12/06/2017, M4.0 near Julian

  • A number of felt earthquakes have occurred near Julian, California, four with magnitude three or above:
    • M4.0, 06 Dec 2017 16:33:15 PST, (33.148, -116.480), depth 11.1km, 14km NE of Julian, California
    • M3.0, 06 Dec 2017 16:38:03 PST, (33.150, -116.482), depth 11.1km, 14km NE of Julian, California
    • M3.6, 06 Dec 2017 19:57:38 PST, (33.150, -116.480), depth 11.4km, 14km NE of Julian, California
    • M3.5, 07 Dec 2017 02:32:47 PST, (33.147, -116.478), depth 11.0km, 14km ENE of Julian, California
  • Aftershocks: so far (07 Dec 2017, 08:00AM PST) there have been 76 aftershocks recorded for the M4.0 event, the largest M3.6 (smallest M0.6). More may be expected in the next few days, the largest expected is approximately 1 magnitude unit smaller than the mainshock. There is a small chance (about 5%) that a larger quake could occur, with the likelihood decreasing over time.
  • Cumulative event number against time (top) and magnitude against time (bottom) for the events near Julian on 6-7 December 2017. In the lower plot, red stars mark the four events with magnitude three or above.

  • There were 3 events during the 3 days prior to the earthquake (within a 15 km radius), the largest was M2.6 (2017/12/07).
  • Historical seismicity: since our records began in 1932 we’ve had 9 events of M4 or greater within 10km of today’s event, the largest was M4.7 (1957/01/24) and the most recent was M4.5 on 10 Oct 1984.
  • Nearby faults: Elsinore fault zone, Julian section (Earthquake Valley fault) (3.5 km), Elsinore fault zone, Earthquake Valley fault, Julian section (4.3 km) and Elsinore fault zone, Julian section (Elsinore fault) (10.0 km).
  • Links for: USGS earthquake page, ShakeMap, DYFI, waveforms.
  • Visit our special reports page for further information on local notable earthquakes.

Below are the waveform data associated with this event, as recorded in our Live Seismograms Feed. The closest station shown to the event is CI.DGR at approximately 75km, and the furthest is CI.MLAC at more than 500km.

Below is a playlist of the waveform data associated with this sequence, as recorded in our Live Seismograms Feed. The closest station shown to the event is CI.DGR at approximately 75km, and the furthest is CI.MLAC at more than 500km. More videos may be added as new events occur.

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Posted in by Dr. Jennifer Andrews, Local Earthquake Tagged with: , , ,