3.0

M3.0 Earthquake 3km E of Simi Valley, CA — February 26, 2021

2021-02-26 20:51:50 UTC (2021-02-26) · approx. 12:51 PM UTC-8 local

Felt by 1,486 people across a wide area.

MagnitudeM3.0(ml)
Time20:51 UTC≈ 12:51 PM UTC-8
Depth10.9 kmshallow crustal
Coordinates34.270°, -118.705°
Felt by1,486DYFI responses· max MMI 3.6
Status✓ Reviewed by USGS

On February 26, 2021 at 20:51 UTC, a magnitude 3.0 shallow crustal earthquake struck 3km E of Simi Valley, CA, at a depth of 10.9 km and coordinates 34.2698°, -118.7047°. The earthquake was reported felt by 1,486 peopleacross a wide area, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 3.6 (light). This earthquake was detected by 110 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 510, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 3.0 releases seismic energy equivalent to roughly 511 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 73 m — a useful intuition for the size of the slip patch on the fault.

The epicenter is located in California, a region characterized by the San Andreas transform fault system, where the Pacific and North American plates slide past each other at roughly 46 mm per year. The nearest mapped fault system is the San Andreas Fault. View all earthquakes in California.

Learn more: San Andreas Fault · Magnitude scale · Aftershock sequences

Map showing earthquake epicenter at 34.27°, -118.70°

ShakeMap — predicted shaking intensity

Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.

USGS ShakeMap intensity contours for the M3.0 earthquake near 3km E of Simi Valley, CA

Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 1,486 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.

USGS DYFI community-reported intensity map for the M3.0 earthquake near 3km E of Simi Valley, CA

Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report

Earthquake Details

Magnitude
3.0 ml
Depth
10.9 km
shallow crustal
Location
34.2698°N
-118.7047°E
Felt Reports
1,486
DYFI responses
Intensity (MMI)
3.6
light
Community Intensity
3.7
CDI from reports

Technical Information

Event ID
ci39803176
Event Type
earthquake
Status
✓ Reviewed
Significance
510
Stations Used
110
Azimuthal Gap
31.0°
Min Station Distance
0.037°
RMS Residual
0.22 sec
Last Updated
2025-07-29 01:07:42 UTC

Common Questions

How strong was the magnitude 3.0 earthquake near Simi Valley, CA?

The magnitude 3.0 earthquake that struck 3km E of Simi Valley, CA on February 26, 2021 at 20:51 UTC had a depth of 10.9 km. It was felt by 1,486 people with maximum shaking intensity of MMI 3.6 (light). For context, this was a minor earthquake typically detected only by instruments.

Where did the earthquake occur?

The earthquake epicenter was located at 34.2698°, -118.7047°, which is 3km E of Simi Valley, CA. View all earthquakes in California.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.0 earthquakes can continue for several days and gradually diminish over time.

Has California had earthquakes this big before?

The largest recorded earthquake in California was the M7.9 Fort Tejon earthquake of January 9, 1857. Today's magnitude 3.0 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: ci39803176). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, February 26, 2021). M3.0 Earthquake 3km E of Simi Valley, CA — February 26, 2021. Retrieved July 29, 2025 from https://www.earthquaketracker.org/earthquakes/event/ci39803176/