California earthquakes

M1.9 earthquake 4 km SSE of Byron, California

A magnitude 1.9 earthquake struck 4 km SSE of Byron, California on Wed, Dec 17, 1986, 9:27 AM PST (17:27 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M4.2 9 km ENE of Morgan Hill, California. This one was a foreshock.

Byron 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
1.9 (Md, duration), micro
Magnitude from
Northern California Seismic System
Local time
UTC
1986-12-17 17:27:30 UTC
Depth
10.3 km (6.4 mi), shallow
Epicenter
37.825° N, 121.624° 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 1.2 km horizontally, 0.9 km in depth
Magnitude uncertainty
±0.20
Depth from
From location
Station coverage gap
259°, poorly surrounded by stations
Stations used
21

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 136 in the 60 days after this one and 70 in the 30 days before it.

After

  1. 1.96 km ENE of Sonoma, California · 14535 days ago · 10 km deep · 86 km away
  2. 2.5Northern California · 14534 days ago · 9 km deep · 73 km away
  3. 1.716 km SSE of Livermore, California · 14534 days ago · 3 km deep · 30 km away
  4. 3.68 km N of East Foothills, California · 14534 days ago · 7 km deep · 44 km away
  5. 2.26 km NNE of Interlaken, California · 14534 days ago · 10 km deep · 91 km away
  6. 1.71 km N of Diablo, California · 14534 days ago · 14 km deep · 29 km away
  7. 1.715 km SE of Livermore, California · 14534 days ago · 4 km deep · 29 km away
  8. 2.17 km ENE of Napa, California · 14533 days ago · 4 km deep · 77 km away
  9. 1.86 km N of Green Valley, California · 14533 days ago · 10 km deep · 72 km away
  10. 1.816 km SE of Livermore, California · 14532 days ago · 2 km deep · 29 km away
  11. 2.016 km SSE of Livermore, California · 14532 days ago · 2 km deep · 30 km away
  12. 1.99 km NW of Broadmoor, California · 14532 days ago · 8 km deep · 82 km away
  13. 1.816 km SSE of Livermore, California · 14531 days ago · 2 km deep · 30 km away
  14. 2.015 km SE of Livermore, California · 14529 days ago · 2 km deep · 29 km away
  15. 1.69 km NE of Milpitas, California · 14528 days ago · 7 km deep · 42 km away
  16. 2.910 km NW of Broadmoor, California · 14528 days ago · 9 km deep · 83 km away
  17. 2.4Northern California · 14528 days ago · 6 km deep · 35 km away
  18. 2.418 km NE of East Foothills, California · 14527 days ago · 6 km deep · 35 km away
  19. 2.35 km SSW of Gilroy, California · 14527 days ago · 4 km deep · 96 km away
  20. 1.71 km NE of East Richmond Heights, California · 14526 days ago · 8 km deep · 61 km away
  21. 1.81 km NE of East Richmond Heights, California · 14526 days ago · 8 km deep · 61 km away
  22. 1.610 km NW of Daly City, California · 14525 days ago · 10 km deep · 82 km away
  23. 4.08 km NNE of East Foothills, California · 14524 days ago · 7 km deep · 44 km away
  24. 2.38 km N of East Foothills, California · 14524 days ago · 6 km deep · 44 km away
  25. 1.97 km NNE of East Foothills, California · 14524 days ago · 7 km deep · 44 km away
  26. 1.97 km NNE of East Foothills, California · 14524 days ago · 7 km deep · 45 km away
  27. 1.68 km NNE of East Foothills, CA · 14524 days ago · 7 km deep · 45 km away
  28. 1.97 km NNE of East Foothills, California · 14524 days ago · 7 km deep · 45 km away
  29. 1.6Northern California · 14523 days ago · 7 km deep · 44 km away
  30. 1.517 km SE of Livermore, CA · 14523 days ago · 1 km deep · 30 km away
  31. 1.7Northern California · 14523 days ago · 7 km deep · 44 km away
  32. 2.1Northern California · 14523 days ago · 1 km deep · 29 km away
  33. 1.99 km E of Gilroy, California · 14522 days ago · 6 km deep · 92 km away
  34. 1.512 km ESE of Gilroy, California · 14522 days ago · 5 km deep · 96 km away
  35. 3.013 km ENE of East Foothills, California · 14522 days ago · 7 km deep · 44 km away
  36. 1.613 km ENE of East Foothills, California · 14522 days ago · 6 km deep · 44 km away
  37. 1.913 km ENE of East Foothills, California · 14522 days ago · 7 km deep · 44 km away
  38. 2.21 km N of Bonny Doon, California · 14522 days ago · 22 km deep · 97 km away
  39. 1.621 km ENE of East Foothills, California · 14522 days ago · 5 km deep · 37 km away
  40. 1.57 km NNE of East Foothills, California · 14521 days ago · 6 km deep · 45 km away
  41. 2.57 km NNE of East Foothills, California · 14521 days ago · 7 km deep · 45 km away
  42. 1.76 km NNE of East Foothills, California · 14521 days ago · 8 km deep · 46 km away
  43. 2.013 km ENE of East Foothills, California · 14521 days ago · 6 km deep · 44 km away
  44. 1.912 km SSE of Livermore, California · 14520 days ago · 3 km deep · 28 km away
  45. 2.412 km SSE of Livermore, California · 14520 days ago · 3 km deep · 28 km away
  46. 2.25 km SW of Yountville, California · 14519 days ago · 6 km deep · 92 km away
  47. 2.016 km SSE of Livermore, California · 14518 days ago · 2 km deep · 30 km away
  48. 2.05 km SSE of Byron, California · 14517 days ago · 9 km deep · 0 km away
  49. 1.95 km SSE of Byron, California · 14517 days ago · 9 km deep · 0 km away
  50. 1.85 km S of Byron, California · 14517 days ago · 8 km deep · 1 km away
  51. 2.05 km S of Byron, California · 14516 days ago · 9 km deep · 1 km away
  52. 1.53 km W of Mountain House, California · 14516 days ago · 4 km deep · 5 km away
  53. 1.75 km SE of Byron, California · 14516 days ago · 10 km deep · 2 km away
  54. 1.65 km SSE of Byron, California · 14516 days ago · 10 km deep · 1 km away
  55. 1.52 km W of La Honda, California · 14516 days ago · 4 km deep · 82 km away
  56. 1.55 km WNW of Mountain House, California · 14516 days ago · 5 km deep · 4 km away
  57. 1.86 km S of Byron, California · 14516 days ago · 6 km deep · 3 km away
  58. 2.0Northern California · 14516 days ago · 6 km deep · 43 km away
  59. 2.05 km SSE of Byron, California · 14515 days ago · 9 km deep · 0 km away
  60. 2.64 km NNW of Benicia, California · 14514 days ago · 11 km deep · 57 km away

The first 60 of 136.

Before

  1. 2.56 km NNE of Interlaken, California · 14536 days ago · 11 km deep · 92 km away
  2. 2.3Northern California · 14537 days ago · 7 km deep · 78 km away
  3. 1.55 km SSE of Byron, California · 14538 days ago · 10 km deep · 1 km away
  4. 2.016 km SE of Livermore, California · 14538 days ago · 2 km deep · 29 km away
  5. 1.85 km N of Morgan Hill, California · 14539 days ago · 4 km deep · 71 km away
  6. 1.75 km N of Morgan Hill, California · 14539 days ago · 5 km deep · 72 km away
  7. 1.716 km SE of Livermore, California · 14539 days ago · 3 km deep · 29 km away
  8. 2.35 km SSW of Gilroy, California · 14539 days ago · 4 km deep · 96 km away
  9. 1.616 km SSE of Livermore, California · 14539 days ago · 2 km deep · 30 km away
  10. 1.816 km SSE of Livermore, California · 14539 days ago · 2 km deep · 30 km away
  11. 1.516 km SE of Livermore, California · 14539 days ago · 3 km deep · 29 km away
  12. 1.915 km SE of Livermore, California · 14540 days ago · 3 km deep · 29 km away
  13. 1.916 km SE of Livermore, California · 14540 days ago · 3 km deep · 29 km away
  14. 3.116 km SSE of Livermore, California · 14540 days ago · 2 km deep · 30 km away
  15. 1.616 km SSE of Livermore, California · 14540 days ago · 3 km deep · 30 km away
  16. 1.716 km SE of Livermore, California · 14541 days ago · 2 km deep · 30 km away
  17. 3.3Northern California · 14541 days ago · 10 km deep · 73 km away
  18. 1.616 km SSE of Livermore, California · 14541 days ago · 3 km deep · 30 km away
  19. 2.213 km N of Morgan Hill, California · 14541 days ago · 4 km deep · 64 km away
  20. 1.516 km SE of Livermore, California · 14541 days ago · 3 km deep · 29 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc90436. Read Sun, Oct 4, 2026, 5:11 PM UTC.