California earthquakes

M3.7 earthquake 3 km SE of Aromas, California

A magnitude 3.7 earthquake struck 3 km SE of Aromas, California on Fri, Mar 23, 1990, 5:50 AM PST (13:50 UTC), 9 km (5 mi) below the surface.

A larger quake followed: M5.4 5 km NNW of Aromas, 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: 3.7 (ML, local (Richter)), minor
Magnitude from: Northern California Seismic System
Local time: Fri, Mar 23, 1990, 5:50 AM PST
UTC: 1990-03-23 13:50:18 UTC
Depth: 8.5 km (5.3 mi), shallow
Epicenter: 36.867° N, 121.608° W
Region: California
Tsunami flag: No
Status: Reviewed by a seismologist

Magnitude estimates

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
3.7	ML, local (Richter)	Northern California Seismic System	Preferred · Final · 0 stations
3.7	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed

What happened

The USGS’s account of the effects of this earthquake.

Felt (IV) at Aromas, Gilroy, Morgan Hill and San Martin. Felt (III) at Carmel Valley, Castroville, Hollister, Moss Landing, Salinas, San Juan Bautista and Watsonville.

From the USGS event page for nc10090980. U.S. Geological Survey text and figures are in the public domain.

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 0.2 km horizontally, 0.3 km in depth
Depth from: From location
Station coverage gap: 55°
Stations used: 90

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 187 in the 60 days after this one and 96 in the 30 days before it.

After

The first 60 of 187.

Before

Earthquakes today California earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc10090980 (also filed as usp00046z4). Read Sat, Oct 3, 2026, 10:54 AM UTC.