California earthquakes

M1.6 earthquake 6 km NE of Ridgemark, California

A magnitude 1.6 earthquake struck 6 km NE of Ridgemark, California on Wed, Mar 11, 1987, 1:40 PM PST (21:40 UTC), 2 km (1 mi) below the surface.

A larger quake followed: M1.7 9 km SSW of Tres Pinos, 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), micro
Local time
UTC
1987-03-11 21:40:11 UTC
Depth
1.7 km (1.0 mi), shallow
Epicenter
36.860° N, 121.314° 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, 0.8 km in depth
Magnitude uncertainty
±0.18
Depth from
From location
Station coverage gap
90°
Stations used
26

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 163 in the 60 days after this one and 0 in the 30 days before it.

After

  1. 1.79 km SSW of Tres Pinos, California · 14438 days ago · 3 km deep · 17 km away
  2. 1.69 km SE of Sunol, California · 14437 days ago · 10 km deep · 87 km away
  3. 1.912 km S of Tres Pinos, California · 14437 days ago · 5 km deep · 20 km away
  4. 1.623 km ENE of Soledad, California · 14437 days ago · 3 km deep · 43 km away
  5. 1.918 km NE of East Foothills, California · 14436 days ago · 5 km deep · 79 km away
  6. 2.028 km NE of Soledad, California · 14436 days ago · 5 km deep · 37 km away
  7. 1.821 km NE of Soledad, California · 14436 days ago · 3 km deep · 33 km away
  8. 2.020 km ENE of East Foothills, California · 14435 days ago · 7 km deep · 74 km away
  9. 1.59 km NNE of Hollister, California · 14435 days ago · 7 km deep · 9 km away
  10. 2.311 km S of Tres Pinos, California · 14435 days ago · 4 km deep · 20 km away
  11. 1.812 km S of Tres Pinos, California · 14435 days ago · 4 km deep · 20 km away
  12. 1.618 km SSE of Livermore, California · 14435 days ago · 4 km deep · 81 km away
  13. 1.66 km NE of Ridgemark, California · 14434 days ago · 4 km deep · 0 km away
  14. 1.716 km SSE of Tres Pinos, California · 14434 days ago · 9 km deep · 24 km away
  15. 1.524 km NE of Greenfield, California · 14434 days ago · 7 km deep · 52 km away
  16. 2.420 km SSE of Tres Pinos, California · 14433 days ago · 5 km deep · 28 km away
  17. 2.522 km NE of Soledad, California · 14433 days ago · 5 km deep · 33 km away
  18. 1.85 km NNE of Tres Pinos, California · 14433 days ago · 6 km deep · 3 km away
  19. 1.616 km SSE of Livermore, California · 14433 days ago · 6 km deep · 84 km away
  20. 1.820 km SSE of Tres Pinos, California · 14432 days ago · 5 km deep · 28 km away
  21. 1.66 km ENE of Hollister, California · 14432 days ago · 6 km deep · 3 km away
  22. 2.710 km SW of Ridgemark, California · 14432 days ago · 8 km deep · 18 km away
  23. 1.916 km S of Three Rocks, California · 14431 days ago · 12 km deep · 99 km away
  24. 1.623 km NE of King City, California · 14431 days ago · 6 km deep · 61 km away
  25. 2.417 km NE of East Foothills, California · 14431 days ago · 6 km deep · 78 km away
  26. 1.820 km SSE of Tres Pinos, California · 14431 days ago · 5 km deep · 28 km away
  27. 2.910 km NNW of Hollister, California · 14431 days ago · 2 km deep · 15 km away
  28. 1.66 km NE of Interlaken, California · 14431 days ago · 10 km deep · 35 km away
  29. 1.513 km ENE of East Foothills, California · 14430 days ago · 8 km deep · 73 km away
  30. 2.1Northern California · 14429 days ago · 5 km deep · 66 km away
  31. 2.07 km NNE of East Foothills, California · 14429 days ago · 7 km deep · 78 km away
  32. 2.124 km NE of Greenfield, California · 14429 days ago · 5 km deep · 50 km away
  33. 1.918 km NE of East Foothills, California · 14429 days ago · 6 km deep · 80 km away
  34. 1.624 km NE of Greenfield, California · 14428 days ago · 6 km deep · 50 km away
  35. 1.79 km ESE of Seven Trees, California · 14428 days ago · 5 km deep · 57 km away
  36. 2.011 km S of Pescadero, California · 14427 days ago · 14 km deep · 99 km away
  37. 1.614 km E of Seven Trees, California · 14427 days ago · 2 km deep · 58 km away
  38. 1.814 km E of Seven Trees, California · 14427 days ago · 2 km deep · 58 km away
  39. 2.014 km E of Seven Trees, California · 14427 days ago · 2 km deep · 58 km away
  40. 1.92 km NNE of Aromas, California · 14426 days ago · 6 km deep · 29 km away
  41. 1.52 km N of Aromas, California · 14426 days ago · 6 km deep · 29 km away
  42. 1.818 km NE of East Foothills, California · 14426 days ago · 6 km deep · 79 km away
  43. 2.1Central California · 14426 days ago · 5 km deep · 25 km away
  44. 2.217 km SSE of Livermore, California · 14425 days ago · 1 km deep · 82 km away
  45. 1.622 km NE of Soledad, California · 14424 days ago · 4 km deep · 39 km away
  46. 2.48 km ENE of San Martin, California · 14424 days ago · 8 km deep · 35 km away
  47. 1.72 km E of Big Sur, California · 14424 days ago · 15 km deep · 77 km away
  48. 1.815 km SSE of Livermore, California · 14424 days ago · 4 km deep · 85 km away
  49. 2.918 km SSE of Livermore, California · 14423 days ago · 2 km deep · 81 km away
  50. 1.5Northern California · 14422 days ago · 13 km deep · 80 km away
  51. 2.020 km NE of East Foothills, California · 14422 days ago · 1 km deep · 79 km away
  52. 1.622 km SE of Tres Pinos, California · 14422 days ago · 8 km deep · 29 km away
  53. 1.76 km NNE of Tres Pinos, California · 14422 days ago · 4 km deep · 1 km away
  54. 1.514 km E of Seven Trees, California · 14422 days ago · 1 km deep · 57 km away
  55. 1.61 km ESE of Tres Pinos, California · 14421 days ago · 8 km deep · 8 km away
  56. 1.94 km ESE of Interlaken, California · 14420 days ago · 10 km deep · 34 km away
  57. 1.55 km N of San Ardo, California · 14420 days ago · 6 km deep · 95 km away
  58. 1.820 km NE of East Foothills, California · 14419 days ago · 0 km deep · 79 km away
  59. 1.712 km NE of East Foothills, California · 14419 days ago · 8 km deep · 77 km away
  60. 2.120 km NE of East Foothills, California · 14419 days ago · 1 km deep · 79 km away

The first 60 of 163.

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc96541. Read Tue, Sep 22, 2026, 3:33 PM UTC.