California earthquakes

M2.9 earthquake 36km W of Petrolia, CA

A magnitude 2.9 earthquake struck 36km W of Petrolia, CA on Sat, Dec 25, 2021, 7:57 AM PST (15:57 UTC), 20 km (13 mi) below the surface.

A larger quake followed: M4.6 50km W of Petrolia, CA. This one was a foreshock.

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Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 2.9 (ML, local (Richter)), micro
Magnitude from: Northern California Seismic System
Local time: Sat, Dec 25, 2021, 7:57 AM PST
UTC: 2021-12-25 15:57:52 UTC
Depth: 20.1 km (12.5 mi), shallow
Epicenter: 40.325° N, 124.711° W
Region: California
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
2.9	ML, local (Richter)	Northern California Seismic System	Preferred · Final · ±0.185 · 14 stations
2.9	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed · ±0.06 · 36 stations
4.0	Mw, moment	EW	Preliminary · ±0.3 · 5 stations

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 0.8 km horizontally, 0.6 km in depth
Magnitude uncertainty: ±0.18
Depth from: From location
Station coverage gap: 231°, poorly surrounded by stations
Stations used: 47

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Nearby

Within 100 km, magnitude 1.5 and up: 113 in the 60 days after this one and 176 in the 30 days before it.

After

The first 60 of 113.

Before

Earthquakes today California earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc73668476 (also filed as ew1640447881, us6000gf92). Read Sun, Oct 4, 2026, 3:16 PM UTC.