California earthquakes

M1.5 earthquake 4 km S of Cobb, California

A magnitude 1.5 earthquake struck 4 km S of Cobb, California on Sun, Sep 23, 1984, 6:20 AM PDT (13:20 UTC), 2 km (1 mi) below the surface.

A larger quake followed: M4.3 11 km ENE of Clearlake, 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
1.5 (md), micro
Local time
UTC
1984-09-23 13:20:03 UTC
Depth
1.5 km (0.9 mi), shallow
Epicenter
38.778° N, 122.726° 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 0.3 km horizontally, 0.5 km in depth
Magnitude uncertainty
±0.15
Depth from
From location
Station coverage gap
77°
Stations used
13

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 170 in the 60 days after this one and 95 in the 30 days before it.

After

  1. 1.64 km S of Cobb, California · 15346 days ago · 1 km deep · 0 km away
  2. 1.58 km W of Cobb, California · 15346 days ago · 1 km deep · 9 km away
  3. 1.83 km SSW of Cobb, California · 15345 days ago · 1 km deep · 2 km away
  4. 1.74 km S of Cobb, California · 15345 days ago · 1 km deep · 1 km away
  5. 4.311 km ENE of Clearlake, California · 15345 days ago · 4 km deep · 31 km away
  6. 1.73 km SW of Cobb, California · 15344 days ago · 1 km deep · 3 km away
  7. 1.72 km NNE of Napa, California · 15343 days ago · 1 km deep · 65 km away
  8. 2.45 km WSW of Glen Ellen, California · 15343 days ago · 5 km deep · 49 km away
  9. 1.95 km WSW of Glen Ellen, California · 15343 days ago · 3 km deep · 50 km away
  10. 2.47 km E of Cloverdale, California · 15342 days ago · 3 km deep · 18 km away
  11. 1.713 km ESE of Hidden Valley Lake, California · 15341 days ago · 0 km deep · 27 km away
  12. 2.012 km ESE of Hidden Valley Lake, California · 15341 days ago · 12 km deep · 26 km away
  13. 1.811 km ESE of Hidden Valley Lake, California · 15341 days ago · 4 km deep · 26 km away
  14. 1.67 km E of Hidden Valley Lake, California · 15341 days ago · 6 km deep · 22 km away
  15. 1.67 km ESE of Hidden Valley Lake, California · 15341 days ago · 5 km deep · 21 km away
  16. 2.25 km ESE of Comptche, California · 15341 days ago · 0 km deep · 87 km away
  17. 1.711 km ESE of Hidden Valley Lake, California · 15341 days ago · 0 km deep · 25 km away
  18. 1.87 km ESE of Hidden Valley Lake, California · 15341 days ago · 5 km deep · 22 km away
  19. 1.815 km ESE of Hidden Valley Lake, California · 15341 days ago · 5 km deep · 28 km away
  20. 2.17 km WSW of Cobb, California · 15341 days ago · 3 km deep · 7 km away
  21. 2.04 km N of Clearlake, California · 15341 days ago · -1 km deep · 25 km away
  22. 2.07 km W of Cobb, California · 15341 days ago · 3 km deep · 9 km away
  23. 1.96 km W of Cobb, California · 15340 days ago · 3 km deep · 8 km away
  24. 2.07 km ESE of Hidden Valley Lake, California · 15340 days ago · 4 km deep · 22 km away
  25. 1.57 km SW of Calistoga, California · 15340 days ago · 5 km deep · 29 km away
  26. 1.96 km WSW of Cobb, California · 15339 days ago · 3 km deep · 7 km away
  27. 2.47 km W of Cobb, California · 15339 days ago · -1 km deep · 9 km away
  28. 1.54 km W of Cobb, California · 15339 days ago · 0 km deep · 7 km away
  29. 2.86 km W of Cobb, California · 15338 days ago · 3 km deep · 7 km away
  30. 2.45 km NW of Montalvin, California · 15336 days ago · 6 km deep · 89 km away
  31. 1.88 km NE of Hopland, California · 15336 days ago · 2 km deep · 40 km away
  32. 1.97 km W of Cobb, California · 15336 days ago · -1 km deep · 9 km away
  33. 2.94 km W of Cobb, California · 15335 days ago · 2 km deep · 6 km away
  34. 1.717 km NE of Upper Lake, California · 15334 days ago · 10 km deep · 56 km away
  35. 1.85 km SW of Cobb, California · 15334 days ago · -1 km deep · 5 km away
  36. 2.25 km SW of Cobb, California · 15334 days ago · -1 km deep · 5 km away
  37. 1.74 km WSW of Cobb, California · 15334 days ago · 1 km deep · 5 km away
  38. 2.220 km NNE of Potter Valley, California · 15333 days ago · 6 km deep · 82 km away
  39. 1.84 km S of Cobb, California · 15333 days ago · 1 km deep · 0 km away
  40. 2.32 km NE of Clear Lake Riviera, California · 15333 days ago · 0 km deep · 21 km away
  41. 1.93 km NE of Clear Lake Riviera, California · 15333 days ago · 1 km deep · 21 km away
  42. 1.82 km ENE of Clear Lake Riviera, California · 15333 days ago · 1 km deep · 21 km away
  43. 1.83 km NE of Clear Lake Riviera, California · 15333 days ago · 1 km deep · 22 km away
  44. 1.96 km W of Cobb, California · 15332 days ago · 3 km deep · 7 km away
  45. 1.97 km WSW of Cobb, California · 15332 days ago · 2 km deep · 7 km away
  46. 2.018 km ENE of Sea Ranch, California · 15331 days ago · 5 km deep · 46 km away
  47. 2.13 km NNW of Moskowite Corner, California · 15331 days ago · 0 km deep · 56 km away
  48. 1.85 km WSW of Cobb, California · 15331 days ago · 1 km deep · 6 km away
  49. 1.717 km ENE of Potter Valley, California · 15330 days ago · 8 km deep · 72 km away
  50. 1.66 km W of Cobb, California · 15330 days ago · 3 km deep · 8 km away
  51. 2.86 km WSW of Cobb, California · 15329 days ago · 1 km deep · 7 km away
  52. 1.84 km SSW of Port Costa, California · 15329 days ago · 10 km deep · 97 km away
  53. 1.58 km SE of Boonville, California · 15329 days ago · 4 km deep · 53 km away
  54. 2.12 km NNW of Hopland, California · 15329 days ago · 3 km deep · 42 km away
  55. 1.63 km ENE of Hidden Valley Lake, California · 15329 days ago · 9 km deep · 18 km away
  56. 1.87 km W of Cobb, California · 15328 days ago · 4 km deep · 9 km away
  57. 2.46 km W of Cobb, California · 15328 days ago · 3 km deep · 8 km away
  58. 1.64 km SSW of Cobb, California · 15328 days ago · -1 km deep · 1 km away
  59. 2.34 km WSW of Cobb, California · 15327 days ago · 1 km deep · 4 km away
  60. 1.62 km WNW of Fulton, California · 15327 days ago · 2 km deep · 31 km away

The first 60 of 170.

Before

  1. 1.821 km ENE of Potter Valley, California · 15346 days ago · 12 km deep · 72 km away
  2. 2.319 km SW of Elk Creek, California · 15346 days ago · -1 km deep · 80 km away
  3. 2.24 km S of Cobb, California · 15346 days ago · 2 km deep · 0 km away
  4. 1.77 km WSW of Cobb, California · 15347 days ago · 0 km deep · 8 km away
  5. 2.18 km WSW of Cobb, California · 15347 days ago · 1 km deep · 9 km away
  6. 1.88 km W of Cobb, California · 15347 days ago · -1 km deep · 9 km away
  7. 2.07 km W of Cobb, California · 15347 days ago · -1 km deep · 9 km away
  8. 4.09 km WSW of Cobb, California · 15347 days ago · 2 km deep · 9 km away
  9. 2.64 km NNE of Geyserville, California · 15347 days ago · 4 km deep · 14 km away
  10. 1.64 km SW of Cobb, California · 15348 days ago · 1 km deep · 3 km away
  11. 1.711 km SW of Hopland, California · 15348 days ago · 4 km deep · 45 km away
  12. 1.99 km W of Cobb, California · 15349 days ago · 1 km deep · 10 km away
  13. 1.68 km WSW of Cobb, California · 15349 days ago · 4 km deep · 7 km away
  14. 1.77 km SW of Calistoga, California · 15349 days ago · 5 km deep · 29 km away
  15. 1.96 km WSW of Cobb, California · 15349 days ago · 0 km deep · 5 km away
  16. 1.58 km W of Cobb, California · 15350 days ago · 0 km deep · 9 km away
  17. 1.825 km SE of Covelo, California · 15350 days ago · 5 km deep · 97 km away
  18. 1.64 km SSE of Clear Lake Riviera, California · 15351 days ago · -1 km deep · 16 km away
  19. 1.70 km WNW of Kelseyville, California · 15351 days ago · -1 km deep · 24 km away
  20. 1.724 km NNE of Potter Valley, California · 15351 days ago · 3 km deep · 85 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc28513. Read Tue, Sep 29, 2026, 1:53 PM UTC.