Earthquake Alert Bulletin No:

    Preliminary data indicates a significant earthquake has occurred:

Regional Location:

Preliminary Magnitude:

Moment Magnitude:

Greenwich Mean Date:
Greenwich Mean Time:
Focal Depth (km):
Analysis Quality:


Ml 4.8 (SCSN)

Mw n/a ( -- )

8.0 km

An earthquake registering a preliminary magnitude of Ml 4.8 (SCSN) occurred at 13:34:40 UTC (06:34 a.m. PDT), August 16, in Southern California. The focal point was estimated at 8.0 km beneath the surface and we do not have a Moment magnitude for this event as of yet. The quake was centered about 7 miles west of Mt. San Gorgonio or about 20 miles east of San Bernardino, near Mountain Home Village. The quake triggered close to the Mill Creek segment of the San Andreas fault, but it is unsure if the quake was centered along the fault or beneath the San Bernardino Mountains. A small aftershock sequence has include a half dozen events in the first hour. The quake was strongly felt in the Inland Empire region and as far away as Los Angeles. Although there have been no reports of damage or injury at this time, this quake was large enough to cause items to topple from tables and shelves. This the strongest earthquake in Southern California since Coso M5.2 and M5.0 earthquakes recorded in March earlier this year.

Subtract 7 hours to obtain PDT or 4 hours for EDT
    Location Quality: A (good), B (fair), C (poor), D (bad)
    Magnitude: Ml (local or Richter magnitude), Lg (mblg), Md (duration), Mb (body wave), Ms (surface wave), Mw (moment)

    Sources Include:
    U.S. Geological Survey, National Earthquake Information Center, Golden, CO (NEIC)
    Harvard Geophysical Observatory, Harvard University, Cambridge, MA (HRV)
    International Data Center, Center for Monitoring Research, Arlington, VA (IDC)
    California Institute of Technology, Pasadena, California (Caltech)
    various wire reports and/or personal communications

    All data are preliminary and subject to change.
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