June 23, 1994

		Weekly Earthquake Report for Southern California
		------------------------------------------------
		               June 16 - 22, 1994

	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 818-395-6326.
	For daily updates, call our Earthquake Information Hotline:
	818-395-6977.

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

	This week's Report covers the time period from midnight Thursday
	morning, June 16, Pacific Daylight Time, to midnight Wednesday
	night, June 22, Pacific Daylight Time.  We recorded 429 earthquakes
	this week.
		The greatest excitement this week occurred last Thursday
	morning, as we were preparing last week's report.  There was a
	M5.0 Landers aftershock at 9:24 am, which was felt at least as
	far away as Pasadena (in other words, I felt it myself). It had
	a strike-slip focal mechanism, as expected for Landers, and was
	located only a few miles northeast of the June 28, 1992 mainshock
	(Mw7.3).  This week's action produced a small amount of public 
	interest, but was generally overshadowed by other news stories.
		Previously, we had calculated that there was about a 6%
	chance of a Landers aftershock above M5.0 during a one month
	period.  So we were not all that surprised when one happened.
	Incidently, during the same one month period (ie., World Cup), the
	Northridge sequence has an 11% chance of producing a M5.0 or 
	larger event.
		The other minor sensation of the week was a small cluster
	of quakes in the Lakewood are, all but one of which were on
	Wednesday (yesterday).  Two of these, M2.6 and M2.5 at 11:50 pm
	on Tuesday and 8:46 am on Wednesday, were felt sharply in the
	epicentral area.
		The table lists the quakes 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 Daylight
	Time listed.

	Table 1
	-------
	Date  Time      N Lat.   W Long.   Mag  
	-------------------------------------------------------------
         6/16  7:33 am  33 31.8  116 28.3  2.6  11 mi. E of Anza
         6/16  8:51 am  33 31.9  116 28.3  2.2  	"
         6/16  9:24 am  34 16.1  116 24.1  5.0  10 mi. N of Yucca Valley
						WIDELY FELT
         6/16  9:29 am  34 15.9  116 24.4  2.8  	"
         6/16  9:30 am  34 14.7  116 25.7  3.0  8 mi. N of Yucca Valley
         6/16  9:35 am  34 15.6  116 24.1  2.1  10 mi. N of Yucca Valley
         6/16  9:44 am  34 16.1  116 24.1  2.2  	"
         6/16  9:45 am  34 15.8  116 23.8  2.9  	"
         6/16  9:47 am  34 16.5  116 24.4  2.5  	"
         6/16  9:47 am  34 16.5  116 24.5  3.0  	"  FELT
         6/16 10:29 am  34  9.6  117 26.3  2.4  3 mi. N of Fontana
         6/16 10:32 am  34 15.9  116 23.8  2.6  10 mi. N of Yucca Valley
         6/16 10:32 am  34 16.0  116 24.5  2.0  	"
         6/16 11:15 am  34 22.2  116 28.0  2.3  17 mi. N of Yucca Valley
         6/16 12:27 pm  34 15.7  116 24.3  2.0  10 mi. N of Yucca Valley
         6/16  2:03 pm  34 16.0  116 24.6  2.1  	"
         6/16  4:36 pm  34 16.1  116 24.3  2.3  	"
         6/16  4:38 pm  34 22.0  116 28.2  2.0  17 mi. N of Yucca Valley
         6/16  7:09 pm  34 16.1  116 24.3  2.4  10 mi. N of Yucca Valley
         6/16  7:20 pm  34 16.1  116 24.3  2.4  	"
         6/17  2:08 am  34 15.9  116 24.0  2.5  	"
         6/17  2:58 am  34 16.2  116 24.3  2.4  	"
         6/17  4:12 am  34  7.2  116 43.9  2.1  5 mi. ENE of Mt. San Gorgonio
         6/17  4:44 am  34 22.0  116 28.3  2.3  17 mi. N of Yucca Valley
         6/17  7:50 am  34 15.6  116 23.8  2.0  10 mi. N of Yucca Valley
         6/17  7:56 am  34 16.3  116 25.9  2.7  	"
         6/17  9:27 am  34  8.9  117 42.8  2.4  2 mi. N of Claremont Colleges
         6/17  1:36 pm  34 19.8  119 36.8  2.0  7 mi. SW of Carpinteria
         6/17  3:40 pm  33 15.1  117 28.3  2.3  6 mi. NW of Oceanside
         6/17  4:07 pm  35 18.7  118 31.6  2.4  13 mi. NNW of Tehachapi
         6/17  4:21 pm  34 12.5  116 26.4  2.0  6 mi. N of Yucca Valley
         6/17  4:32 pm  34 15.8  118 28.9  2.1  2 mi. WSW of San Fernando
         6/18  1:26 am  34 16.5  116 24.8  2.8  10 mi. N of Yucca Valley
         6/18  2:13 am  34  6.3  117 18.2  2.0  Under downtown San Bernardino
         6/18  4:06 am  33 18.8  116 22.6  2.0  4 mi. N of Borrego Springs
         6/18  4:49 am  34 55.6  116 55.3  2.3  6 mi. ENE of Barstow
         6/18  6:21 am  34 16.1  116 24.3  2.2  10 mi. N of Yucca Valley
         6/18  7:56 am  34 22.2  116 28.3  2.7  17 mi. N of Yucca Valley
         6/18 10:47 am  34 22.2  116 28.2  2.1  	"
         6/18  3:19 pm  34 12.8  118 34.6  2.0  1 mi. ENE of Canoga Park
         6/18  3:23 pm  35 18.5  117 39.4  2.0  21 mi. S of Ridgecrest
         6/18  5:34 pm  34 21.9  118 36.6  2.6  4 mi. SSW of Magic Mtn.
         6/18 11:13 pm  34 16.2  116 24.6  2.2  10 mi. N of Yucca Valley
         6/19 12:27 am  34 18.0  118 27.9  2.3  1 mi. NW of San Fernando
         6/19 12:52 am  34 16.9  116 40.8  2.3  9 mi. E of Big Bear City
         6/19  3:15 am  36  3.3  117 52.3  2.1  4 mi. E of Coso Junction
         6/19  3:38 am  34 15.7  116 24.0  2.0  10 mi. N of Yucca Valley
         6/19  5:20 am  33 57.8  118 52.4  2.0  4 mi. WSW of Pt. Dume
         6/19  8:32 am  34 20.7  116 23.6  2.2  15 mi. N of Yucca Valley
         6/19 10:44 am  34 18.5  118 24.5  2.5  2 mi. NE of San Fernando
         6/19 10:44 am  34 18.3  118 24.1  3.0  	"  FELT
         6/19 12:35 pm  34 21.8  118 37.4  2.0  4 mi. SSW of Magic Mtn.
         6/19  1:08 pm  35  5.7  116 40.3  2.0  21 mi. SE of Goldstone (dry) 
						Lake
         6/19  1:58 pm  35  5.3  116 40.7  2.0  	"
         6/19  6:20 pm  34  8.7  116 24.3  2.0  2 mi. NE of Yucca Valley
         6/19  9:33 pm  34 25.2  116 28.4  2.3  20 mi. N of Yucca Valley
         6/20  1:45 am  34  8.7  116 26.1  2.7  1 mi. NNE of Yucca Valley
						FELT
         6/20  2:36 am  34 37.9  116 33.4  2.2  25 mi. ENE of Lucerne Valley
         6/20  3:25 am  34 26.0  119 52.7  2.0  2 mi. NW of Isla Vista
         6/20  1:50 pm  34  8.9  116 25.7  2.4  2 mi. NNE of Yucca Valley
         6/20  4:47 pm  34 18.7  118 27.6  2.2  2 mi. NNW of San Fernando
         6/20  5:45 pm  33 15.4  116  1.3  2.7  3 mi. WSW of Salton City
         6/21  6:06 am  34 14.5  116 26.6  2.0  8 mi. N of Yucca Valley
         6/21  7:20 am  34 19.9  116 28.5  2.2  14 mi. N of Yucca Valley
         6/21  9:55 am  34 15.7  118 26.2  2.1  1 mi. S of San Fernando
         6/21 10:31 am  34 17.4  118 29.6  2.1  3 mi. W of San Fernando
         6/21 12:46 pm  33 13.7  116 15.4  2.9  7 mi. ESE of Borrego Springs
         6/21 12:52 pm  33 13.8  116 15.4  2.3  	"
         6/21 12:52 pm  33 13.8  116 15.2  2.4  	"
         6/21 10:39 pm  33 57.4  116 31.6  2.5  1 mi. WSW of Desert Hot 
						Springs
         6/21 11:50 pm  33 50.3  118  7.7  2.6  2 mi. NE of Long Beach airport
						FELT
         6/22  1:25 am  32 38.1  117  5.9  2.2  6 mi. NNW of San Ysidro
         6/22  8:15 am  34 16.2  116 24.1  2.1  10 mi. N of Yucca Valley
         6/22  8:46 am  33 50.0  118  6.8  2.5  3 mi. NE of Long Beach airport
         6/22  8:48 am  33 50.5  118  5.5  2.0  	"
         6/22  8:51 am  33 50.9  118  4.9  2.0  	"
         6/22  9:05 am  34  6.8  116 59.4  2.9  9 mi. SE of Running Springs
						FELT
         6/22 11:37 am  33 51.2  118  3.5  2.1  4 mi. NE of Long Beach airport
         6/22 12:36 pm  34  5.3  116 25.1  2.9  2 mi. SE of Yucca Valley
						FELT
         6/22  5:25 pm  35 41.4  116 39.0  2.0  26 mi. NNE of Goldstone (dry) 
						Lake
         6/22  7:34 pm  34 11.0  116 49.1  2.0  5 mi. N of Mt. San Gorgonio
         6/22 10:21 pm  33 51.2  118  7.7  2.1  2 mi. NE of Long Beach airport
        -------------------------------------------------------------

        Figure 1. A map of southern California showing the earthquakes
        recorded during the past week by the Caltech/USGS Seismic
        Network.  Major faults are marked, as well as the metropolitan
        areas of Los Angeles (L.A.), Palm Springs (P.S.), San Diego
        (S.D.), and Santa Barbara (S.B.).  The circles denote the
	earthquakes, the size of the circle indicating the magnitude.