12/29/2004 7:27:14 PM Pacific Standard Time

Kent,

Based on this major recent quake (A):
2004/12/26 00:58:50.7   3.5N  95.7E  10   Mw8.9  M+ CSEM  OFF W. CST OF
NORTHERN SUMATERA

I checked a database of large quakes for all of the 20th century.
Here are quakes in history closest to (A):
07/01/1937, 11:49:49.20, lat 3.123, lon 95.787, dep 35.0, Mag 6.8 UK,
10.6 nm away from (3.3N) (95.8E)
08/21/1967, 07:33:03.61, lat 3.696, lon 95.682, dep 42.8, Mag 6.2 mb,
11.8 nautical miles away
06/20/1976, 20:53:12.84, lat 3.437, lon 96.254, dep 16.2, Mag 7.0 Mw,
33.4 nautical miles away
10/30/1976, 09:24:42.22, lat 3.570, lon 96.301, dep 15.4, Mag 5.6 Ms,
36.2 nautical miles away
12/03/1977, 13:41:23.34, lat 3.515, lon 95.890, dep 49.3, Mag 6.1 Mw,
11.4 nautical miles away
11/22/1995, 13:27:55.09, lat 3.113, lon 95.908, dep 27.2, Mag 5.8 Mw,
12.9 nm away from (3.3N) (95.8E)
02/24/1999, 07:20:48.00, lat 3.360, lon 96.000, dep 33.0, Mag 5.3 --,
19.8 nm away from (3.3N) (95.8E)
03/07/2000, 07:32:51.00, lat 3.020, lon 95.660, dep 33.0, Mag 4.9 --,
28.8 nm away from (3.3N) (95.8E)

So if anything, the usual depth for quakes in the Sumatera area is
around 30km, not the 10 as reported.  10km seems to be a "default" focal
depth listed for a lot of quakes, and then the default jumps to 33km.
Always watch out for shallow quakes that are very strong, that occur
multiple times: they are probably caused on purpose.

In case people are wondering, I did a query to see when the last quake
over magnitude 7.0 happened around the world.  I did a query by
Flinn-Engdahl Regions below.  Am I right in thinking one of the safest
places to be is southern Italy?  Chile or Argentina may have their own
quake databases, which is why Iris shows no large quakes.  So wherever a
large 7.0+ quake happened in the last 2 years, an engineered quake could
happen anytime.  Given the current recent quakes, we may have a large
quake every month, somewhere.

http://www.iris.edu/SeismiQuery/events.htm
Last time we had quakes over 7.0, by region
50: NONE (Antarctica, Ross Sea)
49: NONE (Central/Western Siberia)
48: 2002-11-20 (Northwestern Kashmir)
47: 1997-02-27 (Pakistan)
46: 2004-12-26 (Nicobar Islands, India; off W Coast of Northern
Sumatera)
45: 1998-03-25 (Balleny Islands Region)
44: NONE (Galapagos Islands)
43: 2001-08-21 (East of North Island, N.Z.)
42: 1985-12-23 (Northwest Territories, Canada)
41: 2002-11-17 (Sea of Okhotsk)
40: 2000-06-21 (Iceland)
39: 2002-03-20 (North Pacific Ocean)
38: 1979-04-23 (Northwest of Australia)
37: 2001-06-09 (Western Gulf of Aden)
36: (unsure: 1931-07-06 in Dogger Bank, UK)
36: Iris query shows NONE for this area (UK, Southern Norway, Sweden,
most of Europe, Hungary)
35: NONE (Guyana, Suriname, Brazil, French Guiana)
34: 1999-06-15 (Central Mexico)
33: 2003-07-15 (Carlsberg Ridge)
32: 1998-02-16 (North Atlantic Ocean)
31: 1980-11-23 (Southern Italy)
30: 2001-07-26 (Aegean Sea)
29: 2002-03-11 (Eastern Arabian Peninsula)
28: 2003-10-01 (Southwestern Siberia, Russia)
27: 2001-11-14 (Southern XinJiang, China)
26: 2001-01-26 (Southern India)
25: 1995-07-11 (Myanmar-China Border Region)
24: 2004-11-11 (Timor Region, Indonesia)
23: 2003-05-26 (Halmahera, Indonesia)
22: 2002-03-05 (Mindanao, Philippine Islands)
21: 2002-15-15 (Taiwan)
20: 2004-09-05 (Near S. Coast of Western Honshu)
19: 2004-11-28 (Hokkaido, Japan Region)
18: 2002-04-26 (Mariana Islands)
17: 2001-10-12 (South of Mariana Islands)
16: 2004-11-26 (Irian Jaya Region, Indonesia)
15: 2003-01-20 (Solomon Islands)
14: 2004-01-03 (Loyalty Islands Region)
13: 2004-07-15 (Fiji Islands Region)
12: 2002-08-19 (South of Fiji Islands)
11: 2004-12-23 (North of Macquarie Island)
10: 2003-08-04 (Scotia Sea)
09: NONE (near coast of Southern Chile; Argentina)
08: 2004-11-15 (Near West Coast of Colombia)
07: 1999-04-14 (Northern COlombia)
06: 2004-10-09 (Near Coast of Nicaragua)
05: 2003-01-22 (Near Coast of Michoacan, Mexico)
04: 1988-06-18 (Gulf of California)
03: 1999-10-16 (Southern California)
02: 2001-02-28 (Washington state, US)
01: 2003-11-17 (Rat Islands, Aleutian Islands)