M2.2 earthquake 4km ESE of Altadena, CA

A magnitude 2.2 earthquake struck 4km ESE of Altadena, CA on Mon, Jan 4, 2021, 1:24 AM PST (09:24 UTC), 7 km (4 mi) below the surface.

A larger quake followed: M3.5 2km W of Willowbrook, CA. This one was a foreshock.

Map

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

79 people reported to the USGS what they felt; the strongest reported shaking was V, moderate 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: 73 in the 60 days after this one and 43 in the 30 days before it.

The first 60 of 73.

From the USGS Earthquake Hazards Program and its partner networks, event ci39510399. Read Sat, Oct 3, 2026, 7:54 AM UTC.