California earthquakes

M3.1 earthquake 8 km S of Cobb, California

A magnitude 3.1 earthquake struck 8 km S of Cobb, California on Mon, Dec 31, 1973, 10:12 PM PST (06:12 UTC), 4 km (2 mi) below the surface.

A larger quake followed: M3.6 7 km WSW of Cobb, California. This one was a foreshock.

Cobb forecastMore in California

Map

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

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The earthquake

Magnitude
3.1 (Md, duration), minor
Magnitude from
Northern California Seismic System
Local time
UTC
1974-01-01 06:12:13 UTC
Depth
4.0 km (2.5 mi), shallow
Epicenter
38.743° N, 122.740° 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 0.8 km horizontally, 0.6 km in depth
Magnitude uncertainty
±0.38
Depth from
From location
Station coverage gap
188°, poorly surrounded by stations
Stations used
7

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 15 in the 60 days after this one and 0 in the 30 days before it.

After

  1. 3.16 km SW of Kenwood, California · 19263 days ago · 3 km deep · 42 km away
  2. 2.87 km SSW of Cobb, California · 19260 days ago · 2 km deep · 4 km away
  3. 2.50 km WSW of Green Valley, California · 19256 days ago · 10 km deep · 74 km away
  4. 2.91 km SSW of Moskowite Corner, California · 19247 days ago · 16 km deep · 59 km away
  5. 1.810 km E of Angwin, California · 19244 days ago · 7 km deep · 40 km away
  6. 2.05 km E of Santa Rosa, California · 19231 days ago · 10 km deep · 35 km away
  7. 1.86 km E of Black Point-Green Point, California · 19226 days ago · 0 km deep · 73 km away
  8. 2.31 km SSE of Larkfield-Wikiup, California · 19221 days ago · 0 km deep · 27 km away
  9. 1.91 km SE of Larkfield-Wikiup, California · 19221 days ago · 0 km deep · 27 km away
  10. 2.11 km NE of Larkfield-Wikiup, California · 19220 days ago · 8 km deep · 24 km away
  11. 2.88 km WSW of Cobb, California · 19214 days ago · 4 km deep · 9 km away
  12. 3.111 km SE of Hidden Valley Lake, California · 19214 days ago · 12 km deep · 24 km away
  13. 3.67 km WSW of Cobb, California · 19213 days ago · 3 km deep · 9 km away
  14. 2.56 km ESE of Hidden Valley Lake, California · 19211 days ago · 3 km deep · 22 km away
  15. 2.65 km NE of Geyserville, California · 19210 days ago · 2 km deep · 11 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1018293. Read Sun, Oct 4, 2026, 6:40 PM UTC.