California earthquakes

M1.6 earthquake 6 km SSW of Ridgemark, California

A magnitude 1.6 earthquake struck 6 km SSW of Ridgemark, California on Mon, Apr 27, 1981, 12:43 PM PDT (19:43 UTC), 9 km (6 mi) below the surface.

A larger quake followed: M2.6 16 km N of Morgan Hill, 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
1981-04-27 19:43:35 UTC
Depth
8.9 km (5.5 mi), shallow
Epicenter
36.758° N, 121.390° 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, 0.6 km in depth
Magnitude uncertainty
±0.22
Depth from
From location
Station coverage gap
50°
Stations used
32

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 148 in the 60 days after this one and 16 in the 30 days before it.

After

  1. 2.616 km N of Morgan Hill, California · 16584 days ago · 6 km deep · 62 km away
  2. 2.025 km ENE of Greenfield, California · 16583 days ago · 5 km deep · 49 km away
  3. 2.22 km ESE of Aromas, California · 16583 days ago · 7 km deep · 24 km away
  4. 1.69 km ESE of East Foothills, California · 16582 days ago · 8 km deep · 73 km away
  5. 2.29 km ESE of East Foothills, California · 16582 days ago · 8 km deep · 73 km away
  6. 1.78 km W of Gilroy, California · 16580 days ago · 7 km deep · 37 km away
  7. 1.524 km ENE of Greenfield, California · 16579 days ago · 6 km deep · 52 km away
  8. 1.723 km NNE of San Lucas, California · 16578 days ago · 5 km deep · 66 km away
  9. 2.821 km SE of Tres Pinos, California · 16578 days ago · 8 km deep · 23 km away
  10. 1.58 km NE of Gilroy, California · 16577 days ago · 3 km deep · 34 km away
  11. 1.811 km NNW of Pacific Grove, California · 16577 days ago · 0 km deep · 52 km away
  12. 1.721 km SE of Tres Pinos, California · 16577 days ago · 7 km deep · 23 km away
  13. 1.65 km SSW of Tres Pinos, California · 16576 days ago · 7 km deep · 4 km away
  14. 1.52 km SE of San Ardo, California · 16576 days ago · 11 km deep · 95 km away
  15. 2.11 km NE of Tres Pinos, California · 16576 days ago · 9 km deep · 8 km away
  16. 2.93 km W of San Juan Bautista, California · 16576 days ago · 5 km deep · 19 km away
  17. 2.621 km SE of Tres Pinos, California · 16575 days ago · 7 km deep · 23 km away
  18. 1.925 km NNE of King City, California · 16575 days ago · 5 km deep · 54 km away
  19. 1.63 km ESE of Tres Pinos, California · 16575 days ago · 8 km deep · 9 km away
  20. 1.7Northern California · 16575 days ago · 9 km deep · 36 km away
  21. 1.720 km E of Big Sur, California · 16574 days ago · 12 km deep · 55 km away
  22. 1.86 km NE of Ridgemark, California · 16574 days ago · 7 km deep · 13 km away
  23. 2.223 km W of Three Rocks, California · 16574 days ago · 8 km deep · 71 km away
  24. 1.637 km W of Three Rocks, California · 16573 days ago · 3 km deep · 57 km away
  25. 1.626 km ENE of Tres Pinos, California · 16573 days ago · 2 km deep · 33 km away
  26. 2.320 km SSE of Tres Pinos, California · 16573 days ago · 5 km deep · 21 km away
  27. 2.714 km E of East Foothills, California · 16573 days ago · 6 km deep · 71 km away
  28. 1.89 km ENE of Gilroy, California · 16572 days ago · 8 km deep · 31 km away
  29. 1.738 km W of Three Rocks, California · 16572 days ago · 1 km deep · 57 km away
  30. 2.420 km SW of Diablo Grande, California · 16572 days ago · 72 km deep · 60 km away
  31. 1.79 km E of Gilroy, California · 16571 days ago · 8 km deep · 30 km away
  32. 1.817 km SSE of Tres Pinos, California · 16569 days ago · 9 km deep · 18 km away
  33. 1.823 km NE of Soledad, California · 16569 days ago · 8 km deep · 31 km away
  34. 1.722 km NE of Soledad, California · 16569 days ago · 8 km deep · 32 km away
  35. 2.023 km NE of King City, California · 16569 days ago · 7 km deep · 58 km away
  36. 1.611 km ESE of East Foothills, California · 16569 days ago · 7 km deep · 70 km away
  37. 2.29 km ENE of Gilroy, California · 16568 days ago · 9 km deep · 32 km away
  38. 1.85 km SSW of Tres Pinos, California · 16567 days ago · 8 km deep · 5 km away
  39. 1.55 km SSW of Tres Pinos, California · 16567 days ago · 8 km deep · 5 km away
  40. 1.913 km N of Morgan Hill, California · 16566 days ago · 3 km deep · 59 km away
  41. 2.424 km NE of Greenfield, California · 16565 days ago · 8 km deep · 44 km away
  42. 2.110 km ESE of East Foothills, California · 16565 days ago · 7 km deep · 71 km away
  43. 1.725 km SW of Three Rocks, California · 16565 days ago · 14 km deep · 90 km away
  44. 1.914 km SSE of Tres Pinos, California · 16565 days ago · 4 km deep · 14 km away
  45. 1.822 km ENE of Soledad, California · 16565 days ago · 3 km deep · 35 km away
  46. 1.614 km SSE of Tres Pinos, California · 16564 days ago · 4 km deep · 14 km away
  47. 2.222 km NE of Soledad, California · 16564 days ago · 4 km deep · 26 km away
  48. 3.011 km ESE of Gilroy, California · 16564 days ago · 6 km deep · 23 km away
  49. 1.79 km NNW of Hollister, California · 16564 days ago · 7 km deep · 20 km away
  50. 1.815 km E of Seven Trees, California · 16563 days ago · 5 km deep · 64 km away
  51. 1.511 km ESE of Gilroy, California · 16563 days ago · 5 km deep · 23 km away
  52. 2.011 km ESE of Gilroy, California · 16561 days ago · 5 km deep · 24 km away
  53. 3.916 km SW of Volta, California · 16561 days ago · 4 km deep · 39 km away
  54. 1.516 km SW of Volta, California · 16561 days ago · 7 km deep · 40 km away
  55. 1.916 km SW of Volta, California · 16561 days ago · 6 km deep · 39 km away
  56. 2.916 km SW of Volta, California · 16561 days ago · 3 km deep · 39 km away
  57. 1.624 km NE of Greenfield, California · 16561 days ago · 3 km deep · 44 km away
  58. 2.031 km WNW of Three Rocks, California · 16560 days ago · 10 km deep · 62 km away
  59. 2.12 km ESE of Aromas, California · 16559 days ago · 8 km deep · 24 km away
  60. 1.920 km SSW of Davenport, California · 16559 days ago · 9 km deep · 76 km away

The first 60 of 148.

Before

  1. 2.424 km NE of Soledad, California · 16585 days ago · 4 km deep · 30 km away
  2. 2.726 km SE of Tres Pinos, California · 16585 days ago · 10 km deep · 29 km away
  3. 4.18 km N of Day Valley, California · 16586 days ago · 13 km deep · 59 km away
  4. 1.67 km NNE of East Foothills, California · 16586 days ago · 11 km deep · 83 km away
  5. 1.730 km NE of San Lucas, California · 16586 days ago · 9 km deep · 73 km away
  6. 1.626 km NE of King City, California · 16587 days ago · 4 km deep · 58 km away
  7. 2.426 km NE of King City, California · 16587 days ago · 6 km deep · 58 km away
  8. 1.82 km ESE of San Ardo, California · 16589 days ago · 11 km deep · 95 km away
  9. 1.97 km SE of Sunol, California · 16590 days ago · 5 km deep · 96 km away
  10. 1.523 km ENE of San Ardo, California · 16590 days ago · 7 km deep · 96 km away
  11. 1.94 km ESE of Interlaken, California · 16590 days ago · 10 km deep · 33 km away
  12. 1.724 km NE of Greenfield, California · 16590 days ago · 5 km deep · 42 km away
  13. 1.824 km NE of Greenfield, California · 16592 days ago · 5 km deep · 46 km away
  14. 1.52 km SSE of Tres Pinos, California · 16592 days ago · 6 km deep · 7 km away
  15. 1.623 km ENE of King City, California · 16594 days ago · 9 km deep · 65 km away
  16. 1.524 km ENE of Greenfield, California · 16594 days ago · 4 km deep · 49 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1063070. Read Tue, Sep 22, 2026, 9:41 PM UTC.