California earthquakes

M2.3 earthquake 6 km W of Cobb, California

A magnitude 2.3 earthquake struck 6 km W of Cobb, California on Sat, Oct 21, 1978, 6:08 AM PDT (13:08 UTC), 4 km (2 mi) below the surface.

A larger quake followed: M3.8 24 km NE of Potter Valley, 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
2.3 (md), micro
Local time
UTC
1978-10-21 13:08:21 UTC
Depth
3.8 km (2.4 mi), shallow
Epicenter
38.822° N, 122.802° 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, 0.8 km in depth
Magnitude uncertainty
±0.02
Depth from
From location
Station coverage gap
49°
Stations used
14

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 83 in the 60 days after this one and 29 in the 30 days before it.

After

  1. 1.5Northern California · 17511 days ago · 4 km deep · 1 km away
  2. 2.17 km WSW of Cobb, California · 17511 days ago · 0 km deep · 2 km away
  3. 1.87 km W of Cobb, California · 17510 days ago · 3 km deep · 0 km away
  4. 2.09 km E of Moskowite Corner, California · 17509 days ago · 14 km deep · 76 km away
  5. 2.512 km N of Brooktrails, California · 17508 days ago · -1 km deep · 95 km away
  6. 1.616 km ESE of Hidden Valley Lake, California · 17508 days ago · 5 km deep · 37 km away
  7. 1.716 km ESE of Hidden Valley Lake, California · 17505 days ago · 8 km deep · 37 km away
  8. 2.08 km E of Willits, California · 17505 days ago · 10 km deep · 76 km away
  9. 2.16 km WSW of Cobb, California · 17505 days ago · 0 km deep · 2 km away
  10. 1.87 km SW of Calistoga, California · 17504 days ago · 5 km deep · 37 km away
  11. 2.612 km ESE of Hidden Valley Lake, California · 17504 days ago · 7 km deep · 34 km away
  12. 2.16 km NE of Willits, California · 17504 days ago · 5 km deep · 81 km away
  13. 2.513 km WNW of Brooktrails, California · 17502 days ago · 12 km deep · 97 km away
  14. 1.73 km SE of Calpella, California · 17499 days ago · 2 km deep · 54 km away
  15. 2.16 km W of Cobb, California · 17499 days ago · 2 km deep · 1 km away
  16. 2.411 km NNW of Potter Valley, California · 17495 days ago · 4 km deep · 73 km away
  17. 2.610 km NNW of Potter Valley, California · 17495 days ago · 3 km deep · 72 km away
  18. 1.89 km E of Willits, California · 17494 days ago · 8 km deep · 74 km away
  19. 2.326 km NE of Potter Valley, California · 17494 days ago · 14 km deep · 79 km away
  20. 1.57 km WSW of Cobb, California · 17494 days ago · 1 km deep · 2 km away
  21. 2.34 km SW of Clearlake, California · 17492 days ago · 2 km deep · 17 km away
  22. 2.14 km SW of Clearlake, California · 17492 days ago · 0 km deep · 17 km away
  23. 2.38 km WSW of Cobb, California · 17491 days ago · 4 km deep · 2 km away
  24. 1.77 km W of Cobb, California · 17491 days ago · 4 km deep · 1 km away
  25. 1.66 km W of Cobb, California · 17491 days ago · 3 km deep · 0 km away
  26. 3.824 km NE of Potter Valley, California · 17489 days ago · 18 km deep · 77 km away
  27. 2.119 km NE of Potter Valley, California · 17489 days ago · 4 km deep · 73 km away
  28. 2.024 km NE of Potter Valley, California · 17489 days ago · 11 km deep · 76 km away
  29. 1.827 km NE of Potter Valley, California · 17489 days ago · 15 km deep · 78 km away
  30. 2.425 km NE of Potter Valley, California · 17489 days ago · 13 km deep · 78 km away
  31. 1.725 km NE of Potter Valley, California · 17489 days ago · 13 km deep · 77 km away
  32. 1.65 km W of Cobb, California · 17488 days ago · 1 km deep · 1 km away
  33. 1.66 km W of Cobb, California · 17487 days ago · 3 km deep · 0 km away
  34. 1.85 km SSW of Saint Helena, California · 17484 days ago · 5 km deep · 48 km away
  35. 2.112 km SSW of Dillon Beach, California · 17483 days ago · 2 km deep · 77 km away
  36. 2.46 km WSW of Cobb, California · 17482 days ago · 3 km deep · 1 km away
  37. 1.82 km SE of Calpella, California · 17481 days ago · 2 km deep · 55 km away
  38. 1.83 km SE of Calpella, California · 17481 days ago · 3 km deep · 54 km away
  39. 1.610 km W of Cobb, California · 17480 days ago · 0 km deep · 3 km away
  40. 2.19 km SE of Willits, California · 17479 days ago · 9 km deep · 72 km away
  41. 3.37 km NNW of Redwood Valley, California · 17479 days ago · 13 km deep · 68 km away
  42. 1.57 km WSW of Cobb, California · 17479 days ago · 4 km deep · 2 km away
  43. 1.56 km W of Cobb, California · 17478 days ago · 4 km deep · 1 km away
  44. 1.98 km W of Cobb, California · 17477 days ago · 1 km deep · 2 km away
  45. 2.28 km W of Cobb, California · 17477 days ago · 0 km deep · 2 km away
  46. 1.68 km W of Cobb, California · 17477 days ago · 0 km deep · 2 km away
  47. 1.810 km SE of Willits, California · 17475 days ago · 10 km deep · 71 km away
  48. 2.0near the coast of Northern California · 17475 days ago · 4 km deep · 54 km away
  49. 1.78 km W of Cobb, California · 17474 days ago · 1 km deep · 2 km away
  50. 2.17 km W of Cobb, California · 17473 days ago · 1 km deep · 0 km away
  51. 2.113 km ESE of Hidden Valley Lake, California · 17471 days ago · 8 km deep · 34 km away
  52. 2.610 km NNE of Brooktrails, California · 17471 days ago · 8 km deep · 91 km away
  53. 2.212 km ESE of Hidden Valley Lake, California · 17471 days ago · 10 km deep · 33 km away
  54. 1.96 km ESE of Hopland, California · 17470 days ago · 4 km deep · 25 km away
  55. 1.817 km ENE of Potter Valley, California · 17470 days ago · 5 km deep · 61 km away
  56. 2.26 km W of Cobb, California · 17469 days ago · 3 km deep · 1 km away
  57. 1.74 km WNW of Redwood Valley, California · 17468 days ago · 7 km deep · 64 km away
  58. 1.76 km NE of Rohnert Park, California · 17468 days ago · 8 km deep · 50 km away
  59. 1.76 km WSW of Cobb, California · 17467 days ago · 0 km deep · 1 km away
  60. 2.57 km W of Cobb, California · 17467 days ago · 3 km deep · 1 km away

The first 60 of 83.

Before

  1. 1.57 km SE of Boonville, California · 17512 days ago · 4 km deep · 46 km away
  2. 1.88 km W of Cobb, California · 17513 days ago · 1 km deep · 2 km away
  3. 1.98 km W of Cobb, California · 17513 days ago · 0 km deep · 2 km away
  4. 2.06 km ENE of Willits, California · 17514 days ago · 11 km deep · 79 km away
  5. 2.09 km ESE of Willits, California · 17514 days ago · 8 km deep · 73 km away
  6. 1.57 km ESE of Geyserville, California · 17514 days ago · 6 km deep · 15 km away
  7. 2.27 km W of Cobb, California · 17515 days ago · 0 km deep · 1 km away
  8. 1.77 km WSW of Cobb, California · 17516 days ago · 1 km deep · 2 km away
  9. 1.63 km SW of Oakville, California · 17517 days ago · 7 km deep · 56 km away
  10. 2.7Northern California · 17517 days ago · 4 km deep · 2 km away
  11. 2.29 km ESE of Willits, California · 17520 days ago · 8 km deep · 73 km away
  12. 2.32 km SE of Clear Lake Riviera, California · 17523 days ago · 1 km deep · 16 km away
  13. 1.811 km NE of Brooktrails, California · 17524 days ago · 5 km deep · 86 km away
  14. 2.68 km W of Cobb, California · 17525 days ago · 1 km deep · 2 km away
  15. 2.210 km NW of Cobb, California · 17526 days ago · 3 km deep · 6 km away
  16. 1.86 km N of Benicia, California · 17527 days ago · 1 km deep · 97 km away
  17. 2.14 km WSW of Cobb, California · 17527 days ago · 1 km deep · 3 km away
  18. 2.03 km NW of Bayview, California · 17530 days ago · 7 km deep · 96 km away
  19. 1.74 km ESE of Calpella, California · 17530 days ago · 3 km deep · 54 km away
  20. 2.48 km WSW of Cobb, California · 17531 days ago · 0 km deep · 2 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1042945. Read Wed, Sep 30, 2026, 8:06 PM UTC.