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                                        October 27, 1994

        Weekly Earthquake Report for Southern California
        ------------------------------------------------
                      October 20 - 26, 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, October 20, Pacific Daylight Time, to midnight Wednesday
night, October 26, Pacific Daylight Time.  We recorded 387
earthquakes of M1.0 or larger this week.
        We experienced an upsurge in activity this week, compared
to the last couple of weeks.  This is probably not, however,
beyond the range expected statistically.  No single are was
responsible for the increase, and no events exceeded M4.  After-
shocks in the two major sequences (Landers and Northridge) continued
to dominate the map.
        The largest quake was a M3.4 that was part of a cluster in
the Death Valley region, on Sunday.  The M3.4 occurred near the
tail end of the cluster, in the evening.
        The second largest event was a M3.3 in the southern
San Joaquin Valley, early last Friday morning.
        There was also a M3.1 SE of Ridgecrest on Sunday evening.
It was part of a swarm that continued from last week.  That swarm
produced a M4.3 last week.
        Another M3.1, on Monday morning, was a Landers aftershock
and was felt in Yucca Valley.
        The table 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 Daylight
Time listed.

Table 1
-------
Date  Time      N Lat.   W Long.   Mag
-------------------------------------------------------------
10/20  5:05 am  34 17.0  116 23.4  2.4  11 mi. NNE of Yucca Valley
10/20  5:28 am  32 40.4  115 54.5  2.1  6 mi. SE of Ocotillo
10/20 10:10 am  33 45.2  118 23.6  2.0  2 mi. SE of Palos Verdes
                                        Point
10/20 12:19 pm  35  8.1  117 19.3  2.5  24 mi. NW of Barstow
10/21  2:28 am  32 43.3  115 55.2  2.0  4 mi. ESE of Ocotillo
10/21  4:02 am  34 21.5  118 37.3  2.1  4 mi. SSW of Magic Mtn.
10/21  4:42 am  35  1.0  118 57.4  3.3  San Juaquin Valley, I5/99
                                        interchange
10/21  4:52 am  35  0.7  118 57.1  2.2          "
10/21  6:23 am  34 10.6  116 49.6  2.0  5 mi. N of Mt. San Gorgonio
10/21  7:31 pm  35 30.6  117 29.6  2.1  12 mi. SE of Ridgecrest
10/21 11:05 pm  35 23.9  117 49.6  2.3  17 mi. SSW of Ridgecrest
10/22 12:15 am  34 25.0  116 28.7  2.2  20 mi. N of Yucca Valley
10/22  7:00 am  34 20.7  116 53.8  2.2  6 mi. NNW of Big Bear City
10/22  7:26 am  32 17.2  115  7.3  2.8  34 mi. SE of Calexico
10/22  8:07 am  32 17.9  115  7.6  2.5          "
10/22  9:42 am  32 17.8  115  8.1  2.8          "
10/22 10:35 am  33 42.3  116 45.7  2.3  3 mi. SW of Idyllwild
10/22 10:35 am  33 42.6  116 45.8  2.0          "
10/22  9:23 pm  33 42.8  116 49.4  2.2  6 mi. WSW of Idyllwild
10/23  1:33 am  34 58.9  116 56.9  2.0  7 mi. NNE of Barstow
10/23  2:21 am  34 16.3  118 37.0  2.2  4 mi. N of Canoga Park
10/23  4:15 am  35 47.7  117 30.1  2.0  7 mi. WNW of Trona
10/23  7:58 am  34 22.6  116 27.8  2.5  17 mi. N of Yucca Valley
10/23  9:02 am  34 19.1  116 31.0  2.5  14 mi. NNW of Yucca Valley
10/23 10:38 am  35 50.2  116 51.4  2.0  Death Valley, 26 mi. SSE of
                                        Telescope Peak
10/23 10:47 am  35 51.0  116 51.3  2.4          "
10/23 11:05 am  35 50.3  116 52.0  2.9          "
10/23 12:36 pm  35 50.3  116 51.8  2.6          "
10/23  4:37 pm  34 48.9  118 54.8  2.0  1 mi. E of Frazier Park
10/23  6:22 pm  32 15.1  116 27.5  2.5  39 mi. ESE of San Ysidro
10/23  7:52 pm  35 49.9  116 52.1  3.4  Death Valley, 26 mi. SSE of
                                        Telescope Peak
10/23  8:17 pm  35 30.8  117 29.6  3.1  12 mi. SE of Ridgecrest
10/23  9:34 pm  33 58.5  117 48.6  2.4  6 mi. N of Yorba Linda
10/24  4:38 am  34  2.4  116 19.3  2.7  8 mi. SE of Yucca Valley
10/24  8:17 am  34 15.9  116 27.5  3.1  10 mi. N of Yucca Valley
10/24  8:46 am  34  8.8  116 24.5  2.0  2 mi. NE of Yucca Valley
10/24 10:23 am  34 47.1  116 17.7  2.0  35 mi. SSW of Baker
10/24  2:20 pm  35 30.7  117 29.7  2.8  12 mi. SE of Ridgecrest
10/24  2:26 pm  34  2.3  117 30.4  2.0  Fontana, 2 mi. SE of the
                                        I10/I15 interchange
10/24  5:35 pm  33 56.0  116 21.6  2.7  8 mi. ESE of Desert Hot
                                        Springs
10/24  7:47 pm  34 14.9  118 40.8  2.1  2 mi. SE of Simi Valley
10/24  7:52 pm  33 14.6  116  1.7  2.1  4 mi. SW of Salton City
10/24  9:02 pm  32  1.8  115 26.7  2.6  44 mi. S of Calexico
10/25  1:39 am  34 15.6  117 38.5  2.6  1 mi. SSE of Mt. Baldy
10/25  2:40 am  34 15.9  116 27.5  2.8  10 mi. N of Yucca Valley
10/25  5:48 am  36 11.9  120 45.9  2.9  22 mi. W of Coalinga
10/25  9:46 am  34 18.1  116 56.2  2.0  4 mi. NNW of town of Big
                                        Bear Lake
10/25  1:57 pm  34 48.3  116 18.7  2.1  34 mi. SSW of Baker
10/25  4:54 pm  34 10.0  118 41.1  2.3  5 mi. WSW of Canoga Park
10/25  9:14 pm  32 17.0  115  7.7  2.5  34 mi. SE of Calexico
10/25  9:18 pm  34 10.1  118 41.3  2.4  5 mi. WSW of Canoga Park
10/25 10:04 pm  33 15.6  116 50.4  2.0  4 mi. WNW of Lake Henshaw
10/25 11:24 pm  34  2.2  116 19.3  2.0  9 mi. SE of Yucca Valley
10/26  6:02 am  33 36.9  116 41.2  2.1  4 mi. N of Anza
10/26  6:14 am  35 59.8  117 24.2  2.3  16 mi. N of Trona
10/26  9:27 am  32 17.7  115  7.4  2.5  33 mi. SE of Calexico
10/26 11:13 am  32 17.0  115  7.8  2.5          "
10/26 12:00 pm  34  3.0  116 19.2  2.3  8 mi. ESE of Yucca Valley
10/26  3:54 pm  33 57.8  118 54.6  2.1  5 mi. SSE of Leo Carrillo
                                        State Beach
10/26  4:27 pm  33 46.4  116  8.4  2.6  5 mi. NE of Indio
10/26  4:39 pm  33 46.4  116  8.4  2.0          "
-------------------------------------------------------------

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.

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