M3.5 earthquake 16km E of Ocotillo, CA

A magnitude 3.5 earthquake struck 16km E of Ocotillo, CA on Sun, Jan 31, 2021, 8:18 PM PST (04:18 UTC), 11 km (7 mi) below the surface.

A larger quake followed: M4.8 7km NW of Delta, B.C., MX. This one was a foreshock.

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
3.53	ML, local (Richter)	Southern California Seismic Network	Preferred · Final · ±0.14 · 124 stations
3.3	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed · ±0.085 · 18 stations

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

12 people reported to the USGS what they felt; the strongest reported shaking was III, weak shaking.

Reviewed by a seismologist.

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

Within 100 km, magnitude 1.5 and up: 196 in the 60 days after this one and 199 in the 30 days before it.

The first 60 of 196.

From the USGS Earthquake Hazards Program and its partner networks, event ci39537399 (also filed as us6000ddjz). Read Sun, Oct 4, 2026, 5:51 AM UTC.