M3.4 earthquake Central California

A magnitude 3.4 earthquake struck in Central California on Thu, Feb 27, 1975, 3:22 PM PDT (22:22 UTC), 12 km (7 mi) below the surface.

A larger quake followed: M4.2 10 km NNW of Hollister, California. 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
3.4	ML, local (Richter)	Northern California Seismic System	Preferred · Final · 0 stations
3.4	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed

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: 198 in the 60 days after this one and 121 in the 30 days before it.

The first 60 of 198.

From the USGS Earthquake Hazards Program and its partner networks, event nc1022985 (also filed as usp0000a2c). Read Sun, Oct 4, 2026, 4:51 PM UTC.