3.1

M3.1 Earthquake 4 km SSE of Compton, CASeptember 17, 2026

2026-09-17 20:32:30 UTC (54 min ago) · approx. 12:32 PM UTC-8 local

Felt by 453 people across surrounding communities.

MagnitudeM3.1(ml)
Time20:32 UTC12:32 PM UTC-8
Depth13.2 kmshallow crustal
Coordinates33.865°, -118.209°
Felt by453DYFI responses· max MMI 3.2
StatusAutomatic (preliminary)

On September 17, 2026 at 20:32 UTC, a magnitude 3.1 shallow crustal earthquake struck 4 km SSE of Compton, CA, at a depth of 13.2 km and coordinates 33.8648°, -118.2090°. The earthquake was reported felt by 453 peopleacross surrounding communities, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 3.2 (light). This earthquake was detected by 118 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 287, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 3.1 releases seismic energy equivalent to roughly 647 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 81 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 33.86°, -118.21°

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 M3.1 earthquake near 4 km SSE of Compton, CA

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

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 453 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 M3.1 earthquake near 4 km SSE of Compton, CA

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

Earthquake Details

Magnitude
3.1 ml
Depth
13.2 km
shallow crustal
Location
33.8648°N
-118.2090°E
Felt Reports
453
DYFI responses
Intensity (MMI)
3.2
light
Community Intensity
3.1
CDI from reports

Technical Information

Event ID
ci41334231
Event Type
earthquake
Status
Automatic
Significance
287
Stations Used
118
Azimuthal Gap
48.0°
Min Station Distance
0.032°
RMS Residual
0.30 sec
Last Updated
2026-09-17 21:25:59 UTC

Common Questions

How strong was the magnitude 3.1 earthquake near Compton, CA?

The magnitude 3.1 earthquake that struck 4 km SSE of Compton, CA on September 17, 2026 at 20:32 UTC had a depth of 13.2 km. It was felt by 453 people with maximum shaking intensity of MMI 3.2 (light). For context, this was a minor earthquake typically detected only by instruments.

Where did the earthquake occur?

The earthquake epicenter was located at 33.8648°, -118.2090°, which is 4 km SSE of Compton, CA. View all earthquakes in California.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.1 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 3.1 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: ci41334231). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2026, September 17, 2026). M3.1 Earthquake 4 km SSE of Compton, CASeptember 17, 2026. Retrieved September 17, 2026 from https://www.earthquaketracker.org/earthquakes/event/ci41334231/