SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey June 13, 1996 Weekly Earthquake Report for Southern California ------------------------------------------------ June 6 - 12, 1996 Prepared by: Debbie Wells, Seismological Laboratory Nick Scheckel, 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 6, Universal Time (ie. GMT), to midnight Wednesday night, June 12, Universal Time. In local time, the period of coverage is from 5 p.m., June 5, Pacific Daylight Time, to 5 p.m., June 12, Pacific Daylight Time. We detected and processed 307 earthquakes during the 7-day period covered. There were three M3+ events this week. The first two, a M3.4 near Barstow on Thursday and a M3.0 near Yucca Valley on Friday, were both part of the Landers earthquake sequence (Mw7.3, June 28, 1992). The third was a M3.3 9 miles north of Fontana in the San Bernardino Mountains and felt as far away as Pasadena. It was located near the San Jacinto fault as it approaches its merge with the San Andreas. This earthquake showed oblique right-lateral and reverse (rake=40 degrees) slip on a plane parallel to the San Jacinto fault. This mechanism and location are very similar to that of the 1970 M5.4 Lytle Creek earthquake. These reverse mechanisms may reflect the complications involved in the merging of the San Jacinto and San Andreas faults. 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 ------------------------------------------------------------- 6/5 7:24 pm 36 4.6 117 54.5 2.5 3 mi. NE of Coso Junction 6/6 12:03 am 32 7.6 116 21.4 2.2 47 mi. SSW of Ocotillo 6/6 1:13 am 33 34.6 118 19.3 2.0 9 mi. S of Pt. Fermin, San Pedro 6/6 3:55 am 36 35.7 119 22.0 2.0 18 mi. NNW of Visalia 6/6 6:36 am 34 17.7 118 28.9 2.2 1 mi. NE of Granada Hills 6/6 6:50 am 34 43.9 121 0.1 2.6 22 mi. WSW of Pt. Sal 6/6 11:52 am 34 17.3 118 28.9 2.3 1 mi. NE of Granada Hills 6/6 2:29 pm 35 1.1 116 57.5 3.4 9 mi. NNE of Barstow 6/6 5:40 pm 34 14.1 118 27.5 2.0 1 mi. NNW of Panorama City 6/7 1:56 am 32 0.4 116 18.0 2.0 53 mi. SSW of Ocotillo 6/7 2:17 pm 33 42.5 118 47.0 2.9 20 mi. S of Pt. Dume 6/7 3:31 pm 34 21.3 116 27.4 3.0 16 mi. N of Yucca Valley 6/7 7:26 pm 34 21.2 116 27.6 2.7 " 6/8 8:10 am 32 42.7 115 24.2 2.3 6 mi. ENE of Calexico 6/8 8:13 am 32 42.7 115 24.0 2.0 " 6/8 12:41 pm 32 40.8 115 24.7 2.1 4 mi. E of Calexico 6/8 1:08 pm 34 20.5 116 28.2 2.0 15 mi. N of Yucca Valley 6/8 1:09 pm 34 19.4 116 28.7 2.3 14 mi. N of Yucca Valley 6/8 2:57 pm 34 27.8 116 30.1 2.0 24 mi. N of Yucca Valley 6/8 7:50 pm 34 21.6 116 24.5 2.7 16 mi. NNW of Joshua Tree 6/9 1:54 am 33 48.4 119 18.4 2.0 19 mi. SE of Santa Cruz Is. (E end) 6/9 9:37 am 34 17.4 116 43.9 2.0 7 mi. ENE of Big Bear City 6/9 2:12 pm 34 4.8 116 45.1 2.1 4 mi. ESE of Mt. San Gorgonio 6/9 9:48 pm 34 22.7 116 27.5 2.2 17 mi. N of Yucca Valley 6/10 3:17 am 33 59.6 118 20.8 2.0 1 mi. ESE of Baldwin Hills 6/10 8:57 am 36 23.3 118 3.1 2.3 7 mi. NNW of Olancha 6/10 12:19 pm 33 48.2 116 58.2 2.2 3 mi. N of Hemet 6/11 4:45 am 33 11.4 118 42.8 2.2 12 mi. NNW of San Clemente Is. (NW tip) 6/11 4:41 pm 34 20.6 116 28.1 2.3 15 mi. N of Yucca Valley 6/11 9:29 pm 33 26.0 116 29.3 2.4 13 mi. NNW of Borrego Springs 6/11 9:50 pm 35 47.0 117 39.8 2.1 11 mi. N of Ridgecrest 6/12 6:42 am 34 0.0 119 13.7 2.0 10 mi. S of Port Hueneme 6/12 6:55 am 34 37.1 118 37.5 2.1 6 mi. N of Castaic Lake dam 6/12 10:04 am 34 34.5 116 26.1 2.0 31 mi. NNW of Joshua Tree 6/12 11:15 am 34 13.8 117 28.6 3.3 4 mi. W of Devore; FELT 6/12 1:07 pm 34 29.2 116 30.7 2.1 25 mi. N of Yucca Valley 6/12 2:27 pm 36 0.7 117 49.0 2.4 7 mi. ESE of Coso Junction 6/12 3:51 pm 34 37.5 116 30.6 2.0 27 mi. ENE of Lucerne Valley -------------------------------------------------------------