September 15, 1994 Weekly Earthquake Report for Southern California ------------------------------------------------ September 8 - 14, 1994 Prepared by: Kate Hutton, Seismological Laboratory (kate@bombay.gps.caltech.edu) Lucy Jones, U.S. Geological Survey California Institute of Technology This document is a commentary on current seismic activity. The earthquakes discussed have been detected and processed automatically. All epicenters and magnitudes have been reviewed to exclude obvious blunders; however, they must still be considered preliminary. 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, September 8, Pacific Daylight Time, to midnight Wednesday night, September 14, Pacific Daylight Time. We recorded 310 earthquakes of M1.0 or larger this week. It was a relatively quiet week again this week. Only two events seem to have been noticed by the public. The first was a M3.1 Northridge aftershock near San Fernando, very early last Thursday morning. The second, a M3.5 near Hemet, occurred on Sunday afternoon. The latter was not an aftershock of any recent earthquake. The seismicity was pretty much what was expected from the Northridge and Landers/Big Bear aftershock sequences, plus the normal background seismic activity. The table lists the quakes 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 Daylight Time listed. Table 1 ------- Date Time N Lat. W Long. Mag ------------------------------------------------------------- 9/8 1:33 am 34 23.4 116 27.4 2.5 18 mi. N of Yucca Valley 9/8 2:56 am 34 18.8 118 27.4 2.1 2 mi. NNW of San Fernando 9/8 2:57 am 34 18.9 118 27.2 3.1 2 mi. NNW of San Fernando FELT 9/8 11:57 am 34 0.7 116 46.8 2.9 6 mi. N of Cabazon 9/8 12:02 pm 34 23.3 116 27.5 2.0 18 mi. N of Yucca Valley 9/8 3:46 pm 34 29.7 116 30.5 2.0 26 mi. N of Yucca Valley 9/8 8:18 pm 34 29.6 116 30.5 2.1 " 9/8 10:57 pm 34 9.9 116 49.1 2.0 4 mi. N of Mt. San Gorgonio 9/9 1:25 am 34 14.5 118 30.1 2.2 1 mi. E of Northridge 9/9 6:42 am 33 52.9 119 17.9 2.2 16 mi. SE of Santa Cruz Is. 9/9 7:49 am 34 58.8 116 56.8 2.5 7 mi. NE of Barstow 9/9 10:27 am 34 9.9 120 11.1 2.4 13 mi. NE of San Miguel Is. 9/9 10:35 am 33 59.9 118 41.4 2.0 2 mi. S of Malibu 9/9 4:06 pm 34 34.5 116 35.3 2.4 22 mi. ENE of Lucerne Valley 9/10 1:03 am 33 12.7 116 3.8 2.8 6 mi. NE of Ocotillo Wells 9/10 1:11 am 33 12.6 116 3.5 2.0 " 9/10 9:11 am 32 25.9 115 24.9 2.0 16 mi. SSE of Calexico 9/10 7:00 pm 34 22.8 116 27.2 2.2 18 mi. N of Yucca Valley 9/10 11:06 pm 34 15.6 118 27.5 2.3 1 mi. SW of San Fernando 9/11 10:25 am 34 29.2 116 30.5 2.0 25 mi. N of Yucca Valley 9/11 3:37 pm 34 21.8 116 27.1 2.0 16 mi. N of Yucca Valley 9/11 4:44 pm 36 21.7 118 0.8 2.1 5 mi. N of Olancha 9/11 5:16 pm 33 45.8 116 57.1 3.5 1 mi. NE of Hemet; FELT 9/12 2:43 am 36 54.0 118 13.3 2.4 6 mi. N of Independence 9/12 8:45 am 32 25.0 115 25.5 2.9 17 mi. SSE of Calexico 9/12 12:43 pm 34 23.8 116 27.8 2.0 19 mi. N of Yucca Valley 9/12 3:40 pm 33 42.9 117 59.3 2.0 7 mi. NNW of Newport Beach 9/12 7:01 pm 34 33.7 116 29.9 2.0 30 mi. N of Yucca Valley 9/12 11:42 pm 34 24.5 118 47.9 2.1 6 mi. E of Fillmore 9/13 1:26 am 33 57.7 116 51.6 2.1 2 mi. NNE of Banning 9/13 11:37 am 33 58.5 116 58.8 2.0 3 mi. N of Beaumont 9/13 3:39 pm 34 38.0 116 30.9 2.2 27 mi. ENE of Lucerne Valley 9/13 4:20 pm 33 48.9 116 11.8 2.0 6 mi. N of Indio 9/13 6:36 pm 34 13.1 116 26.3 2.4 6 mi. N of Yucca Valley 9/14 2:16 am 34 15.7 116 24.7 2.2 10 mi. N of Yucca Valley 9/14 6:50 am 34 22.5 118 42.7 2.3 6 mi. N of Simi Valley 9/14 9:11 am 34 0.7 118 57.5 2.5 2 mi. SSW of Leo Carrillo State Beach 9/14 10:57 am 34 20.0 116 28.0 2.1 14 mi. N of Yucca Valley 9/14 2:15 pm 34 15.8 118 27.5 2.1 1 mi. SW of San Fernando 9/14 3:26 pm 34 15.6 118 27.0 2.2 " 9/14 7:46 pm 34 47.5 116 17.8 2.7 35 mi. SSW of Baker 9/14 7:49 pm 34 47.3 116 17.9 2.6 " ------------------------------------------------------------- Figure 1. A map of southern California showing the earthquakes recorded during the past week by the Caltech/USGS Seismic Network. Major faults are marked, as well as the metropolitan areas of Los Angeles (L.A.), Palm Springs (P.S.), San Diego (S.D.), and Santa Barbara (S.B.). The circles denote the earthquakes, the size of the circle indicating the magnitude.