SOUTHERN CALIFORNIA SEISMOGRAPHIC NETWORK A Cooperative Project of Caltech and the U.S. Geological Survey January 11, 1996 Weekly Earthquake Report for Southern California ------------------------------------------------ January 4 - 10, 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 818-395-6326. For daily updates, call our Earthquake Information Hotline: 818-395-6977. -------------------------------- This week's Report covers the time period from midnight Thursday morning, January 4, Universal Time (ie. GMT), to midnight Wednesday night, January 10, 1995, Universal Time. In local time, the period of coverage is from 4 p.m., January 3 to 4 p.m., January 10, Pacific Standard Time. We detected and processed 832 earthquakes during the 7-day period covered. The biggest event of the week was Sunday morning's M5.2 earthquake north of Ridgecrest, which was felt by a few people as far away as the greater Los Angeles area. It's aftershocks account for all of the increase in seismicity this week. This particular Ridgecrest event had a mostly strike-slip focal mechanism. It occurred about a mile to the north of the September 20, 1995 M5.8 quake, and about two miles to the east of the August 17, 1995 M5.4 quake. This week's events had a significantly lower b-value than those in August and September, meaning that, this time, the number of small aftershocks is much less compared to the number of large aftershocks. The two largest aftershocks were M4.2 and M4.3, both on Sunday. Because of the relatively high numer of larger aftershocks, we would expect at least four more of M3 or larger in the next week, and perhaps an aftershock above M4. The chance of another M5 event in the next week is about 1 in 10. (These statistics are generated by assuming the rate of aftershocks in the next week will continue to follow the rate of decay and magnitude distribution seen in the last four days.) Other earthquakes worth mentioning this week include: a M3.4 at the northern end of the Landers aftershock zone, near Barstow, late last Wednesday afternoon; a M3.8 near the southern end of the Landers aftershock zone, near Desert Hot Springs, early Friday morning; and a M3.8 in the Panamint Sprins area in the early hours of Sunday morning, before the Ridgecrest quake. The table lists the quakes this week that were M2.0 or larger in the central part of the coverage area. Aftershocks of this week's Ridgecrest quake are only listed if they are M2.5 or larger. 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 ------------------------------------------------------------- 1/3 4:25 pm 35 1.4 116 57.3 3.4 10 mi. NNE of Barstow FELT 1/3 5:16 pm 35 1.2 116 57.3 2.8 " 1/3 5:20 pm 35 1.3 116 57.8 2.6 " 1/4 8:48 am 34 10.3 116 26.0 2.1 3 mi. N of Yucca Valley 1/4 10:53 am 34 24.0 116 27.5 2.1 19 mi. N of Yucca Valley 1/4 12:15 pm 34 19.9 118 36.6 2.0 5 mi. N of Chatsworth 1/4 2:30 pm 35 57.2 117 40.2 2.5 16 mi. ESE of Coso Junction 1/4 5:06 pm 35 43.7 117 37.5 2.0 7 mi. NNE of Ridgecrest 1/4 10:36 pm 34 37.1 116 40.3 2.3 19 mi. NE of Lucerne Valley 1/4 10:48 pm 34 29.1 116 30.4 2.0 25 mi. N of Yucca Valley 1/4 10:54 pm 34 29.1 116 30.3 3.0 " 1/5 2:21 am 34 2.9 116 23.8 2.2 5 mi. SSE of Yucca Valley 1/5 3:57 am 33 56.7 116 22.1 3.8 7 mi. E of Desert Hot Springs; FELT in Palm Springs 1/5 5:26 am 34 2.3 116 19.3 2.1 6 mi. S of Joshua Tree 1/5 7:56 am 34 27.9 116 31.5 2.4 24 mi. N of Yucca Valley 1/5 7:47 pm 36 9.1 120 4.1 2.5 16 mi. E of Coalinga 1/5 8:27 pm 35 1.3 116 58.0 2.2 9 mi. NNE of Barstow 1/6 2:26 am 36 6.3 118 15.3 2.4 18 mi. SW of Olancha 1/6 2:35 am 35 48.0 117 38.3 2.0 12 mi. N of Ridgecrest 1/6 9:30 am 35 45.2 117 38.7 2.1 9 mi. N of Ridgecrest 1/6 11:30 am 35 1.2 116 58.0 2.7 9 mi. NNE of Barstow 1/7 2:32 am 36 28.2 117 37.0 3.8 12 mi. NW of Panamint Springs 1/7 3:27 am 36 28.9 117 36.2 2.8 " 1/7 6:32 am 35 46.0 117 38.9 5.2 10 mi. N of Ridgecrest 1/7 6:35 am 35 46.2 117 39.1 2.5 " 1/7 6:44 am 35 46.1 117 38.8 2.8 " 1/7 6:50 am 35 46.0 117 38.8 3.3 " 1/7 6:52 am 35 43.8 117 37.5 2.6 7 mi. NNE of Ridgecrest 1/7 6:52 am 35 44.4 117 36.4 2.6 8 mi. NNE of Ridgecrest 1/7 6:56 am 35 46.0 117 38.9 2.7 10 mi. N of Ridgecrest 1/7 6:57 am 35 45.3 117 38.4 2.8 9 mi. N of Ridgecrest 1/7 6:58 am 35 45.7 117 38.7 2.8 " 1/7 6:59 am 35 46.4 117 38.4 3.2 10 mi. N of Ridgecrest 1/7 7:06 am 35 45.7 117 37.9 3.2 9 mi. NNE of Ridgecrest 1/7 7:40 am 35 46.2 117 39.2 3.5 10 mi. N of Ridgecrest 1/7 8:04 am 35 46.1 117 38.5 3.5 " 1/7 8:24 am 35 46.0 117 39.2 3.3 " 1/7 8:53 am 35 46.2 117 38.9 2.5 " 1/7 12:09 pm 36 17.4 117 26.1 2.6 3 mi. SSE of Panamint Springs 1/7 12:48 pm 35 45.6 117 37.7 2.5 9 mi. NNE of Ridgecrest 1/7 5:24 pm 36 9.3 117 53.3 2.1 3 mi. ENE of Haiwee Reservoir 1/7 6:38 pm 35 45.7 117 37.9 2.6 9 mi. N of Ridgecrest 1/7 6:43 pm 35 44.4 117 38.2 2.6 8 mi. NNE of Ridgecrest 1/8 12:16 am 36 28.5 117 37.0 2.3 12 mi. NW of Panamint Springs 1/8 12:57 am 35 45.5 117 37.3 4.2 9 mi. NNE of Ridgecrest 1/8 1:15 am 35 46.0 117 38.6 2.5 10 mi. N of Ridgecrest 1/8 1:50 am 35 44.6 117 37.7 2.5 8 mi. NNE of Ridgecrest 1/8 2:42 am 35 45.6 117 37.3 2.6 9 mi. NNE of Ridgecrest 1/8 2:52 am 35 47.0 117 38.1 4.3 11 mi. N of Ridgecrest 1/8 2:53 am 35 48.0 117 37.9 2.7 12 mi. N of Ridgecrest 1/8 6:32 am 35 46.4 117 38.2 2.6 10 mi. N of Ridgecrest 1/8 6:49 am 35 46.6 117 38.2 3.7 " 1/8 6:59 am 35 47.0 117 38.6 3.1 " 1/8 8:18 am 35 47.4 117 37.2 2.6 11 mi. NNE of Ridgecrest 1/8 8:36 am 35 46.8 117 38.3 3.3 11 mi. N of Ridgecrest 1/8 9:16 am 35 47.8 117 38.2 2.7 12 mi. N of Ridgecrest 1/8 9:17 am 35 48.0 117 37.3 2.6 12 mi. NNE of Ridgecrest 1/8 1:24 pm 35 46.0 117 39.0 2.9 10 mi. N of Ridgecrest 1/8 2:40 pm 35 46.0 117 38.8 3.8 " 1/8 8:17 pm 35 44.9 117 37.2 2.5 9 mi. NNE of Ridgecrest 1/8 9:16 pm 35 46.5 117 38.3 2.7 10 mi. N of Ridgecrest 1/9 2:42 am 35 47.8 117 38.3 2.5 12 mi. N of Ridgecrest 1/9 2:43 am 35 47.7 117 38.3 2.9 " 1/9 5:23 am 35 46.5 117 38.3 3.4 10 mi. N of Ridgecrest FELT in Ridgecrest 1/9 8:54 am 36 1.5 117 25.2 2.6 18 mi. N of Trona 1/9 9:21 am 35 46.2 117 39.1 3.2 10 mi. N of Ridgecrest 1/9 9:21 am 35 45.8 117 38.3 3.0 9 mi. N of Ridgecrest 1/9 9:37 am 33 56.5 116 22.1 2.1 7 mi. E of Desert Hot Springs 1/9 11:50 am 34 3.3 116 23.8 2.5 5 mi. SSE of Yucca Valley 1/9 1:08 pm 35 45.7 117 38.0 3.2 9 mi. N of Ridgecrest 1/9 3:36 pm 35 45.9 117 38.6 2.5 " 1/9 6:47 pm 34 15.4 118 27.0 2.1 2 mi. SSW of Pacoima 1/9 9:37 pm 36 21.5 116 59.8 2.0 10 mi. SW of Furnace Creek 1/10 4:17 am 33 58.3 118 6.1 2.0 2 mi. NNE of Downey 1/10 9:44 am 36 1.7 117 25.0 2.5 18 mi. N of Trona 1/10 9:46 am 32 59.5 117 49.1 2.1 31 mi. SSW of San Clemente 1/10 11:33 am 36 2.6 117 43.1 2.1 12 mi. E of Coso Junction -------------------------------------------------------------