M3.0 earthquake 6 km SSE of Three Rocks, California

A magnitude 3.0 earthquake struck 6 km SSE of Three Rocks, California on Wed, Aug 1, 1984, 8:55 PM PDT (03:55 UTC), 9 km (6 mi) below the surface.

A larger quake followed: M3.5 11 km SSE of Huron, 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
2.98	Md, duration	Northern California Seismic System	Preferred · Final · ±0.15 · 101 stations
3.18	Mc	Southern California Seismic Network	Final · 29 stations

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: 188 in the 60 days after this one and 74 in the 30 days before it.

The first 60 of 188.

From the USGS Earthquake Hazards Program and its partner networks, event nc24772 (also filed as ci46505). Read Thu, Oct 1, 2026, 12:22 PM UTC.