SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey October 17, 1996 Weekly Earthquake Report for Southern California ------------------------------------------------ October 10 - 16, 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, October 10, Universal Time (ie. GMT), to midnight Wednesday night, October 16, Universal Time. In local time, the period of coverage is from 5 p.m., October 9, Pacific Daylight Time, to 5 p.m., October 16, Pacific Daylight Time. We detected and processed 316 earthquakes during the seven-day period covered. One reason that the weekly total is higher, than it has been, this week and last week is this: due to a bug still in our new software somewhere, mining blasts are included. They usually are not. These blasts cause seismic waves, just like earthquakes do. An experienced analyst can tell the difference by the location, depth (or rather shallowness), and the frequency content of the seismic waves. We normally keep them in the earthquake catalog, but labelled properly. For some reason, this week the software isn't reading the labels properly. The largest events in the area this week were both M3.5. Neither was apparently felt. The first occurred near Lake Isabella just after midnight last Thursday, and the other was offshore, northeast of San Clemente Island, on Saturday after- noon. One small quake near Palmdale late last Wednesday night was reported felt. It had a magnitude of M2.0. 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 ------------------------------------------------------------- 10/9 8:18 pm 34 12.3 117 34.3 2.0 6 mi. N of Rancho Cucamonga 10/9 10:40 pm 34 34.6 118 1.6 2.0 4 mi. E of Palmdale FELT 10/10 12:57 am 35 29.6 118 17.5 3.5 13 mi. SE of town of Lake Isabella 10/10 1:09 am 34 18.0 118 28.4 2.3 2 mi. WNW of Pacoima 10/11 5:20 am 33 6.3 118 3.9 2.1 22 mi. SE of Avalon, Catalina Island 10/11 6:45 am 34 14.2 119 17.2 2.7 3 mi. SSE of Ventura 10/11 6:51 am 34 0.8 116 19.0 2.3 8 mi. S of Joshua Tree 10/11 7:37 am 35 41.0 117 56.5 2.0 15 mi. WNW of Ridgecrest 10/11 4:30 pm 34 19.5 116 50.0 2.0 4 mi. NNE of Big Bear City 10/11 10:22 pm 35 59.2 117 54.8 2.6 4 mi. SSE of Coso Junction 10/11 10:34 pm 36 3.8 117 42.0 2.4 13 mi. E of Coso Junction 10/12 3:25 pm 33 1.5 118 8.7 3.5 18 mi. NE of San Clemente Is. 10/12 3:44 pm 33 1.3 118 8.6 2.5 " 10/12 10:05 pm 34 31.1 116 32.4 2.0 25 mi. NE of Big Bear City 10/13 4:50 am 34 21.7 116 28.3 2.1 16 mi. N of Yucca Valley 10/13 8:30 am 33 42.0 118 39.5 2.0 14 mi. WSW of Palos Verdes Point 10/13 1:18 pm 34 54.3 116 41.2 2.0 19 mi. E of Barstow 10/13 5:30 pm 36 31.3 118 32.8 2.7 14 mi. WSW of Mt. Whitney 10/13 8:38 pm 36 31.1 117 29.4 2.2 12 mi. N of Panamint Springs 10/14 3:55 am 35 44.0 117 37.5 2.0 8 mi. NNE of Ridgecrest 10/14 2:36 pm 35 59.0 117 54.9 2.0 4 mi. SSE of Coso Junction 10/15 7:12 am 32 42.5 115 58.3 2.1 2 mi. SSE of Ocotillo 10/16 7:25 am 34 43.0 120 18.4 2.1 9 mi. NW of Buellton 10/16 11:12 am 34 20.8 116 28.1 2.2 15 mi. N of Yucca Valley 10/16 3: 9 pm 34 6.1 117 29.8 2.4 3 mi. W of Fontana 10/16 3:26 pm 34 17.0 118 27.0 2.1 Under Pacoima -------------------------------------------------------------