SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey December 12, 1996 Weekly Earthquake Report for Southern California ------------------------------------------------ December 5 - 11, 1996 Prepared by: Kate Hutton, Seismological Laboratory (kate@bombay.gps.caltech.edu) Lucy Jones, U. S. Geological Survey California Institute of Technology For further information, please contact the authors or the Caltech Public Relations Office at 818-395-6327. For daily updates, call our Earthquake Information Hotline: 818-395-6977. -------------------------------- This week's Report covers the time period from midnight Thursday morning, December 5, Universal Time (ie. GMT), to midnight Wednesday night, December 11, Universal Time. In local time, the period of coverage is from 4 p.m., December 4, Pacific Standard Time, to 4 p.m., December 11, Pacific Standard Time. We detected and processed 540 earthquakes during the seven-day period covered. The high seismicity this week is because of the continuing aftershocks of the M5.3 earthquake that occurred on November 27 near Coso Juntion in the Owens Valley. Since November 27, we have processed 1220 aftershocks to that event. Of this week's earth- quakes, 332 events were Coso aftershocks, including three above M3: a M3.5 on Friday morning, a M3.3 on Tuesday evening and a M3.4 early Wednesday morning. We received no felt reports for any of these events. Given the rate of aftershocks in the last two weeks (slightly higher than an "average" California aftershock sequence, but very typical for the Owens Valley), we would expect to have one or two more M3 aftershocks in the next week. Except for the Coso aftershocks it was a nice, seismically quiet week in southern California. Table 1 lists the quakes this 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. Table 1 ------- Date Time N Lat. W Long. Mag ------------------------------------------------------------- 12/4 7:35 pm 36 4.2 117 38.7 2.0 Coso Range, 17 mi. E of Coso Junction 12/4 10:33 pm 36 3.6 117 38.5 2.0 " 12/4 10:45 pm 34 59.3 116 57.5 2.0 7 mi. NNE of Barstow 12/5 1:36 am 36 5.2 117 39.8 2.7 16 mi. E of Coso Junction 12/5 2:08 am 36 5.2 117 39.4 2.1 " 12/5 4:33 am 36 3.9 117 38.6 2.1 17 mi. E of Coso Junction 12/5 5:36 am 36 4.3 117 39.0 2.3 16 mi. E of Coso Junction 12/5 8:26 am 36 17.2 120 23.7 2.6 10 mi. N of Coalinga 12/5 8:36 am 36 4.0 117 38.1 2.1 17 mi. E of Coso Junction 12/5 9:03 am 36 4.2 117 38.3 2.5 " 12/5 9:05 am 36 4.1 117 38.4 2.5 " 12/5 9:06 am 36 17.9 120 24.8 3.3 11 mi. NNW of Coalinga 12/5 9:23 am 36 4.7 117 38.8 2.1 17 mi. E of Coso Junction 12/5 9:32 am 36 5.0 117 38.0 2.0 " 12/5 11:44 am 36 4.8 117 38.8 2.2 16 mi. E of Coso Junction 12/5 2:43 pm 36 3.6 117 38.8 2.3 " 12/5 3:10 pm 36 3.5 117 38.8 2.7 " 12/5 3:33 pm 36 5.3 117 39.2 2.6 " 12/5 4:36 pm 36 4.6 117 38.6 2.9 17 mi. E of Coso Junction 12/5 5:04 pm 36 4.3 117 38.8 2.2 16 mi. E of Coso Junction 12/5 5:06 pm 36 4.0 117 38.7 2.2 " 12/6 7:49 am 36 4.5 117 38.7 2.4 17 mi. E of Coso Junction 12/6 10:30 am 36 4.6 117 39.0 3.5 16 mi. E of Coso Junction 12/6 10:44 am 36 4.4 117 38.9 2.6 " 12/6 12:51 pm 34 59.3 116 56.6 2.4 8 mi. NNE of Barstow 12/6 3:49 pm 36 4.8 117 39.1 2.1 16 mi. E of Coso Junction 12/6 5:58 pm 36 4.9 117 39.3 2.0 " 12/6 10:24 pm 33 23.3 116 24.3 2.6 9 mi. NNW of Borrego Springs 12/7 5:20 am 36 4.2 117 38.9 2.4 16 mi. E of Coso Junction 12/7 9:18 am 36 4.1 117 39.0 2.4 " 12/7 10:49 am 35 47.0 117 40.1 2.5 11 mi. N of Ridgecrest 12/8 12:39 am 36 4.5 117 39.2 2.3 16 mi. E of Coso Junction 12/8 3:56 pm 34 13.0 118 35.2 2.0 1 mi. NE of Canoga Park 12/8 4:34 pm 36 3.8 117 38.6 2.0 17 mi. E of Coso Junction 12/8 8:27 pm 36 4.6 117 38.0 2.3 " 12/9 1:13 am 35 59.8 117 55.2 2.2 3 mi. SSE of Coso Junction 12/9 2:32 am 34 19.7 116 27.6 2.1 14 mi. N of Yucca Valley 12/9 8:53 am 34 56.4 118 59.2 2.0 3 mi. W of Grapevine 12/9 12:40 pm 35 39.6 117 32.0 2.0 7 mi. ENE of Ridgecrest 12/9 3:19 pm 36 4.5 117 38.5 2.4 17 mi. E of Coso Junction 12/9 4:30 pm 36 4.7 117 38.2 2.4 " 12/9 5:06 pm 36 4.0 117 38.2 2.8 " 12/9 5:06 pm 36 3.8 117 38.0 2.5 " 12/9 5:10 pm 35 39.5 117 32.2 2.6 7 mi. ENE of Ridgecrest 12/9 5:33 pm 36 4.1 117 37.9 2.1 17 mi. E of Coso Junction 12/9 5:47 pm 36 3.8 117 39.9 2.2 15 mi. E of Coso Junction 12/9 6:06 pm 35 39.5 117 32.3 2.2 7 mi. ENE of Ridgecrest 12/9 6:31 pm 35 39.6 117 32.1 2.1 " 12/9 7:15 pm 33 51.7 116 49.7 2.0 4 mi. SSW of Cabazon 12/9 8:33 pm 36 4.1 117 38.2 2.2 17 mi. E of Coso Junction 12/9 8:50 pm 36 24.7 117 51.8 2.4 11 mi. NE of Olancha 12/10 5:43 am 36 4.1 117 38.8 2.3 16 mi. E of Coso Junction 12/10 5:46 am 33 8.9 115 35.5 2.1 3 mi. ESE of Obsidian Butte 12/10 8:21 am 34 9.5 116 25.8 2.2 2 mi. NNE of Yucca Valley 12/10 10:16 am 36 4.1 117 38.0 2.1 17 mi. E of Coso Junction 12/10 11:22 am 34 5.4 117 18.9 2.0 1 mi. SW of San Bernardino 12/10 9:01 pm 36 5.0 117 39.3 3.3 16 mi. E of Coso Junction 12/11 12:01 am 36 4.0 117 38.3 2.0 17 mi. E of Coso Junction 12/11 1:05 am 36 5.4 117 39.3 3.4 16 mi. E of Coso Junction 12/11 1:08 am 36 5.5 117 39.3 2.2 " 12/11 1:27 am 34 35.9 116 16.5 2.5 32 mi. N of Joshua Tree 12/11 3:54 am 36 5.0 117 40.1 2.0 15 mi. E of Coso Junction 12/11 6:03 am 32 39.7 115 40.8 2.1 11 mi. SW of El Centro 12/11 7:27 am 36 4.1 117 38.4 2.3 17 mi. E of Coso Junction 12/11 11:10 am 36 5.0 117 39.3 2.2 16 mi. E of Coso Junction 12/11 11:48 am 36 3.8 117 38.5 2.0 17 mi. E of Coso Junction 12/11 2:15 pm 32 39.3 115 40.4 2.0 10 mi. W of Calexico -------------------------------------------------------------