California earthquakes

M1.5 earthquake 5 km SW of Ridgemark, California

A magnitude 1.5 earthquake struck 5 km SW of Ridgemark, California on Mon, Sep 26, 1983, 9:58 PM PDT (04:58 UTC), 10 km (6 mi) below the surface.

A larger quake followed: M3.6 12 km ESE of East Foothills, 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
1.5 (Md, duration), micro
Magnitude from
Northern California Seismic System
Local time
UTC
1983-09-27 04:58:56 UTC
Depth
9.8 km (6.1 mi), shallow
Epicenter
36.778° N, 121.403° 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 0.4 km horizontally, 0.9 km in depth
Magnitude uncertainty
±0.23
Depth from
From location
Station coverage gap
98°
Stations used
16

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 107 in the 60 days after this one and 66 in the 30 days before it.

After

  1. 2.026 km ENE of Soledad, California · 15711 days ago · 4 km deep · 42 km away
  2. 1.79 km NE of Gilroy, California · 15710 days ago · 8 km deep · 33 km away
  3. 1.833 km W of Lockwood, California · 15710 days ago · 17 km deep · 87 km away
  4. 2.124 km WSW of Volta, California · 15709 days ago · 0 km deep · 34 km away
  5. 2.638 km SSW of South Dos Palos, California · 15709 days ago · 4 km deep · 55 km away
  6. 3.237 km SSW of South Dos Palos, California · 15709 days ago · -1 km deep · 57 km away
  7. 2.138 km SSW of South Dos Palos, California · 15709 days ago · 5 km deep · 55 km away
  8. 2.539 km SSW of South Dos Palos, California · 15709 days ago · 3 km deep · 55 km away
  9. 2.139 km SSW of South Dos Palos, California · 15709 days ago · 4 km deep · 55 km away
  10. 1.724 km NE of Greenfield, California · 15709 days ago · 7 km deep · 47 km away
  11. 1.99 km ESE of East Foothills, California · 15709 days ago · 0 km deep · 69 km away
  12. 1.536 km WSW of Mendota, California · 15707 days ago · 3 km deep · 59 km away
  13. 1.636 km SSW of South Dos Palos, California · 15707 days ago · 6 km deep · 54 km away
  14. 3.112 km W of Three Rocks, California · 15707 days ago · 10 km deep · 83 km away
  15. 1.538 km SSW of South Dos Palos, California · 15706 days ago · 4 km deep · 55 km away
  16. 1.514 km SSE of Livermore, California · 15705 days ago · 8 km deep · 92 km away
  17. 3.24 km SSE of San Juan Bautista, California · 15704 days ago · 6 km deep · 12 km away
  18. 2.54 km SSE of San Juan Bautista, California · 15704 days ago · 5 km deep · 11 km away
  19. 1.612 km S of Tres Pinos, California · 15704 days ago · 3 km deep · 14 km away
  20. 1.9Central California · 15704 days ago · 4 km deep · 27 km away
  21. 1.515 km W of Three Rocks, California · 15702 days ago · 7 km deep · 81 km away
  22. 2.39 km S of Tres Pinos, California · 15702 days ago · 4 km deep · 10 km away
  23. 1.99 km W of Volta, California · 15701 days ago · 6 km deep · 48 km away
  24. 2.58 km NE of Morgan Hill, California · 15701 days ago · 3 km deep · 48 km away
  25. 1.537 km SSW of South Dos Palos, California · 15700 days ago · 5 km deep · 55 km away
  26. 1.718 km NNW of Coalinga, California · 15700 days ago · 9 km deep · 100 km away
  27. 2.521 km NE of Soledad, California · 15698 days ago · 5 km deep · 30 km away
  28. 3.17 km E of East Foothills, California · 15698 days ago · 8 km deep · 72 km away
  29. 2.67 km E of East Foothills, California · 15698 days ago · 8 km deep · 72 km away
  30. 1.637 km ENE of Greenfield, California · 15698 days ago · 14 km deep · 55 km away
  31. 1.68 km SSW of Tres Pinos, California · 15697 days ago · 7 km deep · 8 km away
  32. 2.422 km NE of Soledad, California · 15697 days ago · 4 km deep · 29 km away
  33. 2.421 km NE of Soledad, California · 15697 days ago · 5 km deep · 30 km away
  34. 1.8Central California · 15696 days ago · 6 km deep · 19 km away
  35. 2.320 km NW of Coalinga, California · 15696 days ago · 8 km deep · 98 km away
  36. 2.314 km S of Mountain House, California · 15696 days ago · 9 km deep · 98 km away
  37. 2.522 km NE of Soledad, California · 15695 days ago · 7 km deep · 36 km away
  38. 1.67 km SSE of San Juan Bautista, California · 15695 days ago · 9 km deep · 10 km away
  39. 2.614 km ESE of Big Sur, California · 15694 days ago · 8 km deep · 68 km away
  40. 1.621 km NE of Soledad, California · 15694 days ago · 3 km deep · 33 km away
  41. 1.921 km NE of Soledad, California · 15694 days ago · 4 km deep · 34 km away
  42. 2.0Central California · 15694 days ago · 4 km deep · 47 km away
  43. 1.727 km ENE of Soledad, California · 15694 days ago · 6 km deep · 42 km away
  44. 1.74 km SW of Tres Pinos, California · 15693 days ago · 8 km deep · 4 km away
  45. 1.5Central California · 15693 days ago · 9 km deep · 4 km away
  46. 1.722 km ENE of San Ardo, California · 15692 days ago · 3 km deep · 99 km away
  47. 1.921 km SW of Los Banos, California · 15690 days ago · 0 km deep · 40 km away
  48. 1.814 km E of Seven Trees, California · 15689 days ago · 7 km deep · 64 km away
  49. 1.725 km ENE of Soledad, California · 15689 days ago · 7 km deep · 39 km away
  50. 2.27 km NE of San Juan Bautista, California · 15687 days ago · 5 km deep · 15 km away
  51. 1.98 km ENE of Morgan Hill, California · 15686 days ago · 2 km deep · 45 km away
  52. 3.612 km ESE of East Foothills, California · 15686 days ago · 7 km deep · 66 km away
  53. 1.68 km NE of Milpitas, California · 15685 days ago · 6 km deep · 88 km away
  54. 1.931 km ENE of Soledad, California · 15684 days ago · 7 km deep · 40 km away
  55. 1.822 km NE of Soledad, California · 15683 days ago · 8 km deep · 34 km away
  56. 2.723 km ENE of Soledad, California · 15683 days ago · 5 km deep · 40 km away
  57. 1.919 km NNW of Coalinga, California · 15683 days ago · 9 km deep · 100 km away
  58. 1.931 km ENE of Soledad, California · 15682 days ago · 8 km deep · 40 km away
  59. 2.022 km ENE of San Ardo, California · 15682 days ago · 5 km deep · 97 km away
  60. 2.08 km SW of Ridgemark, California · 15681 days ago · 7 km deep · 3 km away

The first 60 of 107.

Before

  1. 3.58 km ENE of Gilroy, California · 15712 days ago · 7 km deep · 30 km away
  2. 1.937 km SSW of South Dos Palos, California · 15712 days ago · 5 km deep · 50 km away
  3. 2.144 km SSE of Big Sur, California · 15712 days ago · 3 km deep · 99 km away
  4. 1.828 km NE of Greenfield, California · 15712 days ago · 6 km deep · 51 km away
  5. 2.121 km NE of Soledad, California · 15712 days ago · 7 km deep · 33 km away
  6. 1.526 km ENE of Soledad, California · 15712 days ago · 6 km deep · 41 km away
  7. 2.219 km SSE of Tres Pinos, California · 15713 days ago · 4 km deep · 22 km away
  8. 1.821 km NE of Soledad, California · 15713 days ago · 6 km deep · 33 km away
  9. 2.521 km NE of Soledad, California · 15713 days ago · 7 km deep · 33 km away
  10. 2.021 km SW of Diablo Grande, California · 15714 days ago · 0 km deep · 57 km away
  11. 1.54 km WSW of Cupertino, California · 15714 days ago · 5 km deep · 84 km away
  12. 1.85 km WSW of Cupertino, California · 15714 days ago · 5 km deep · 84 km away
  13. 1.621 km NE of Soledad, California · 15714 days ago · 2 km deep · 29 km away
  14. 1.57 km NE of Aromas, California · 15715 days ago · 6 km deep · 23 km away
  15. 1.66 km NNE of San Juan Bautista, California · 15715 days ago · 5 km deep · 16 km away
  16. 2.122 km NNE of Soledad, California · 15715 days ago · 8 km deep · 26 km away
  17. 1.719 km NNW of Coalinga, California · 15716 days ago · 7 km deep · 100 km away
  18. 2.232 km SW of Three Rocks, California · 15716 days ago · 13 km deep · 85 km away
  19. 2.121 km SSE of Tres Pinos, California · 15716 days ago · 4 km deep · 24 km away
  20. 1.922 km ENE of Soledad, California · 15716 days ago · 4 km deep · 40 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1103774. Read Fri, Oct 2, 2026, 3:04 PM UTC.