California earthquakes

M1.8 earthquake 4 km W of Cobb, California

A magnitude 1.8 earthquake struck 4 km W of Cobb, California on Sat, May 30, 1987, 11:57 PM PDT (06:57 UTC), 0 km (0 mi) below the surface.

A larger quake followed: M2.4 5 km N of Port Costa, 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
1987-05-31 06:57:01 UTC
Depth
-0.1 km (-0.1 mi), shallow
Epicenter
38.817° N, 122.774° 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, 0.3 km in depth
Magnitude uncertainty
±0.21
Depth from
From location
Station coverage gap
85°
Stations used
20

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 173 in the 60 days after this one and 0 in the 30 days before it.

After

  1. 1.64 km SW of Cobb, California · 14344 days ago · 4 km deep · 3 km away
  2. 2.45 km N of Port Costa, California · 14344 days ago · 10 km deep · 96 km away
  3. 2.06 km W of Cobb, California · 14343 days ago · 2 km deep · 2 km away
  4. 1.94 km NW of Potter Valley, California · 14341 days ago · 4 km deep · 67 km away
  5. 2.38 km W of Cobb, California · 14341 days ago · -1 km deep · 4 km away
  6. 1.84 km WSW of Cobb, California · 14341 days ago · 1 km deep · 1 km away
  7. 2.57 km W of Cobb, California · 14340 days ago · 4 km deep · 3 km away
  8. 2.27 km WSW of Cobb, California · 14340 days ago · 3 km deep · 3 km away
  9. 2.04 km W of Cobb, California · 14340 days ago · -1 km deep · 1 km away
  10. 1.6Northern California · 14340 days ago · 1 km deep · 1 km away
  11. 2.017 km NNE of Angwin, California · 14340 days ago · 9 km deep · 36 km away
  12. 1.77 km W of Cobb, California · 14340 days ago · 3 km deep · 3 km away
  13. 1.87 km W of Cobb, California · 14340 days ago · 2 km deep · 3 km away
  14. 1.65 km WNW of Cobb, California · 14339 days ago · 1 km deep · 2 km away
  15. 1.95 km W of Cobb, California · 14339 days ago · 0 km deep · 1 km away
  16. 1.65 km WNW of Cobb, California · 14339 days ago · 1 km deep · 2 km away
  17. 2.15 km SSW of Cobb, California · 14339 days ago · 0 km deep · 4 km away
  18. 1.66 km W of Cobb, California · 14339 days ago · 3 km deep · 2 km away
  19. 1.66 km W of Cobb, California · 14339 days ago · 2 km deep · 2 km away
  20. 1.64 km W of Cobb, California · 14339 days ago · 1 km deep · 1 km away
  21. 2.03 km SW of Moskowite Corner, California · 14339 days ago · 8 km deep · 64 km away
  22. 1.521 km ENE of Potter Valley, California · 14338 days ago · 9 km deep · 61 km away
  23. 2.19 km WSW of Cobb, California · 14338 days ago · 1 km deep · 5 km away
  24. 1.85 km WSW of Cobb, California · 14337 days ago · 0 km deep · 2 km away
  25. 1.82 km N of Cloverdale, California · 14337 days ago · 0 km deep · 21 km away
  26. 1.94 km WSW of Cobb, California · 14337 days ago · 5 km deep · 2 km away
  27. 1.88 km WSW of Cobb, California · 14336 days ago · -1 km deep · 4 km away
  28. 1.85 km SSW of Cobb, California · 14336 days ago · 1 km deep · 5 km away
  29. 1.86 km SW of Cobb, California · 14336 days ago · 1 km deep · 3 km away
  30. 1.610 km SE of Boonville, California · 14336 days ago · 2 km deep · 46 km away
  31. 1.810 km SE of Boonville, California · 14336 days ago · 1 km deep · 46 km away
  32. 2.15 km W of Cobb, California · 14335 days ago · 1 km deep · 1 km away
  33. 1.73 km ENE of Calpella, California · 14335 days ago · 2 km deep · 58 km away
  34. 1.54 km ENE of Calpella, California · 14335 days ago · 5 km deep · 58 km away
  35. 2.2near the coast of Northern California · 14335 days ago · 2 km deep · 58 km away
  36. 1.54 km ENE of Calpella, California · 14335 days ago · 5 km deep · 58 km away
  37. 1.54 km WSW of Cobb, California · 14335 days ago · 2 km deep · 2 km away
  38. 1.53 km N of Cloverdale, California · 14335 days ago · 0 km deep · 22 km away
  39. 1.67 km E of Willits, California · 14334 days ago · 8 km deep · 79 km away
  40. 1.55 km SW of Cobb, California · 14334 days ago · 0 km deep · 4 km away
  41. 1.65 km WSW of Cobb, California · 14334 days ago · 1 km deep · 2 km away
  42. 1.84 km WSW of Cobb, California · 14334 days ago · 1 km deep · 2 km away
  43. 1.68 km W of Cobb, California · 14333 days ago · 1 km deep · 4 km away
  44. 1.68 km NW of Redwood Valley, California · 14333 days ago · 3 km deep · 71 km away
  45. 1.66 km WSW of Cobb, California · 14333 days ago · 3 km deep · 2 km away
  46. 2.46 km WNW of Cobb, California · 14333 days ago · 0 km deep · 3 km away
  47. 2.87 km WNW of Cobb, California · 14333 days ago · -1 km deep · 3 km away
  48. 1.66 km W of Cobb, California · 14333 days ago · 3 km deep · 2 km away
  49. 1.55 km W of Cobb, California · 14332 days ago · 1 km deep · 1 km away
  50. 1.86 km W of Cobb, California · 14332 days ago · 3 km deep · 2 km away
  51. 2.24 km WSW of Cobb, California · 14332 days ago · 0 km deep · 2 km away
  52. 1.94 km W of Cobb, California · 14331 days ago · 0 km deep · 1 km away
  53. 2.05 km W of Cobb, California · 14331 days ago · -1 km deep · 1 km away
  54. 1.66 km WSW of Cobb, California · 14331 days ago · 0 km deep · 2 km away
  55. 1.66 km W of Cobb, California · 14331 days ago · 3 km deep · 2 km away
  56. 2.55 km SW of Cobb, California · 14331 days ago · 2 km deep · 3 km away
  57. 2.35 km WSW of Cobb, California · 14330 days ago · 3 km deep · 1 km away
  58. 3.223 km NE of Potter Valley, California · 14329 days ago · 9 km deep · 77 km away
  59. 1.59 km SSE of Boonville, California · 14329 days ago · 3 km deep · 49 km away
  60. 1.87 km W of Cobb, California · 14329 days ago · -1 km deep · 3 km away

The first 60 of 173.

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc101220. Read Tue, Sep 22, 2026, 9:20 PM UTC.