M3.7 earthquake 31km WSW of Ludlow, CA

A magnitude 3.7 earthquake struck 31km WSW of Ludlow, CA on Wed, Jul 31, 2002, 1:31 AM PDT (08:31 UTC), 2 km (1 mi) below the surface.

A larger quake followed: M3.8 27km NW of Ludlow, 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
3.73	ML, local (Richter)	Southern California Seismic Network	Preferred · Final · ±0.9 · 125 stations
3.7	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed

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

Felt (II) at Big Bear City.

From the USGS event page for ci9805021. 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: 168 in the 60 days after this one and 77 in the 30 days before it.

The first 60 of 168.

From the USGS Earthquake Hazards Program and its partner networks, event ci9805021 (also filed as usp000b92s). Read Mon, Oct 5, 2026, 11:58 AM UTC.