SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey December 4, 1997 Weekly Earthquake Report for Southern California ------------------------------------------------ November 26 - December 3, 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 626-395-6327. For daily updates, call our Earthquake Information Hotline: 626-395-6977. -------------------------------- ***************************************************************** If you receive this Report by FAX and if you have recently had a change of AREA CODE, please notify us ASAP. We have no other way to know which fax numbers need to be changed!! Actually, if your area code is 818 and it HASN'T changed, it would be helpful to know that, too. ***************************************************************** This week's Report covers the time period from midnight Thursday morning, November 26, Universal Time (ie. UTC), to midnight Wednesday night, December 3, Universal Time. In local time, the period of coverage is from 4 p.m., November 25, Pacific Standard Time, to 4 p.m., December 3, Pacific Standard Time. This week's Report covers a longer time period than usual because of last week's holiday. We detected 213 earthquakes during the eight-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 Although none of the quakes this week have been reported felt, the seismicity is back out of the doldrums. The largest one, aside from the M3.7 Baja quake on Friday, was a M3.5 offshore, near San Clemente Island, the previous Tuesday night. We also had three M2.9's: one in the Owens Valley very early Saturday morning, one in San Gorgonio Pass later the same morning, and one in the Imperial Valley this Wednesday after- noon. The Imperial Valley quake was a strike-slip, and the San Gorgonio Pass quake was oblique thrust. The Imperial Valley quake was part of a small swarm, in a very common swarm location. 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 ------------------------------------------------------------- 11/25 9:14 pm 34 0.1 117 13.3 2.3 3 mi. SSE of Loma Linda 11/25 9:56 pm 32 42.1 118 6.9 3.5 15 mi. ESE of San Clemente Is. (SE tip) 11/25 10:33 pm 32 41.8 118 5.7 2.1 " 11/26 4:11 am 35 43.8 118 3.9 2.3 22 mi. SSW of Coso Junction 11/26 10:49 pm 35 5.2 117 30.6 2.7 9 mi. NE of Boron 11/26 10:49 pm 35 5.0 117 30.6 2.3 " 11/27 2:43 am 34 25.9 118 22.1 2.4 10 mi. N of Lake View Terrace 11/28 6:51 am 32 16.4 115 18.0 3.7 29 mi. SSE of Calexico 11/28 3:08 pm 33 0.8 115 34.9 2.0 2 mi. SE of Westmorland 11/28 7:00 pm 35 1.5 119 31.0 2.3 8 mi. SSW of Taft 11/28 11:28 pm 33 11.6 115 36.1 2.0 2 mi. NE of Obsidian Butte, Imperial Valley 11/29 1:03 am 36 56.2 118 13.6 2.9 9 mi. N of Independence 11/29 1:06 am 32 46.3 115 33.0 2.0 1 mi. S of El Centro 11/29 1:49 am 36 56.1 118 15.2 2.3 9 mi. NNW of Independence 11/29 4:23 am 36 54.9 118 17.5 2.0 " 11/29 5:51 am 33 58.3 116 57.0 2.9 3 mi. NNE of Beaumont 11/29 6:09 am 34 9.0 116 25.1 2.1 2 mi. NE of Yucca Valley 11/29 7:01 am 36 58.7 118 18.1 2.0 13 mi. S of Big Pine 11/29 10:06 am 32 34.9 117 16.0 2.3 11 mi. SW of San Diego 11/29 10:19 am 34 9.1 116 25.3 2.1 2 mi. NNE of Yucca Valley 11/29 12:34 pm 34 17.6 117 6.7 2.2 6 mi. N of Running Springs 11/29 1:49 pm 33 5.1 118 33.1 2.2 4 mi. NE of San Clemente Is. (NW tip) 11/29 9:45 pm 33 29.0 116 28.5 2.0 12 mi. ESE of Anza 11/30 4:05 am 34 2.9 116 23.7 2.3 5 mi. SSE of Yucca Valley 11/30 1:07 pm 33 30.2 116 27.7 2.3 12 mi. ESE of Anza 12/1 2:20 pm 34 0.1 119 11.4 2.2 9 mi. S of Port Hueneme 12/1 6:59 pm 34 4.4 116 23.5 2.1 4 mi. SE of Yucca Valley 12/1 10:00 pm 33 15.6 116 6.5 2.2 8 mi. N of Ocotillo Wells 12/2 1:12 pm 34 52.5 119 22.6 2.0 18 mi. SSE of Taft 12/3 1:52 am 33 58.5 118 51.6 2.6 3 mi. WSW of Pt. Dume 12/3 10:40 am 34 58.0 116 57.0 2.0 6 mi. NE of Barstow 12/3 11:01 am 33 9.6 115 38.3 2.3 Under Obsidian Butte, Imperial Valley 12/3 11:02 am 33 9.7 115 37.5 2.2 " 12/3 11:07 am 33 9.6 115 38.3 2.0 " 12/3 11:09 am 33 9.7 115 38.7 2.6 " 12/3 11:10 am 33 9.5 115 38.7 2.5 " 12/3 11:18 am 33 9.7 115 38.4 2.6 " 12/3 12:00 pm 33 9.6 115 38.3 2.0 " 12/3 2:42 pm 33 9.4 115 38.0 2.0 " 12/3 3:06 pm 33 9.9 115 39.2 2.9 1 mi. WSW of Obsidian Butte -------------------------------------------------------------