SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey March 13, 1997 Weekly Earthquake Report for Southern California ------------------------------------------------ March 6 - 12, 1997 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, March 6, Universal Time (ie. GMT), to midnight Wednesday night, March 12, Universal Time. In local time, the period of coverage is from 4 p.m., March 5, Pacific Standard Time, to 4 p.m., March 12, Pacific Standard Time. We detected and processed 340 earthquakes during the seven-day period covered. The weekly seismicity total is somewhat higher this week, due mainly to small events in the Coso and Ridgecrest areas. The largest quake was a Coso quake: M3.6 on Saturday morning, part of on-going activity at that location. Only one quake was reported felt; that was a M3.0 in the Ontario area on Friday afternoon. Ontario is a relatively common source of small, shallow earthquakes. This week's quake was strike slip, as most of them are. 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 ------------------------------------------------------------- 3/5 11:41 pm 36 4.6 117 39.1 2.2 16 mi. E of Coso Junction 3/6 1:47 am 34 22.3 116 28.1 2.0 17 mi. N of Yucca Valley 3/6 3:21 am 33 58.0 116 46.3 2.2 3 mi. NNE of Cabazon 3/6 3:47 am 36 5.8 117 39.7 2.0 16 mi. E of Coso Junction 3/6 11:12 am 36 4.9 117 39.2 2.0 " 3/6 11:42 am 33 47.2 118 38.2 2.0 12 mi. W of Palos Verdes Point 3/6 12:53 pm 33 16.1 116 0.4 2.5 2 mi. WSW of Salton City 3/6 8:29 pm 36 5.7 117 39.9 2.0 16 mi. E of Coso Junction 3/7 12:35 pm 33 3.8 116 28.2 2.2 7 mi. E of Julian 3/7 4:44 pm 33 59.9 117 34.8 3.0 6 mi. SE of Ontario; FELT 3/7 7:04 pm 34 0.1 117 34.9 2.4 " 3/7 8:14 pm 36 56.3 117 57.9 2.0 15 mi. NE of Independence 3/8 7:36 am 36 5.8 117 39.8 2.0 16 mi. E of Coso Junction 3/8 7:36 am 36 5.5 117 40.0 3.6 " 3/8 11:18 am 36 4.5 117 39.0 2.1 " 3/8 6:31 pm 33 37.6 117 49.4 2.0 2 mi. S of Irvine 3/9 3:07 am 36 5.6 117 39.8 2.3 16 mi. E of Coso Junction 3/9 3:43 am 35 29.6 118 17.6 2.0 13 mi. SE of town of Lake Isabella 3/9 5:37 am 35 45.9 117 38.3 2.0 10 mi. N of Ridgecrest 3/9 7:27 am 36 4.6 117 37.7 2.4 18 mi. E of Coso Junction 3/9 12:18 pm 36 5.7 117 39.8 2.3 16 mi. E of Coso Junction 3/9 1:56 pm 33 58.4 117 3.6 2.3 4 mi. SSW of Yucaipa 3/9 4:05 pm 36 5.6 117 40.0 2.0 16 mi. E of Coso Junction 3/9 11:08 pm 36 5.9 117 40.0 2.0 " 3/10 12:54 am 34 0.6 117 13.6 2.1 3 mi. SSE of Loma Linda 3/10 1:52 am 32 36.6 117 17.3 2.0 10 mi. SW of San Diego 3/10 7:29 pm 35 3.9 119 6.8 2.1 10 mi. WNW of Wheeler Ridge 3/10 7:30 pm 35 4.5 119 7.4 2.0 " 3/11 2:22 am 32 38.1 115 54.8 2.3 8 mi. SE of Ocotillo 3/11 5:47 am 34 13.1 117 25.4 2.4 1 mi. W of Devore 3/11 10:28 am 34 22.8 116 27.9 2.1 18 mi. N of Yucca Valley 3/11 1:12 pm 35 46.8 117 39.2 2.1 10 mi. N of Ridgecrest 3/12 3:47 am 35 28.6 120 47.0 2.1 6 mi. W of Atascadero 3/12 9:45 am 32 54.3 115 31.6 2.0 3 mi. S of Brawley -------------------------------------------------------------