M3.9 earthquake 15km E of Willows, CA

A magnitude 3.9 earthquake struck 15km E of Willows, CA on Sun, Dec 27, 2020, 6:44 AM PST (14:44 UTC), 26 km (16 mi) below the surface.

Map

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

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
3.86	Mw, moment	Northern California Seismic System	Preferred · Final · 4 stations
3.9	Mwr, regional moment	USGS National Earthquake Information Center	Reviewed · 4 stations

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

624 people reported to the USGS what they felt; the strongest reported shaking was IV, light shaking.

How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.

Reviewed by a seismologist.

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

Within 100 km, magnitude 1.5 and up: 52 in the 60 days after this one and 7 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event nc73503450 (also filed as us6000d3ga). Read Sat, Oct 3, 2026, 11:01 PM UTC.