M1.5 earthquake 21km ESE of Anza, CA

A magnitude 1.5 earthquake struck 21km ESE of Anza, CA on Wed, Oct 31, 1990, 2:24 AM PST (10:24 UTC), 7 km (5 mi) below the surface.

A larger quake followed: M3.5 8km E of Running Springs, 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: 194 in the 60 days after this one and 128 in the 30 days before it.

The first 60 of 194.

From the USGS Earthquake Hazards Program and its partner networks, event ci2007268. Read Sun, Oct 4, 2026, 2:38 PM UTC.