M1.7 earthquake 2km W of Willowbrook, CA

A magnitude 1.7 earthquake struck 2km W of Willowbrook, CA on Wed, Jan 20, 2021, 10:48 PM PST (06:48 UTC), 19 km (12 mi) below the surface.

A larger quake followed: M3.0 2km ESE of Ontario, CA. This one was a foreshock.

Map

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

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

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

Within 100 km, magnitude 1.5 and up: 61 in the 60 days after this one and 30 in the 30 days before it.

The first 60 of 61.

From the USGS Earthquake Hazards Program and its partner networks, event ci39763840. Read Sat, Oct 3, 2026, 2:02 PM UTC.