California earthquakes

M1.5 earthquake 8 km W of Cobb, California

A magnitude 1.5 earthquake struck 8 km W of Cobb, California on Mon, Aug 21, 1978, 4:51 AM PDT (11:51 UTC), 0 km (0 mi) below the surface.

A larger quake followed: M1.8 7 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
1.5 (md), micro
Local time
UTC
1978-08-21 11:51:46 UTC
Depth
0.4 km (0.2 mi), shallow
Epicenter
38.812° N, 122.818° 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
±0.31
Depth from
From location
Station coverage gap
86°
Stations used
11

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 79 in the 60 days after this one and 27 in the 30 days before it.

After

  1. 1.59 km W of Cobb, California · 17564 days ago · 0 km deep · 2 km away
  2. 1.510 km W of Cobb, California · 17562 days ago · 0 km deep · 2 km away
  3. 1.87 km W of Cobb, California · 17562 days ago · 3 km deep · 2 km away
  4. 1.53 km ENE of Calpella, California · 17561 days ago · 5 km deep · 57 km away
  5. 2.37 km WSW of Cobb, California · 17561 days ago · 1 km deep · 1 km away
  6. 1.98 km WSW of Cobb, California · 17561 days ago · 3 km deep · 2 km away
  7. 2.63 km WSW of Moskowite Corner, California · 17559 days ago · 5 km deep · 66 km away
  8. 2.43 km W of Moskowite Corner, California · 17559 days ago · 8 km deep · 66 km away
  9. 3.20 km WSW of Monument Hills, California · 17558 days ago · 8 km deep · 83 km away
  10. 2.22 km SSE of Monument Hills, California · 17556 days ago · 9 km deep · 85 km away
  11. 1.88 km E of Hopland, California · 17555 days ago · 6 km deep · 26 km away
  12. 2.07 km W of Cobb, California · 17555 days ago · 3 km deep · 2 km away
  13. 2.27 km W of Cobb, California · 17555 days ago · 3 km deep · 1 km away
  14. 1.98 km E of Willits, California · 17553 days ago · 4 km deep · 76 km away
  15. 2.09 km NE of Inverness, California · 17553 days ago · 4 km deep · 74 km away
  16. 1.79 km ESE of Willits, California · 17553 days ago · 4 km deep · 72 km away
  17. 2.19 km ESE of Willits, California · 17553 days ago · 4 km deep · 73 km away
  18. 2.69 km ESE of Willits, California · 17552 days ago · 2 km deep · 72 km away
  19. 1.99 km ESE of Willits, California · 17552 days ago · 4 km deep · 73 km away
  20. 2.39 km ESE of Willits, California · 17552 days ago · 3 km deep · 73 km away
  21. 1.69 km ESE of Willits, California · 17551 days ago · 4 km deep · 72 km away
  22. 2.77 km W of Cobb, California · 17551 days ago · 3 km deep · 1 km away
  23. 2.66 km E of Willits, California · 17549 days ago · 14 km deep · 77 km away
  24. 2.24 km SE of Cottonwood, California · 17549 days ago · 11 km deep · 80 km away
  25. 2.21 km SW of Monument Hills, California · 17549 days ago · 10 km deep · 83 km away
  26. 1.94 km SSW of Monument Hills, California · 17549 days ago · 16 km deep · 84 km away
  27. 2.57 km ESE of Willits, California · 17548 days ago · 5 km deep · 75 km away
  28. 2.86 km ESE of Willits, California · 17548 days ago · 10 km deep · 77 km away
  29. 1.92 km S of Monument Hills, California · 17548 days ago · 10 km deep · 83 km away
  30. 2.37 km WSW of Cobb, California · 17547 days ago · -1 km deep · 1 km away
  31. 2.320 km NE of Potter Valley, California · 17546 days ago · 6 km deep · 72 km away
  32. 4.24 km SSW of Monument Hills, California · 17546 days ago · 10 km deep · 82 km away
  33. 2.02 km S of Monument Hills, California · 17546 days ago · 9 km deep · 84 km away
  34. 2.519 km NE of Potter Valley, California · 17546 days ago · 5 km deep · 71 km away
  35. 3.32 km SW of Monument Hills, California · 17546 days ago · 12 km deep · 82 km away
  36. 1.77 km W of Cobb, California · 17546 days ago · 2 km deep · 2 km away
  37. 2.33 km SSE of Cottonwood, California · 17545 days ago · 11 km deep · 78 km away
  38. 2.910 km WSW of Hopland, California · 17544 days ago · 4 km deep · 39 km away
  39. 2.56 km SSW of Clear Lake Riviera, California · 17543 days ago · 3 km deep · 12 km away
  40. 2.13 km WNW of Monument Hills, California · 17543 days ago · 1 km deep · 80 km away
  41. 2.412 km SW of Esparto, California · 17543 days ago · 11 km deep · 66 km away
  42. 2.22 km ESE of Calpella, California · 17542 days ago · 6 km deep · 55 km away
  43. 2.710 km W of Hopland, California · 17542 days ago · 4 km deep · 39 km away
  44. 2.17 km W of Cobb, California · 17542 days ago · 1 km deep · 1 km away
  45. 2.14 km SSE of Cloverdale, California · 17540 days ago · 3 km deep · 17 km away
  46. 1.95 km ENE of Willits, California · 17539 days ago · 6 km deep · 79 km away
  47. 2.08 km E of Sea Ranch, California · 17538 days ago · 21 km deep · 48 km away
  48. 2.06 km N of Hopland, California · 17535 days ago · 5 km deep · 35 km away
  49. 1.96 km ESE of Santa Rosa, California · 17534 days ago · 8 km deep · 46 km away
  50. 1.53 km NE of Hopland, California · 17534 days ago · 4 km deep · 31 km away
  51. 2.77 km W of Cobb, California · 17534 days ago · 4 km deep · 1 km away
  52. 1.78 km W of Cobb, California · 17530 days ago · 1 km deep · 1 km away
  53. 2.116 km ENE of Lower Lake, California · 17529 days ago · 3 km deep · 38 km away
  54. 1.811 km NNW of Redwood Valley, California · 17528 days ago · 6 km deep · 71 km away
  55. 1.710 km WNW of Potter Valley, California · 17528 days ago · 4 km deep · 71 km away
  56. 1.811 km WNW of Potter Valley, California · 17528 days ago · 4 km deep · 71 km away
  57. 2.06 km WSW of Kenwood, California · 17527 days ago · 7 km deep · 49 km away
  58. 1.61 km SSW of Monument Hills, California · 17526 days ago · 9 km deep · 83 km away
  59. 1.67 km E of Willits, California · 17525 days ago · 5 km deep · 76 km away
  60. 1.98 km W of Cobb, California · 17525 days ago · 1 km deep · 1 km away

The first 60 of 79.

Before

  1. 2.814 km E of Angwin, California · 17565 days ago · 7 km deep · 53 km away
  2. 1.86 km NE of Willits, California · 17566 days ago · 4 km deep · 82 km away
  3. 1.86 km NE of Willits, California · 17566 days ago · 4 km deep · 83 km away
  4. 2.06 km NE of Willits, California · 17566 days ago · 4 km deep · 82 km away
  5. 1.88 km W of Cobb, California · 17568 days ago · 0 km deep · 1 km away
  6. 1.68 km W of Cobb, California · 17568 days ago · 1 km deep · 1 km away
  7. 2.0Northern California · 17568 days ago · 0 km deep · 24 km away
  8. 2.715 km E of Angwin, California · 17568 days ago · 0 km deep · 54 km away
  9. 1.56 km ESE of Hidden Valley Lake, California · 17569 days ago · 2 km deep · 29 km away
  10. 2.59 km NNW of Redwood Valley, California · 17569 days ago · 2 km deep · 70 km away
  11. 2.17 km W of Cobb, California · 17569 days ago · 4 km deep · 1 km away
  12. 2.08 km W of Lakeport, California · 17570 days ago · 4 km deep · 31 km away
  13. 1.75 km WNW of Cobb, California · 17572 days ago · 3 km deep · 4 km away
  14. 1.52 km ESE of Clear Lake Riviera, California · 17573 days ago · 1 km deep · 18 km away
  15. 1.82 km ESE of Clear Lake Riviera, California · 17573 days ago · 1 km deep · 18 km away
  16. 1.85 km NNE of Crockett, California · 17576 days ago · 1 km deep · 97 km away
  17. 2.08 km NE of Inverness, California · 17577 days ago · 0 km deep · 74 km away
  18. 2.320 km WNW of Jenner, California · 17579 days ago · 0 km deep · 53 km away
  19. 1.710 km ENE of Clearlake Oaks, California · 17582 days ago · -1 km deep · 36 km away
  20. 2.26 km W of Cobb, California · 17582 days ago · 3 km deep · 2 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1041786. Read Tue, Sep 22, 2026, 10:24 PM UTC.