M3.9 Earthquake 62 km W of Petrolia, CA — May 21, 2026
2026-05-21 19:00:10 UTC (2026-05-21) · approx. 11:00 AM UTC-8 local
On May 21, 2026 at 19:00 UTC, a magnitude 3.9 shallow crustal earthquake struck 62 km W of Petrolia, CA, at a depth of 10.0 km and coordinates 40.3773°, -125.0107°.
Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 10 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 291 m — a useful intuition for the size of the slip patch on the fault.
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 3 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
-125.0107°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.9 earthquake near Petrolia, CA?
The magnitude 3.9 earthquake that struck 62 km W of Petrolia, CA on May 21, 2026 at 19:00 UTC had a depth of 10.0 km. For context, this was a minor earthquake typically detected only by instruments.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.9 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.9 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: nc75366637). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, May 21, 2026). M3.9 Earthquake 62 km W of Petrolia, CA — May 21, 2026. Retrieved June 3, 2026 from https://www.earthquaketracker.org/earthquakes/event/nc75366637/