurred at 72W earlier on October 26 in the
Central Peru area. A second Mb5.6-6.0 event occurred in Yunnan
this morning at 101E.

EXTREMELY RARE (ML 5.1) EARTHQUAKES SHAKES SOUTHEASTERN AUSTRALIA

O: 27OCT2001 07:58 35.3S 143.6E ML=5.1 MEL Swan Hill, Vic/NSW Australia
Note (MEL): This earthquake occurred near Swan Hill on the Victoria - New
South Wales border. It was the largest earthquake to have occurred in southeast
Australia since the Ellalong NSW earthquake in August 1994. Its epicentre was
about 10 km east of Swan Hill, about 300 km northwest of Melbourne. There have
been reports of minor damage in the Swan Hill area, with some chimneys being
toppled. Power to the region was briefly interrupted. An earthquake of this
size would be expected to be felt to a distance of about 100km from the
epicentre.
This is the first earthquake of Ml>=5 ever to be located within
200 km of this epicenter, so it is indeed a rare event.

FAR-FIELD EFFECTS

This earthquake is probably a FFA from the Banda Sea Earthquake (Mw 7.5)
of 19 October as it lies at 36.0 degrees from that event, a distance
at which FFA's are expected to occur. A small shock occurred west of
this location on 25 October (see yesterday's report). This is the second
unusual earthquake in Australia since the Banda Sea earthquake, the
previous was on October 19 in southwest Australia (see previous reports).

The FFA forecast from Banda had stated:

"Secondary location where event tend to occur but are not
as large or as likely . MB>=4.8 considered likely in next
10 days.

GEOMAGNETIC STORM EFFECTS

The area was also under seismic watch conditions from the geomagnetic
storms of 21-23 October as stated in the report from 26 October:

"Large earthquakes are possible today and tomorrow [26 and 27 October],
especially within 30 degrees of 80W and 100E due to the geomagnetic storms
of October 21-23, with less potential within 20 degrees of 160E
and 20W as well as at high latitudes."

TIDAL TRIGGERING

The region of Australia shows mathematically significant (at 0.03 level)
seismicity rate increases (33% over background at Ml>=4 level) at this time
during the lunar cycle. This was noted in yesterday's report under
"tidal triggering" as:

"Australia MB>=4.0 33 2.6 0.03"

VANUATU AND YUNNAN CHINA EARTHQUAKES

Following the report a moderately strong (Mb 5.6-6.0) earthquakes
also occurred in Yunnan, China at 101E. Initial reports indicate
this event was highly destructive in the epicentral area leveling
up to 1500 buildings, injuring more than 100 and killing one person.
A Mb5.6-6.0 also occurred in the Vanuatu Islands at 168E last night.

GLOBAL

In addition to the strong events in Yunnan (Ml 6.0); Vanuatu (Mb 5.8);
and Australia (Ml 5.1) yesterday (described above) the most active
area of the world was the region from Hokkaido to Kamchatka. Events of
Mb 3.8 (Northern Kurils); Mb 4.7 (Hokkaido, Jampa), and MB 5.0 (Kamchatka)
occurred in this area since last report.
Tidal forces were expected to increase seismicity in southern Alaska
where four events of Ml>3 and one of Ml 3.6 were recorded in the
Kodiak Island area. Two moderate earthquakes were also located in
the Andreanoff Islands in southwestern Alaska (Mb 5.0 and 4.9, preliminary).
The only other regions showing moderate activity today were the Hindu Kush/
Afghanistan region where events of Mb 4.9 and 4.4 occurred and the
northern Philippines where a Mb 4.8 was recorded on northern Luzon.

U.S./CANADA

The only networks reporting today from the U.S./Canada region were
the Pacific coast states and Montana. Other centers were closed for
the weekend.
A Ml 2.0 was recorded near Enumclaw, Washington, the only report
from that region. Two small events were reported on the automatic
Montana recording system (Ml 0.8 and 1.1).
Four earthquakes of Ml>=3 and one of Ml 3.6 were recorded in southern
Alaska and Kodiak Island respectively. Alaska also saw the strongest
events listed for North America with a Mb 5.0 and 4.9 in the eastern
Andreanoff Islands. The largest event in Hawaii today was Ml 2.6.
The California/Nevada region saw a moderate rate of seismicity
at the Ml>=2 magnitude range today. Nine events of Ml>=2 occurred
in the area today, an average rate for this region. The most active
area was the Cloverdale/Geysers region of northern California where
events of Ml 2.5, 2.4, 2.1 and 2.0 occurred. Also in northern and
central California a Ml 2.2 was registered WSW of Redwood City, near
San Francisco; Ml 2.4 nd 2.0 events were listed near the Pinnacles as well.
The only event of Ml>=2 in southern California today occurred in the
Hector Mine aftershock zone near Ludlow (Ml 2.3) and near Lake
Isabella (the town) (Ml 2.2).
No earthquakes of Ml>=3 were listed since the last report outside
Alaska.

NEW ZEALAND

Seismicity in New Zealand was relatively light today. The only
event reported from IGNS occurred yesterday near Hawkes Bay, North
Island (Ml 3.7). The on-line seismograph did not register any
events other than a few light tremors 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 throughout
October 27, 2001. There were no solar flares of M- or X-class
observed.

For general space weather conditions see:
http://sec.noaa.gov/today.html
For Solar flare data see:
http://sec.noaa.gov/ftpdir/indices/events/20011027events.txt

TROPICAL STORMS

A new tropical depression formed today in the Central North
Atlantic Ocean (TD fourteen). This system does not appear
likely to affect the North American continent. Tracking details at:
http://www.wunderground.com/auto/HurricaneSite/tropical/tracking/at200114.html

Typhoon Podul is currently far south of the Kamchatka Peninsula
moving to the northeast and dissipating rapidly. Podul poses no
threat to seismicity at this time. For public advisory see:
http://www.wunderground.com/auto/HurricaneSite/tropical/wp200101.public.html

Tropical Cyclone Alex is approximately 7S 90E (south of Sumatera)
and moving WSW at this time, posing no threat to land or seismicity
at this time. For public advisory see:
http://www.wunderground.com/auto/HurricaneSite/tropical/sp200101.public.html

TIDAL TRIGGERING (LUNAR)

Statistics have been done on many regions of the world in terms of
relationship of significant regional earthquakes with respect to lunar cycle.
Each report will summarize the most likely areas for tidal triggering
for the next day based on these statistics. It is expected
that tidal triggering will add an additional 0.5 - 1.0 units of
magnitude to events which are about to occur or will move these
events forward in time by up to seven days in the regions where
there is a statistical correlation between lunar phase and
earthquakes.

October 28 is twelve days after the beginning 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

Australia MB>=4.0 38 3.0 0.01
So Indonesia MB>=4.0 49 3.7 0.01
Global MB>=5.0 5 1.9 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

Tonga MB>=4.0 -28 -2.0 0.05
Turkey MB>=4.0 -10 -2.0 0.05

EARTHQUAKE LISTINGS

GLOBAL

AUSTRALIA

NEW ZEALAND

O: 27Oct2001 00:40 40.4S 176.8E ML=3.8 IGNS SE of Porangahau, N.Z.
Note: (IGNS) May have been felt in southern Hawkes Bay.

SOUTH PACIFIC ISLANDS

O: 26OCT2001 23:05:52 18.2S 168.6E Ms=5.8 GSSC VANUATU ISLANDS

ASIA

O: 26OCT2001 19:46:25 31.7N 141.2E MS=4.2 GSSC SOUTHEAST OF HONSHU,

O: 27OCT2001 10:43:59 43.5N 143.2E MS=4.7 GSSC HOKKAIDO, JAPAN, REGI

O: 27OCT2001 07:23:34 18.1N 121.0E MS=4.8 GSSC LUZON, PHILIPPINE ISL

O: 27OCT2001 06:13:02 49.0N 155.8E Ms=3.8 GSSC KURIL ISLANDS, RUSSIA

O: 27OCT2001 05:35:42 26.1N 100.7E Ms=5.4 GSSC YUNNAN, CHINA
Note: According to the first reports, 1 dead, 130 injured, more than
1500 buildings collapsed.
A news account of this earthquake can be found at:
http://abcnews.go.com/wire/World/reuters20011027_124.html

O: 26OCT2001 23:27:05 35.9N 70.1E MS=4.4 GSSC HINDU KUSH, AFGHANISTAN
Note: A stronger event occurred on October 27 (see next event below).

O: 27OCT2001 19:30:22 36.4N 70.4E Mb=4.9 MIX HINDU KUSH, AFGHANISTAN
Note: This earthquake may be a FFA from both Guam (distance = 70 degrees)
and from Kamchatka (D=61 degrees). It could also be related to the
Banda Sea earthquake (D=64 degrees). The FFA forecasts had stated:

From the Banda Sea:

"The most likely events of M>=5 in the next 10 days on the
basis of history and far-field triggering theory appear to be:

Afghanistan/Hindu Kush"

From Guam:
"71-73 degrees: ... Pakistan"

and from Kamchatka

"59-61 degrees: ... No. Afghanistan"

CENTRAL/SOUTH AMERICA

O: 27OCT2001 00:20:27 12.7N 88.7W MC=3.7 SIS EL SALVADOR, C.A.

O: 27OCT2001 08:25:48 11.2N 85.7W MC=3.8 SIS NICARAGUA, C.A.

EUROPE

O: 24OCT2001 21:27:51 41.3N 28.2E ML=3.1 KAN TEKYRDAD, TURKEY

O: 24OCT2001 08:13:13 39.6N 26.2E ML=3.2 KAN CANAKKALE, TURKEY

O: 22OCT2001 00:35:32 38.6N 25.6E ML=3.4 KAN IZMIR, TURKEY

O: 26OCT2001 11:11:42 67.0N 18.4W ML=3.1 ISO Iceland

O: 24OCT2001 01:15:31 63.6N 19.4W ML=2.7 ISO Iceland
O: 25OCT2001 20:10:59 63.7N 19.3W ML=2.5 ISO Iceland
O: 26OCT2001 18:41:18 63.9N 19.2W ML=3.0 ISO Iceland

O: 27OCT2001 23:56:48 35.9N 4.7W Ml=3.7 IMP STRAIT OF GIBRALTAR
Note: Largest in a series of events Ml 2.5-3.7 near this epicenter
in the past day.

U.S/CANADA

CALIFORNIA/NEVADA

O: 27OCT2001 21:14:08 34.7N 118.7W ML=1.7 SCSN SE of Gorman, CA

O: 27OCT2001 23:26:55 34.8N 116.4W ML=2.3 SCSN WNW of Ludlow, CA

O: 27OCT2001 9:38:55 35.7N 118.1W ML=2.2 SCSN ENE of Lake Isabella, CA

O: 27OCT2001 21:03:12 36.6N 121.1W ML=2.4 NCSN NNE of Pinnacles, CA
O: 27OCT2001 6:03:11 36.6N 121.2W ML=2.0 NCSN NW of Pinnacles, CA

O: 27OCT2001 6:20:25 37.5N 122.3W ML=2.2 NCSN WSW of Redwood City, CA

O: 27OCT2001 16:54:01 37.5N 121.9W ML=1.2 NCSN E of Fremont, CA

O: 27OCT2001 6:06:35 38.8N 122.9W ML=1.8 NCSN ESE of Cloverdale, CA
O: 27OCT2001 22:39:09 38.8N 122.8W ML=2.1 NCSN ENE of The Geysers, CA
O: 27OCT2001 10:03:26 38.8N 122.8W ML=2.4 NCSN N of The Geysers, CA
O: 27OCT2001 10:05:37 38.8N 122.8W ML=2.0 NCSN N of The Geysers, CA
O: 27OCT2001 9:57:49 38.8N 122.8W ML=2.5 NCSN N of The Geysers, CA

PACIFIC NORTHWEST/CANADA

O: 27OCT2001 23:49:43 47.1N 122.0W ML=2.0 PNSN S of Enumclaw, WA

ROCKY MOUNTAIN AREA

O: 27OCT2001 04:21:36 47.0N 113.1W MD=0.6 MBMG MONTANA

EASTERN U.S./CANADA

ALASKA

O: 27OCT2001 22:10:54 53.8N 174.1W Mb=4.9 LDG ANDREANOF ISLANDS, ALASKA
O: 27OCT2001 21:43:11 53.2N 173.7W Mb=5.0 MIX ANDREANOF ISLANDS, ALASKA
O: 27OCT2001 21:43:03 51.5N 173.4W Mb=5.1 NOR ANDREANOF ISLANDS, ALASKA
Note: These are probably FFA from the Banda Sea. The FFA forecast
from that event had stated:

"Areas of U.S. and Canada where triggering may occur (Ml>=4.0)

...Central Andreanoff Islands"

and

"71-73 degrees: Central Aleutians"

and from the New Zealand FFA forecast we find:

"While the distance is 90 degrees, wave fronts hit the Central
San Andreas parallel to the fault. This can cause larger events
to occur in the Central California region following strong events
in this area of New Zealand. A similar effect may be observed
along the Central Andreanoff Islands where strong triggering potential
from the Banda Sea also exists."

O: 27OCT2001 17:44:43 57.0N 154.6W ML=3.6 AEIC WSW of Kodiak, Alaska