California earthquakes

M1.7 earthquake 8 km W of Cobb, California

A magnitude 1.7 earthquake struck 8 km W of Cobb, California on Wed, Sep 23, 1987, 10:54 PM PDT (05:54 UTC), 1 km (1 mi) below the surface.

A larger quake followed: M3.2 5 km SW 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
1.7 (md), micro
Local time
UTC
1987-09-24 05:54:52 UTC
Depth
1.2 km (0.8 mi), shallow
Epicenter
38.822° N, 122.820° 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 0.7 km horizontally, 0.5 km in depth
Magnitude uncertainty
±0.15
Depth from
From location
Station coverage gap
204°, poorly surrounded by stations
Stations used
7

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 161 in the 60 days after this one and 102 in the 30 days before it.

After

  1. 1.711 km W of Cobb, California · 14248 days ago · 4 km deep · 3 km away
  2. 2.15 km SW of Cobb, California · 14248 days ago · 0 km deep · 7 km away
  3. 3.05 km SW of Cobb, California · 14248 days ago · 0 km deep · 7 km away
  4. 1.86 km WSW of Cobb, California · 14248 days ago · 0 km deep · 3 km away
  5. 1.76 km SW of Cobb, California · 14248 days ago · 0 km deep · 6 km away
  6. 1.65 km WSW of Cobb, California · 14247 days ago · 0 km deep · 4 km away
  7. 2.25 km SSW of Cobb, California · 14247 days ago · 12 km deep · 7 km away
  8. 2.55 km W of Cobb, California · 14247 days ago · 3 km deep · 2 km away
  9. 2.97 km WSW of Cobb, California · 14246 days ago · 1 km deep · 2 km away
  10. 1.77 km WSW of Cobb, California · 14246 days ago · 1 km deep · 3 km away
  11. 1.86 km WSW of Cobb, California · 14246 days ago · 0 km deep · 3 km away
  12. 2.62 km ESE of Mendocino, California · 14246 days ago · 26 km deep · 97 km away
  13. 1.54 km WSW of Cobb, California · 14245 days ago · 0 km deep · 5 km away
  14. 3.05 km SW of Cobb, California · 14244 days ago · 0 km deep · 6 km away
  15. 3.25 km SW of Cobb, California · 14244 days ago · 0 km deep · 5 km away
  16. 1.64 km N of Clear Lake Riviera, California · 14243 days ago · 1 km deep · 21 km away
  17. 2.011 km W of Cobb, California · 14243 days ago · 2 km deep · 3 km away
  18. 2.06 km W of Cobb, California · 14243 days ago · 3 km deep · 2 km away
  19. 1.710 km W of Cobb, California · 14243 days ago · 1 km deep · 3 km away
  20. 1.57 km W of Cobb, California · 14242 days ago · 3 km deep · 1 km away
  21. 1.86 km WSW of Cobb, California · 14241 days ago · 4 km deep · 3 km away
  22. 1.96 km S of Clear Lake Riviera, California · 14241 days ago · -1 km deep · 11 km away
  23. 2.19 km W of Cobb, California · 14241 days ago · 0 km deep · 1 km away
  24. 1.75 km WSW of Cobb, California · 14240 days ago · -1 km deep · 5 km away
  25. 1.54 km SW of Kenwood, California · 14240 days ago · 2 km deep · 52 km away
  26. 1.85 km W of Cobb, California · 14239 days ago · 1 km deep · 3 km away
  27. 1.77 km W of Cobb, California · 14239 days ago · 0 km deep · 1 km away
  28. 2.112 km NE of Philo, California · 14239 days ago · -1 km deep · 60 km away
  29. 1.57 km W of Cobb, California · 14238 days ago · 3 km deep · 1 km away
  30. 1.74 km WSW of Cobb, California · 14238 days ago · 2 km deep · 5 km away
  31. 1.57 km W of Cobb, California · 14238 days ago · 0 km deep · 1 km away
  32. 1.7Northern California · 14237 days ago · 2 km deep · 52 km away
  33. 1.56 km WNW of Cobb, California · 14237 days ago · 0 km deep · 2 km away
  34. 1.71 km ENE of American Canyon, California · 14236 days ago · 9 km deep · 87 km away
  35. 3.16 km W of Cobb, California · 14236 days ago · 3 km deep · 2 km away
  36. 1.611 km WNW of Calistoga, California · 14236 days ago · 7 km deep · 25 km away
  37. 1.72 km NNW of Clear Lake Riviera, California · 14236 days ago · 8 km deep · 18 km away
  38. 2.04 km SW of Hopland, California · 14234 days ago · 4 km deep · 32 km away
  39. 3.16 km W of Cobb, California · 14233 days ago · 4 km deep · 2 km away
  40. 1.86 km W of Cobb, California · 14233 days ago · 3 km deep · 2 km away
  41. 1.54 km WSW of Cobb, California · 14233 days ago · 1 km deep · 4 km away
  42. 1.56 km W of Cobb, California · 14233 days ago · 3 km deep · 2 km away
  43. 2.16 km SW of Cobb, California · 14232 days ago · 1 km deep · 6 km away
  44. 1.67 km W of Cobb, California · 14232 days ago · 1 km deep · 2 km away
  45. 1.85 km WSW of Cobb, California · 14232 days ago · 0 km deep · 4 km away
  46. 1.94 km NW of Philo, California · 14232 days ago · -1 km deep · 65 km away
  47. 1.59 km WSW of Cobb, California · 14232 days ago · 1 km deep · 2 km away
  48. 2.3Northern California · 14231 days ago · 1 km deep · 2 km away
  49. 2.37 km NNE of Hopland, California · 14231 days ago · 1 km deep · 31 km away
  50. 1.96 km W of Cobb, California · 14231 days ago · 3 km deep · 2 km away
  51. 1.66 km W of Cobb, California · 14231 days ago · 3 km deep · 2 km away
  52. 1.85 km W of Cobb, California · 14231 days ago · 2 km deep · 2 km away
  53. 2.55 km W of Cobb, California · 14231 days ago · 2 km deep · 3 km away
  54. 1.68 km W of Cobb, California · 14230 days ago · 3 km deep · 2 km away
  55. 1.66 km SW of Cobb, California · 14230 days ago · 0 km deep · 6 km away
  56. 2.24 km S of Cobb, California · 14230 days ago · 2 km deep · 10 km away
  57. 2.28 km WSW of Cobb, California · 14230 days ago · 0 km deep · 2 km away
  58. 1.54 km W of Cobb, California · 14229 days ago · -1 km deep · 4 km away
  59. 1.913 km SSW of Willits, California · 14229 days ago · 3 km deep · 76 km away
  60. 2.04 km SSE of Napa, California · 14228 days ago · 12 km deep · 78 km away

The first 60 of 161.

Before

  1. 2.77 km WSW of Cobb, California · 14250 days ago · 3 km deep · 3 km away
  2. 2.06 km WSW of Cobb, California · 14250 days ago · 1 km deep · 3 km away
  3. 1.97 km W of Cobb, California · 14250 days ago · 3 km deep · 1 km away
  4. 1.74 km SE of Clear Lake Riviera, California · 14250 days ago · 7 km deep · 17 km away
  5. 2.05 km WSW of Cobb, California · 14250 days ago · 1 km deep · 4 km away
  6. 1.77 km WSW of Cobb, California · 14251 days ago · 2 km deep · 2 km away
  7. 1.55 km WNW of Cobb, California · 14252 days ago · 1 km deep · 3 km away
  8. 1.77 km W of Cobb, California · 14252 days ago · -1 km deep · 1 km away
  9. 3.44 km W of Cobb, California · 14252 days ago · 2 km deep · 4 km away
  10. 1.97 km WSW of Cobb, California · 14252 days ago · 1 km deep · 2 km away
  11. 1.93 km NNW of Cloverdale, California · 14253 days ago · -1 km deep · 18 km away
  12. 2.58 km W of Cobb, California · 14253 days ago · 1 km deep · 0 km away
  13. 1.98 km W of Cobb, California · 14253 days ago · -1 km deep · 1 km away
  14. 2.46 km W of Cobb, California · 14254 days ago · 2 km deep · 2 km away
  15. 2.55 km SW of Cobb, California · 14254 days ago · 1 km deep · 6 km away
  16. 1.76 km W of Cobb, California · 14254 days ago · 1 km deep · 2 km away
  17. 2.018 km NE of Potter Valley, California · 14254 days ago · 6 km deep · 72 km away
  18. 1.65 km SW of Cobb, California · 14255 days ago · -1 km deep · 7 km away
  19. 1.617 km N of Upper Lake, California · 14255 days ago · 1 km deep · 55 km away
  20. 1.52 km NNE of Cloverdale, California · 14256 days ago · 0 km deep · 17 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1152829. Read Sun, Sep 27, 2026, 8:22 PM UTC.