SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey June 8, 1995 Weekly Earthquake Report for Southern California ------------------------------------------------ June 1 - 7, 1995 Prepared by: Kate Hutton, 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 818-395-6326. For daily updates, call our Earthquake Information Hotline: 818-395-6977. -------------------------------- This week's Report covers the time period from midnight Thursday morning, June 1, Pacific Daylight Time, to midnight Wednesday night, June 7, 1995, Pacific Daylight Time. We recorded 236 earthquakes of M1.0 or larger during the 7-day period covered. It has been another relatively quiet week. There were two M3 or greater quakes, neither of which was an aftershock. The first, M3.2, occurred Monday morning, in the Wheeler Ridge area NNW of Frazier Park. It was felt in Gorman. This earthquake was located about 5 kilmoeters to the north of the San Andreas Fault, along strike of a projection of the While Wolf fault (which produced the Mw7.5 1952 Kern County earthquake). It has a somewhat unusual mechanism for the region, where earthquake are primarily reverse (or thrust) faulting with some strike-slip. This week's quake was primarily strike-slip, with an oblique component of normal faulting (a rake of -140 degrees). The left-lateral plane strikes parallel to the White Wolf fault, a reverse fault. The right-lateral plane strikes 20 degrees west of north, or 50 degrees away from the strike of the San Andreas fault in that region. However, the principal stress axis trends just a few degrees east of north, compatible with the regional stress field. The other one, M3.0, occurred during the wee hours on Wednesday morning, west of the Imperial Valley, with a strike-slip focal mechanism. We got no reports of it having been felt. 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 Pacific Daylight Time or 8 hrs to the Pacific Standard Time listed. Table 1 ------- Date Time N Lat. W Long. Mag ------------------------------------------------------------- 6/1 12:30 pm 32 30.8 115 16.4 2.1 16 mi. SE of Calexico 6/1 3:45 pm 34 59.5 117 5.6 2.3 8 mi. NNW of Barstow 6/1 4:03 pm 34 6.1 116 25.1 2.7 1 mi. SE of Yucca Valley 6/1 6:42 pm 33 11.3 115 35.8 2.8 5 mi. SW of Niland 6/1 9:14 pm 34 37.2 116 33.2 2.1 25 mi. ENE of Lucerne Valley 6/2 8:43 am 34 29.7 118 3.5 2.2 6 mi. SSE of Palmdale 6/2 3:54 pm 34 9.3 116 25.4 2.0 2 mi. NNE of Yucca Valley 6/2 4:12 pm 33 30.8 118 18.4 2.0 11 mi. N of Avalon, Catalina Island 6/2 10:34 pm 34 38.3 116 31.1 2.2 27 mi. ENE of Lucerne Valley 6/3 1:40 am 34 2.3 116 21.9 2.3 7 mi. SE of Yucca Valley 6/3 2:46 am 35 32.9 118 17.1 2.0 11 mi. ESE of Lake Isabella 6/3 10:00 am 36 6.7 117 51.7 2.4 Coso Range, 4 mi. ESE of Haiwee Reservoir 6/3 1:06 pm 35 21.2 118 34.8 2.0 17 mi. NNW of Tehachapi 6/3 3:16 pm 33 39.0 116 44.9 2.1 6 mi. SSW of Idyllwild 6/3 10:26 pm 34 24.1 118 18.3 2.1 9 mi. NNE of Lakeview Terrace 6/4 1:01 pm 34 38.0 116 31.0 2.0 27 mi. ENE of Lucerne Valley 6/5 2:50 am 34 38.2 116 31.2 2.7 " 6/5 5:14 am 34 17.6 118 26.9 2.4 Under San Fernando 6/5 5:51 am 34 17.8 118 26.6 2.0 1 mi. NNW of San Fernando 6/5 7:59 am 34 53.2 119 11.9 3.2 15 mi. WNW of Frazier Park; FELT 6/5 8:15 am 33 56.4 117 43.8 2.2 5 mi. NE of Yorba Linda 6/5 11:36 am 34 59.7 119 7.9 2.1 10 mi. W of the I5/99 interchange 6/5 7:03 pm 34 6.1 116 59.9 2.0 9 mi. SE of Running Springs 6/5 11:38 pm 32 51.2 118 22.1 2.3 2 mi. NNW of San Clemente Is. 6/6 2:57 am 34 55.8 116 55.2 2.6 6 mi. ENE of Barstow 6/6 4:53 am 33 58.0 117 14.2 2.2 7 mi. SSW of Redlands 6/6 5:04 am 34 55.8 116 55.3 2.3 6 mi. ENE of Barstow 6/6 12:24 pm 33 40.3 118 17.5 2.0 2 mi. S of Pt. Fermin, San Pedro 6/6 7:05 pm 32 18.5 115 13.2 2.5 29 mi. SSE of Calexico 6/7 3:10 am 32 51.8 115 46.5 3.0 14 mi. SW of Westmorland 6/7 5:24 am 34 18.2 116 26.7 2.3 12 mi. N of Yucca Valley 6/7 5:24 am 34 18.3 116 26.1 2.0 " 6/7 7:48 am 34 48.8 120 14.7 2.0 14 mi. SE of Santa Maria 6/7 9:14 am 34 18.4 117 0.6 2.1 7 mi. NW of town of Big Bear Lake 6/7 10:49 am 32 55.4 116 14.0 2.3 16 mi. SSW of Ocotillo Wells 6/7 3:16 pm 34 14.7 118 41.6 2.1 2 mi. SSE of Simi Valley -------------------------------------------------------------