California earthquakes

M1.8 earthquake 12 km SW of Ridgemark, California

A magnitude 1.8 earthquake struck 12 km SW of Ridgemark, California on Tue, Oct 31, 1989, 10:21 AM PST (18:21 UTC), 14 km (9 mi) below the surface.

A larger quake followed: M4.7 6 km NE of Day Valley, 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
1.8 (Md, duration), micro
Magnitude from
Northern California Seismic System
Local time
UTC
1989-10-31 18:21:16 UTC
Depth
14.5 km (9.0 mi), shallow
Epicenter
36.742° N, 121.467° 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, 0.4 km in depth
Magnitude uncertainty
±0.11
Depth from
From location
Station coverage gap
84°
Stations used
27

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 193 in the 60 days after this one and 196 in the 30 days before it.

After

  1. 1.62 km SSW of Lexington Hills, California · 13485 days ago · 13 km deep · 64 km away
  2. 1.74 km SE of Aromas, California · 13485 days ago · 7 km deep · 18 km away
  3. 1.65 km ENE of Day Valley, California · 13485 days ago · 5 km deep · 47 km away
  4. 2.614 km N of Morgan Hill, California · 13485 days ago · 7 km deep · 60 km away
  5. 1.5Northern California · 13484 days ago · 6 km deep · 60 km away
  6. 2.5Northern California · 13484 days ago · 3 km deep · 46 km away
  7. 1.87 km W of Gilroy, California · 13484 days ago · 2 km deep · 33 km away
  8. 2.58 km NNE of Day Valley, California · 13484 days ago · 4 km deep · 52 km away
  9. 1.82 km WNW of Lexington Hills, California · 13484 days ago · 10 km deep · 67 km away
  10. 2.44 km ENE of Day Valley, California · 13484 days ago · 4 km deep · 46 km away
  11. 1.67 km N of Day Valley, California · 13484 days ago · 2 km deep · 53 km away
  12. 3.68 km NNE of Day Valley, California · 13484 days ago · 4 km deep · 52 km away
  13. 2.18 km NNE of Day Valley, California · 13484 days ago · 4 km deep · 52 km away
  14. 1.91 km ENE of San Juan Bautista, California · 13484 days ago · 6 km deep · 13 km away
  15. 1.79 km NNE of Day Valley, California · 13484 days ago · 4 km deep · 52 km away
  16. 2.12 km SSW of San Juan Bautista, California · 13484 days ago · 5 km deep · 12 km away
  17. 1.94 km N of Interlaken, California · 13484 days ago · 12 km deep · 37 km away
  18. 1.724 km NE of Greenfield, California · 13484 days ago · 6 km deep · 50 km away
  19. 2.18 km NNE of Day Valley, California · 13484 days ago · 4 km deep · 51 km away
  20. 1.914 km E of Seven Trees, California · 13484 days ago · 6 km deep · 66 km away
  21. 2.26 km NE of Ridgemark, California · 13484 days ago · 4 km deep · 19 km away
  22. 1.75 km W of Hollister, California · 13484 days ago · 4 km deep · 13 km away
  23. 2.111 km SW of Ridgemark, California · 13484 days ago · 15 km deep · 0 km away
  24. 2.17 km NW of Day Valley, California · 13484 days ago · 13 km deep · 56 km away
  25. 1.93 km ESE of Day Valley, California · 13484 days ago · 16 km deep · 45 km away
  26. 1.71 km E of Aromas, California · 13484 days ago · 8 km deep · 21 km away
  27. 1.66 km NE of Ridgemark, California · 13484 days ago · 4 km deep · 19 km away
  28. 2.10 km WSW of Lexington Hills, California · 13483 days ago · 6 km deep · 65 km away
  29. 1.82 km N of Interlaken, California · 13483 days ago · 14 km deep · 35 km away
  30. 2.66 km ENE of Day Valley, California · 13483 days ago · 9 km deep · 47 km away
  31. 4.76 km NE of Day Valley, California · 13483 days ago · 9 km deep · 47 km away
  32. 1.66 km NE of Day Valley, California · 13483 days ago · 7 km deep · 48 km away
  33. 1.96 km ENE of Day Valley, California · 13483 days ago · 8 km deep · 46 km away
  34. 1.67 km ENE of Day Valley, California · 13483 days ago · 9 km deep · 47 km away
  35. 1.66 km ENE of Day Valley, California · 13483 days ago · 8 km deep · 46 km away
  36. 1.97 km ENE of Day Valley, California · 13483 days ago · 8 km deep · 46 km away
  37. 2.16 km NE of Day Valley, California · 13483 days ago · 8 km deep · 47 km away
  38. 1.67 km ENE of Day Valley, California · 13483 days ago · 7 km deep · 46 km away
  39. 2.37 km NE of Ridgemark, California · 13483 days ago · 6 km deep · 19 km away
  40. 1.64 km WSW of Cupertino, California · 13483 days ago · 4 km deep · 83 km away
  41. 2.56 km NW of Day Valley, California · 13483 days ago · 15 km deep · 54 km away
  42. 1.89 km N of Day Valley, California · 13483 days ago · 3 km deep · 56 km away
  43. 1.52 km N of Aromas, California · 13483 days ago · 6 km deep · 24 km away
  44. 1.91 km SSE of Lexington Hills, California · 13483 days ago · 9 km deep · 64 km away
  45. 2.27 km SW of Gilroy, California · 13483 days ago · 4 km deep · 29 km away
  46. 1.73 km SSW of Lexington Hills, California · 13483 days ago · 14 km deep · 63 km away
  47. 2.00 km ESE of Zayante, California · 13483 days ago · 8 km deep · 64 km away
  48. 1.92 km SSW of Lexington Hills, California · 13483 days ago · 13 km deep · 64 km away
  49. 2.06 km ENE of Interlaken, California · 13483 days ago · 0 km deep · 31 km away
  50. 1.83 km WNW of Lexington Hills, California · 13483 days ago · 11 km deep · 69 km away
  51. 2.36 km SSW of Sunol, California · 13483 days ago · 6 km deep · 96 km away
  52. 2.23 km W of San Juan Bautista, California · 13483 days ago · 6 km deep · 15 km away
  53. 1.96 km SSW of Sunol, California · 13483 days ago · 6 km deep · 96 km away
  54. 2.010 km NNE of East Foothills, California · 13483 days ago · 6 km deep · 86 km away
  55. 1.824 km ENE of Soledad, California · 13483 days ago · 2 km deep · 45 km away
  56. 1.76 km ESE of East Foothills, California · 13483 days ago · 0 km deep · 72 km away
  57. 2.56 km ESE of East Foothills, California · 13483 days ago · 1 km deep · 72 km away
  58. 2.02 km WSW of Lexington Hills, California · 13483 days ago · 10 km deep · 66 km away
  59. 1.522 km NE of Soledad, California · 13483 days ago · 4 km deep · 34 km away
  60. 1.75 km S of Gilroy, California · 13482 days ago · 3 km deep · 26 km away

The first 60 of 193.

Before

  1. 2.14 km ENE of Interlaken, California · 13485 days ago · 6 km deep · 32 km away
  2. 2.65 km WNW of Day Valley, California · 13485 days ago · 16 km deep · 53 km away
  3. 2.53 km NNE of Amesti, California · 13485 days ago · 15 km deep · 38 km away
  4. 1.63 km ESE of Day Valley, California · 13485 days ago · 15 km deep · 45 km away
  5. 1.73 km NNW of Corralitos, California · 13485 days ago · 15 km deep · 44 km away
  6. 1.77 km NNW of Day Valley, California · 13485 days ago · 6 km deep · 54 km away
  7. 2.511 km SW of Ridgemark, California · 13485 days ago · 15 km deep · 0 km away
  8. 1.816 km S of Pescadero, California · 13485 days ago · 9 km deep · 89 km away
  9. 1.923 km NE of King City, California · 13485 days ago · 7 km deep · 62 km away
  10. 2.37 km ENE of Interlaken, California · 13485 days ago · 4 km deep · 31 km away
  11. 1.67 km N of Day Valley, California · 13485 days ago · 6 km deep · 53 km away
  12. 1.616 km SSE of Pescadero, California · 13485 days ago · 7 km deep · 88 km away
  13. 3.56 km NE of Day Valley, California · 13485 days ago · 11 km deep · 47 km away
  14. 2.32 km SSW of Lexington Hills, California · 13485 days ago · 13 km deep · 64 km away
  15. 1.98 km NNE of Day Valley, California · 13485 days ago · 4 km deep · 52 km away
  16. 2.07 km SW of Saratoga, California · 13485 days ago · 11 km deep · 75 km away
  17. 2.57 km SW of Davenport, California · 13485 days ago · 6 km deep · 73 km away
  18. 2.414 km N of Morgan Hill, California · 13486 days ago · 6 km deep · 60 km away
  19. 2.46 km ESE of Lexington Hills, California · 13486 days ago · 11 km deep · 59 km away
  20. 2.47 km SW of Monte Sereno, California · 13486 days ago · 14 km deep · 72 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc146264. Read Fri, Oct 2, 2026, 3:48 PM UTC.