With the Mw 7.2+ aftershock in the region of Peru today, it seems a good
time to evaluate the far-field forecast which was posted on June 23, 2001.
This forecast has since been updated to include the period through
July 15, 2001.

The forecast expects eartquakes to occur with greater magnitude
and frequency in areas where seismic energy is concentrated after
great earthquakes. The best way to test the results is to see whether
an increase over background has occurred in the areas listed in the
forecast compared with normal seismicity of the earth. To do this
we compare the total global seismicity at Ml>4.5 over the period 1900-2000
in the PDE (NEIS) catalog with the seismicity recorded at the same
magnitude and time levels in the areas where seismicity was supposed
to increase during the period following the Peru great quake.

The forecast is separated into three sections, primary areas where
seismicity may reach Mb>=6 levels, secondary areas where seismicity
of Mb>=5 may occur and local seismicity increases expected where
seismicity of M>=4 is uncommon. Following are the background rates
compared with global seismicity for the forecast areas:

Primary areas (PDE data Mb>=4.5, 1900-2000)

Total PDE events Events in Primary areas Percentage of total
131327 13143 10.0%

Secondary areas

131327 2518 1.9%

Local areas

131327 2068 1.5%

All areas

131327 17729 13.5%

This shows that during any given period, 13.5% of events should
occur in the forecast areas, the remaining 86.5% of events should
occur outside the areas forecast to have increased seismicity during
the period after the Peru mainshock. If a larger percentage
of events occur in the regions cited during the given period, the
seismicity of those regions may be considered anomalous with respect
to the normal seismicity of the earth.

During the 2 weeks following the Peru earthquake, NEIS recorded
152 events of Mb>=4.5. Of these 64 were local aftershocks in the
Peru region, 88 were events outside the local aftershock area.
Of the 88 non-local aftershocks, 40 (46%) occurred in areas included
as likely locations for far-field aftershocks in the forecast.
Only 10 such events should have occurred since 12% of events
in normal background seismicity should occur outside the aftershock
zone and within the regions forecast. This means that about 4 times
as much activity occurred in the forecast regions as should have
been expected suggesting their seismicity was anomalous during
this period.

All primary and secondary areas except for Eastern Siberia showed
strong events or activity. Unusual activity was also observed in
most of the local regions, the exception was the Virginia area
and the area west of Los Angeles where seismicity was near background
levels. Of 23 listed regions where seismicity was expected to increase,
NEIS recorded events of Ml>=4.5 or swarms of earthquakes occurred
in 20. The forecast therefore appears to have been successful
in identifying areas where seismicity would be high during this
period, the stated goal of the forecast.

The next section will give details on the events which did
occur in each region identified by the forecast.
---> identifies an event or item relating to the forecast.

The forecast and subsequent occurring events were:

Far-field aftershocks from Peru
Posted by Lowell on June 23, 2001 at 18:11:32:

As promised we have received the far-field aftershock potentials from the
great earthquake in Peru. The most interesting likely events appear to be in
the aftershock zone with a strong potential for another large event and in
the region of Northern Peru-Ecuador. I will leave the rest to you.

---> Earthquake of Mw>=6.5 occurred as local aftershocks as follows:
---> 05Jul2001 13:53:44.2 15.9S 73.5W 33 MW=6.6 M NEI SOUTHERN PERU
---> 26Jun2001 04:18:31.8 17.7S 71.3W 33 MW=6.6 M NEI NEAR COAST OF PERU
---> 07Jul2001 09:38:43.4 17.4S 71.8W 33 MW=7.2 M NEI NEAR COAST OF PERU

---> Earthquakes in Northern Peru-Ecuador occurred as follows:
---> 24Jun2001 00:28:32.5 4.1S 80.7W 33 MB=5.0 M NEI PERU-ECUADOR BORDER REG
---> 26Jun2001 12:33:50.5 4.3S 104.5W 10 MS=5.8 M NEI CENTRAL EAST PACIFIC RISE
---> 29Jun2001 03:11:28.3 3.9S 80.7W 33 MB=4.9 M NEI PERU-ECUADOR BORDER REG

In general, the following areas are most likely to see
significant increases in seismicity in the forthcoming 10 days
(until July 3, 2001):

Primary regions (Earthquake of Mb>6 Possible):

East Coast of Honshu to Kuril Islands

--->NEID (Japan) gives the largest events in the area southeast of
--->Honshu Mj 5.8, 5.7 and 5.6 and the largest events in the Kurils
--->Mj 6.0, 6.0.

---> Earthquakes along the East Coast of Honshu and the Kurils were:
--->24Jun2001 13:18:51.5 44.3N 148.4E 33 MS=5.7 M NEI KURIL ISLANDS
--->25Jun2001 06:14:44.4 43.4N 147.4E 33 MB=4.6 M NEI KURIL ISLANDS
--->02Jul2001 11:55:26.1 44.5N 148.1E101 MB=4.7 M NEI KURIL ISLANDS
--->06Jul2001 11:33:48.7 44.5N 149.3E 33 MB=5.4 M NEI KURIL ISLANDS

--->03Jul2001 06:39:06.8 32.4N 139.5E 33 MB=4.8 M NEI SOUTHEAST OF HONSHU, JAPAN
--->03Jul2001 14:22:42.2 33.4N 139.2E149 MB=4.5 M NEI SOUTHEAST OF HONSHU, JAPAN
--->03Jul2001 15:53:50.1 32.3N 139.4E 33 MB=4.7 M NEI SOUTHEAST OF HONSHU, JAPAN
--->04Jul2001 09:25:10.7 32.4N 139.5E 33 MB=5.0 M NEI SOUTHEAST OF HONSHU, JAPAN
--->04Jul2001 09:42:55.7 31.9N 139.9E 33 MB=4.6 M NEI SOUTHEAST OF HONSHU, JAPAN
--->04Jul2001 09:48:34.1 32.6N 139.7E 33 MB=4.9 M NEI SOUTHEAST OF HONSHU, JAPAN
--->04Jul2001 10:23:33.6 32.6N 139.6E 33 MB=4.9 M NEI SOUTHEAST OF HONSHU, JAPAN
--->04Jul2001 10:36:33.7 31.9N 139.7E 33 MB=4.3 M NEI SOUTHEAST OF HONSHU, JAPAN
--->04Jul2001 17:47:46.3 32.3N 139.5E 33 MS=5.5 M NEI SOUTHEAST OF HONSHU, JAPAN
--->04Jul2001 18:12:52.0 32.6N 139.6E 33 MB=4.6 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 01:41:18.7 32.3N 139.6E 33 MB=5.3 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 02:05:50.2 32.5N 139.6E 33 MB=5.2 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 02:15:42.5 32.3N 139.6E 33 MB=5.2 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 02:18:34.8 32.2N 139.8E 33 MB=4.7 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 02:33:26.9 32.6N 139.6E 33 MB=4.9 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 03:47:32.2 32.3N 139.6E 33 MB=5.3 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 04:06:42.1 32.4N 139.6E 33 MB=4.3 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 05:08:31.1 32.4N 139.6E 33 MB=5.1 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 05:41:23.0 32.5N 139.6E 33 MB=5.1 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 05:48:01.8 33.0N 140.1E 33 MB=4.4 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 10:40:58.7 32.6N 139.8E 33 MB=4.3 M NEI SOUTHEAST OF HONSHU, JAPAN
--->05Jul2001 13:12:06.7 43.2N 145.1E 91 MB=5.1 M NEI HOKKAIDO, JAPAN REGION

Ecuador to Northern Peru
---> Earthquakes in Northern Peru-Ecuador occurred as follows:
---> 24Jun2001 00:28:32.5 4.1S 80.7W 33 MB=5.0 M NEI PERU-ECUADOR BORDER REG
---> 26Jun2001 12:33:50.5 4.3S 104.5W 10 MS=5.8 M NEI CENTRAL EAST PACIFIC RISE
---> 29Jun2001 03:11:28.3 3.9S 80.7W 33 MB=4.9 M NEI PERU-ECUADOR BORDER REG

Guerrero/Michoacan Mexico
29Jun2001 11:29:23.3 17.6N 105.9W 33 MB=4.8 M NEI OFF COAST JALISCO, MEXICO

UNAM (University of Mexico) also gives the following events Ml>=4.5:

2001/07/06 11:54:03 18.89 -107.11 10 4.5 OCEANO PACIFICO
2001/07/06 02:02:04 17.98 -102.57 24 4.5 COSTA GUERRERO-MICH
2001/06/29 06:29:23 17.89 -106.20 20 5.0 OCEANO PACIFICO
See:
http://www.ssn.unam.mx/~yi/SSN/ssn-ultimos.html

In addition, Popocatepetl has been erupting during this period.
This was noted in a post by Petra on July 5, 2001. Popocatepetl
is located in Guerrero Mexico

Hindu Kush

--->Earthquakes which occurred with Mb>=4.5 in the Hindu Kush area were:

--->30Jun2001 11:48:35.1 31.1N 69.9E 33 MB=5.2 M NEI PAKISTAN
--->02Jul2001 22:52:26.5 38.3N 73.1E117 MB=4.7 M NEI TAJIK-XINJIANG BDR REG.
--->05Jul2001 11:53:22.5 41.3N 72.2E 33 MB=4.5 M NEI KYRGYZSTAN

Earthquake of Mb>5.0 possible):

South Island to Southern North Island, New Zealand (Alert status)
--->Earthquakes which occurred with Ml>=4.5 in this region included:

--->24JUN2001 20:47 42.5S 173.5E 12 ML=4.6 M IGNS SW of Kaikoura, N.Z.
--->27JUN2001 16:50:25 49.7S 163.9E 10 ML=4.1 M IGNS AUCKLAND ISL, N.Z. REG

El Salvador
--->Earthquakes which occurred with Ml>=4.5 in this region included:

--->07JUL2001 04:59:38 12.5N 87.7W 67 ML=5.6 M CAS EL SALVADOR
--->04Jul2001 22:19:25.4 12.7N 87.1W253 MB=4.5 M NEI NEAR COAST OF NICARAGUA
--->05Jul2001 01:13:52.7 11.8N 86.9W 33 MB=4.6 M NEI NEAR COAST OF NICARAGUA
--->05Jul2001 17:14:44.1 14.0N 92.1W 33 MB=5.1 M NEI NEAR COAST CHIAPAS, MEXICO
--->25JUN2001 12:48:37 15.1N 90.6W 75 ML=5.3 M SSN GUATEMALA

Northern Caribbean boundary (Leeward Isl. Puerto Rico, Dominican Republic area)
--->Earthquakes which occurred with Ml>=4.2 in this region included:

--->02Jul2001 15:05:04.5 16.8N 60.3W 33 MB=4.2 M NEI LEEWARD ISLANDS
--->03Jul2001 02:08:17.5 17.0N 60.4W 33 MB=4.4 M NEI LEEWARD ISLANDS

Alaska Peninsula to Unimak Island
--->Earthquakes which occurred with Ml>=4.2 in this region included:

--->26Jun2001 02:48:06.4 56.7N 156.6W 79 MB=4.3 M NEI ALASKA PENINSULA
--->26Jun2001 12:46:53.3 55.0N 159.2W 33 MB=4.4 M NEI SOUTH OF ALASKA
--->01Jul2001 14:46:10.6 56.2N 153.5W 33 MB=4.4 M NEI KODIAK ISL REGION, ALASKA
--->01Jul2001 14:47:08.0 56.2N 153.5W 33 MB=4.5 M NEI KODIAK ISL REGION, ALASKA
--->26Jun2001 14:05:36.8 61.6N 140.0W 10 MB=5.8 M NEI S YUKON TERRITORY, CANADA

Aegean Sea to No. Greece
--->Earthquakes which occurred with Ml>=4.2 in this region included:

--->23JUN2001 06:53:00 35.6N 28.3E 5 ML=5.1 KAN DODECANESE Islands
--->23JUN2001 12:18:20.2 39.5N 28.2E 5 ML=4.7 NOA NO GREECE
--->24JUN2001 11:49:37.3 39.4N 27.9E 5 ML=4.2 NOA NO GREECE
--->26JUN2001 17:19:47.4 38.6N 26.4E 21 ML=4.3 NOA NO GREECE/AEGEAN SEA
--->28JUN2001 07:34:47.8 34.3N 22.9E 9 ML=4.3 NOA CRETE

Vanuatu Islands
--->Earthquakes which occurred with Ml>=4.5 in this region included:

--->02Jul2001 14:29:06.7 16.1S 168.1E 33 MB=4.8 M NEI VANUATU ISLANDS
--->04Jul2001 16:58:04.0 21.7S 171.0E 33 MB=4.9 M NEI SE OF LOYALTY ISLANDS
--->06Jul2001 03:41:41.1 21.2S 169.8E 33 MB=4.5 M NEI SE OF LOYALTY ISLANDS

Banda Sea
--->Earthquakes which occurred with Ml>=4.5 in this region included:

--->06Jul2001 14:55:25.7 6.1S 130.5E 33 MB=4.9 M NEI BANDA SEA
--->02Jul2001 20:18:10.1 7.1S 129.2E 33 MB=4.6 M NEI BANDA SEA
--->03Jul2001 08:34:37.2 8.5S 127.3E 33 MB=5.2 M NEI TIMOR REGION

Fiji Islands
--->Earthquakes which occurred with Ml>=4.5 in this region included:

--->29Jun2001 10:00:22.0 17.7S 178.0W454 MB=4.7 M NEI FIJI ISLANDS REGION
--->30Jun2001 00:46:44.2 17.4S 178.7W395 MB=4.5 M NEI FIJI ISLANDS REGION
--->04Jul2001 07:06:31.6 21.7S 176.7W185 MW=6.5 M NEI FIJI ISLANDS REGION

Eastern Siberia

No earthquakes of Ml>4.5 were recorded by NEIS in Eastern Siberia

Central Chile near Valparaiso
--->Earthquakes which occurred with Ml>=4.5 in this region included:

--->27Jun2001 23:04:25.6 31.6S 71.5W 33 MB=4.9 M NEI NEAR COAST OF CEN CHILE
--->27Jun2001 23:04:26.0 31.6S 71.5W 25 MB=5.0 M DGF NEAR COAST OF CEN CHILE

Local Increase in Seismicity (Ml>4.0 possible)

Mammoth Lakes, California
---> A swarm including 45 local earthquakes occurred on 29-30 June.
---> This was the strongest swarm including the most number of events
---> in more than 2 years in the region.

Area west of Los Angeles, CA

---> The area west of Los Angeles remained at approximately
---> background seismicity.

Yellowstone, WY to No. Utah

---> The Yellowstone area had a swarm of earthquakes on 29-30 June
---> at the same time as the events in Mammoth Lakes were occurring.
---> This was the largest swarm in the region in more than 6 months
---> and the largest event in Yellowstone this year.

New England region to Quebec (M>3)

---> No earthquake of M>3 occurred in New England or Quebec during
---> this period. However, the Charlevoix Seismic zone experienced
---> 4 minor events, and southern Ontario had two events of Ml 2.7,
---> the strongest there in several montha.

Virginia/West Virginia (M>3)

---> No earthquakes of Ml>= 3.0 were located in Virginia, however
---> the unedited forecast included the New Madrid region. The following
---> event occurred in the New Madrid area. It was the largest in more
---> than two years in the region:
--->07Jul2001 20:45:41.9 36.3N 89.4W 5 LG=3.1 M NEI NEW MADRID, MISSOURI REG

Eastern Turkey
--->Earthquakes which occurred with Ml>=4.5 in this region included:

--->25Jun2001 13:28:46.4 37.2N 36.2E 5 MB=5.6 M NEI TURKEY

Sichuan China
--->Earthquakes which occurred with Ml>=4.5 in this region included:

--->24Jun2001 08:35:42.8 27.7N 101.0E 33 MB=4.5 M NEI SICHUAN, CHINA

ADDENDA FOR CALIFORNIA:

Re: Far-field aftershocks from Peru
Posted by Lowell on June 24, 2001 at 13:39:09:

In Reply to: Re: Far-field aftershocks from Peru posted by Lowell
on June 24, 2001 at 13:22:14:

The far-field forecast as posted did not include the statement regarding
Central California that I noted in the previous post. The COMPLETE far-field
forecast some portions of which were not posted, did include the following
statement, however, and was received yesterday:

Some areas of the western U.S. most likely to see increased seismic activity:

" ...Mammoth Lakes*, Central San Andreas,... California (so. of San Jose),
Yellowstone, ...No. Utah "

I should add that the original (unedited) forecast also noted likely
far-field activity in the New Madrid region (not included in the
posted version).

---> Notable earthquakes and swarms in the area of the Central
---> San Andreas ... California (So. of San Jose) occurred as follows:
---> Gustine, Gilroy and Tres Pinos all are south of San Jose.

---> GUSTINE CALIFORNIA:

---> 24Jun2001 19:57:21.0 37.1N 121.1W 0 ML=3.1 M NEI CENTRAL CALIFORNIA

---> TRES PINOS CALIFORNIA:

---> 02Jul2001 17:32:32.0 36.7N 121.3W 5 ML=3.4 M NEI CENTRAL CALIFORNIA
---> 02Jul2001 17:33:53.0 36.7N 121.3W 6 ML=4.1 M NEI CENTRAL CALIFORNIA
---> 02Jul2001 22:47:38.0 36.7N 121.3W 5 MD=3.0 M NEI CENTRAL CALIFORNIA
---> 03Jul2001 19:02:50.0 36.7N 121.3W 6 ML=4.0 M NEI CENTRAL CALIFORNIA
---> 03Jul2001 19:07:16.0 36.7N 121.3W 6 ML=3.9 M NEI CENTRAL CALIFORNIA
---> 03Jul2001 19:31:58.0 36.7N 121.3W 4 ML=3.0 M NEI CENTRAL CALIFORNIA
---> 03Jul2001 21:57:18.0 36.7N 121.3W 4 ML=3.8 M NEI CENTRAL CALIFORNIA
---> 03Jul2001 22:13:26.0 36.7N 121.3W 4 ML=3.0 M NEI CENTRAL CALIFORNIA
---> 04Jul2001 06:55:28.0 36.7N 121.3W 6 ML=3.0 M NEI CENTRAL CALIFORNIA
---> 04Jul2001 15:49:57.0 36.7N 121.3W 5 MD=3.0 M NEI CENTRAL CALIFORNIA

---> GILROY, CALIFORNIA:

---> 06Jul2001 13:37:32.0 37.0N 121.5W 5 ML=3.0 M NEI CENTRAL CALIFORNIA

---> ROHNERT PARK, CALIFORNIA:

---> 06Jul2001 15:07:31.0 38.3N 122.6W 7 ML=3.7 M NEI NORTHERN CALIFORNIA

---> KINGS BEACH, CALIFORNIA:

---> 07Jul2001 07:33:54.3 39.3N 119.9W 5 ML=3.5 M NEI NEVADA

---> The swarm near Tres Pinos was the most active since 1982.