October 14, 1993 Weekly Earthquake Report for Southern California ------------------------------------------------ October 7 - October 13, 1993 Prepared by: Helen Qian, 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 7, Pacific Daylight Time, to midnight Wednesday night, October 13, Pacific Daylight Time. The map includes a virtually complete set of earthquakes of M2.0 or larger, plus many smaller ones that happen to have made it through the data processing. There are 553 this time. The swarm in northern Mexico continues to dominate the map. (They are the events with reference to either Calexico or Yuma in the table.) Most of these events are small. The largest event in the swarm, also the largest this week, was a M3.9 on Saturday. There were 4 other M3 or greater events in the swarm. Because they were well south of the border, we did not receive any inquiries regarding these events. Again the shape of the swarm is mostly due to the location errors. The largest event within our network was an offshore event on Wednesday, a M3.5. It was not felt. The only event apparently felt was a M2.3 on Sunday evening near Glendora. The table lists the quakes that were M2.0 or larger in the central part of the coverage area. Only M2.5 and larger events are listed for south of the U.S./Mexico border, and for the Coalinga/Parkfield area. For more information on the latter, see the Northern California Report issued by the U.S.G.S. in Menlo Park. Times are local times; if you want Greenwich Mean Time, add 7 hrs. to the Pacific Daylight Time listed. Table 1 ------- Date Time N Lat. W Long. Mag ------------------------------------------------------------- 10/ 7 3:57 am 34 20.2 116 28.2 2.5 15 mi. N of Yucca Valley 10/ 7 5:58 am 34 20.8 116 28.2 2.2 " 10/ 7 6:29 am 34 20.9 116 28.1 2.1 15 mi. N of Yucca Valley 10/ 7 8:04 am 34 28.0 116 27.9 2.4 24 mi. N of Yucca Valley 10/ 7 11:14 am 34 24.5 116 27.6 3.3 20 mi. N of Yucca Valley 10/ 7 1:19 pm 34 20.5 116 28.1 2.1 15 mi. N of Yucca Valley 10/ 7 2:11 pm 34 1.0 116 46.0 2.0 6 mi. N of dinosaurs, Cabazon 10/ 7 5:18 pm 34 33.8 116 27.5 2.5 30 mi. N of Yucca Valley 10/ 7 6:54 pm 32 22.3 115 3.2 2.7 32 mi. SE of Calexico 10/ 7 7:31 pm 34 21.8 116 27.2 2.2 16 mi. N of Yucca Valley 10/ 7 7:32 pm 34 21.7 116 27.2 2.3 " 10/ 7 7:36 pm 32 20.8 115 3.5 2.6 33 mi. SE of Calexico 10/ 7 8:15 pm 33 54.5 118 36.1 2.1 9 mi. SSE of Malibu 10/ 8 4:20 am 33 57.4 116 20.1 2.5 9 mi. E of Desert Hot Springs 10/ 8 9:42 am 33 42.1 119 39.3 2.1 24 mi. SSW of Santa Cruz Is. (E end) 10/ 8 11:30 am 34 23.3 116 27.7 3.4 18 mi. N of Yucca Valley 10/ 8 10:01 pm 34 16.5 117 4.9 2.3 5 mi. NNE of Running Springs 10/ 8 10:14 pm 32 20.1 115 2.3 2.6 34 mi. SW of Yuma, Arizona 10/ 8 10:38 pm 34 36.1 121 28.5 2.5 47 mi. W of Pt. Arguello 10/ 9 2:19 am 33 15.4 116 19.4 2.1 2 mi. E of Borrego Springs 10/ 9 2:21 am 33 15.6 116 19.5 2.1 " 10/ 9 5:43 am 32 24.0 115 2.3 2.6 31 mi. SW of Yuma, Arizona 10/ 9 8:14 am 32 21.1 115 3.2 3.1 33 mi. SE of Calexico 10/ 9 8:35 am 32 20.9 115 3.2 2.5 " 10/ 9 2:14 pm 35 14.8 120 56.5 2.6 9 mi. SW of Morro Bay 10/ 9 3:04 pm 34 57.4 116 47.0 2.5 14 mi. ENE of Barstow 10/ 9 3:41 pm 34 57.3 116 46.9 2.0 " 10/ 9 11:07 pm 36 14.8 120 17.0 2.1 8 mi. NNE of Coalinga 10/10 1:17 am 34 0.9 116 20.6 2.1 9 mi. SE of Yucca Valley 10/10 9:25 am 32 18.0 116 6.9 2.5 30 mi. SSW of Ocotillo 10/10 1:26 pm 33 14.0 116 6.0 2.0 6 mi. NNE of Ocotillo Wells 10/10 1:29 pm 34 27.3 116 29.7 2.0 23 mi. N of Yucca Valley 10/10 5:08 pm 34 21.4 116 53.8 2.3 6 mi. SSE of Lucerne Valley 10/10 5:16 pm 33 42.1 116 45.2 2.5 3 mi. SW of Idyllwild 10/10 6:02 pm 34 11.2 116 47.7 2.1 6 mi. NNE of Mt. San Gorgonio 10/10 6:35 pm 33 15.2 116 14.0 3.1 8 mi. E of Borrego Springs 10/10 10:05 pm 32 22.8 115 3.2 3.0 32 mi. SE of Calexico 10/10 11:04 pm 34 4.9 117 51.8 2.3 3 mi. WNW of the I210/I10/57 interchange 10/10 11:28 pm 32 23.4 115 3.8 2.6 31 mi. SE of Calexico 10/10 11:30 pm 32 30.0 114 59.7 2.6 25 mi. WSW of Yuma, Arizona 10/11 3:08 am 32 21.9 115 3.2 2.7 33 mi. SE of Calexico 10/11 3:26 am 32 21.1 115 3.9 2.5 " 10/11 4:10 am 32 21.8 115 3.0 2.5 " 10/11 4:59 am 32 23.0 115 2.6 2.6 32 mi. SW of Yuma, Arizona 10/11 6:29 am 32 23.1 115 3.5 2.9 32 mi. SE of Calexico 10/11 6:34 am 32 23.7 115 3.8 2.7 " 10/11 7:29 am 35 9.5 119 7.3 2.2 13 mi. NW of the I5/99 interchange 10/11 9:02 am 32 22.1 115 3.6 2.6 32 mi. SE of Calexico 10/11 9:43 am 34 57.1 116 55.8 2.1 6 mi. NE of Barstow 10/11 11:59 am 32 21.7 115 4.5 3.9 32 mi. SE of Calexico 10/11 12:06 pm 32 22.2 115 3.2 2.7 " 10/11 12:29 pm 32 22.9 115 3.9 2.9 " 10/11 2:30 pm 34 37.9 116 31.0 2.2 27 mi. ENE of Lucerne Valley 10/11 2:52 pm 32 22.7 115 4.2 2.6 31 mi. SE of Calexico 10/11 4:07 pm 34 0.7 117 32.5 2.3 3 mi. S of the I10/I15 interchange 10/11 4:07 pm 33 5.3 115 46.6 2.0 9 mi. WNW of Westmorland 10/11 6:41 pm 32 22.6 115 4.3 3.0 31 mi. SE of Calexico 10/11 8:14 pm 35 54.5 117 43.8 2.0 15 mi. SE of Coso Junction 10/11 8:30 pm 32 21.8 115 3.5 2.8 32 mi. SE of Calexico 10/12 3:02 am 34 59.5 116 57.3 2.6 8 mi. NNE of Barstow 10/12 7:05 am 35 53.8 118 17.0 2.0 20 mi. NNE of the town of Lake Isabella 10/12 12:02 pm 34 33.5 116 32.1 2.0 24 mi. ENE of Lucerne Valley 10/12 5:39 pm 32 23.7 115 4.1 3.4 31 mi. SE of Calexico 10/12 5:44 pm 32 24.0 115 3.0 2.6 32 mi. SW of Yuma, Arizona 10/12 5:46 pm 32 23.8 115 3.1 2.5 31 mi. SE of Calexico 10/12 5:49 pm 32 22.0 115 3.0 2.5 " 10/12 6:01 pm 34 37.9 116 41.1 2.3 19 mi. NE of Lucerne Valley 10/12 6:24 pm 32 23.5 115 3.8 2.7 31 mi. SE of Calexico 10/12 6:29 pm 32 20.7 115 3.3 2.5 " 10/12 8:41 pm 37 4.1 117 42.3 2.6 32 mi. NE of Independence 10/13 2:54 am 34 49.4 120 56.9 3.5 24 mi. NW of Pt. Arguello 10/13 8:34 am 34 14.8 116 25.6 2.1 8 mi. N of Yucca Valley 10/13 9:41 am 32 24.0 115 3.3 2.5 31 mi. SE of Calexico 10/13 1:30 pm 32 21.8 115 4.0 2.6 " 10/13 6:32 pm 34 58.3 116 56.0 2.3 7 mi. NE of Barstow ------------------------------------------------------------- Figure. 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.