SCSNM5.3 – SCSN

08/06/2024, M5.3 near Lamont

Zackary Newman — Wed, 07 Aug 2024 04:34:01 +0000

Event

M5.2, 06 Aug 2024 21:09:56 PDT, (35.108, -119.097), depth 11.6km. 24km SW of Lamont, California.

Aftershocks

As of 08 Aug 2024, 07:30AM PDT, there have been 400 aftershocks recorded.
The largest was M4.6 (smallest M0.9).
The following event numbers have been recorded in the sequence:

M≥5: 1
M≥4: 4
M≥3: 32
M≥2: 165

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 1 events during the 3 days prior to the earthquake (within a 10 km radius).
The largest was M1.4 (2024/08/05).

Historical Seismicity

Since our records began in 1932 we’ve had 80 events of M4 or greater within 10km of today’s event.
The largest historic event was M7.5 on 1952/07/21.
The most recent historic event was M4.1 on 24 Jun 2024.

Faults

CFM fault associations: most likely Not associated with a CFM modeled fault (99%). Alternates: White Wolf fault (1%).*
Nearby faults: unnamed faults (1952 earthquake fractures) (2.2 km), Wheeler Ridge fault zone (Wheeler Ridge fault) (9.7 km) and Pleito fault zone, western Pleito section (Pleito fault) (11.3 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.

*Earthquakes can occur both near or on major known faults, and in places where no clear fault zones are known. Using the statistical method of Evans et al. (in prep. 2019) the location and focal mechanism of this earthquake suggest the above association with modeled faults in the Community Fault Model (CFM) provided by the Southern California Earthquake Center (SCEC) and Harvard University. Note that the CFM fault association may be different from the nearby faults list. Differences may arise due to different fault databases, and because the CFM fault association uses the hypocenter with relation to subsurface 3-dimensional fault orientation models, while the nearby faults list utilizes mapped surface traces as they relate to the epicenter.

CFM Fault: SCEC CFM 5.0 Fault name and closest segment if available; The CFM is maintained by Harvard University, Dept of Earth & Planetary Sciences.

Probability: The probability in percent the earthquake is associated with this fault.

SCSN: Caltech/USGS Southern California Seismic Network

**U.S. Geological Survey and California Geological Survey, 2006, Quaternary fault and fold database for the United States, accessed 2015, from USGS web site: https://earthquake.usgs.gov/hazards/qfaults/

This information is subject to change as more up-to-date data become available.

06/05/2021, M5.3 swarm near Calipatria

Jennifer Andrews — Sat, 05 Jun 2021 18:58:06 +0000

Significant Events

Largest event: M5.3, 05 Jun 2021 10:55:58 PDT, (33.140, -115.635), depth 5.8km. 11km W of Calipatria, California.
As of 07 Jun 2021, 03:30PM PDT, the following event numbers have been recorded in the swarm:

M≥5: 1
M≥4: 5
M≥3: 34
M≥2: 292

All M5 events recorded:

M 5.3 05 Jun 2021 10:55:58 PDT, (33.140, -115.635), 39919392

Swarm Numbers

As of 07 Jun 2021, 03:30PM PDT, we have recorded 1004 events in the swarm (within a 20 km radius, and counting 5 days before the largest event). The smallest event is magnitude 0.5. 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, swarm activity in Southern California can continue for hours, days, weeks, months or years. For more information on swarms please see our Swarm page.

Historical Seismicity

Since our records began in 1932 we’ve had 110 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 M4.0 on 05 Jun 2021.

Faults

CFM fault associations: most likely Westmorland fault; main segment (94%). Alternates: Not associated with a CFM modeled fault (3%), Other CFM faults (3%).*
Nearby faults: San Jacinto fault zone, Superstition Hills section (Lone Tree fault) (13.9 km) and San Jacinto fault zone, Superstition Hills section (Superstition Hills flt) (14.7 km).**

Additional Information

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 the M5.3 event, as recorded in our Live Seismograms Feed. Additional waveform data associated with other M3.5+ events in this swarm will be added at a later date.

*Earthquakes can occur both near or on major known faults, and in places where no clear fault zones are known. Using the statisticalmethod of Evans et al. (in prep. 2019) the location and focal mechanism of this earthquake suggest the above association with modeled faults in the Community Fault Model (CFM) provided by the Southern California Earthquake Center (SCEC) and Harvard University. Note that the CFM fault association may be different from the nearby faults list. Differences may arise due to different fault databases, and because the CFM fault association uses the hypocenter with relation to subsurface 3-dimensional fault orientation models, while the nearby faults list utilizes mapped surface traces as they relate to the epicenter.

CFM Fault: SCEC CFM 5.0 Fault name and closest segment if available; The CFM is maintained by Harvard University, Dept of Earth & Planetary Sciences.

Probability: The probability in percent the earthquake is associated with this fault.

SCSN: Caltech/USGS Southern California Seismic Network

This information is subject to change as more up-to-date data become available.

04/05/2018, M5.3 near Santa Cruz Is

Jennifer Andrews — Thu, 05 Apr 2018 20:19:32 +0000

05 Apr 2018 12:29:16 PDT, (33.837, -119.725), depth 9.9km, 29km SW of Santa Cruz Is.
Foreshocks:No earthquakes were detected within 20 km of this earthquake in the preceding week. This is not unusual and is a reminder that earthquakes often occur without any previous short-term seismic activity.
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.
The earthquake occurred on an offshore strike-slip fault; further analysis will be needed to identify the fault or fault system with which it is associated. An earthquake of this size is not necessarily associated with a major, named fault. Nearby faults: Santa Cruz Island fault (14.2 km). The strike slip mechanism is shown below.

Moment tensor solution for the 05 Apr 2018 earthquake near Santa Cruz Is.
Historic seismicity: two earthquakes with magnitudes of 4-5 have occurred in the general region since 1940 (M4.8 in 1954/08/26 and M4.1 2005/07/24). On December 21, 1812, a large earthquake struck in the Santa Barbara Channel, generating a tsunami that carried a ship inland. This earthquake is poorly understood due to its timing, but illustrates that offshore faults are capable of hosting earthquakes with magnitudes upwards of 7. On June 29, 1925, a magnitude 6.6 earthquake occurred offshore of Santa Barbara.

The earthquake was widely felt along the California coast as shown in the felt report plot below. Anything more than light shaking would only be expected on the channel islands, close to the epicenter.

Instrumental shaking is shown in the ShakeMap below.

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 epicenter represented below is CI.LCP in Santa Maria, at a distance of 112 km from the event. The furthest station shown is CI.MLAC in Mammoth Lakes, over 400 km away. With an event of this magnitude, and the sensitivity of our seismic instruments, we detect this earthquake across our entire seismic network.