California earthquakes

M1.8 earthquake 7 km W of Cobb, California

A magnitude 1.8 earthquake struck 7 km W of Cobb, California on Sun, Dec 20, 1981, 12:29 PM PST (20:29 UTC), 3 km (2 mi) below the surface.

A larger quake followed: M2.5 4 km ESE of Penngrove, 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
1.8 (md), micro
Local time
UTC
1981-12-20 20:29:38 UTC
Depth
3.2 km (2.0 mi), shallow
Epicenter
38.816° N, 122.805° 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 0.2 km horizontally, 0.5 km in depth
Magnitude uncertainty
±0.09
Depth from
From location
Station coverage gap
65°
Stations used
22

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 163 in the 60 days after this one and 29 in the 30 days before it.

After

  1. 2.54 km ESE of Penngrove, California · 16347 days ago · 0 km deep · 61 km away
  2. 1.94 km E of Penngrove, California · 16347 days ago · 0 km deep · 60 km away
  3. 1.94 km E of Penngrove, California · 16347 days ago · 0 km deep · 60 km away
  4. 1.85 km E of Penngrove, California · 16347 days ago · 1 km deep · 59 km away
  5. 1.8Northern California · 16346 days ago · 4 km deep · 12 km away
  6. 1.5Northern California · 16346 days ago · 1 km deep · 4 km away
  7. 2.0Northern California · 16346 days ago · 3 km deep · 1 km away
  8. 1.95 km WSW of Cobb, California · 16345 days ago · 1 km deep · 2 km away
  9. 1.64 km E of Penngrove, California · 16344 days ago · 0 km deep · 60 km away
  10. 1.65 km E of Penngrove, California · 16344 days ago · 2 km deep · 59 km away
  11. 1.631 km ESE of Covelo, California · 16343 days ago · 7 km deep · 100 km away
  12. 1.59 km SW of Calistoga, California · 16343 days ago · 4 km deep · 37 km away
  13. 1.77 km S of Comptche, California · 16343 days ago · 4 km deep · 81 km away
  14. 1.83 km ENE of Clear Lake Riviera, California · 16343 days ago · 2 km deep · 20 km away
  15. 2.97 km WSW of Cobb, California · 16343 days ago · 1 km deep · 1 km away
  16. 2.28 km NW of Redwood Valley, California · 16342 days ago · 3 km deep · 69 km away
  17. 1.96 km W of Cobb, California · 16342 days ago · 3 km deep · 1 km away
  18. 2.84 km NE of Hopland, California · 16341 days ago · 6 km deep · 31 km away
  19. 2.59 km WSW of Cobb, California · 16341 days ago · 2 km deep · 3 km away
  20. 2.77 km WSW of Cobb, California · 16341 days ago · 0 km deep · 1 km away
  21. 1.96 km W of Cobb, California · 16340 days ago · 1 km deep · 2 km away
  22. 2.37 km W of Cobb, California · 16340 days ago · 0 km deep · 1 km away
  23. 1.74 km E of Penngrove, California · 16340 days ago · 2 km deep · 60 km away
  24. 1.64 km E of Penngrove, California · 16340 days ago · 0 km deep · 60 km away
  25. 1.511 km N of Brooktrails, California · 16340 days ago · 6 km deep · 96 km away
  26. 1.83 km WSW of Moskowite Corner, California · 16339 days ago · 12 km deep · 66 km away
  27. 1.63 km NE of Willits, California · 16339 days ago · 5 km deep · 82 km away
  28. 1.95 km NNE of Clearlake, California · 16339 days ago · -1 km deep · 28 km away
  29. 1.86 km WSW of Geyserville, California · 16339 days ago · 21 km deep · 21 km away
  30. 2.06 km WSW of Cobb, California · 16338 days ago · -1 km deep · 2 km away
  31. 1.95 km W of Cobb, California · 16338 days ago · 1 km deep · 2 km away
  32. 1.75 km SW of Cobb, California · 16338 days ago · 0 km deep · 4 km away
  33. 1.68 km WSW of Cobb, California · 16338 days ago · 2 km deep · 2 km away
  34. 1.87 km WSW of Cobb, California · 16338 days ago · 1 km deep · 1 km away
  35. 3.57 km N of Brooktrails, California · 16338 days ago · 7 km deep · 91 km away
  36. 3.2near the coast of Northern California · 16337 days ago · 8 km deep · 92 km away
  37. 2.77 km W of Cobb, California · 16337 days ago · 0 km deep · 1 km away
  38. 1.96 km ESE of Talmage, California · 16337 days ago · 8 km deep · 41 km away
  39. 1.77 km WSW of Cobb, California · 16337 days ago · 3 km deep · 2 km away
  40. 2.35 km SW of Cobb, California · 16337 days ago · 0 km deep · 4 km away
  41. 1.86 km WSW of Cobb, California · 16336 days ago · 1 km deep · 3 km away
  42. 1.57 km N of Brooktrails, California · 16336 days ago · 8 km deep · 92 km away
  43. 1.66 km WSW of Cobb, California · 16336 days ago · 0 km deep · 2 km away
  44. 2.16 km ENE of Willits, California · 16335 days ago · 3 km deep · 80 km away
  45. 1.87 km W of Cobb, California · 16335 days ago · 2 km deep · 1 km away
  46. 1.69 km WSW of Cobb, California · 16335 days ago · 2 km deep · 2 km away
  47. 2.07 km W of Cobb, California · 16335 days ago · 1 km deep · 1 km away
  48. 2.09 km W of Healdsburg, California · 16335 days ago · 0 km deep · 26 km away
  49. 1.56 km W of Cobb, California · 16333 days ago · 1 km deep · 1 km away
  50. 1.912 km NE of Lucerne, California · 16333 days ago · 0 km deep · 40 km away
  51. 1.67 km WSW of Cobb, California · 16332 days ago · 0 km deep · 1 km away
  52. 2.65 km WSW of Cobb, California · 16332 days ago · -1 km deep · 2 km away
  53. 2.47 km WSW of Cobb, California · 16331 days ago · 3 km deep · 1 km away
  54. 2.04 km E of Penngrove, California · 16331 days ago · 5 km deep · 59 km away
  55. 2.44 km WSW of Cobb, California · 16331 days ago · 1 km deep · 3 km away
  56. 2.54 km SW of Rutherford, California · 16330 days ago · 8 km deep · 52 km away
  57. 2.013 km NE of Angwin, California · 16330 days ago · 11 km deep · 42 km away
  58. 2.35 km E of Penngrove, California · 16330 days ago · 6 km deep · 60 km away
  59. 2.47 km W of Cobb, California · 16330 days ago · 4 km deep · 1 km away
  60. 1.87 km E of Willits, California · 16329 days ago · 7 km deep · 77 km away

The first 60 of 163.

Before

  1. 1.65 km E of Penngrove, California · 16347 days ago · 2 km deep · 60 km away
  2. 3.25 km E of Penngrove, California · 16347 days ago · 7 km deep · 60 km away
  3. 1.720 km NE of Potter Valley, California · 16347 days ago · 7 km deep · 73 km away
  4. 1.620 km NE of Potter Valley, California · 16347 days ago · 4 km deep · 72 km away
  5. 3.14 km E of Penngrove, California · 16347 days ago · 8 km deep · 59 km away
  6. 2.44 km E of Penngrove, California · 16348 days ago · 5 km deep · 59 km away
  7. 3.04 km E of Penngrove, California · 16348 days ago · 9 km deep · 59 km away
  8. 2.64 km E of Penngrove, California · 16348 days ago · 4 km deep · 59 km away
  9. 1.55 km ESE of Roseland, California · 16348 days ago · 10 km deep · 47 km away
  10. 1.57 km W of Cobb, California · 16348 days ago · 1 km deep · 0 km away
  11. 2.29 km WSW of Cobb, California · 16349 days ago · 2 km deep · 2 km away
  12. 1.66 km W of Cobb, California · 16349 days ago · 2 km deep · 1 km away
  13. 1.66 km W of Cobb, California · 16349 days ago · 2 km deep · 1 km away
  14. 2.15 km E of Penngrove, California · 16349 days ago · 6 km deep · 60 km away
  15. 3.14 km E of Penngrove, California · 16349 days ago · 8 km deep · 60 km away
  16. 1.57 km WSW of Cobb, California · 16350 days ago · 0 km deep · 2 km away
  17. 2.66 km W of Cobb, California · 16350 days ago · 4 km deep · 1 km away
  18. 1.89 km WSW of Cobb, California · 16351 days ago · 0 km deep · 3 km away
  19. 1.97 km WSW of Cobb, California · 16351 days ago · 1 km deep · 1 km away
  20. 1.87 km WSW of Cobb, California · 16351 days ago · 2 km deep · 2 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1070494. Read Tue, Sep 22, 2026, 8:25 PM UTC.