SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey February 22, 1996 Weekly Earthquake Report for Southern California ------------------------------------------------ February 15 - 21, 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 818-395-6326. For daily updates, call our Earthquake Information Hotline: 818-395-6977. -------------------------------- This week's Report covers the time period from midnight Thursday morning, February 15, Universal Time (ie. GMT), to midnight Wednesday night, February 21, Universal Time. In local time, the period of coverage is from 4 p.m., February 14 to 4 p.m., February 21, Pacific Standard Time. We detected and processed 378 earthquakes during the 7-day period covered. Of the three quakes felt this week, two were aftershocks and one was not. The first felt quake occurred last Thursday afternoon, near Simi Valley. It had a magnitude of M2.9 and was an aftershock of the January 17, 1994 Mw6.7 Northridge quake. The second felt quake occurred on Saturday evening near Compton, with a magnitude of M2.8. The third, on Wednesday morning, was a Landers aftershock (of the June 28, 1992 Mw7.3 quake), magnitude M3.8. It was felt in Yucca Valley and also in Barstow. The Landers aftershock had the expected strike-slip focal mechanism. The Compton quake had a thrust mechanism, on an east northeast striking fault. Two other M3+ quakes occurred this week. One was last Thursday afternoon in Imperial Valley, M3.0, and the other was a Landers aftershock, M3.2, early Monday morning. The table 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 ------------------------------------------------------------- 2/14 4:00 pm 34 37.5 116 33.2 2.2 25 mi. ENE of Lucerne Valley 2/14 4:57 pm 32 31.9 115 17.3 2.0 15 mi. SE of Calexico 2/15 2:18 pm 35 44.2 117 37.7 2.5 8 mi. NNE of Ridgecrest 2/15 3:56 pm 34 21.0 118 41.7 2.9 5 mi. N of Simi Valley FELT 2/15 4:20 pm 32 46.1 115 27.1 3.0 6 mi. ESE of El Centro 2/15 11:14 pm 33 42.5 116 50.4 2.1 7 mi. WSW of Idyllwild 2/16 6:01 am 34 17.8 118 27.5 2.0 1 mi. NW of Pacoima 2/16 9:41 am 32 47.5 115 26.8 2.1 6 mi. E of El Centro 2/16 11:11 am 34 17.9 118 27.4 2.1 1 mi. NW of Pacoima 2/16 3:34 pm 36 0.8 117 49.6 2.0 Coso Range, 7 mi. ESE of Coso Junction 2/16 4:28 pm 34 9.7 116 25.5 2.0 3 mi. NNE of Yucca Valley 2/16 5:28 pm 34 59.5 116 57.1 2.3 8 mi. NNE of Barstow 2/16 7:40 pm 32 46.7 115 26.6 2.3 6 mi. E of El Centro 2/16 10:20 pm 34 14.1 117 26.4 2.2 2 mi. WNW of Devore 2/17 12:35 am 33 21.5 116 23.3 2.2 7 mi. N of Borrego Springs 2/17 12:53 am 35 44.4 117 37.6 2.0 8 mi. NNE of Ridgecrest 2/17 5:42 pm 34 25.4 120 48.0 2.3 13 mi. SW of Pt. Arguello 2/17 7:18 pm 33 51.6 118 14.5 2.8 2 mi. SW of Compton FELT 2/18 3:32 am 33 14.8 116 14.2 2.2 7 mi. E of Borrego Springs 2/18 6:47 am 33 58.3 116 24.3 2.0 5 mi. E of Desert Hot Springs 2/18 4:47 pm 36 10.9 117 53.4 2.2 Coso Range, 4 mi. E of Haiwee Reservoir 2/18 10:13 pm 34 12.6 116 50.0 2.3 4 mi. SSE of Big Bear City 2/18 11:25 pm 36 5.3 118 14.5 2.1 16 mi. W of Coso Junction 2/18 11:48 pm 35 55.9 117 40.2 2.0 Coso Range, 17 mi. ESE of Coso Junction 2/19 5:04 am 35 47.2 117 39.7 2.1 11 mi. N of Ridgecrest 2/19 5:08 am 34 38.0 116 30.8 3.2 27 mi. ENE of Lucerne Valley 2/19 11:16 am 34 37.4 116 33.2 2.3 25 mi. ENE of Lucerne Valley 2/19 2:04 pm 35 44.1 117 39.6 2.2 7 mi. N of Ridgecrest 2/19 4:43 pm 35 14.1 116 53.3 2.4 8 mi. S of Goldstone Lake 2/19 4:44 pm 34 15.3 118 28.9 2.1 1 mi. SE of Granada Hills 2/19 5:07 pm 35 14.3 116 53.4 2.5 7 mi. S of Goldstone Lake 2/20 1:49 am 35 44.6 117 37.5 2.0 8 mi. NNE of Ridgecrest 2/20 3:04 am 36 11.5 117 54.2 2.1 Coso Range, 4 mi. E of Haiwee Reservoir 2/20 7:49 am 34 55.6 116 45.4 2.1 15 mi. E of Barstow 2/20 3:50 pm 34 17.4 118 27.9 2.0 1 mi. WNW of Pacoima 2/20 3:50 pm 35 46.4 117 37.2 2.1 10 mi. NNE of Ridgecrest 2/20 6:09 pm 33 58.2 116 44.6 2.0 4 mi. NE of Cabazon 2/20 8:45 pm 34 17.7 118 28.0 2.2 1 mi. WNW of Pacoima 2/21 1:57 am 35 11.3 117 21.4 2.0 27 mi. NW of Barstow 2/21 6:43 am 34 16.2 118 27.7 2.1 1 mi. SW of Pacoima 2/21 7:54 am 34 23.4 116 27.5 3.8 18 mi. N of Yucca Valley FELT 2/21 9:47 am 34 23.4 116 27.6 2.1 18 mi. N of Yucca Valley 2/21 12:40 pm 33 15.7 116 23.1 2.0 Under Borrego Springs -------------------------------------------------------------