March 3, 1994 Weekly Earthquake Report for Southern California ------------------------------------------------ February 24 - March 2, 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, February 24, Pacific Standard Time, to midnight Wednesday night, March 2, Pacific Standard Time. There are 612 this week. Most of the week's activity was still aftershocks, mostly from the Northridge earthquake with some from the Landers earth- quake (Mw7.3 on June 28, 1992). The largest one was a Northridge aftershock of M4.0 early Friday morning. There were 12 more quakes along the northern part of Ventura Basin, a continuation of last week's activity. This week, however, all were less than M2.0. There were 4 small quakes near Bombay Beach, the largest being M2.0. This is an "interesting" location, since it is the southern end of the locked section of the San Andreas fault, where it connects to the active Brawley Seismic Zone. Since the quakes were all very small, there is not likely to be any reason for greater concern than normal. The table lists the quakes that were M2.0 or larger in the central part of the coverage area. Aftershocks must be at least M2.5 to be listed. Times are local times; if you want Greenwich Mean Time, add 8 hrs, to the Pacific Standard Time listed. Table 1 ------- Date Time N Lat. W Long. Mag ------------------------------------------------------------- 2/24 12:21 am 34 58.2 116 57.8 2.4 6 mi. NNE of Barstow 2/24 12:22 am 34 0.2 116 22.3 2.1 7 mi. ENE of Desert Hot Springs 2/24 3:50 am 34 58.1 116 57.6 2.5 6 mi. NNE of Barstow 2/24 3:50 am 34 58.7 116 58.5 2.7 " 2/24 3:51 am 34 57.7 116 59.1 2.0 " 2/24 6:51 am 36 16.5 120 14.5 2.7 11 mi. NE of Coalinga 2/24 7:05 am 34 58.0 116 57.5 2.1 6 mi. NE of Barstow 2/24 8:24 am 34 0.6 116 50.4 2.0 6 mi. S of Mt. San Gorgonio 2/24 10:39 am 33 20.0 116 11.9 2.4 11 mi. ENE of Borrego Springs 2/24 10:58 am 34 18.1 118 26.6 2.5 1 mi. NNW of San Fernando 2/24 3:18 pm 33 19.7 115 42.7 2.0 1 mi. SE of Bombay Beach 2/25 4:59 am 34 21.4 118 28.8 4.0 3 mi. ESE of Newhall; FELT 2/25 5:11 am 34 21.5 118 28.8 3.1 " FELT 2/25 5:56 am 34 19.2 118 25.3 3.6 2 mi. NNE of San Fernando FELT 2/25 6:04 am 34 16.5 117 32.1 2.1 6 mi. E of Mt. Baldy 2/25 10:07 am 34 34.1 116 32.8 2.2 24 mi. ENE of Lucerne Valley 2/25 11:25 am 35 36.1 118 23.3 2.5 5 mi. ESE of the town of Lake Isabella 2/25 1:16 pm 34 19.3 118 25.9 2.9 2 mi. N of San Fernando 2/25 1:16 pm 34 19.5 118 25.8 2.6 " 2/25 10:35 pm 35 40.7 117 36.9 2.2 4 mi. NE of Ridgecrest 2/25 11:03 pm 33 30.4 116 55.5 2.0 11 mi. NNW of Palomar Observatory 2/26 5:03 am 34 20.0 118 43.9 2.6 4 mi. NNW of Simi Valley 2/26 7:51 am 35 40.7 117 37.0 2.4 4 mi. NE of Ridgecrest 2/26 12:40 pm 34 0.6 116 18.9 2.0 10 mi. SE of Yucca Valley 2/26 6:51 pm 34 36.5 116 39.4 2.0 19 mi. NE of Lucerne Valley 2/26 11:47 pm 34 56.4 116 57.5 2.7 5 mi. NE of Barstow 2/27 2:15 am 34 34.3 116 35.1 2.1 22 mi. ENE of Lucerne Valley 2/27 3:20 am 34 12.5 116 26.1 2.2 6 mi. N of Yucca Valley 2/27 4:01 am 34 9.8 118 34.9 2.6 2 mi. SSE of Canoga Park 2/27 4:01 am 34 8.5 116 25.9 2.6 1 mi. NNE of Yucca Valley 2/27 4:50 am 34 57.9 116 58.0 2.5 6 mi. NNE of Barstow 2/27 9:36 am 34 10.0 116 50.0 2.0 4 mi. N of Mt. San Gorgonio 2/27 10:01 am 34 14.6 116 25.8 2.2 8 mi. N of Yucca Valley 2/27 5:26 pm 34 9.4 116 49.7 2.5 3 mi. N of Mt. San Gorgonio 2/27 9:23 pm 34 12.3 116 26.4 2.5 6 mi. N of Yucca Valley 2/27 9:24 pm 34 13.1 116 26.2 2.1 " 2/27 9:24 pm 34 12.4 116 26.2 2.3 " 2/27 9:31 pm 34 12.7 116 26.7 2.0 " 2/27 9:39 pm 34 17.0 118 28.0 3.1 1 mi. W of San Fernando 2/27 9:40 pm 34 12.2 116 26.2 3.2 6 mi. N of Yucca Valley; FELT 2/27 9:43 pm 34 12.4 116 26.2 2.2 " 2/27 10:20 pm 33 14.6 116 46.5 2.5 Under Lake Henshaw 2/27 10:45 pm 34 28.5 116 31.5 2.0 25 mi. N of Yucca Valley 2/27 11:55 pm 34 28.5 116 31.1 2.0 " 2/28 5:24 am 36 10.2 118 1.3 2.5 4 mi. WNW of south end of Haiwee Reservoir 2/28 6:06 am 33 28.4 116 27.4 2.1 13 mi. ESE of Anza 2/28 1:01 pm 33 14.8 116 46.3 2.0 Under Lake Henshaw 2/28 2:44 pm 35 1.4 116 58.2 2.1 9 mi. NNE of Barstow 2/28 5:21 pm 33 15.8 116 15.9 2.0 6 mi. E of Borrego Springs 2/28 11:54 pm 34 19.8 116 24.2 2.2 14 mi. N of Yucca Valley 3/1 5:28 am 32 53.3 115 31.1 2.0 5 mi. S of Brawley 3/1 5:41 am 34 15.0 116 44.0 2.1 6 mi. E of Big Bear City 3/1 5:55 am 32 53.0 115 31.1 2.7 5 mi. S of Brawley 3/1 6:52 am 36 36.3 117 51.1 2.8 11 mi. E of Lone Pine 3/1 6:59 am 35 3.3 119 8.4 2.3 10 mi. WNW of the I5/99 interchange 3/1 12:06 pm 36 31.4 117 0.8 2.4 9 mi. SE of Stovepipe Wells 3/1 2:52 pm 33 56.6 116 37.9 2.6 7 mi. W of Desert Hot Springs FELT 3/1 6:11 pm 34 10.7 118 32.8 2.7 4 mi. S of Northridge 3/1 7:35 pm 34 11.6 116 26.4 3.1 5 mi. N of Yucca Valley; FELT 3/1 7:37 pm 34 12.1 116 26.4 2.6 " 3/2 2:15 am 33 58.0 117 10.5 2.7 6 mi. S of Redlands 3/2 3:18 am 35 18.9 116 39.8 2.0 12 mi. ESE of Goldstone (dry) Lake 3/2 4:50 am 34 14.8 118 28.9 2.7 3 mi. ENE of Northridge; FELT 3/2 7:50 am 34 14.0 116 26.5 2.7 7 mi. N of Yucca Valley 3/2 8:57 am 35 1.2 116 57.6 2.1 9 mi. NNE of Barstow 3/2 12:06 pm 34 12.1 118 36.8 3.1 Under Canoga Park; FELT 3/2 12:45 pm 34 58.4 116 57.7 2.9 6 mi. NNE of Barstow 3/2 5:17 pm 33 54.5 118 40.9 2.0 8 mi. S of Malibu 3/2 9:51 pm 34 17.8 118 36.3 2.0 5 mi. NW of Northridge ------------------------------------------------------------- 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.