California earthquakes

M3.4 earthquake 6 km SSW of Ridgemark, California

A magnitude 3.4 earthquake struck 6 km SSW of Ridgemark, California on Sun, Apr 27, 1975, 7:20 AM PDT (14:20 UTC), 6 km (4 mi) below the surface.

A larger quake followed: M3.5 8 km NE of San Juan Bautista, 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
3.4 (md), minor
Local time
UTC
1975-04-27 14:20:27 UTC
Depth
5.7 km (3.5 mi), shallow
Epicenter
36.765° N, 121.404° 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, 0.6 km in depth
Magnitude uncertainty
±0.56
Depth from
From location
Station coverage gap
46°
Stations used
28

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 188 in the 60 days after this one and 0 in the 30 days before it.

After

  1. 3.17 km SSE of Gustine, California · 18755 days ago · 0 km deep · 62 km away
  2. 2.116 km E of Seven Trees, California · 18755 days ago · 6 km deep · 63 km away
  3. 1.816 km SSE of Tres Pinos, California · 18754 days ago · 5 km deep · 18 km away
  4. 1.727 km ENE of Soledad, California · 18754 days ago · 8 km deep · 38 km away
  5. 2.97 km NNE of Interlaken, California · 18753 days ago · 10 km deep · 39 km away
  6. 3.06 km NE of Hollister, California · 18753 days ago · 4 km deep · 15 km away
  7. 2.411 km E of Gilroy, California · 18753 days ago · 4 km deep · 25 km away
  8. 2.45 km S of Gilroy, California · 18753 days ago · 6 km deep · 26 km away
  9. 3.58 km NE of San Juan Bautista, California · 18752 days ago · 5 km deep · 17 km away
  10. 2.57 km E of San Lucas, California · 18752 days ago · 0 km deep · 81 km away
  11. 2.521 km ENE of San Lucas, California · 18752 days ago · 3 km deep · 80 km away
  12. 3.022 km ENE of San Lucas, California · 18751 days ago · 8 km deep · 82 km away
  13. 1.88 km NW of Hollister, California · 18751 days ago · 3 km deep · 17 km away
  14. 3.921 km NNE of Soledad, California · 18751 days ago · 7 km deep · 27 km away
  15. 2.722 km ENE of San Lucas, California · 18751 days ago · 8 km deep · 82 km away
  16. 2.010 km ESE of Gilroy, California · 18751 days ago · 3 km deep · 24 km away
  17. 3.314 km SSE of Tres Pinos, California · 18751 days ago · 3 km deep · 15 km away
  18. 1.79 km SW of San Martin, California · 18751 days ago · 8 km deep · 37 km away
  19. 1.54 km SSE of Sunol, California · 18750 days ago · 14 km deep · 97 km away
  20. 1.76 km S of Sunol, California · 18750 days ago · 6 km deep · 96 km away
  21. 2.716 km SE of Tres Pinos, California · 18750 days ago · 11 km deep · 22 km away
  22. 3.723 km NE of San Ardo, California · 18750 days ago · 7 km deep · 86 km away
  23. 1.921 km NE of Soledad, California · 18750 days ago · 8 km deep · 33 km away
  24. 3.321 km NE of Soledad, California · 18750 days ago · 6 km deep · 34 km away
  25. 2.624 km NE of Greenfield, California · 18749 days ago · 5 km deep · 47 km away
  26. 2.39 km NW of Hollister, California · 18749 days ago · 3 km deep · 19 km away
  27. 4.37 km SSE of Gustine, California · 18749 days ago · 1 km deep · 61 km away
  28. 2.57 km S of Livermore, California · 18748 days ago · 8 km deep · 100 km away
  29. 3.021 km NE of Soledad, California · 18748 days ago · 2 km deep · 31 km away
  30. 2.719 km SSW of Los Banos, California · 18748 days ago · 2 km deep · 46 km away
  31. 3.29 km NW of Hollister, California · 18747 days ago · 6 km deep · 18 km away
  32. 2.49 km NW of Hollister, California · 18747 days ago · 4 km deep · 17 km away
  33. 3.78 km SSW of Tres Pinos, California · 18747 days ago · 3 km deep · 7 km away
  34. 2.39 km NE of San Juan Bautista, California · 18747 days ago · 3 km deep · 18 km away
  35. 1.525 km SE of Tres Pinos, California · 18747 days ago · 7 km deep · 29 km away
  36. 3.65 km SSW of Gilroy, California · 18746 days ago · 7 km deep · 28 km away
  37. 2.620 km ENE of San Lucas, California · 18746 days ago · 6 km deep · 81 km away
  38. 2.720 km ENE of San Lucas, California · 18746 days ago · 6 km deep · 81 km away
  39. 2.25 km SSW of Gilroy, California · 18746 days ago · 7 km deep · 28 km away
  40. 1.77 km NE of Interlaken, California · 18745 days ago · 2 km deep · 35 km away
  41. 2.736 km NE of San Lucas, California · 18745 days ago · 9 km deep · 69 km away
  42. 1.815 km SSE of Tres Pinos, California · 18745 days ago · 5 km deep · 18 km away
  43. 3.624 km NE of Greenfield, California · 18745 days ago · 7 km deep · 45 km away
  44. 3.021 km NE of Soledad, California · 18745 days ago · 2 km deep · 32 km away
  45. 2.58 km NE of San Juan Bautista, California · 18745 days ago · 4 km deep · 18 km away
  46. 2.010 km NNW of Hollister, California · 18745 days ago · 5 km deep · 19 km away
  47. 2.45 km WNW of San Juan Bautista, California · 18744 days ago · 6 km deep · 20 km away
  48. 1.722 km NE of Soledad, California · 18743 days ago · 9 km deep · 35 km away
  49. 2.521 km NE of Soledad, California · 18743 days ago · 5 km deep · 30 km away
  50. 2.89 km NW of Hollister, California · 18743 days ago · 5 km deep · 17 km away
  51. 2.99 km ENE of Milpitas, California · 18742 days ago · 7 km deep · 87 km away
  52. 2.014 km E of Seven Trees, California · 18742 days ago · 2 km deep · 64 km away
  53. 2.27 km N of Hollister, California · 18741 days ago · 4 km deep · 17 km away
  54. 1.627 km NE of Soledad, California · 18740 days ago · 8 km deep · 37 km away
  55. 2.621 km ENE of San Ardo, California · 18740 days ago · 3 km deep · 98 km away
  56. 2.018 km SSE of Tres Pinos, California · 18740 days ago · 5 km deep · 20 km away
  57. 2.25 km WSW of Gilroy, California · 18740 days ago · 3 km deep · 32 km away
  58. 2.64 km WSW of Gilroy, California · 18740 days ago · 6 km deep · 32 km away
  59. 2.19 km NW of Hollister, California · 18740 days ago · 5 km deep · 17 km away
  60. 2.323 km ENE of San Lucas, California · 18740 days ago · 5 km deep · 81 km away

The first 60 of 188.

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1023674. Read Tue, Sep 22, 2026, 10:33 PM UTC.