Regional Location:

    Preliminary Magnitude:

    Greenwich Mean Date:
    Greenwich Mean Time:
    Latitude:
    Longitude:
    Focal Depth:

    		 CENTRAL CALIFORNIA

    ML 4.0 (NCSN)

    Mw 4.2 (Berkeley)

    01/07/03
    19:02:50
    36.6955N
    121.32.85W
    5.9 km

    		CENTRAL CALIFORNIA

    ML 3.9 (NCSN)

    Mw 4.0 (Berkeley)

    01/07/03
    19:07:16
    36.6828N
    121.3190W
    5.8 km

    Seismo-Watch Significant Earthquake Reports- No. 01-21
    More Special Earthquake Reports
    HOLLISTER, CALIFORNIA, JULY 3, 2001 (Seismo-Watch) -- Preliminary data indicates that two moderate earthquake measuring M4.2 and M4.0 occurred during the beginning of the lunch hour on Tuesday, July 3, in the hills of Central California south of Hollister, but was too weak to topple any items from tables or shelves. They occurred in nearly the same location as a M4.1 jolt yesterday morning.
    Seismo-Watch EQ Flash! Alert Bulletins subscribers received a notification of the earthquake within minutes of the shaking (See a copy of this bulletin). You should subscribe to the service too! It's FREE and     Fast!
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    The quakes were centered about 12 miles south of Hollister and 15 miles northwest of the Pinnacles National Monument along the back side of the Gabilan Range in Cienega Valley, at the junction of Cienega Valley and Harlin Mountain Roads. See a Topo Zone location map.

    While the NCSN local surface wave magnitudes registered a bit less, ML 4.0 and ML 3.9, the U.C. Berkeley moment tensor solutions registered slightly larger, Mw 4.1 and Mw 4.0 (see moment tensor solutions: 1st quake, 2nd quake). The fault plane solutions for both events indicated the earthquake was caused by strike-slip motion along a northwest trending fault, similar to yesterday's quake. This suggesting the quakes triggered along the San Andreas Fault. See some seismic waveforms below.

    Aftershocks
    There have been a number of aftershocks detected following these pair of M4s, the largest of which measured     M3.0 and occurred at 12:32 p.m. - a half hour after today's main jolt.

    Felt Reports
    The larger of the two     M4 quakes, the M4.2 at 12:02 p.m., was sharply felt in the Hollister and Gilroy area and there are unconfirmed reports of light objects toppling from tables or shelves.

    Brief Background
    These were the third     M4 temblors in two days and the fifth south of San Francisco Bay this year.

    Additional Seismic information links:

    • Seismo-Watch Links to California Activity
    • NCSN Recent Earthquakes Page.
    • USGS Community Intensity Report
    Seismograms of the earthquake series from nearby stations:
    • Stanford (NCSN)
    • Fremont Peak (NCSN)
    • Parkfield (NCSN)
    • Mt. Ununhum (NCSN)
    Mainstream media news reports:
    • None at this time
    Report update: 1:25 p.m. PDT, Tuesday, July 3, 2001
    See a local epicenter map.
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