October 13, 1994 Weekly Earthquake Report for Southern California ------------------------------------------------ October 6 - 12, 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, October 6, Pacific Daylight Time, to midnight Wednesday night, October 12, Pacific Daylight Time. We recorded 307 earthquakes of M1.0 or larger this week. Although the total number of events was up slightly from last week (but still within the expected range), most of this week's quakes were small. Only two were felt, neither of which was an aftershock. The largest was a M3.9 in the Ocotillo Wells area south of Borrego Springs. This quake occurred on Saturday night, and we got a few calls. A much smaller quake (M2.8) occurred in the Idyllwild area on Tuesday afternoon. It was felt in Idyllwild. Aside from these, not much of note occurred. Our two aftershock sequences, namely Northridge and Landers/Big Bear, still dominate the map. 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 Daylight Time listed. Table 1 ------- Date Time N Lat. W Long. Mag ------------------------------------------------------------- 10/6 4:31 am 33 21.1 116 21.8 2.5 6 mi. N of Borrego Springs 10/6 5:25 am 34 43.5 120 44.2 2.6 10 mi. NNW of Pt. Arguello 10/6 8:04 am 34 42.8 120 44.1 2.8 " 10/6 4:00 pm 34 1.6 117 10.8 2.1 1 mi. S of Redlands 10/6 7:32 pm 34 47.0 116 17.9 2.5 35 mi. SSW of Baker 10/6 7:33 pm 34 22.3 118 39.6 2.4 5 mi. SW of Magic Mtn. 10/6 7:33 pm 34 22.3 118 39.6 2.0 " 10/6 9:01 pm 34 47.3 116 18.1 2.5 35 mi. SSW of Baker 10/6 9:01 pm 34 39.3 116 30.1 2.5 29 mi. ENE of Lucerne Valley 10/6 11:58 pm 34 18.5 119 16.8 2.6 2 mi. NNE of Ventura 10/7 3:50 am 34 12.3 118 35.5 2.1 Under Canoga Park 10/7 6:13 am 34 36.6 116 37.5 2.5 21 mi. ENE of Lucerne Valley 10/7 9:14 am 34 59.0 116 56.8 2.7 7 mi. NNE of Barstow 10/7 12:14 pm 34 46.5 116 17.8 2.0 36 mi. SSW of Baker 10/7 1:57 pm 35 0.1 116 57.5 2.5 8 mi. NNE of Barstow 10/7 4:20 pm 34 20.9 116 28.7 2.4 15 mi. N of Yucca Valley 10/8 5:32 am 33 24.0 116 22.8 2.1 10 mi. N of Borrego Springs 10/8 5:49 am 35 48.7 117 57.4 2.7 16 mi. S of Coso Junction 10/8 11:46 am 33 30.2 116 58.0 2.0 11 mi. NNW of Palomar Observatory 10/8 12:18 pm 34 45.4 116 17.7 2.1 37 mi. SSW of Baker 10/8 12:40 pm 36 6.1 119 57.2 2.3 22 mi. E of Coalinga 10/8 12:49 pm 36 6.0 119 58.1 2.7 " 10/8 2:20 pm 33 44.1 118 2.6 2.0 3 mi. E of Seal Beach 10/8 2:38 pm 34 46.8 116 17.9 2.4 35 mi. SSW of Baker 10/8 9:10 pm 33 13.8 116 6.0 3.9 6 mi. NNE of Ocotillo Wells FELT 10/8 9:41 pm 34 9.9 116 26.3 2.0 3 mi. N of Yucca Valley 10/8 9:48 pm 34 27.1 116 30.1 2.2 23 mi. N of Yucca Valley 10/8 11:34 pm 33 41.8 117 24.9 2.4 3 mi. NW of Lake Elsinore 10/8 11:49 pm 35 33.0 118 25.6 2.2 6 mi. SSE of the town of Lake Isabella 10/9 2:56 am 32 40.3 115 54.7 2.4 6 mi. SE of Ocotillo 10/9 7:13 am 34 19.8 116 38.0 2.1 13 mi. ENE of Big Bear City 10/9 7:42 am 35 37.2 116 1.5 2.0 24 mi. N of Baker 10/9 12:20 pm 32 19.4 115 13.7 3.1 Baja, 28 mi. SSE of Calexico 10/9 5:39 pm 34 14.8 118 29.0 2.0 2 mi. ENE of Northridge 10/10 12:02 am 33 55.7 116 19.6 2.7 10 mi. ESE of Desert Hot Springs 10/10 5:01 am 34 18.0 118 25.5 2.0 1 mi. NNE of San Fernando 10/10 9:46 am 35 56.4 118 23.0 2.0 21 mi. NNE of the town of Lake Isabella 10/10 6:51 pm 36 12.7 120 47.6 2.5 24 mi. WNW of Coalinga 10/10 10:15 pm 34 21.9 116 28.1 2.0 17 mi. N of Yucca Valley 10/10 10:51 pm 34 2.3 117 15.4 2.2 Loma Linda, 2 mi. SE of the I10/I215 interchange 10/10 11:58 pm 34 47.5 118 55.4 2.6 2 mi. SSE of Frazier Park 10/11 1:28 am 34 11.8 116 48.4 2.2 5 mi. SSE of Big Bear City 10/11 5:35 am 33 59.6 116 16.4 2.1 13 mi. SE of Yucca Valley 10/11 12:03 pm 34 55.1 116 22.1 2.1 29 mi. SW of Baker 10/11 12:20 pm 34 46.9 116 18.3 2.3 35 mi. SSW of Baker 10/11 4:05 pm 36 0.6 117 49.1 2.7 7 mi. ESE of Coso Junction 10/11 4:14 pm 33 40.4 116 43.3 2.8 4 mi. S of Idyllwild; FELT 10/11 4:15 pm 33 40.4 116 43.0 2.0 " 10/11 4:22 pm 33 40.6 116 43.3 2.1 " 10/11 7:33 pm 34 55.3 116 21.8 2.2 28 mi. SW of Baker 10/11 8:38 pm 34 47.5 116 18.0 2.9 35 mi. SSW of Baker 10/12 7:22 am 34 58.3 116 34.7 2.3 25 mi. ENE of Barstow 10/12 11:33 am 34 16.4 118 32.4 2.0 2 mi. N of Northridge 10/12 11:39 am 34 45.7 116 17.5 2.2 36 mi. SSW of Baker 10/12 1:18 pm 34 28.1 116 31.0 2.0 24 mi. N of Yucca Valley 10/12 2:13 pm 34 28.4 116 29.9 2.2 " 10/12 3:24 pm 34 58.2 116 56.7 2.3 7 mi. NE of Barstow 10/12 8:46 pm 34 34.4 116 34.8 2.0 22 mi. ENE of Lucerne Valley 10/12 10:36 pm 34 17.5 118 27.8 2.5 1 mi. WNW of San Fernando 10/12 11:17 pm 34 30.5 116 30.8 2.4 27 mi. N of Yucca Valley ------------------------------------------------------------- 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.