M3.0 earthquake 1km W of Concord, CA

A magnitude 3.0 earthquake struck 1km W of Concord, CA on Thu, Jan 21, 2021, 4:48 PM PST (00:48 UTC), 15 km (10 mi) below the surface.

A larger quake followed: M3.2 10km NE of Milpitas, CA. 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
3.01	ML, local (Richter)	Northern California Seismic System	Preferred · Final · ±0.15 · 74 stations
2.7	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed · ±0.038 · 93 stations

728 people reported to the USGS what they felt; the strongest reported shaking was IV, light 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: 57 in the 60 days after this one and 44 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event nc73514715 (also filed as us7000d29a). Read Sun, Oct 4, 2026, 9:37 AM UTC.