California earthquakes

M1.8 earthquake 8 km SSW of Ridgemark, California

A magnitude 1.8 earthquake struck 8 km SSW of Ridgemark, California on Thu, Sep 6, 1990, 10:26 AM PDT (17:26 UTC), 7 km (4 mi) below the surface.

A larger quake followed: M4.4 14 km S 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
1.8 (Md, duration), micro
Magnitude from
Northern California Seismic System
Local time
UTC
1990-09-06 17:26:55 UTC
Depth
6.6 km (4.1 mi), shallow
Epicenter
36.741° N, 121.412° 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 0.1 km horizontally, 0.3 km in depth
Magnitude uncertainty
±0.25
Depth from
From location
Station coverage gap
30°
Stations used
45

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 182 in the 60 days after this one and 131 in the 30 days before it.

After

  1. 2.82 km SW of Hollister, California · 13176 days ago · 7 km deep · 11 km away
  2. 2.5Northern California · 13176 days ago · 5 km deep · 73 km away
  3. 2.25 km SE of Sunol, California · 13176 days ago · 6 km deep · 98 km away
  4. 3.021 km NE of Soledad, California · 13176 days ago · 2 km deep · 30 km away
  5. 2.921 km NE of Soledad, California · 13175 days ago · 6 km deep · 31 km away
  6. 2.53 km W of San Juan Bautista, California · 13175 days ago · 5 km deep · 19 km away
  7. 1.76 km SSE of Gilroy, California · 13175 days ago · 5 km deep · 26 km away
  8. 4.112 km S of Tres Pinos, California · 13175 days ago · 7 km deep · 12 km away
  9. 3.712 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 12 km away
  10. 1.712 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 12 km away
  11. 3.011 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 10 km away
  12. 1.712 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 11 km away
  13. 3.112 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 12 km away
  14. 3.712 km S of Tres Pinos, California · 13175 days ago · 7 km deep · 12 km away
  15. 1.911 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 10 km away
  16. 1.912 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 12 km away
  17. 1.811 km S of Tres Pinos, California · 13175 days ago · 5 km deep · 10 km away
  18. 1.612 km S of Tres Pinos, California · 13175 days ago · 5 km deep · 12 km away
  19. 3.112 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 12 km away
  20. 2.812 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 12 km away
  21. 1.613 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 13 km away
  22. 1.611 km S of Tres Pinos, California · 13175 days ago · 6 km deep · 11 km away
  23. 1.95 km SE of Sunol, California · 13174 days ago · 6 km deep · 98 km away
  24. 1.95 km SE of Sunol, California · 13174 days ago · 6 km deep · 98 km away
  25. 1.811 km S of Tres Pinos, California · 13174 days ago · 6 km deep · 10 km away
  26. 1.711 km S of Tres Pinos, California · 13174 days ago · 6 km deep · 10 km away
  27. 2.012 km S of Tres Pinos, California · 13174 days ago · 6 km deep · 12 km away
  28. 2.312 km S of Tres Pinos, California · 13174 days ago · 5 km deep · 12 km away
  29. 1.813 km S of Tres Pinos, California · 13174 days ago · 4 km deep · 13 km away
  30. 2.112 km S of Tres Pinos, California · 13174 days ago · 6 km deep · 12 km away
  31. 2.57 km ENE of Gilroy, California · 13174 days ago · 6 km deep · 33 km away
  32. 3.51 km ENE of Aromas, California · 13174 days ago · 7 km deep · 26 km away
  33. 1.61 km ENE of Aromas, California · 13174 days ago · 6 km deep · 26 km away
  34. 1.62 km E of Aromas, California · 13174 days ago · 6 km deep · 25 km away
  35. 2.11 km ENE of Aromas, California · 13173 days ago · 7 km deep · 26 km away
  36. 1.71 km ENE of Aromas, California · 13173 days ago · 7 km deep · 26 km away
  37. 2.112 km S of Tres Pinos, California · 13173 days ago · 5 km deep · 12 km away
  38. 1.712 km S of Tres Pinos, California · 13173 days ago · 5 km deep · 12 km away
  39. 1.83 km NNE of San Juan Bautista, California · 13173 days ago · 7 km deep · 18 km away
  40. 2.13 km NNE of San Juan Bautista, California · 13173 days ago · 7 km deep · 18 km away
  41. 1.911 km S of Tres Pinos, California · 13173 days ago · 5 km deep · 11 km away
  42. 1.97 km NNE of Hollister, California · 13173 days ago · 6 km deep · 20 km away
  43. 2.512 km S of Tres Pinos, California · 13173 days ago · 6 km deep · 12 km away
  44. 3.124 km ENE of San Ardo, California · 13173 days ago · 8 km deep · 96 km away
  45. 2.724 km ENE of San Ardo, California · 13173 days ago · 9 km deep · 96 km away
  46. 1.814 km S of Tres Pinos, California · 13172 days ago · 7 km deep · 14 km away
  47. 4.414 km S of Tres Pinos, California · 13172 days ago · 8 km deep · 14 km away
  48. 2.214 km SSE of Tres Pinos, California · 13172 days ago · 7 km deep · 14 km away
  49. 2.015 km SSE of Tres Pinos, California · 13172 days ago · 6 km deep · 15 km away
  50. 2.58 km SSE of San Juan Bautista, California · 13172 days ago · 7 km deep · 9 km away
  51. 1.94 km WNW of Day Valley, California · 13172 days ago · 16 km deep · 56 km away
  52. 1.84 km ESE of Interlaken, California · 13172 days ago · 10 km deep · 33 km away
  53. 1.79 km ESE of Lexington Hills, California · 13172 days ago · 2 km deep · 60 km away
  54. 1.616 km SE of Livermore, California · 13172 days ago · 7 km deep · 94 km away
  55. 1.721 km NE of Soledad, California · 13171 days ago · 6 km deep · 30 km away
  56. 2.512 km S of Tres Pinos, California · 13171 days ago · 4 km deep · 12 km away
  57. 1.57 km SW of Monte Sereno, California · 13170 days ago · 13 km deep · 77 km away
  58. 1.6Northern California · 13170 days ago · 6 km deep · 98 km away
  59. 2.215 km SSE of Tres Pinos, California · 13170 days ago · 6 km deep · 15 km away
  60. 2.312 km S of Tres Pinos, California · 13169 days ago · 4 km deep · 12 km away

The first 60 of 182.

Before

  1. 2.12 km WSW of San Juan Bautista, California · 13177 days ago · 7 km deep · 18 km away
  2. 2.119 km W of Three Rocks, California · 13178 days ago · 3 km deep · 75 km away
  3. 2.121 km NE of Soledad, California · 13178 days ago · 3 km deep · 30 km away
  4. 2.74 km ESE of Aromas, California · 13178 days ago · 6 km deep · 22 km away
  5. 2.83 km WSW of San Juan Bautista, California · 13178 days ago · 6 km deep · 18 km away
  6. 2.26 km E of East Foothills, California · 13178 days ago · 9 km deep · 78 km away
  7. 1.67 km E of East Foothills, California · 13178 days ago · 9 km deep · 77 km away
  8. 1.87 km E of East Foothills, California · 13178 days ago · 9 km deep · 78 km away
  9. 1.72 km N of Seacliff, California · 13178 days ago · 4 km deep · 54 km away
  10. 1.82 km N of Seacliff, California · 13178 days ago · 4 km deep · 54 km away
  11. 2.612 km S of Tres Pinos, California · 13179 days ago · 6 km deep · 12 km away
  12. 1.62 km SE of San Ardo, California · 13179 days ago · 9 km deep · 95 km away
  13. 1.56 km ENE of Corralitos, California · 13179 days ago · 7 km deep · 42 km away
  14. 2.04 km S of San Juan Bautista, California · 13179 days ago · 7 km deep · 13 km away
  15. 2.311 km S of Tres Pinos, California · 13179 days ago · 4 km deep · 10 km away
  16. 2.15 km NNE of Corralitos, California · 13179 days ago · 11 km deep · 46 km away
  17. 1.521 km NNE of Soledad, California · 13179 days ago · 8 km deep · 25 km away
  18. 1.79 km SSW of Tres Pinos, California · 13180 days ago · 3 km deep · 7 km away
  19. 2.721 km NE of Soledad, California · 13180 days ago · 6 km deep · 31 km away
  20. 2.421 km NE of Soledad, California · 13180 days ago · 6 km deep · 31 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc163762. Read Sun, Oct 4, 2026, 3:55 PM UTC.