SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey October 10, 1996 Weekly Earthquake Report for Southern California ------------------------------------------------ October 3 - 9, 1996 Prepared by: Nick Scheckel, Seismological Laboratory Debbie Wells, 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, October 3, Universal Time (ie. GMT), to midnight Wednesday night, October 9, Universal Time. In local time, the period of coverage is from 5 p.m., October 2, Pacific Daylight Time, to 5 p.m., October 9, Pacific Daylight Time. We detected and processed 312 earthquakes during the seven-day period covered. The only two earthquakes over a M3 for this week were both felt. The first and largest event of the week was a M3.3 Northridge aftershock (M6.7, January 17th, 1994) which shook the people of San Fernando Saturday evening. The second, a M3.2, was part of a short lived swarm which started Sunday afternoon near Niland. It produced 6 earthquakes over a M2, half of those in less than 10 minutes. This swarm was located near Obsidian Butte at the southern end of the Salton Sea, a continuing site of many small swarms. Also felt, was another Northridge aftershock occurring near Granada Hills Wednesday morning, that was a M2.9. 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 ------------------------------------------------------------- 10/ 2 8:53 pm 34 20.4 116 28.0 2.0 15 mi. N of Yucca Valley 10/ 3 1:04 am 32 45.8 115 26.1 2.3 7 mi. NNE of Calexico 10/ 3 1:07 am 32 46.1 115 26.6 2.1 6 mi. ESE of El Centro 10/ 3 5:05 am 32 45.9 115 26.4 2.0 7 mi. NNE of Calexico 10/ 3 5:05 pm 32 46.1 115 26.4 2.1 " 10/ 3 6:58 pm 34 20.6 116 28.4 2.0 15 mi. N of Yucca Valley 10/ 3 9:57 pm 34 7.7 117 1.5 2.4 6 mi. N of Yucaipa 10/ 3 11:05 pm 34 13.2 116 46.2 2.2 5 mi. ESE of Big Bear City 10/ 4 12:21 pm 33 57.1 117 48.9 2.4 3 mi. S of Diamond Bar 10/ 4 8:55 pm 33 22.2 116 19.2 2.2 8 mi. NNE of Borrego Springs 10/ 4 11:38 pm 33 33.6 118 13.1 2.0 10 mi. SSE of Pt. Fermin, San Pedro 10/ 5 4:56 am 33 11.5 115 35.8 2.0 2 mi. ENE of Obsidian Butte 10/ 5 10:33 pm 34 17.7 118 26.6 3.3 Under San Fernando; FELT 10/ 6 4:18 am 34 8.7 116 25.6 2.0 2 mi. NNE of Yucca Valley 10/ 6 4:31 am 33 58.0 116 53.5 2.1 2 mi. NNW of Banning 10/ 6 6:06 am 34 17.6 118 27.2 2.0 1 mi. NW of Pacoima 10/ 6 12:18 pm 33 11.3 115 34.1 2.2 4 mi. SW of Niland 10/ 6 2:39 pm 34 17.9 118 27.1 2.1 1 mi. NW of San Fernando 10/ 6 3:00 pm 33 11.5 115 33.9 2.8 4 mi. SW of Niland 10/ 6 3:01 pm 33 11.3 115 33.7 2.7 " 10/ 6 3:08 pm 33 11.4 115 34.0 2.8 " 10/ 6 3:32 pm 33 11.1 115 33.8 2.2 " 10/ 6 6:21 pm 33 11.5 115 34.0 3.2 4 mi. SW of Niland; FELT 10/ 6 10:20 pm 33 11.2 115 33.8 2.0 " 10/ 7 10:30 am 34 7.5 116 24.6 2.1 2 mi. ENE of Yucca Valley 10/ 7 5:26 pm 35 56.7 117 43.2 2.3 14 mi. ESE of Coso Junction 10/ 8 12:17 am 34 20.7 116 26.0 2.0 15 mi. N of Yucca Valley 10/ 8 12:50 am 34 15.6 118 33.0 2.1 1 mi. NNW of Northridge 10/ 8 6:41 am 34 15.0 116 25.9 2.1 9 mi. N of Yucca Valley 10/ 8 9:37 am 35 49.3 117 45.2 2.1 14 mi. NNW of Ridgecrest 10/ 8 9:46 am 34 17.3 118 33.1 2.8 3 mi. WNW of Granada Hills 10/ 8 9:50 am 34 58.6 117 25.6 2.2 12 mi. E of Boron 10/ 8 12:00 pm 35 51.3 117 40.3 2.2 16 mi. N of Ridgecrest 10/ 8 12:03 pm 35 44.3 117 37.4 2.0 8 mi. NNE of Ridgecrest 10/ 9 3:04 am 33 58.9 117 4.4 2.2 4 mi. SSW of Yucaipa 10/ 9 3:50 am 32 38.5 115 55.2 2.1 7 mi. SSE of Ocotillo 10/ 9 8:32 am 34 16.0 116 57.1 2.2 2 mi. WNW of town of Big Bear Lake 10/ 9 11:23 am 34 19.0 118 24.2 2.9 2 mi. NE of San Fernando FELT 10/ 9 11:34 am 34 18.5 118 24.1 2.3 " 10/ 9 2:06 pm 33 38.6 116 45.8 2.2 7 mi. SSW of Idyllwild -------------------------------------------------------------