SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey June 12, 1997 Weekly Earthquake Report for Southern California ------------------------------------------------ June 5 - 11, 1997 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 818-395-6327. For daily updates, call our Earthquake Information Hotline: 818-395-6977. -------------------------------- This week's Report covers the time period from midnight Thursday morning, June 5, Universal Time (ie. GMT), to midnight Wednesday night, June 11, Universal Time. In local time, the period of coverage is from 5 p.m., June 4, Pacific Daylight Time, to 5 p.m., June 11, Pacific Daylight Time. We detected 222 earthquakes during the seven-day period covered. These Weekly Reports should not be used for archival purposes. Further data processing often changes the magnitudes slightly and, especially during times of high seismicity, sometimes changes the estimates of total seismicity. For the best earthquake catalog currently available, see: http://scec.gps.caltech.edu/catalog-search.html There were three M3+ quakes this week. The first one was in the Salton City area, west of Imperial Valley, on Monday morning. It was the largest of a small cluster of events. The focal mechanism was strike-slip. The next was a M3.4 on Wednesday afternoon, one of several events in the Coso Range, southeast of the southern end of Owens Valley. The Coso Range, being a geothermal area, is a common source of seismic activity. Four M5+ events have occurred in this general vicinity since 1995, but none were at this specific epicenter. The third was a felt earthquake, in the Loma Linda area, very early Tuesday morning. The magnitude was M3.2 and the focal mechanism was strike-slip, consistent with the San Jacinto Fault system. This event was felt in the San Bernardino and Riverside area. In addition to these, we saw another small cluster along the Garlock Fault, southwest of Tehachapi. This cluster included three events in the M2 range, the largest of which was M2.7, on Saturday afternoon. Table 1 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 ------------------------------------------------------------- 6/5 10:06 am 36 17.3 118 19.6 2.5 20 mi. S of Mt. Whitney 6/5 1:28 pm 33 28.2 116 27.5 2.1 13 mi. ESE of Anza 6/5 3:43 pm 35 58.2 117 59.0 2.9 5 mi. SSW of Coso Junction 6/5 5:53 pm 36 1.8 117 46.7 2.2 9 mi. E of Coso Junction 6/5 10:43 pm 33 24.9 116 25.9 2.0 11 mi. NNW of Borrego Springs 6/6 12:15 am 35 58.8 117 40.4 2.1 16 mi. ESE of Coso Junction 6/6 1:21 am 32 31.3 118 10.5 2.3 22 mi. SSE of San Clemente Is. (SE tip) 6/6 2:31 am 35 47.3 117 39.4 2.6 11 mi. N of Ridgecrest 6/6 12:18 pm 34 19.1 118 34.3 2.1 4 mi. NNE of Chatsworth 6/6 1:06 pm 34 59.4 116 56.9 2.4 8 mi. NNE of Barstow 6/6 1:07 pm 32 50.1 118 0.2 2.3 19 mi. E of San Clemente Is. (SE tip) 6/6 2:22 pm 34 58.6 116 57.4 2.6 7 mi. NNE of Barstow 6/7 5:21 am 33 30.3 116 30.2 2.5 10 mi. ESE of Anza 6/7 6:33 am 32 9.5 115 48.1 2.9 39 mi. SSW of Calexico 6/7 9:26 am 32 15.8 115 15.5 2.9 31 mi. SSE of Calexico 6/7 5:25 pm 35 0.3 118 30.4 2.5 9 mi. SSW of Tehachapi 6/7 5:31 pm 35 0.3 118 30.4 2.7 " 6/8 7:59 am 34 23.0 119 32.4 2.1 1 mi. SW of Carpinteria 6/8 10:16 pm 32 42.3 115 58.9 2.2 2 mi. SSE of Ocotillo 6/9 9:54 am 33 59.9 117 8.4 2.9 4 mi. SSE of Redlands 6/9 10:42 am 33 15.6 116 1.5 2.3 3 mi. WSW of Salton City 6/9 10:47 am 33 15.5 116 2.0 3.0 4 mi. WSW of Salton City 6/9 2:46 pm 35 59.0 117 40.3 2.4 16 mi. ESE of Coso Junction 6/9 6:02 pm 35 59.0 117 40.2 3.4 " 6/9 7:18 pm 35 58.9 117 40.3 2.1 " 6/9 9:01 pm 33 14.9 116 17.5 2.2 4 mi. E of Borrego Springs 6/10 12:56 am 34 31.5 120 41.6 2.0 4 mi. SW of Pt. Arguello 6/10 1:02 am 35 1.3 116 58.8 2.4 9 mi. NNE of Barstow 6/10 2:21 am 34 2.7 117 16.1 3.2 Under Loma Linda FELT 6/10 6:23 am 35 0.3 118 30.4 2.3 9 mi. SSW of Tehachapi 6/10 6:51 am 34 0.5 118 17.7 2.4 1 mi. SSW of USC 6/10 7:01 am 36 11.5 118 3.2 2.0 6 mi. SSW of Olancha 6/10 12:52 pm 33 15.6 116 1.9 2.4 4 mi. WSW of Salton City 6/10 1:40 pm 34 24.3 118 26.8 2.7 4 mi. ENE of Newhall 6/10 5:55 pm 33 15.6 116 2.0 2.4 4 mi. WSW of Salton City 6/10 10:34 pm 36 47.2 118 8.8 2.4 3 mi. ESE of Independence 6/11 12:08 am 36 49.1 118 8.9 2.6 2 mi. ENE of Independence 6/11 10:24 am 34 7.0 116 23.6 2.1 2 mi. E of Yucca Valley 6/11 1:15 pm 35 45.5 116 32.4 2.0 21 mi. SW of Shoshone -------------------------------------------------------------