SCSNM4.4 – SCSN http://www.scsn.org Southern California Seismic Network Fri, 09 Nov 2018 22:11:55 +0000 en-US hourly 1 https://wordpress.org/?v=4.9.2 09/28/2018, M4.4 near Delta, Baja California ../../../../index.php/2018/10/01/09-28-2018-m4-4-near-delta/ ../../../../index.php/2018/10/01/09-28-2018-m4-4-near-delta/#respond Mon, 01 Oct 2018 15:08:41 +0000 http://www.scsn.org/?p=2903 ]]>
  • 28 Sep 2018 19:17:46 PDT, (32.348, -115.183), depth 28.7km, 1km SE of Delta, B.C., Mexico
  • Aftershocks: so far there have been no aftershocks recorded. Some 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.
  • Historical seismicity: since our records began in 1932 we’ve had 118 events of M4 or greater within 10km of today’s event, the largest was M7.2 (2010/04/04) and the most recent was M4.0 on 08 Apr 2015.
  • 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.

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    08/28/2018, M4.4 near La Verne ../../../../index.php/2018/08/29/08-28-2018-m4-4-near-la-verne/ ../../../../index.php/2018/08/29/08-28-2018-m4-4-near-la-verne/#respond Wed, 29 Aug 2018 02:43:55 +0000 http://www.scsn.org/?p=2886 ]]>
  • 28 Aug 2018 19:33:28 PDT, (34.137, -117.775), depth 5.5km, 4km N of La Verne, California
  • Aftershocks: so far (29 Aug 2018, 08:05AM PDT) there have been 37 aftershocks recorded, the largest M3.4 (smallest M0.5). 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.
  • 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 M5.5 (1990/02/28) and the most recent was M4.5 on 17 Apr 1990.
  • Nearby faults: Sierra Madre fault zone, Sierra Madre E section (Sierra Madre fault) (0.6 km), San Antonio fault (2.5 km), Sierra Madre fault zone, Sierra Madre D section (Sierra Madre fault) (6.5 km), San Jose fault (6.8 km), Sierra Madre fault zone, Sierra Madre D section (Upper Duarte fault) (8.0 km), Stoddard Canyon fault (8.9 km), San Gabriel fault zone, San Gabriel River section (San Gabriel fault) (10.1 km), Sierra Madre fault zone, Cucamonga section (Cucamonga fault) (10.5 km), San Gabriel fault zone, San Gabriel River section (Weber fault) (11.2 km) and Sierra Madre fault zone, Clamshell-Sawpit section (Clamshell-Sawpit Canyon flt) (12.6 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.

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    08/14/2018, M4.4 near Aguanga ../../../../index.php/2018/08/15/08-14-2018-m4-4-near-aguanga/ ../../../../index.php/2018/08/15/08-14-2018-m4-4-near-aguanga/#respond Wed, 15 Aug 2018 01:42:19 +0000 http://www.scsn.org/?p=2847 ]]>
  • 14 Aug 2018 18:24:26 PDT, (33.477, -116.803), depth 1.9km, 7km NE of Aguanga, California
  • Aftershocks: so far (16 Aug 2018, 10:48AM PDT) there have been 435 aftershocks recorded, the largest M2.9 (smallest M0.0). 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.
  • There were 95 events during the 3 days prior to the earthquake (within a 10 km radius), the largest was M2.3 (2018/08/12). This area has been experiencing swarm activity for over 2 years (referred to as Cahuilla swarm), seeing elevated seismicity rates since early 2016. This region has hosted earthquake swarms since the 1980s, each lasting for weeks or a few months. The swarm starting early 2016 is the most prolific swarm recorded, with several thousand events observed so far.
  • 2018 seismicity in the region of the Cahuilla swarm as of 15 August 2018. Circles plot individual earthquakes at all magnitudes in the SCSN catalogue, with size indicating magnitude. Events with magnitude 3.0 or greater are shown as red stars. The red line plots the cumulative number of events with magnitude 1.49 or greater.

    Seismicity in the Cahuilla swarm from 1 day before the M4.4 event to approximately 40 hours after. Top plot shows the cumulative event number and the number of events per 20 minutes, both showing the aftershock event rate decay. Bottom plot shows event magnitudes against time.

  • Historical seismicity: since our records began in 1932 we’ve had 13 events of M4 or greater within 10km of today’s event, the largest was M5.6 (2005/06/12) and the most recent was M4.1 on 17 Nov 2008.
  • 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 to the earthquake shown in the view is CI.HMT2 near Anza-Borrego at approximately 30km from the epicenter.

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    12/29/2015, M4.4 near Devore ../../../../index.php/2015/12/30/12292015-m4-4-event-near-devore/ ../../../../index.php/2015/12/30/12292015-m4-4-event-near-devore/#respond Wed, 30 Dec 2015 03:45:47 +0000 http://www.scsn.org/?p=1295 ]]>
  • 29 Dec 2015 17:48:57 PST, (34.192, -117.413), depth 7.0km, 4km SSW of Devore, California
  • Aftershocks: so far (06 Jan 2016, 07:44PM PST) there have been 112 aftershocks recorded, the largest M3.8. 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.
  • There was 1 event during the 3 days prior to the earthquake (within a 1 km radius), with magnitude M1.4 (2015/12/29).
  • The figure shows the cumulative event rate as well as magnitude against time for the sequence.
  • caeqtimes

  • Historical seismicity: since our records began in 1932 we’ve had 10 events of M4 or greater within 10km of today’s event, the largest was M4.6 (1965/04/15) and the most recent was M4.4 on 15 Jan 2014.
  • The figure shows the historic seismicity as grey stars and the recent sequence as circles, coloured by the time of occurrence (blue early, red late) and sized by magnitude. The main M4.4 event is shown as a black star. Red lines indicate the fault traces and the town of Devore is marked by a green triangle.
  • caeqplot

  • The event occurred in a geologically complex area, at the junction of a number of major fault strands (the San Andreas, San Jacinto and Cucamonga). The focal mechanism is more consistent with motions on the San Andreas and San Jacinto.
  • Nearby faults: San Jacinto fault zone (0.4 km), Sierra Madre fault zone, Cucamonga section (Cucamonga fault) (2.8 km), San Andreas fault zone, San Bernardino Mountains section (Tokay Hill fault) (3.8 km), Waterman Canyon fault zone (Waterman Canyon fault) (5.1 km), Red Hill-Etiwanda Avenue fault (Etiwanda Avenue fault) (9.6 km), Cleghorn fault zone, southern Cleghorn section (Cleghorn fault) (10.3 km), San Gabriel fault zone, San Gabriel River section (San Gabriel fault) (13.2 km).
  • Preliminary relocations for events in the sequence are shown in the figure below, indicating one larger and two small adjacent clusters. All three are associated with adjacent segments of the San Jacinto fault. (Prepared by Egill Hauksson.)
  • Devore_31Dec2015_Hauksson_edit

  • Links for: USGS earthquake page, ShakeMap, DYFI.
  • Visit our special reports page for further information on local notable earthquakes.
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