California earthquakes

M1.6 earthquake 1 km SSW of Portola Valley, California

A magnitude 1.6 earthquake struck 1 km SSW of Portola Valley, California on Thu, Oct 19, 1989, 6:11 AM PDT (13:11 UTC), 11 km (7 mi) below the surface.

A larger quake followed: M4.7 4 km NW of Day Valley, California. This one was a foreshock.

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Map

Where this earthquake was located, with the others nearby. Select one for its page.

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The earthquake

Magnitude: 1.6 (Md, duration), micro
Magnitude from: Northern California Seismic System
Local time: Thu, Oct 19, 1989, 6:11 AM PDT
UTC: 1989-10-19 13:11:43 UTC
Depth: 10.5 km (6.5 mi), shallow
Epicenter: 37.369° N, 122.240° W
Region: California
Tsunami flag: No
Status: Reviewed by a seismologist

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 0.3 km horizontally, 0.8 km in depth
Magnitude uncertainty: ±0.15
Depth from: From location
Station coverage gap: 67°
Stations used: 13

Nearest places

Distance and direction from each place to the epicenter, with its forecast.

Nearby

Within 100 km, magnitude 1.5 and up: 199 in the 60 days after this one and at least 200 in the 30 days before it.

After

The first 60 of 199.

Before

Earthquakes today California earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc267708. Read Sun, Oct 4, 2026, 8:43 AM UTC.