• 29 Jul 2024 13:00:52 PDT, (34.950, -116.787), depth 7.3km.
• 22km ENE of Barstow, California

Aftershocks

• As of 06 Aug 2024, 09:18PM PDT, there have been 9 aftershocks recorded.
• The largest was M3.5 (smallest M1.5).
• More aftershocks 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 22 events of M4 or greater within 10km of today’s event.
• The largest historic event was M5.3 on 1997/03/18.
• The most recent historic event was M5.3 on 18 Mar 1997.

Faults

• CFM fault associations: most likely Calico; Hidalgo fault segment (63%). Alternates: Not associated with a CFM modeled fault (14%), Other CFM faults (23%).*
• Nearby faults: Calico-Hidalgo fault zone, Calico section (Calico fault) (2.5 km), Manix fault (6.5 km) and Calico-Hidalgo fault zone, Calico section (Newberry fracture zone) (13.9 km).**

Additional Information

• Links for: USGS earthquake page, ShakeMap, DYFI, waveforms.
• Visit our special reports page for further information on local notable earthquakes.
• Visit scedc.caltech.edu to access any data recorded by the SCSN.

Below are the waveform data associated with this event, as recorded in our Live Seismograms Feed.

• 12 May 2024 11:22:42 PDT, (32.425, -115.242), depth 6.9km.
• 9km NNW of Delta, B.C., Mexico

Aftershocks

• As of 12 May 2024, 12:14PM PDT, there have been 17 aftershocks recorded.
• The largest was M4.5 (smallest M1.4).(A list will be provided in the coming days)
• More aftershocks 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.

Possible Foreshocks

• There were 10 events during the 3 days prior to the earthquake (within a 10 km radius).
• The largest was M3.2 (2024/05/12).

Historical Seismicity

• Since our records began in 1932 we’ve had 91 events of M4 or greater within 10km of today’s event.
• The largest historic event was M7.2 on 2010/04/04.
• The most recent historic event was M4.1 on 08 May 2024.

Faults

• CFM fault associations: most likely Cierro Prieto fault (62%). Alternates: Not associated with a CFM modeled fault (25%), Other CFM faults (13%).*

Additional Information

• Links for: USGS earthquake page, ShakeMap, DYFI, waveforms.
• Visit our special reports page for further information on local notable earthquakes.
• Visit scedc.caltech.edu to access any data recorded by the SCSN.

Below are the waveform data associated with this event, as recorded in our Live Seismograms Feed.

• Largest event: M4.9, 30 Sep 2020 17:31:27 PDT, (33.057, -115.590), depth 11.5km. 4km NE of Westmorland, California
• As of 01 Oct 2020, 05:54AM PDT, the following events have been recorded in the swarm:
• M≥4: 6
• M≥3: 54
• M≥2: 270
• Other M4 events recorded:
• Ml 4.0 Oct 1, 2020 03:37:04UTC 33.052, -115.575 ci37456405
• Mw 4.5 Oct 1, 2020 03:36:34UTC 33.068, -115.597 ci39643328
• Mw 4.1 Oct 1, 2020 01:10:25UTC 33.049, -115.592 ci39641880
• Mw 4.1 Oct 1, 2020 00:58:13UTC 33.065, -115.593 ci39641768
• Mw 4.2 Oct 1, 2020 00:41:18UTC 33.073, -115.601 ci39641616

Swarm Numbers

• There were 96 events during the 3 days prior to the M4.9 (within a 10 km radius). As of 01 Oct 2020, 01:37PM PDT, there have been 632 events recorded after the M4.9.
• The SCSN has so far recorded over 700 events in the swarm, the smallest M1.1. Many of the smaller events are still being analyzed and will be gradually added to the catalogue.
• More activity is expected in the next few days. 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 112 events of M4 or greater within 10km of today’s event.
• The largest historic event was M6.2 on 1987/11/24.
• The most recent historic event was M4.3 on 30 Sep 2020.
• Similar swarms in this area have been recorded in 1981 and 2012 with similar/same sense of motion and maximum magnitudes within the M5 range. For more informtation about the 2012 swarm visit M5.5 Brawley Swarm.

Faults

• CFM fault associations: most likely Westmorland fault; splay segment (94%). Alternates: Not associated with a CFM modeled fault (4%), Other CFM faults (2%).*
• Nearby faults: Imperial fault (13.8 km).**

Additional Information

• Links for: USGS earthquake page, ShakeMap, DYFI, waveforms.
• Visit our special reports page for further information on local notable earthquakes.
• Visit our SoCal swarms page for general information on local swarm monitoring.

Below are the waveform data associated with this event, as recorded in our Live Seismograms Feed. Note that a M2.7 event is visible for the first 36 seconds before the M4.9 is detected. More videos of the swarm will be available soon.

• 03 Apr 2020 18:53:18 PDT, (33.490, -116.507), depth 10.4km.
• 17km ESE of Anza, California
• The highest intensity shaking recorded by an instrument was MMI VI, strong shaking, at 9km from the event epicenter. Felt (mostly weak/light) shaking was reported along much of the length of the southern California coast, from Santa Monica to San Diego, with over 19,000 felt reports submitted to the USGS Did You Feel It? website.

Aftershocks

• As of 07 Apr 2020, 02:21PM PDT, there have been 1426 aftershocks recorded. There have been 8 aftershocks of M3 or larger, and 68 aftershocks of M2 or larger.
• The largest was M3.8 (smallest M-0.1).
• More aftershocks 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.

Possible Foreshocks

• There were 3 events during the 3 days prior to the earthquake (within a 10 km radius).
• The largest was M1.0 (2020/04/02).

Historical Seismicity

• Since our records began in 1932 we’ve had 42 events of M4 or greater within 10km of today’s event.
• The largest historic event was M5.6 on 2005/06/12.
• The most recent historic event was M5.2 on 10 Jun 2016.

Faults

• CFM fault associations: most likely Clark fault (San Jacinto fault zone); north segment (50%). Alternates: Not associated with a CFM modeled fault (3%), Other CFM faults (47%).*
• Nearby faults: San Jacinto fault zone, Anza section (Clark fault) (1.5 km), San Jacinto fault zone, Anza section (Buck Ridge fault) (1.9 km), San Jacinto fault zone, Anza section (2.9 km), San Jacinto fault zone, Coyote Creek section (Coyote Creek fault) (3.6 km) and San Jacinto fault zone, Coyote Creek section (7.4 km).**
• The San Jacinto fault zone is the most active fault, in terms of regular seismic activity, in southern California. The focal mechanism suggests this was a right-lateral strike-slip earthquake, consistent with the motion of the San Jacinto fault (and the Pacific:North American plate boundary motion).

Additional Information

• Links for: USGS earthquake page, ShakeMap, DYFI, waveforms.
• Visit our special reports page for further information on local notable earthquakes:
• 2016/06/10 M5.2 near Borrego Springs (9km from 2020/04/03 event)
• 2005/06/12 M5.2 near Anza (7 km from 2020/04/03 event)
• 2001/10/30 M5.1 near Anza (2 km from 2020/04/03 event)

Below are the waveform data associated with this sequence, as recorded in our Live Seismograms Feed. The mainshock m4.9 and subsequent m3.5+ aftershocks can be viewed in the playlist below.The closest stations to the epicenter represented below are CI.HMT2 and CI.WWC at approximately 51 km away.