California earthquakes

M1.7 earthquake 10 km SW of Ridgemark, California

A magnitude 1.7 earthquake struck 10 km SW of Ridgemark, California on Sun, Jul 28, 1991, 1:51 PM PDT (20:51 UTC), 9 km (6 mi) below the surface.

A larger quake followed: M4.3 1 km NNE of Aromas, 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
1.7 (Md, duration), micro
Magnitude from
Northern California Seismic System
Local time
UTC
1991-07-28 20:51:09 UTC
Depth
9.1 km (5.6 mi), shallow
Epicenter
36.755° N, 121.458° 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, 0.3 km in depth
Magnitude uncertainty
±0.14
Depth from
From location
Station coverage gap
31°
Stations used
42

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 149 in the 60 days after this one and 76 in the 30 days before it.

After

  1. 1.52 km SSW of Saratoga, California · 12853 days ago · 6 km deep · 75 km away
  2. 2.140 km SE of Big Sur, California · 12852 days ago · 15 km deep · 88 km away
  3. 2.412 km S of Tres Pinos, California · 12852 days ago · 6 km deep · 16 km away
  4. 1.722 km NE of Soledad, California · 12851 days ago · 10 km deep · 37 km away
  5. 1.65 km SSW of Tres Pinos, California · 12851 days ago · 8 km deep · 11 km away
  6. 1.942 km W of Lockwood, California · 12850 days ago · 17 km deep · 92 km away
  7. 1.55 km SSW of Ridgemark, California · 12850 days ago · 9 km deep · 7 km away
  8. 2.05 km S of Ridgemark, California · 12850 days ago · 10 km deep · 7 km away
  9. 1.76 km NE of East Foothills, California · 12849 days ago · 7 km deep · 79 km away
  10. 1.621 km NE of Soledad, California · 12848 days ago · 7 km deep · 35 km away
  11. 2.824 km NE of Greenfield, California · 12848 days ago · 4 km deep · 49 km away
  12. 2.438 km WNW of Lockwood, California · 12848 days ago · 16 km deep · 82 km away
  13. 1.637 km WNW of Lockwood, California · 12848 days ago · 17 km deep · 83 km away
  14. 1.917 km SSE of Tres Pinos, California · 12847 days ago · 4 km deep · 22 km away
  15. 2.211 km ESE of East Foothills, California · 12847 days ago · 8 km deep · 68 km away
  16. 1.812 km ENE of Big Sur, California · 12847 days ago · 15 km deep · 53 km away
  17. 1.80 km N of Day Valley, California · 12847 days ago · 13 km deep · 48 km away
  18. 2.56 km NNW of Day Valley, California · 12847 days ago · 10 km deep · 54 km away
  19. 1.826 km NE of Soledad, California · 12846 days ago · 5 km deep · 39 km away
  20. 2.721 km SSE of Tres Pinos, California · 12846 days ago · 7 km deep · 27 km away
  21. 2.130 km SE of Big Sur, California · 12845 days ago · 13 km deep · 76 km away
  22. 1.612 km SSW of Pescadero, California · 12844 days ago · 8 km deep · 97 km away
  23. 1.72 km WSW of Lexington Hills, California · 12844 days ago · 11 km deep · 65 km away
  24. 2.06 km WSW of Davenport, California · 12842 days ago · 7 km deep · 76 km away
  25. 2.78 km ENE of Morgan Hill, California · 12841 days ago · 2 km deep · 46 km away
  26. 3.44 km WSW of Davenport, California · 12841 days ago · 12 km deep · 74 km away
  27. 1.612 km ENE of East Foothills, California · 12841 days ago · 5 km deep · 76 km away
  28. 2.024 km NE of Greenfield, California · 12841 days ago · 4 km deep · 48 km away
  29. 3.117 km SSE of Tres Pinos, California · 12840 days ago · 7 km deep · 22 km away
  30. 2.34 km SSE of Sunol, California · 12840 days ago · 7 km deep · 96 km away
  31. 1.95 km SSW of Ridgemark, California · 12840 days ago · 5 km deep · 5 km away
  32. 1.616 km SSE of Tres Pinos, California · 12839 days ago · 7 km deep · 21 km away
  33. 1.92 km SW of San Juan Bautista, California · 12839 days ago · 7 km deep · 12 km away
  34. 1.912 km ENE of East Foothills, California · 12839 days ago · 5 km deep · 78 km away
  35. 1.82 km NNE of Aromas, California · 12839 days ago · 6 km deep · 23 km away
  36. 1.710 km ESE of East Foothills, California · 12838 days ago · 7 km deep · 69 km away
  37. 1.922 km NNE of Soledad, California · 12838 days ago · 2 km deep · 29 km away
  38. 1.515 km E of Seven Trees, California · 12838 days ago · 3 km deep · 62 km away
  39. 2.626 km NE of Soledad, California · 12838 days ago · 9 km deep · 37 km away
  40. 2.318 km W of Three Rocks, California · 12838 days ago · 0 km deep · 81 km away
  41. 2.814 km SSE of Tres Pinos, California · 12837 days ago · 6 km deep · 19 km away
  42. 2.616 km SSE of Tres Pinos, California · 12837 days ago · 6 km deep · 21 km away
  43. 1.923 km NE of San Ardo, California · 12836 days ago · 3 km deep · 88 km away
  44. 1.94 km ENE of Tres Pinos, California · 12836 days ago · 9 km deep · 17 km away
  45. 1.86 km WSW of San Ardo, California · 12836 days ago · 23 km deep · 94 km away
  46. 2.015 km N of Morgan Hill, California · 12835 days ago · 4 km deep · 60 km away
  47. 2.211 km S of Tres Pinos, California · 12835 days ago · 5 km deep · 15 km away
  48. 2.47 km WSW of Gilroy, California · 12834 days ago · 5 km deep · 31 km away
  49. 1.630 km ENE of Soledad, California · 12834 days ago · 7 km deep · 43 km away
  50. 2.011 km NW of Davenport, California · 12834 days ago · 10 km deep · 82 km away
  51. 2.04 km WNW of San Juan Bautista, California · 12834 days ago · 6 km deep · 16 km away
  52. 1.74 km SSW of Gilroy, California · 12833 days ago · 2 km deep · 26 km away
  53. 1.68 km ENE of San Martin, California · 12833 days ago · 7 km deep · 42 km away
  54. 1.925 km NNE of King City, California · 12833 days ago · 1 km deep · 58 km away
  55. 1.624 km NE of Greenfield, California · 12832 days ago · 5 km deep · 47 km away
  56. 2.311 km SSE of Tres Pinos, California · 12832 days ago · 4 km deep · 17 km away
  57. 1.73 km WNW of San Juan Bautista, California · 12831 days ago · 5 km deep · 15 km away
  58. 1.82 km E of San Ardo, California · 12831 days ago · 13 km deep · 97 km away
  59. 1.78 km ESE of East Foothills, California · 12830 days ago · 6 km deep · 71 km away
  60. 2.321 km NE of Soledad, California · 12830 days ago · 5 km deep · 32 km away

The first 60 of 149.

Before

  1. 1.624 km NE of Greenfield, California · 12853 days ago · 5 km deep · 48 km away
  2. 1.517 km WNW of Davenport, California · 12854 days ago · 5 km deep · 89 km away
  3. 3.07 km S of Pescadero, California · 12854 days ago · 16 km deep · 95 km away
  4. 1.95 km NNE of Tres Pinos, California · 12854 days ago · 6 km deep · 17 km away
  5. 2.19 km ENE of Gilroy, California · 12855 days ago · 7 km deep · 33 km away
  6. 1.711 km W of Volta, California · 12855 days ago · 7 km deep · 51 km away
  7. 2.421 km NE of Soledad, California · 12855 days ago · 5 km deep · 32 km away
  8. 2.221 km NE of Soledad, California · 12855 days ago · 5 km deep · 32 km away
  9. 2.421 km NE of Soledad, California · 12855 days ago · 5 km deep · 32 km away
  10. 2.421 km NE of Soledad, California · 12856 days ago · 5 km deep · 32 km away
  11. 1.64 km WNW of San Juan Bautista, California · 12856 days ago · 4 km deep · 17 km away
  12. 1.813 km SW of Santa Cruz, California · 12856 days ago · 7 km deep · 62 km away
  13. 2.04 km W of San Juan Bautista, California · 12856 days ago · 8 km deep · 15 km away
  14. 1.816 km WNW of Davenport, California · 12857 days ago · 4 km deep · 88 km away
  15. 2.03 km W of San Juan Bautista, California · 12857 days ago · 8 km deep · 15 km away
  16. 1.85 km ESE of Aromas, California · 12857 days ago · 5 km deep · 17 km away
  17. 1.63 km S of Ridgemark, California · 12857 days ago · 4 km deep · 8 km away
  18. 2.816 km S of Davenport, California · 12858 days ago · 5 km deep · 64 km away
  19. 2.318 km SSE of Tres Pinos, California · 12858 days ago · 6 km deep · 23 km away
  20. 1.54 km WNW of San Juan Bautista, California · 12860 days ago · 6 km deep · 17 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc225616. Read Mon, Oct 5, 2026, 1:41 PM UTC.