California earthquakes

M2.5 earthquake 8 km W of Cobb, California

A magnitude 2.5 earthquake struck 8 km W of Cobb, California on Fri, Nov 20, 1987, 1:10 PM PST (21:10 UTC), 1 km (1 mi) below the surface.

A larger quake followed: M2.8 6 km W 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
2.5 (md), micro
Local time
UTC
1987-11-20 21:10:42 UTC
Depth
1.3 km (0.8 mi), shallow
Epicenter
38.822° N, 122.826° 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
±0.10
Depth from
From location
Station coverage gap
52°
Stations used
18

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 171 in the 60 days after this one and 0 in the 30 days before it.

After

  1. 1.74 km NNE of Calistoga, California · 14177 days ago · 15 km deep · 33 km away
  2. 1.920 km ENE of Potter Valley, California · 14177 days ago · 7 km deep · 63 km away
  3. 1.69 km WNW of Cobb, California · 14176 days ago · 14 km deep · 4 km away
  4. 2.213 km NNW of Moskowite Corner, California · 14176 days ago · 5 km deep · 57 km away
  5. 1.64 km WSW of Cobb, California · 14176 days ago · 1 km deep · 5 km away
  6. 1.67 km WNW of Cobb, CA · 14176 days ago · 0 km deep · 3 km away
  7. 2.17 km W of Cobb, California · 14176 days ago · 3 km deep · 2 km away
  8. 2.0Northern California · 14176 days ago · 1 km deep · 8 km away
  9. 1.86 km S of Cobb, California · 14176 days ago · 1 km deep · 11 km away
  10. 1.77 km WSW of Cobb, California · 14175 days ago · 4 km deep · 4 km away
  11. 1.67 km WSW of Cobb, California · 14175 days ago · 1 km deep · 2 km away
  12. 2.012 km WSW of Hopland, California · 14175 days ago · 6 km deep · 38 km away
  13. 2.16 km W of Cobb, California · 14175 days ago · 3 km deep · 2 km away
  14. 1.69 km W of Cobb, California · 14175 days ago · 0 km deep · 1 km away
  15. 2.86 km W of Cobb, California · 14175 days ago · 1 km deep · 2 km away
  16. 1.69 km W of Cobb, California · 14175 days ago · -1 km deep · 2 km away
  17. 1.78 km W of Cobb, California · 14175 days ago · 0 km deep · 1 km away
  18. 2.57 km WSW of Cobb, California · 14173 days ago · 3 km deep · 3 km away
  19. 1.97 km WSW of Cobb, California · 14173 days ago · 3 km deep · 3 km away
  20. 1.6Northern California · 14173 days ago · 1 km deep · 3 km away
  21. 2.17 km E of Potter Valley, California · 14173 days ago · 0 km deep · 58 km away
  22. 2.719 km ENE of Sea Ranch, California · 14172 days ago · 4 km deep · 38 km away
  23. 1.519 km ENE of Sea Ranch, California · 14172 days ago · 4 km deep · 38 km away
  24. 1.95 km W of Cobb, California · 14171 days ago · 1 km deep · 4 km away
  25. 1.97 km WSW of Cobb, California · 14171 days ago · 1 km deep · 3 km away
  26. 2.05 km WSW of Cobb, California · 14171 days ago · 0 km deep · 4 km away
  27. 2.56 km WSW of Cobb, California · 14171 days ago · 0 km deep · 4 km away
  28. 1.89 km W of Cobb, California · 14170 days ago · 0 km deep · 0 km away
  29. 2.16 km WNW of Cobb, California · 14170 days ago · 1 km deep · 3 km away
  30. 1.79 km ESE of Hidden Valley Lake, California · 14170 days ago · 7 km deep · 33 km away
  31. 1.94 km WSW of Cobb, California · 14170 days ago · 1 km deep · 5 km away
  32. 1.94 km WSW of Cobb, California · 14169 days ago · 2 km deep · 5 km away
  33. 1.97 km SW of Cobb, California · 14169 days ago · -1 km deep · 7 km away
  34. 2.16 km W of Cobb, California · 14169 days ago · 3 km deep · 2 km away
  35. 1.68 km WNW of American Canyon, California · 14168 days ago · 13 km deep · 81 km away
  36. 3.25 km SW of Cobb, California · 14168 days ago · 1 km deep · 7 km away
  37. 1.65 km SW of Cobb, California · 14168 days ago · -1 km deep · 7 km away
  38. 2.08 km W of Cobb, California · 14168 days ago · 1 km deep · 0 km away
  39. 1.68 km W of Cobb, California · 14168 days ago · 4 km deep · 1 km away
  40. 1.78 km W of Cobb, California · 14167 days ago · 2 km deep · 1 km away
  41. 1.94 km WSW of Cobb, California · 14167 days ago · -1 km deep · 4 km away
  42. 2.9near the coast of Northern California · 14166 days ago · -1 km deep · 72 km away
  43. 1.7Northern California · 14166 days ago · 2 km deep · 4 km away
  44. 2.16 km WSW of Cobb, California · 14165 days ago · 3 km deep · 3 km away
  45. 1.64 km WSW of Cobb, California · 14164 days ago · 0 km deep · 5 km away
  46. 2.06 km SW of Cobb, California · 14163 days ago · 1 km deep · 6 km away
  47. 1.96 km SW of Cobb, California · 14163 days ago · 1 km deep · 6 km away
  48. 1.75 km SW of Cobb, California · 14163 days ago · 1 km deep · 6 km away
  49. 1.75 km WNW of Cobb, California · 14163 days ago · 4 km deep · 4 km away
  50. 1.68 km W of Cobb, California · 14163 days ago · 0 km deep · 1 km away
  51. 1.67 km WSW of Cobb, California · 14163 days ago · 4 km deep · 3 km away
  52. 2.15 km W of Cobb, California · 14163 days ago · 3 km deep · 3 km away
  53. 1.86 km W of Cobb, California · 14163 days ago · 2 km deep · 3 km away
  54. 1.77 km W of Cobb, California · 14162 days ago · 0 km deep · 2 km away
  55. 1.76 km W of Cobb, California · 14162 days ago · 2 km deep · 3 km away
  56. 1.89 km S of Moskowite Corner, California · 14161 days ago · 8 km deep · 76 km away
  57. 1.76 km W of Cobb, California · 14161 days ago · 3 km deep · 3 km away
  58. 2.14 km S of Cobb, California · 14161 days ago · 1 km deep · 10 km away
  59. 1.64 km ESE of Santa Rosa, California · 14161 days ago · 9 km deep · 46 km away
  60. 1.77 km WSW of Cobb, California · 14161 days ago · -1 km deep · 3 km away

The first 60 of 171.

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc108740. Read Tue, Sep 22, 2026, 9:31 PM UTC.