At 4:49 pm this afternoon, a ML3.5 quake occurred 2 miles south-southwest of Diamond Bar. We don’t have many “felt reports” yet, but we know it was felt as far as Pasadena.
December 28, 2003
December 26, 2003
Commentary
Two small quakes were felt overnight in the Inland Empire region: a ML2.8 at 9:54 pm & a ML2.9 at 3:00 am. Both quake occurred 4 mi. south-southwest of Devore, or 5 miles north-northeast of Fontana. Felt reports came from San Bernardino, Rialto, Fontana, Rancho Cucamonga, Riverside & Colton.
Comments Off
December 25, 2003
Commentary
Southern California Earthquakes in the Past Week
Kate Hutton ,
Seismological Laboratory
Lucy Jones,
U. S. Geological Survey
California Institute of Technology
December 19 – 25, 2003
Kate Hutton ,
Seismological Laboratory
Lucy Jones,
U. S. Geological Survey
California Institute of Technology
December 19 – 25, 2003
The time period covered is 4 pm on Thursday, December 18 (PDT)
through 4 pm on Thursday, December 25 (PDT). During this period
we dectected and analysed 227 earthquakes. Click
here to see a map.
The table below lists the quakes during the past week
that were M2.0 or larger in the central part of the coverage area.
Times are local times; if you want Greenwich Mean Time, add 7 hrs
to the Pacific Daylight Time or 8 hrs to the Pacific Standard Time
listed.
Mag. Local Date Local Time Lat. Long. Depth Descriptive location
-------------------------------------------------------------------------------------------
9965821 2.6 2003/12/19 03:27:33 36 44.8 N 116 23.1 W 0.1 53 km (33 mi) NE of Furnace Creek, CA
9965829 3.0 2003/12/19 03:45:26 34 1.2 N 117 13.5 W 15.1 4 km (3 mi) SE of Loma Linda, CA
FELT in Riverside & San Bernardino areas
9965833 2.5 2003/12/19 03:50:35 34 1.2 N 117 13.8 W 15.7 4 km (2 mi) SE of Loma Linda, CA
9965889 2.1 2003/12/19 11:45:51 33 51.3 N 117 3.4 W 14.6 11 km (7 mi) SW of Beaumont, CA
9965893 2.0 2003/12/19 13:14:25 35 31.6 N 118 25.7 W 5.6 13 km (8 mi) SSE of town of Lake Isabella, CA
9966017 3.3 2003/12/20 04:52:43 34 41.5 N 116 17.4 W 1.9 62 km (38 mi) N of Joshua Tree, CA
9966109 2.0 2003/12/20 16:42:55 33 29.1 N 116 27.1 W 4.6 22 km (14 mi) ESE of Anza, CA
9966117 2.4 2003/12/20 18:03:24 33 16.2 N 116 4.7 W 2.6 11 km (7 mi) W of Salton City, CA
9966129 2.2 2003/12/20 18:27:57 33 16.1 N 116 4.5 W 3.3 10 km (6 mi) W of Salton City, CA
9966169 2.1 2003/12/20 22:41:53 33 16.0 N 116 5.1 W 2.1 11 km (7 mi) W of Salton City, CA
9966205 2.1 2003/12/21 03:10:42 33 15.8 N 116 5.0 W 1.9 11 km (7 mi) W of Salton City, CA
9966281 2.0 2003/12/21 12:02:44 34 10.0 N 117 43.6 W 8.7 7 km (4 mi) N of Claremont Colleges, CA
9966981 2.1 2003/12/22 17:21:13 35 14.4 N 118 35.7 W 7.9 18 km (11 mi) NW of Tehachapi, CA
9967049 2.8 2003/12/22 18:38:59 31 50.0 N 115 47.4 W 6.0 97 km (60 mi) SSW of Calexico, CA
9967153 2.1 2003/12/22 20:07:00 35 3.5 N 119 3.5 W 15.6 12 km (7 mi) WNW of Wheeler Ridge, CA
9967225 2.0 2003/12/22 21:05:08 35 3.9 N 119 4.4 W 16.4 13 km (8 mi) WNW of Wheeler Ridge, CA
9967457 2.0 2003/12/23 00:19:37 35 3.9 N 119 3.6 W 15.7 13 km (8 mi) WNW of Wheeler Ridge, CA
9967465 2.1 2003/12/23 00:21:51 35 3.7 N 119 4.1 W 16.9 13 km (8 mi) WNW of Wheeler Ridge, CA
9967589 2.0 2003/12/23 02:24:22 35 3.8 N 119 4.5 W 19.4 14 km (8 mi) WNW of Wheeler Ridge, CA
9967713 2.4 2003/12/23 04:54:07 32 8.5 N 115 24.0 W 6.0 59 km (37 mi) S of Calexico, CA
9968005 2.1 2003/12/23 13:00:36 32 41.9 N 115 56.3 W 5.2 7 km (4 mi) SE of Ocotillo, CA
9968525 3.7 2003/12/24 09:42:23 34 46.6 N 120 30.9 W 1.1 16 km (10 mi) NNW of Lompoc, CA
FELT in Lompoc, Santa Maria, Paso Robles, Santa Barbara
9968581 2.0 2003/12/24 13:38:35 33 50.7 N 117 6.6 W 11.7 8 km (5 mi) NNE of Perris, CA
9968597 2.6 2003/12/24 14:09:02 34 3.6 N 116 40.0 W 9.1 8 km (5 mi) WNW of Morongo Valley, CA
9968681 2.7 2003/12/24 18:32:00 36 57.5 N 117 57.3 W 3.2 28 km (17 mi) NE of Independence, CA
9968737 2.6 2003/12/24 20:58:58 33 9.2 N 116 0.8 W 5.9 11 km (7 mi) E of Ocotillo Wells, CA
9968757 3.2 2003/12/24 21:47:53 32 8.6 N 116 25.4 W 1.3 74 km (46 mi) SE of San Ysidro, CA
9968841 2.3 2003/12/24 23:29:59 34 11.8 N 117 35.1 W 4.1 10 km (6 mi) N of Rancho Cucamonga, CA
-------------------------------------------------------------------------------------------
Comments Off
December 24, 2003
Commentary
The earthquake of 9:42 am today (12/24) was not a San Simeon aftershock. It was located 3 miles north-northwest of Vandenberg Air Force Base, near Lompoc. Magnitude was ML3.7. It is being reported felt at Vandenberg AFB & also in Lompoc, Santa Maria, Paso Robles & even Santa Barbara.
Comments Off
December 23, 2003
Commentary
There was an update today from the U.S.G.S. in Menlo Park, indicating that surface rupture was found on the Oceanic fault. This makes it the probably culprit for the Mw6.5. Aftershocks continue. The largest so far is still the Mw4.7 that happened 11 minutes after the mainshock.
Comments Off
December 22, 2003
Commentary
Late this morning (11:15 and 56 seconds), Central California experienced a Mw6.5 earthquake. The epicenter was located 7 miles northeast of San Simeon. This is within the Northern California Seismic Network, operated by the U.S. Geological Survey out of Menlo Park. Our colleagues there report that the aftershocks are indicating a unilateral fault rupture to the southeast, with a fault length of possibly up to 15 or 20 miles. The Oceanic fault (which is actually on land, not offshore) is at the moment considered a likely culprit. It is one of a series of thrust faults located between strike-slip faults, themselves parallel to the San Andreas fault, which is about 35 miles to the northeast.
Today’s earthquake was clearly felt as far away as the Bay area and Orange County, with a few reports from south of Oceanside. The town of Lockwood reported intensity Modified Mercalli VIII. Paso Robles & Shandon have reported intensity VII. These levels of shaking can easily cause damage to older structures.
Many feelable aftershocks are to be expected. The U.S.G.S. aftershock warning indicates a 90% chance of a M5.0 or larger aftershock within the next week. The chances of a bigger quake are, of course, much smaller. The usual chance that any quake in California is a foreshock is 5% or 1 out of 20. Since it has been nearly three hours since the mainshock & no larger quake has happened, this risk is probably now down in the 2 to 3% level.
Also of possibly some interest was a ML4.1 earthquake on Saturday, in the remote mountains 24 miles east of Big Pine, in the northern Owens Valley. The time was 8:35 am on Saturday. It was reported lightly felt in Bishop, Big Pine, Independence, Lone Pine & surrounding areas.
Comments Off
December 19, 2003
Commentary
Early this morning, there was a ML3.0 quake near the intersection of the Banning & San Jacinto faults, 3 miles southeast of Loma Linda. The time was 3:45 am & the quake was reported felt throughout the Riveerside & San Bernardino areas.
Comments Off
December 18, 2003
Commentary
Southern California Earthquakes in the Past Week
Seismological Laboratory
Lucy Jones,
U. S. Geological Survey
California Institute of Technology
December 18, 2003
Seismological Laboratory
Lucy Jones,
U. S. Geological Survey
California Institute of Technology
December 18, 2003
The time period covered is 4 pm on Thursday, December 11, 2003 (PST)
through 4 pm on Thursday, December 18, 2003 (PST). During this period
we dectected and analysed 206 earthquakes. Click
here to see a map.
The table below lists the quakes during the past week
that were M2.0 or larger in the central part of the coverage area.
Times are local times; if you want Greenwich Mean Time, add 7 hrs
to the Pacific Daylight Time or 8 hrs to the Pacific Standard Time
listed.
Mag. PDT Date PDT Time Lat. Long. Depth Descriptive location
-------------------------------------------------------------------------------------------
#EVID MAG YYYY/MM/DD HH:mm:SS LAT LON DEP LOCATION
9963181 2.7 2003/12/11 20:42:13 33 18.2 N 116 51.0 W 13.8 6 km ( 4 mi) SSE of Palomar Observatory, CA
Felt in Escondido, Valley Center, & Ramona
9963697 2.3 2003/12/13 01:42:03 32 58.4 N 117 43.5 W 6.0 40 km (25 mi) SW of Oceanside, CA
9963801 2.2 2003/12/13 07:53:38 34 30.6 N 120 10.8 W 5.1 10 km ( 6 mi) SSW of Solvang, CA
9963861 2.7 2003/12/13 10:46:40 34 11.4 N 117 32.9 W 4.6 10 km ( 6 mi) NNE of Rancho Cucamonga, CA
Felt in Rancho Cucamonga
9963989 2.1 2003/12/14 01:33:04 35 1.8 N 116 58.0 W 7.2 17 km (10 mi) NNE of Barstow, CA
9964589 2.0 2003/12/15 02:25:43 35 7.0 N 119 1.3 W 13.1 14 km ( 9 mi) NNW of Wheeler Ridge, CA
9964969 2.4 2003/12/15 14:44:50 34 15.0 N 116 45.3 W 3.1 9 km ( 6 mi) E of Big Bear City, CA
9964973 2.1 2003/12/15 14:45:22 34 15.2 N 116 45.3 W 4.1 9 km ( 6 mi) E of Big Bear City, CA
9965005 2.3 2003/12/15 16:57:00 33 20.0 N 116 47.3 W 14.1 7 km ( 5 mi) ESE of Palomar Observatory, CA
9965357 2.5 2003/12/17 02:01:36 33 48.0 N 116 10.9 W 5.6 10 km ( 6 mi) NNE of Indio, CA
9965381 2.5 2003/12/17 05:12:33 34 31.8 N 116 16.5 W 5.3 44 km (27 mi) N of Joshua Tree, CA
9965401 2.4 2003/12/17 07:16:48 32 42.3 N 115 57.7 W 5.5 4 km ( 3 mi) SE of Ocotillo, CA
9965453 2.1 2003/12/17 13:10:25 35 7.3 N 119 0.8 W 7.1 14 km ( 9 mi) NNW of Wheeler Ridge, CA
9965533 2.2 2003/12/17 21:56:12 35 6.8 N 119 1.0 W 10.9 14 km ( 9 mi) NNW of Wheeler Ridge, CA
9965545 2.4 2003/12/17 22:38:18 34 0.5 N 116 19.3 W 4.9 14 km ( 9 mi) S of Joshua Tree, CA
9965573 2.4 2003/12/18 04:12:02 32 43.9 N 115 25.0 W 15.4 10 km ( 6 mi) NE of Calexico, CA
9965581 2.2 2003/12/18 05:05:58 35 7.1 N 119 0.9 W 11.8 14 km ( 9 mi) NNW of Wheeler Ridge, CA
9965585 2.0 2003/12/18 05:17:40 34 22.5 N 116 53.1 W 2.9 9 km ( 6 mi) SE of Lucerne Valley, CA
-------------------------------------------------------------------------------------------
Comments Off
December 15, 2003
Commentary
A small quake on Saturday was reported felt in Rancho Cucamonga. The quake was a ML2.7, loated 6 miles north-northeast of Ranch Cucamonga. The time was 10:46 am on Saturday.
Comments Off
Commentary
The Diamond Bar earthquake just mentioned was followed at 5:03 pm by a ML3.2 at the same location. Both quakes were widely felt between about Pasadena and Riverside, and into Orange County.