California earthquakes

M2.2 earthquake 3km SSW of Half Moon Bay, CA

A magnitude 2.2 earthquake struck 3km SSW of Half Moon Bay, CA on Mon, Dec 13, 2021, 1:48 PM PST (21:48 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M3.1 2km ENE of San Leandro, CA. This one was a foreshock.

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

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The earthquake

Magnitude
2.2 (Md, duration), micro
Magnitude from
Northern California Seismic System
Local time
UTC
2021-12-13 21:48:15 UTC
Depth
10.0 km (6.2 mi), shallow
Epicenter
37.437° N, 122.441° W
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 0.6 km horizontally, 0.2 km in depth
Magnitude uncertainty
±0.12
Depth from
From location
Station coverage gap
205°, poorly surrounded by stations
Stations used
36

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 49 in the 60 days after this one and 43 in the 30 days before it.

After

Before

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc73663366. Read Sun, Oct 4, 2026, 5:43 AM UTC.