California earthquakes

M1.6 earthquake 5 km NNE of Ridgemark, California

A magnitude 1.6 earthquake struck 5 km NNE of Ridgemark, California on Thu, Aug 18, 1983, 2:11 AM PDT (09:11 UTC), 4 km (2 mi) below the surface.

A larger quake followed: M4.0 20 km NNW of Coalinga, California. This one was a foreshock.

Ridgemark 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
1.6 (Md, duration), micro
Magnitude from
Northern California Seismic System
Local time
UTC
1983-08-18 09:11:55 UTC
Depth
3.9 km (2.4 mi), shallow
Epicenter
36.859° N, 121.337° 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, 0.5 km in depth
Magnitude uncertainty
±0.22
Depth from
From location
Station coverage gap
53°
Stations used
37

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 155 in the 60 days after this one and 110 in the 30 days before it.

After

  1. 2.25 km NNE of Ridgemark, California · 15751 days ago · 5 km deep · 0 km away
  2. 1.824 km NE of Greenfield, California · 15751 days ago · 4 km deep · 49 km away
  3. 1.825 km ENE of Greenfield, California · 15750 days ago · 5 km deep · 56 km away
  4. 1.824 km ENE of Greenfield, California · 15750 days ago · 6 km deep · 56 km away
  5. 1.525 km WNW of Coalinga, California · 15750 days ago · 4 km deep · 97 km away
  6. 1.717 km SSE of Tres Pinos, California · 15750 days ago · 5 km deep · 25 km away
  7. 2.414 km SSE of Tres Pinos, California · 15750 days ago · 10 km deep · 22 km away
  8. 3.314 km SSE of Tres Pinos, California · 15750 days ago · 10 km deep · 22 km away
  9. 1.611 km SSE of Livermore, California · 15750 days ago · 6 km deep · 87 km away
  10. 2.34 km ENE of La Honda, California · 15749 days ago · 0 km deep · 95 km away
  11. 1.81 km WNW of Greenfield, California · 15749 days ago · 23 km deep · 59 km away
  12. 1.512 km S of Tres Pinos, California · 15749 days ago · 2 km deep · 20 km away
  13. 1.85 km SSW of Tres Pinos, California · 15749 days ago · 6 km deep · 12 km away
  14. 3.12 km ESE of Aromas, California · 15748 days ago · 7 km deep · 25 km away
  15. 2.12 km E of Aromas, California · 15748 days ago · 6 km deep · 25 km away
  16. 1.82 km E of Aromas, California · 15747 days ago · 7 km deep · 25 km away
  17. 1.82 km ESE of Aromas, California · 15747 days ago · 7 km deep · 25 km away
  18. 3.24 km S of San Juan Bautista, California · 15747 days ago · 7 km deep · 18 km away
  19. 1.612 km ESE of East Foothills, California · 15747 days ago · 4 km deep · 60 km away
  20. 2.92 km ESE of Aromas, California · 15747 days ago · 6 km deep · 25 km away
  21. 1.625 km WSW of Volta, California · 15746 days ago · 4 km deep · 24 km away
  22. 2.33 km SSE of San Juan Bautista, California · 15745 days ago · 4 km deep · 18 km away
  23. 2.415 km SSE of Tres Pinos, California · 15745 days ago · 3 km deep · 23 km away
  24. 2.225 km ENE of Greenfield, California · 15745 days ago · 5 km deep · 56 km away
  25. 1.67 km E of East Foothills, CA · 15744 days ago · 7 km deep · 69 km away
  26. 1.625 km NE of Soledad, California · 15744 days ago · 2 km deep · 35 km away
  27. 1.730 km ENE of Soledad, California · 15744 days ago · 7 km deep · 42 km away
  28. 2.024 km NNE of San Lucas, California · 15744 days ago · 3 km deep · 72 km away
  29. 2.323 km NE of King City, California · 15744 days ago · 5 km deep · 63 km away
  30. 1.925 km NE of Greenfield, California · 15743 days ago · 1 km deep · 54 km away
  31. 2.919 km NNW of Coalinga, California · 15743 days ago · 11 km deep · 100 km away
  32. 1.615 km ESE of Tres Pinos, California · 15743 days ago · 9 km deep · 22 km away
  33. 4.020 km NNW of Coalinga, California · 15743 days ago · 11 km deep · 99 km away
  34. 3.020 km NNW of Coalinga, California · 15743 days ago · 11 km deep · 99 km away
  35. 1.920 km NNW of Coalinga, California · 15743 days ago · 9 km deep · 99 km away
  36. 1.919 km NNW of Coalinga, California · 15743 days ago · 9 km deep · 99 km away
  37. 1.719 km NNW of Coalinga, California · 15743 days ago · 11 km deep · 100 km away
  38. 2.320 km NW of Coalinga, California · 15743 days ago · 9 km deep · 99 km away
  39. 2.118 km ESE of Livermore, California · 15743 days ago · 4 km deep · 84 km away
  40. 1.921 km NW of Coalinga, California · 15743 days ago · 7 km deep · 98 km away
  41. 2.020 km NNW of Coalinga, California · 15743 days ago · 10 km deep · 99 km away
  42. 1.920 km NNW of Coalinga, California · 15743 days ago · 11 km deep · 99 km away
  43. 2.229 km ENE of Soledad, California · 15742 days ago · 5 km deep · 43 km away
  44. 2.15 km SSW of Ridgemark, California · 15742 days ago · 9 km deep · 11 km away
  45. 2.924 km NE of Greenfield, California · 15742 days ago · 1 km deep · 50 km away
  46. 2.63 km SSE of San Juan Bautista, California · 15742 days ago · 4 km deep · 18 km away
  47. 1.911 km S of Tres Pinos, California · 15740 days ago · 3 km deep · 19 km away
  48. 2.119 km SSE of Tres Pinos, California · 15740 days ago · 5 km deep · 28 km away
  49. 1.517 km SW of King City, California · 15740 days ago · 1 km deep · 83 km away
  50. 2.519 km NNW of Coalinga, California · 15739 days ago · 9 km deep · 99 km away
  51. 2.523 km WNW of Three Rocks, California · 15738 days ago · 10 km deep · 70 km away
  52. 1.914 km WSW of Three Rocks, California · 15738 days ago · 19 km deep · 83 km away
  53. 2.224 km ENE of Greenfield, California · 15738 days ago · 5 km deep · 55 km away
  54. 1.69 km ENE of Milpitas, California · 15737 days ago · 7 km deep · 80 km away
  55. 1.64 km S of San Juan Bautista, California · 15737 days ago · 6 km deep · 19 km away
  56. 2.316 km SSE of Tres Pinos, California · 15736 days ago · 5 km deep · 24 km away
  57. 2.69 km NE of Gilroy, California · 15736 days ago · 8 km deep · 25 km away
  58. 1.616 km SSE of Tres Pinos, California · 15736 days ago · 5 km deep · 24 km away
  59. 1.624 km NE of Greenfield, California · 15735 days ago · 5 km deep · 49 km away
  60. 2.03 km ENE of Fremont, California · 15734 days ago · 5 km deep · 95 km away

The first 60 of 155.

Before

  1. 2.65 km NNE of Ridgemark, California · 15751 days ago · 6 km deep · 0 km away
  2. 3.25 km NNE of Ridgemark, California · 15751 days ago · 6 km deep · 0 km away
  3. 2.637 km SSW of South Dos Palos, California · 15751 days ago · 6 km deep · 46 km away
  4. 1.630 km ENE of Soledad, California · 15751 days ago · 8 km deep · 41 km away
  5. 1.621 km NE of Soledad, California · 15752 days ago · 8 km deep · 39 km away
  6. 1.612 km ESE of Gilroy, California · 15752 days ago · 7 km deep · 15 km away
  7. 1.69 km ENE of San Martin, California · 15753 days ago · 9 km deep · 34 km away
  8. 2.17 km E of East Foothills, California · 15753 days ago · 9 km deep · 68 km away
  9. 2.321 km NE of Soledad, California · 15754 days ago · 4 km deep · 34 km away
  10. 2.35 km NNE of Ridgemark, California · 15754 days ago · 6 km deep · 0 km away
  11. 1.721 km NE of Soledad, California · 15754 days ago · 8 km deep · 39 km away
  12. 1.622 km NE of Soledad, California · 15756 days ago · 9 km deep · 36 km away
  13. 2.023 km ENE of Soledad, California · 15756 days ago · 2 km deep · 43 km away
  14. 1.515 km SE of Livermore, California · 15756 days ago · 4 km deep · 84 km away
  15. 2.238 km SSW of South Dos Palos, California · 15757 days ago · 6 km deep · 49 km away
  16. 1.925 km NE of Soledad, California · 15757 days ago · 8 km deep · 39 km away
  17. 1.830 km ENE of Soledad, California · 15757 days ago · 7 km deep · 42 km away
  18. 2.231 km ENE of Soledad, California · 15758 days ago · 8 km deep · 41 km away
  19. 1.621 km ESE of Big Sur, California · 15758 days ago · 10 km deep · 76 km away
  20. 1.6Central California · 15758 days ago · 3 km deep · 27 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1100624. Read Fri, Oct 2, 2026, 2:33 AM UTC.