From: cowen@jade.ucdavis.edu
Newsgroups: ca.earthquakes,sci.geo.geology
Subject: Text of Caltech Weekly Report, 30 July 1992
Date: 30 Jul 92 23:41:46 GMT
Reply-To: cowen@jade.ucdavis.edu
Followup-To: ca.earthquakes
Organization: Geology Department, University of California, Davis

Here is the text of the Caltech weekly report. It accompanies a postscript
map that I can't or won't re-post because it's a very big file. You can
ftp the text and map from seismo.gps.caltech.edu under successive
directories pub and ca.earthquakes. I recommend the Dartmouth utility
Fetch for ftp, by the way.

I've edited the text very lightly, but the information is unaffected.

Weekly Earthquake Report for Southern California, 
July 23 - 29, 1992

	Prepared by:  Kate Hutton, Seismological Laboratory
                      (kate@bombay.gps.caltech.edu)
		      Lucy Jones, U.S. Geological Survey
		      California Institute of Technology

	This document is a commentary on current seismic activity. The 
	earthquakes discussed have been detected and processed 
	automatically. All epicenters and magnitudes have been reviewed 
	to exclude obvious blunders; however, they must still be 
	considered preliminary.  For further information, please contact 
	the authors or the Caltech Public Relations Office at (818) 356-6326.

			--------------------------------

	This week's Report covers the time period from midnight Thursday
	morning, July 23, Pacific Daylight Time, to midnight Wednesday 
	night, July 29, PDT. Aftershocks the Landers earthquake continue, 
 as they will for several months at least. The activity is still 
 so high that we are unable to keep up with the processing, but 
 it has decreased to the point that we have processed most
	events > M2.5; only about 10% are automatic locations. The result 
 is a somewhat crisper definition of the Landers and Big Bear 
 aftershock zones on the map. We have included events of M2.5 or 
 larger on the map, 188 of them.
	Landers and Big Bear aftershocks, of course, continue, as
	they will for some time. This week the most significant events
	were the M4.9 and M4.7 that occurred on Friday, at the southern
	end of the Landers zone. Although these events were rather close 
	to the San Andreas fault, both of their focal mechanisms agreed
	with the Landers fault rather than with the San Andreas. In other
	words, they are ordinary aftershocks of the M7.5 quake of June 28.
		Table 1 lists only earthquakes of M2.8 or larger this week,
	due to the high level of activity. Times are local times; if you 
	want GMT, add 7 hrs. to the PDT listed. 

	Table 1
	-------
	Date  Time     N Lat.   W Long.   Mag

	-------------------------------------------------------------
         7/23 12:37 am  34 10.4  116 48.3  3.5  5 mi. NNE of Mt. San Gorgonio
         7/23  6:50 am  34 10.7  116 48.8  2.9  5 mi. N of Mt. San Gorgonio
         7/23 12:38 pm  34 55.8  116 45.7  2.9  15 mi. E of Barstow
         7/23  1:47 pm  35  1.3  116 58.2  2.9  9 mi. NNE of Barstow
         7/23  2:53 pm  32 53.2  118 26.8  2.8  7 mi. NW of San Clemente Is.
         7/23  3:42 pm  34  5.1  116 51.2  3.2  1 mi. SW of Mt. San Gorgonio
         7/23  4:05 pm  34  5.1  116 51.3  3.6  	"
         7/23  4:16 pm  34  5.3  116 51.2  3.0  	"
         7/23 11:37 pm  34 19.5  116 38.2  3.1  13 mi. ENE of Big Bear City
         7/24 12:23 am  34 29.3  116 29.0  3.9  25 mi. N of Yucca Valley
         7/24 12:52 am  34 32.7  116 32.5  2.9  23 mi. ENE of Lucerne Valley
         7/24  2:49 am  34  6.8  116 51.4  3.0  1 mi. WNW of Mt. San Gorgonio
         7/24  5:19 am  34 56.9  116 54.0  2.9  8 mi. ENE of Barstow
         7/24  5:26 am  34 11.6  116 52.1  3.0  4 mi. SE  of town of Big

						Bear Lake
         7/24 11:14 am  33 54.1  116 17.0  4.9  13 mi. NNW of Indio;
						Widely felt
         7/24 11:21 am  33 54.1  116 17.1  3.4  	"
         7/24 11:44 am  33 54.2  116 17.4  2.9  	"
         7/24  2:37 pm  33 53.7  116 17.0  2.8  	"
         7/24  3:31 pm  34 16.8  116 46.6  3.2  4 mi. ENE of Big Bear City
         7/24  5:22 pm  34 13.9  116 51.8  2.8  2 mi. SSW of Big Bear City
         7/24  5:35 pm  34 16.3  116 43.5  3.1  7 mi. E of Big Bear City
         7/24  9:11 pm  34  4.8  116 22.6  3.1  4 mi. SE of Yucca Valley
         7/24  9:31 pm  33 56.2  116 18.3  4.7  11 mi. E of Desert Hot
						Springs; widely felt
         7/24 11:35 pm  34 11.6  116 25.9  3.2  5 mi. N of Yucca Valley
         7/25  1:21 am  34  6.6  116 55.1  3.4  5 mi. W of Mt. San Gorgonio
         7/25  1:38 am  34 37.5  116 36.0  2.9  23 mi. ENE of Lucerne Valley
         7/25  2:10 am  34 26.6  116 29.8  2.9  22 mi. N of Yucca Valley
         7/25  3:13 am  34 38.3  116 33.2  2.8  26 mi. ENE of Lucerne Valley
         7/25  3:23 am  34 52.7  116 38.7  3.1  21 mi. E of Barstow
         7/25  3:27 am  34 16.0  116 55.0  3.7  1 mi. NNW of town of Big

						Bear Lake
         7/25  4:03 am  34 38.3  116 33.2  2.9  25 mi. ENE of Lucerne Valley
         7/25  5:37 am  34 56.8  116 44.8  3.0  16 mi. ENE of Barstow
         7/25  5:41 am  33 54.1  116 17.3  3.1  13 mi. NNW of Indio
         7/25  8:11 am  35 57.7  116 43.7  3.3  24 mi. SE of Telescope

						Peak, Panamint Range
         7/25  8:34 am  35 56.9  116 43.7  2.8  	"
         7/25 10:02 am  33 56.5  116 18.2  3.7  11 mi. E of Desert Hot

						Springs
         7/25 12:01 pm  32 25.5  115 16.9  3.1  20 mi. SE of Calexico
         7/25  3:21 pm  34 38.0  116 41.5  3.1  19 mi. NE of Lucerne Valley
         7/25  4:37 pm  33 56.7  116 18.7  2.8  10 mi. E of Desert Hot

						Springs
         7/25  5:18 pm  34  6.6  116 59.0  2.7  10 mi. SSW of town of Big

						Bear Lake
         7/25  7:05 pm  33 55.9  116 18.4  2.8  11 mi. E of Desert Hot

						Springs
         7/25  7:33 pm  35  8.3  116 51.1  2.9  14 mi. S of Goldstone (dry)

						Lake
         7/25  7:42 pm  32 29.5  115 17.0  2.8  17 mi. SE of Calexico
         7/25  9:30 pm  34  8.9  116 24.7  2.8  2 mi. NE of Yucca Valley
         7/26  4:19 am  33 54.0  116 16.9  3.0  13 mi. NNW of Indio
         7/26  7:20 am  34 58.0  116 55.9  2.8  7 mi. NE of Barstow
         7/26  8:39 am  34  6.6  116 59.0  2.9  10 mi. SSW of town of Big

						Bear Lake
         7/26  8:49 am  34 21.4  116 27.4  2.8  16 mi. N of Yucca Valley
         7/26 12:15 pm  34 56.6  116 46.7  2.8  14 mi. ENE of Barstow
         7/26 12:25 pm  34 24.5  116 29.1  3.1  20 mi. N of Yucca Valley
         7/26 12:26 pm  34 18.8  116 27.0  3.2  13 mi. N of Yucca Valley
         7/26 12:53 pm  32 23.9  115  5.5  2.8  30 mi. SE of Calexico
         7/26 12:53 pm  34 59.0  116 56.7  3.0  7 mi. NNE of Barstow
         7/26  3:08 pm  33 53.6  116 17.0  2.9  12 mi. NNW of Indio
         7/26  7:21 pm  34 22.8  116 27.7  3.0  18 mi. N of Yucca Valley
         7/26  8:57 pm  34 21.5  116 26.9  2.8  16 mi. N of Yucca Valley
         7/26  9:33 pm  33 26.1  117 58.7  2.8  12 mi. SSW of Newport Beach
         7/27  1:00 am  34 15.0  116 25.8  2.8  9 mi. N of Yucca Valley
         7/27  2:12 am  33 54.3  116 17.3  2.9  13 mi. NNW of Indio
         7/27  4:12 am  34 14.4  116 50.1  3.1  2 mi. SSE of Big Bear City
         7/27  4:44 am  34 14.9  116 25.9  2.8  9 mi. N of Yucca Valley
         7/27  5:15 am  34  7.3  116 54.0  2.8  4 mi. WNW of Mt. San

						Gorgonio
         7/27 11:53 am  34 23.8  116 27.2  3.0  19 mi. N of Yucca Valley
         7/27 12:04 pm  34 21.4  116 27.5  2.8  16 mi. N of Yucca Valley
         7/27  1:37 pm  34 58.0  116 56.3  3.2  7 mi. NE of Barstow
         7/27  1:40 pm  32 36.7  115 37.7  3.9  8 mi. WSW of Calexico
         7/27  3:10 pm  36  5.1  117 40.7  3.1  15 mi. ESE of south end

						of Haiwee Reservoir
         7/27  3:17 pm  34 17.6  116 51.9  3.1  2 mi. NNW of Big Bear City
         7/27  3:54 pm  32 36.8  115 37.5  3.0  8 mi. WSW of Calexico
         7/27  3:55 pm  32 37.2  115 37.4  2.8  	"
         7/27  4:54 pm  34 12.4  116 45.9  2.8  6 mi. SE of Big Bear City
         7/27  6:42 pm  34 15.1  116 25.8  3.0  9 mi. N of Yucca Valley
         7/27  9:31 pm  34 21.8  116 27.0  2.9  16 mi. N of Yucca Valley
         7/27 10:40 pm  34 21.0  116 26.9  2.9  	"
         7/27 11:17 pm  35 37.3  118 16.7  2.8  10 mi. E of the town of

						Lake Isabella
         7/28 10:41 am  34 26.8  116 29.0  3.0  22 mi. N of Yucca Valley
         7/28 11:27 am  34  6.7  116 24.9  3.4  1 mi. ESE of Yucca Valley;
						Felt
         7/28  3:37 pm  34 13.4  116 44.5  2.9  6 mi. ESE of Big Bear City
         7/28  4:09 pm  34 56.7  116 46.7  2.9  14 mi. ENE of Barstow
         7/28  4:30 pm  33 57.0  116 18.7  2.8  10 mi. E of Desert Hot

						Springs
         7/28  5:32 pm  34  2.9  116 24.2  3.0  5 mi. SSE of Yucca Valley
         7/28  5:36 pm  34 56.3  116 50.4  2.8  10 mi. ENE of Barstow
         7/28  6:04 pm  34  7.0  116 25.1  3.1  1 mi. E of Yucca Valley
         7/28  7:59 pm  34  8.4  116 25.1  2.8  2 mi. NE of Yucca Valley
         7/28  9:43 pm  34 19.6  116 24.0  2.8  14 mi. N of Yucca Valley
         7/29 12:43 am  34 37.7  116 39.8  3.1  20 mi. NE of Lucerne Valley
         7/29  6:20 am  35 17.1  116 51.8  3.1  4 mi. SSE of Goldstone

						(dry) Lake
         7/29  6:34 am  34 12.1  116 51.8  3.3  3 mi. SE of town of Big

						Bear Lake
         7/29  9:27 am  34 18.5  116 25.9  2.9  13 mi. N of Yucca Valley
         7/29  9:48 am  34 21.2  116 28.1  3.0  16 mi. N of Yucca Valley
         7/29 10:00 am  34  7.1  116 24.8  2.8  1 mi. E of Yucca Valley
         7/29 10:01 am  34 34.1  116 32.7  3.0  24 mi. ENE of Lucerne Valley
         7/29 10:39 am  35 17.2  116 51.9  3.2  4 mi. SSE of Goldstone (dry)

						Lake
         7/29  1:18 pm  33 21.0  116 26.5  2.9  7 mi. NNW of Borrego Springs
	-------------------------------------------------------------