SCSN Earthquake Commentary

May 30, 2003

Commentary

Filed under: Old Commentary — kate @ 12:56 pm

Late this morning, a small quake was felt in Goleta. It had a magnitude of M2.1 & was located beneath the Santa Barbara channel, 14 miles southwest of Santa Barbara.

May 29, 2003

Commentary

Filed under: Weekly — kate @ 12:00 am



Southern California Earthquakes in the Past Week


Nick Scheckel ,

Seismological Laboratory
Lucy Jones,

U. S. Geological Survey
California Institute of Technology

May 29, 2003

The time period covered is 5 pm on Thursday, May 22 (PDT)
through 5 pm on Thursday, May 29 (PDT). During this period
we dectected and analysed 352 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. PST Date   PST Time  Lat.       Long.    Depth  Descriptive location
-------------------------------------------------------------------------------------------
13966128  3.0  2003/05/23 11:35:41 35 12.5 N 118  7.0 W  5.0   17 km (11 mi) WNW  of California City, CA
13966180  2.6  2003/05/23 14:43:13 32 57.0 N 115 33.5 W 14.7    3 km ( 2 mi) WSW  of Brawley, CA
13966192  2.8  2003/05/23 14:55:14 32 56.6 N 115 33.3 W 16.8    3 km ( 2 mi) SW   of Brawley, CA
13966196  2.2  2003/05/23 14:57:18 32 56.9 N 115 33.2 W 15.4    2 km ( 1 mi) SW   of Brawley, CA
13966220  2.8  2003/05/23 15:43:57 32 56.9 N 115 33.1 W 15.2    2 km ( 1 mi) SW   of Brawley, CA
13966240  2.1  2003/05/23 16:53:10 36  7.5 N 117 21.8 W  3.2   25 km (16 mi) W    of Telescope Peak, CA
13966244  3.5  2003/05/23 16:53:37 32 56.9 N 115 33.3 W 15.8    2 km ( 1 mi) SW   of Brawley, CA
               Felt in the Brawley, El Centro, and Imperial areas.
13966248  2.0  2003/05/23 16:57:54 32 57.1 N 115 34.1 W 10.8    3 km ( 2 mi) WSW  of Brawley, CA
13966252  2.1  2003/05/23 17:04:32 32 56.5 N 115 33.1 W 15.4    3 km ( 2 mi) SW   of Brawley, CA
13966272  2.3  2003/05/23 17:12:48 32 56.7 N 115 33.1 W 15.1    2 km ( 2 mi) SW   of Brawley, CA
13966276  2.1  2003/05/23 17:14:48 32 57.3 N 115 33.3 W 14.8    2 km ( 1 mi) WSW  of Brawley, CA
13966284  2.1  2003/05/23 17:18:59 32 56.9 N 115 33.7 W 11.6    3 km ( 2 mi) WSW  of Brawley, CA
 9519018  2.6  2003/05/23 17:20:52 32 56.6 N 115 33.2 W 15.5    3 km ( 2 mi) SW   of Brawley, CA
13966288  3.1  2003/05/23 17:20:58 32 56.6 N 115 33.2 W 15.2    3 km ( 2 mi) SW   of Brawley, CA
 9519262  2.1  2003/05/23 17:34:36 32 56.9 N 115 33.3 W 14.7    2 km ( 1 mi) SW   of Brawley, CA
13966328  2.3  2003/05/23 18:12:34 32 57.0 N 115 33.1 W 15.2    2 km ( 1 mi) SW   of Brawley, CA
13966348  2.6  2003/05/23 18:38:37 32 56.9 N 115 32.9 W 12.9    2 km ( 1 mi) SW   of Brawley, CA
13966364  2.4  2003/05/23 18:42:42 32 57.0 N 115 33.4 W 15.6    2 km ( 1 mi) WSW  of Brawley, CA
13966384  2.3  2003/05/23 18:50:39 32 56.8 N 115 33.3 W 15.8    3 km ( 2 mi) SW   of Brawley, CA
13966388  2.2  2003/05/23 18:52:40 32 57.3 N 115 32.6 W 16.6    1 km ( 1 mi) SW   of Brawley, CA
13966392  2.3  2003/05/23 18:56:29 32 57.3 N 115 33.1 W 15.1    2 km ( 1 mi) WSW  of Brawley, CA
13966396  4.2  2003/05/23 19:04:28 32 56.9 N 115 33.0 W 16.0    2 km ( 1 mi) SW   of Brawley, CA
               Felt in the Brawley, El Centro, Imperial, and Niland areas.
13966400  2.6  2003/05/23 19:07:45 32 57.0 N 115 32.8 W 14.9    2 km ( 1 mi) SW   of Brawley, CA
 9519022  2.1  2003/05/23 19:13:54 32 56.5 N 115 32.9 W 16.5    3 km ( 2 mi) SSW  of Brawley, CA
 9519026  2.1  2003/05/23 19:16:35 32 57.1 N 115 33.8 W 14.0    3 km ( 2 mi) WSW  of Brawley, CA
13966416  2.4  2003/05/23 19:17:56 32 57.7 N 115 33.3 W 14.0    2 km ( 1 mi) W    of Brawley, CA
13966432  2.1  2003/05/23 19:26:32 32 56.6 N 115 33.5 W 16.4    3 km ( 2 mi) SW   of Brawley, CA
13966436  2.2  2003/05/23 19:28:26 32 57.0 N 115 32.9 W 15.3    2 km ( 1 mi) SW   of Brawley, CA
13966452  2.7  2003/05/23 19:37:42 32 57.2 N 115 33.2 W 15.0    2 km ( 1 mi) WSW  of Brawley, CA
13966456  2.1  2003/05/23 19:39:56 32 57.6 N 115 33.3 W 15.9    2 km ( 1 mi) W    of Brawley, CA
13966468  2.1  2003/05/23 19:47:15 32 58.4 N 115 33.0 W 15.4    2 km ( 1 mi) NW   of Brawley, CA
13966480  2.7  2003/05/23 19:50:12 32 56.8 N 115 32.7 W 14.7    2 km ( 1 mi) SSW  of Brawley, CA
13966492  2.5  2003/05/23 20:03:21 32 56.8 N 115 32.7 W 15.3    2 km ( 1 mi) SSW  of Brawley, CA
13966516  2.3  2003/05/23 20:25:15 32 57.6 N 115 33.1 W 15.1    2 km ( 1 mi) W    of Brawley, CA
13966520  2.5  2003/05/23 20:30:38 32 57.1 N 115 32.2 W 14.8    1 km ( 1 mi) S    of Brawley, CA
13966532  2.2  2003/05/23 20:46:32 32 57.3 N 115 33.1 W 14.3    2 km ( 1 mi) WSW  of Brawley, CA
13966544  2.1  2003/05/23 21:01:05 32 57.2 N 115 32.4 W 15.1    1 km ( 1 mi) SSW  of Brawley, CA
13966564  2.5  2003/05/23 21:29:01 32 56.8 N 115 33.5 W 17.1    3 km ( 2 mi) SW   of Brawley, CA
13966568  2.2  2003/05/23 21:46:40 32 57.1 N 115 33.8 W 13.5    3 km ( 2 mi) WSW  of Brawley, CA
13966572  2.0  2003/05/23 21:48:37 32 57.3 N 115 33.2 W 13.0    2 km ( 1 mi) WSW  of Brawley, CA
13966576  2.8  2003/05/23 21:51:49 32 56.8 N 115 33.1 W 14.5    2 km ( 1 mi) SW   of Brawley, CA
13966612  2.2  2003/05/23 22:24:52 34 21.3 N 116  7.6 W  7.6   25 km (16 mi) NNW  of Twentynine Palms, CA
13966616  2.5  2003/05/23 22:29:52 32 57.3 N 115 32.9 W 13.7    1 km ( 1 mi) SW   of Brawley, CA
13966636  2.5  2003/05/23 23:30:03 32 57.5 N 115 32.9 W 14.7    1 km ( 1 mi) WSW  of Brawley, CA
13966672  3.8  2003/05/23 23:51:10 32 57.7 N 115 32.7 W 16.7    1 km ( 1 mi) W    of Brawley, CA
          Felt in the Brawley, El Centro, and Imperial areas.
13966676  2.1  2003/05/23 23:55:54 32 57.4 N 115 32.8 W 14.9    1 km ( 1 mi) WSW  of Brawley, CA
13966684  2.7  2003/05/23 23:58:07 32 57.1 N 115 33.0 W 14.5    2 km ( 1 mi) SW   of Brawley, CA
13966692  2.6  2003/05/24 00:01:27 32 57.5 N 115 32.6 W 14.4    1 km ( 1 mi) WSW  of Brawley, CA
13966708  2.3  2003/05/24 00:11:32 32 57.4 N 115 32.4 W 14.9    1 km ( 0 mi) SW   of Brawley, CA
13966712  2.1  2003/05/24 00:13:54 32 57.6 N 115 32.9 W 16.2    1 km ( 1 mi) WSW  of Brawley, CA
13966756  2.3  2003/05/24 01:25:56 32 57.5 N 115 33.1 W 15.5    2 km ( 1 mi) WSW  of Brawley, CA
13966796  2.2  2003/05/24 03:01:58 32 57.0 N 115 32.7 W 14.9    2 km ( 1 mi) SW   of Brawley, CA
13966836  2.0  2003/05/24 07:30:26 32 57.7 N 115 32.6 W 14.5    1 km ( 0 mi) W    of Brawley, CA
13966880  2.7  2003/05/24 10:36:43 34 39.4 N 116 17.5 W  4.8   58 km (36 mi) N    of Joshua Tree, CA
13966932  2.1  2003/05/24 13:46:39 32 29.3 N 117 27.2 W  7.0   37 km (23 mi) SW   of San Diego, CA
13966988  2.6  2003/05/24 19:27:37 35 12.5 N 118  7.5 W  4.2   18 km (11 mi) WNW  of California City, CA
13967032  2.0  2003/05/24 21:03:36 34 44.8 N 116 18.6 W  8.8   62 km (38 mi) SSW  of Baker, CA
13967100  2.6  2003/05/25 14:01:12 35 19.8 N 119 13.2 W 28.6   20 km (13 mi) WSW  of Bakersfield, CA
13967144  2.1  2003/05/25 20:31:30 34 53.7 N 119 31.3 W  5.6   28 km (18 mi) SSW  of Taft, CA
13967172  2.2  2003/05/26 00:46:51 35 17.3 N 118 35.2 W  5.5   22 km (13 mi) NW   of Tehachapi, CA
13967176  2.2  2003/05/26 00:58:22 32 15.2 N 115 47.1 W  7.0   54 km (33 mi) SSW  of Calexico, CA
13967216  2.4  2003/05/26 05:32:19 32 15.1 N 115 47.0 W  7.0   54 km (33 mi) SSW  of Calexico, CA
13967368  2.0  2003/05/27 03:14:29 35 15.7 N 118 33.3 W  8.1   18 km (11 mi) NW   of Tehachapi, CA
 9919217  2.3  2003/05/27 11:49:33 34  0.4 N 116 43.7 W 19.6   11 km ( 7 mi) NNE  of Cabazon, CA
 9919253  2.1  2003/05/27 16:39:10 33 55.5 N 117 46.6 W  9.5    5 km ( 3 mi) NE   of Yorba Linda, CA
 9919337  2.1  2003/05/28 03:22:30 32 58.3 N 115 33.9 W 13.5    3 km ( 2 mi) WNW  of Brawley, CA
 9919485  2.1  2003/05/28 12:54:52 33 45.0 N 116  1.2 W  7.8   19 km (12 mi) ENE  of Indio, CA
 9919625  2.2  2003/05/29 06:52:42 32 14.5 N 115 46.6 W  7.0   54 km (34 mi) SSW  of Calexico, CA
 9919733  2.1  2003/05/29 16:57:56 32 25.9 N 115 10.6 W  7.0   40 km (25 mi) SE   of Calexico, CA
-------------------------------------------------------------------------------------------


May 24, 2003

Commentary

Filed under: Old Commentary — kate @ 8:32 am

The Brawley swarm continued overnight at a somewhat reduced rate. Nothing that would be noticed by the public has occurred since about midnight. We have had a slight revision in magnitudes: M3.5 at 4:53 pm, M3.1 at 5:20 pm, M4.2 at 7:04 pm & M3.5 at 11:51 pm. We are aware of a software bug that causes the real-time system, which is responsible for the initial estimates, to underestimate the magnitudes in some geographic areas. We are currently testing a new version off-line which should fix this problem.

May 23, 2003

Commentary

Filed under: Old Commentary — kate @ 7:30 pm

It looks like the “tiny” Brawley swarm mentioned in the last entry is not so small any more. So far this evening, there have been: a M3.5 at 4:53 pm, a M3.0 at 5:20 pm & a M4.0 at 7:04 pm, plus a few dozen smaller quakes. “Felt reports” have come in from Brawley, El Centro & even the Yuma AZ area. The M4.0 was reported at Modified Mercalli intensity V in the Brawley area (see the “Did You Feel It?” link above), which means items were knocked off shelves & so forth. The typical Imperial Valley swarm could go on for two to three days. Some historical swarms have included quakes in the M5 range (for example, the Westmorland sequence in April of 1981), but most swarms do not include quakes of this size.

Commentary

Filed under: Old Commentary — kate @ 3:26 pm

We’ve just had two more small “felt” quakes: a M2.6 at 2:43 pm & a M2.8 at 2:55 pm. They are the largest of another tiny swarm, located 2 miles southwest of Brawley, in the Imperial Valley. Both these quakes were felt in Brawley.

Commentary

Filed under: Old Commentary — kate @ 1:32 pm

There was a M3.0 quake late this morning, at 11:35 am, located 11 miles north of Mojave or 11 miles west-northwest of California City. This quake has been reported felt in Mojave & Rosamond.

Commentary

Filed under: Old Commentary — kate @ 7:16 am

A small swarm seems to have been going on yesterday in the southern Sierra region, 20 miles south-southwest of Coso Junction. There were two quakes that would have been feelable, if the epicentral area were more populated, plus a handful of smaller ones. The two largest were a M2.8 at 12:03 pm & a M2.9 at 1:20 pm.

May 22, 2003

Commentary

Filed under: Old Commentary — kate @ 9:32 am

A small quake (M2.5) was fairly widely felt in the San Gabriel Valley this morning, at 8:53 am. The epicenter was located 1 mile north-northwest of San Gabriel, not too far from the Raymond Hill fault. The focal mechanism is strike-slip & consistent with that fault. So far, we have reports that it was felt in Pasadena (including the Seismological Lab), South Pasadena, Temple City, Monterey Park & nearby areas of Los Angeles.

Commentary

Filed under: Weekly — kate @ 12:00 am



Southern California Earthquakes in the Past Week


Nick Scheckel ,

Seismological Laboratory
Lucy Jones,

U. S. Geological Survey
California Institute of Technology

May 22, 2003

The time period covered is 5 pm on Thursday, May 15 (PDT)
through 5 pm on Thursday, May 22 (PDT). During this period
we dectected and analysed 181 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. PST Date   PST Time  Lat.       Long.    Depth  Descriptive location
-------------------------------------------------------------------------------------------
 9916053  2.2  2003/05/15 21:15:55 34 40.6 N 116 21.1 W  4.7   60 km (37 mi) N    of Joshua Tree, CA
 9916109  2.1  2003/05/16 07:37:41 36  5.9 N 117 54.0 W  4.4    7 km ( 5 mi) NE   of Coso Junction, CA
 9916233  2.9  2003/05/16 17:35:14 34 47.4 N 118 55.4 W 14.5    4 km ( 2 mi) SSE  of Frazier Park, CA
 9916309  2.7  2003/05/17 00:18:09 34 30.0 N 116 14.8 W  8.2   41 km (25 mi) N    of Joshua Tree, CA
 9916317  2.1  2003/05/17 01:48:24 34 17.9 N 116 53.7 W  8.3    5 km ( 3 mi) NW   of Big Bear City, CA
 9916341  3.1  2003/05/17 04:27:26 33 10.9 N 115 36.3 W  3.0    3 km ( 2 mi) ENE  of Obsidian Butte, CA
 9916481  2.3  2003/05/17 23:26:32 33 59.3 N 116 40.7 W 18.0   11 km ( 7 mi) SW   of Morongo Valley, CA
 9916501  2.0  2003/05/18 02:38:44 33 58.7 N 118 54.7 W 14.7    8 km ( 5 mi) SSE  of Leo Carrillo State Beach, CA
 9916541  2.0  2003/05/18 11:38:47 32  5.6 N 115 23.6 W  7.0   65 km (40 mi) S    of Calexico, CA
 9916569  2.4  2003/05/18 18:15:57 33 10.6 N 115 36.0 W  1.9    4 km ( 2 mi) ENE  of Obsidian Butte, CA
 9916593  2.7  2003/05/18 20:05:02 34 23.2 N 119 19.5 W  7.1   10 km ( 6 mi) SW   of Ojai, CA
 9916597  2.6  2003/05/18 20:06:20 34 24.8 N 119 19.1 W  7.8    7 km ( 5 mi) WSW  of Ojai, CA
 9916601  2.7  2003/05/18 20:13:55 34 23.7 N 119 19.3 W  9.2    9 km ( 6 mi) SW   of Ojai, CA
 9916613  2.2  2003/05/18 22:18:05 32 52.6 N 116 15.6 W  8.1   29 km (18 mi) WNW  of Ocotillo, CA
 9916617  2.9  2003/05/18 23:19:08 34 33.4 N 116 29.7 W  2.8   43 km (27 mi) ENE  of Lucerne Valley, CA
 9916641  2.4  2003/05/19 01:56:31 36  6.2 N 117 54.1 W  3.8    8 km ( 5 mi) NNE  of Coso Junction, CA
 9916661  2.3  2003/05/19 06:17:57 35 39.2 N 118 26.5 W  4.5    3 km ( 2 mi) NE   of town of Lake Isabella, CA
 9916941  2.8  2003/05/20 03:06:17 36  7.8 N 117 22.3 W  1.6   26 km (16 mi) W    of Telescope Peak, CA
 9916957  2.0  2003/05/20 05:18:59 33 15.0 N 115 33.6 W  7.8    4 km ( 3 mi) WNW  of Niland, CA
 9917245  2.0  2003/05/21 04:42:17 34 41.1 N 118 28.2 W 12.6    8 km ( 5 mi) WNW  of Elizabeth Lake, CA
 9917273  2.3  2003/05/21 08:21:14 35 57.2 N 117  2.2 W  5.6   25 km (15 mi) S    of Telescope Peak, CA
13965712  2.0  2003/05/21 18:36:40 33 55.0 N 116 39.3 W 16.4   12 km ( 7 mi) E    of Cabazon, CA
13965784  2.3  2003/05/22 06:44:43 34 18.9 N 117  0.9 W  5.7   13 km ( 8 mi) NW   of town of Big Bear Lake, CA
13965804  2.0  2003/05/22 08:06:04 34 12.6 N 119 38.0 W  7.0   22 km (14 mi) NNW  of Santa Cruz Is.
13965816  2.5  2003/05/22 08:53:19 34  6.3 N 118  6.3 W  8.4    2 km ( 1 mi) NNW  of San Gabriel, CA
               Felt around San Gabriel Valley area.
13965836  2.2  2003/05/22 10:01:24 35 45.7 N 118  2.0 W  3.5   32 km (20 mi) SSW  of Coso Junction, CA
13965884  2.8  2003/05/22 12:03:33 35 45.9 N 118  1.9 W  3.6   32 km (20 mi) SSW  of Coso Junction, CA
13965908  2.9  2003/05/22 13:20:24 35 45.7 N 118  1.9 W  3.4   32 km (20 mi) SSW  of Coso Junction, CA
-------------------------------------------------------------------------------------------


May 19, 2003

Commentary

Filed under: Old Commentary — kate @ 9:39 am

There were several small earthquakes of interst over the weekend:

Late Friday afternoon, at 5:35 pm, a M2.9 quake was felt in Frazier Park & Lebec. The epicenter was located 2 miles south-southeast of Frazier Park, not too far from the San Andreas fault.

Later, at 12:18 am, there was a M2.7 Hector Mines aftershock, which took place 25 miles north of Joshua Tree. It was, as far as we know, not felt, probably due to its remote location.

At 4:27 am (also on Saturday), a M3.1 quake occurred in the often active Brawley Seismic zone, in the Imperial Valley. This quake was centered 2 miles east-northeast of Obsidian Butte. We have a single report of its being felt in Calipatria.

Also, there was a pair of M2.7 quakes late Sunday night, 6 miles southwest of Ojai. They occurred at 8:05 pm & 8:13 pm. Both were felt in Ojai & Ventura.

Finally, there was a M2.9 Landers aftershock, at 11:19 pm on Sunday, located 26 miles east-northeast of Lucerne Valley. We have no “felt reports” on this quake, again due to the remote location of the epicenter.

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