M1.7 earthquake 18km SW of Olancha, CA

A magnitude 1.7 earthquake struck 18km SW of Olancha, CA on Wed, Sep 9, 1987, 2:09 AM PDT (09:09 UTC), 4 km (3 mi) below the surface.

A larger quake followed: M3.4 16km WSW of Johannesburg, 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: 197 in the 60 days after this one and 95 in the 30 days before it.

The first 60 of 197.

From the USGS Earthquake Hazards Program and its partner networks, event ci622921. Read Sun, Oct 4, 2026, 8:15 AM UTC.