M2.1 earthquake 2km WNW of Castro Valley, CA

A magnitude 2.1 earthquake struck 2km WNW of Castro Valley, CA on Mon, Feb 1, 2021, 5:57 AM PST (13:57 UTC), 5 km (3 mi) below the surface.

A larger quake followed: M3.8 9km ENE of Gilroy, CA. This one was a foreshock.

Map

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

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: 64 in the 60 days after this one and 40 in the 30 days before it.

The first 60 of 64.

From the USGS Earthquake Hazards Program and its partner networks, event nc73519255. Read Sat, Oct 3, 2026, 6:34 PM UTC.