SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey November 21, 1996 Weekly Earthquake Report for Southern California ------------------------------------------------ November 14 - 20, 1996 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, November 14, Universal Time (ie. GMT), to midnight Wednesday night, November 20, Universal Time. In local time, the period of coverage is from 4 p.m., November 13, Pacific Daylight Time, to 4 p.m., November 20, Pacific Daylight Time. We detected and processed 249 earthquakes during the seven-day period covered. There were three M3+ quakes in our area this week: a M3.0 Northridge aftershock near Pacoima, in the wee hours on Saturday; a M3.2 near Lake Isabella on Sunday evening, and a M3.1 near the Calexico very early Wednesday morning. The last actually occurred in Mexico, but was felt in Calexico and El Centro. The Pacoima quake on Saturday was also felt. The Pacoima quake showed the usual east-striking thrust mechanism common to Northridge aftershocks. The Isabella quake was a strike-slip quake, with the usual California northwest and northeast nodal planes. In addition to these, we got a few reports from people who felt very small earthquakes: a M2.4 near Pacoima last Thursday evening (a Northridge aftershock and a foreshock to the Saturday M3.0), and a M2.1 near Wrightwood early Friday morning. A person has to be sitting very quietly to feel a quake that small! 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 ------------------------------------------------------------- 11/13 7:32 pm 32 59.1 116 26.3 2.0 11 mi. SE of Julian 11/13 10:08 pm 35 26.8 118 31.6 2.1 13 mi. SSW of town of Lake Isabella 11/14 3:17 am 36 50.1 117 23.2 2.0 20 mi. NW of Stovepipe Wells 11/14 4:57 am 36 52.6 117 21.0 2.0 " 11/14 12:27 pm 32 20.7 115 13.1 3.7 27 mi. SE of Calexico 11/14 12:45 pm 32 20.2 115 13.0 2.7 " 11/14 4:32 pm 35 57.3 117 59.0 2.1 6 mi. SSW of Coso Junction 11/14 6:54 pm 34 17.7 118 28.3 2.4 2 mi. WNW of Pacoima FELT 11/14 7:34 pm 35 57.5 117 59.1 2.4 6 mi. SSW of Coso Junction 11/14 9:02 pm 33 21.0 116 13.3 2.2 10 mi. NE of Borrego Springs 11/15 7:49 am 34 22.4 117 39.9 2.1 2 mi. WNW of Wrightwood FELT 11/15 7:24 pm 33 17.8 115 42.5 2.0 3 mi. SSE of Bombay Beach 11/15 7:48 pm 34 15.2 116 25.7 2.4 9 mi. N of Yucca Valley 11/15 11:34 pm 34 16.5 117 59.3 2.8 5 mi. NE of Mt. Wilson Observatory 11/16 3:26 am 34 17.6 118 28.4 3.0 2 mi. WNW of Pacoima FELT 11/16 7:40 am 34 21.1 116 28.1 2.1 16 mi. N of Yucca Valley 11/16 11:23 am 36 0.3 120 30.0 2.4 8 mi. NNW of Parkfield 11/16 6:30 pm 33 15.4 119 5.4 2.2 14 mi. S of Santa Barbara Is. 11/16 6:37 pm 35 49.3 115 40.5 2.5 35 mi. ESE of Shoshone 11/17 11:00 am 34 24.4 120 3.3 2.1 11 mi. W of Isla Vista 11/17 3:14 pm 33 45.2 119 21.8 2.2 21 mi. SSE of Santa Cruz Is. (E end) 11/17 7:24 pm 35 2.6 117 41.3 2.0 3 mi. NW of Boron 11/17 7:26 pm 35 28.3 118 19.4 2.5 13 mi. SE of town of Lake Isabella 11/17 8:06 pm 35 28.4 118 19.5 3.2 " 11/18 7:00 am 35 28.4 118 19.3 2.5 " 11/18 10:29 am 33 28.3 116 28.7 2.4 12 mi. ESE of Anza 11/18 10:39 pm 32 12.6 115 7.3 2.6 38 mi. SE of Calexico 11/19 12:27 am 34 9.5 117 34.3 2.1 3 mi. NNE of Rancho Cucamonga 11/19 5:26 am 34 1.4 116 36.1 2.0 1 mi. SW of Morongo Valley 11/19 6:51 am 32 28.7 117 26.8 2.1 23 mi. SSW of Mission Beach 11/19 7:05 am 35 57.5 118 34.4 2.2 23 mi. NNW of town of Lake Isabella 11/19 11:31 pm 36 0.6 117 48.7 2.3 7 mi. ESE of Coso Junction 11/20 5:23 am 32 32.7 115 36.2 3.1 10 mi. SW of Calexico FELT -------------------------------------------------------------