M2.4 earthquake 4km NW of Willowbrook, CA

A magnitude 2.4 earthquake struck 4km NW of Willowbrook, CA on Mon, Feb 28, 1983, 10:11 AM PST (18:11 UTC), 2 km (2 mi) below the surface.

A larger quake followed: M3.7 2km NW of Willowbrook, 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
2.4	Mh	Southern California Seismic Network	Preferred · Final · ±0.257 · 11 stations
2.4	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed

The USGS’s account of the effects of this earthquake.

Felt at Lakewood.

From the USGS event page for ci1102076. U.S. Geological Survey text and figures are in the public domain.

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: 90 in the 60 days after this one and 58 in the 30 days before it.

The first 60 of 90.

From the USGS Earthquake Hazards Program and its partner networks, event ci1102076 (also filed as usp0001tcv). Read Thu, Oct 1, 2026, 8:55 AM UTC.