California earthquakes

M2.3 earthquake 6 km NE of Ridgemark, California

A magnitude 2.3 earthquake struck 6 km NE of Ridgemark, California on Sat, Sep 16, 1978, 3:01 AM PDT (10:01 UTC), 6 km (4 mi) below the surface.

A larger quake followed: M3.9 10 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
2.3 (md), micro
Local time
UTC
1978-09-16 10:01:53 UTC
Depth
6.1 km (3.8 mi), shallow
Epicenter
36.845° N, 121.310° 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, 0.4 km in depth
Magnitude uncertainty
±0.09
Depth from
From location
Station coverage gap
53°
Stations used
47

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 164 in the 60 days after this one and 84 in the 30 days before it.

After

  1. 1.75 km SSE of San Juan Bautista, California · 17546 days ago · 5 km deep · 18 km away
  2. 1.89 km S of Tres Pinos, California · 17545 days ago · 4 km deep · 16 km away
  3. 3.39 km S of Tres Pinos, California · 17545 days ago · 4 km deep · 16 km away
  4. 3.010 km S of Tres Pinos, California · 17545 days ago · 4 km deep · 16 km away
  5. 2.410 km S of Tres Pinos, California · 17545 days ago · 5 km deep · 17 km away
  6. 1.610 km S of Tres Pinos, California · 17545 days ago · 4 km deep · 16 km away
  7. 2.910 km S of Tres Pinos, California · 17545 days ago · 4 km deep · 17 km away
  8. 3.910 km S of Tres Pinos, California · 17545 days ago · 4 km deep · 16 km away
  9. 2.810 km S of Tres Pinos, California · 17545 days ago · 4 km deep · 17 km away
  10. 2.5Central California · 17545 days ago · 1 km deep · 50 km away
  11. 1.69 km S of Tres Pinos, California · 17545 days ago · 4 km deep · 16 km away
  12. 3.810 km S of Tres Pinos, California · 17545 days ago · 4 km deep · 16 km away
  13. 2.2Central California · 17545 days ago · 4 km deep · 16 km away
  14. 2.410 km S of Tres Pinos, California · 17545 days ago · 4 km deep · 17 km away
  15. 2.710 km S of Tres Pinos, California · 17545 days ago · 5 km deep · 16 km away
  16. 2.210 km S of Tres Pinos, California · 17544 days ago · 4 km deep · 17 km away
  17. 1.8Central California · 17544 days ago · 4 km deep · 17 km away
  18. 2.3Central California · 17544 days ago · 4 km deep · 17 km away
  19. 2.710 km S of Tres Pinos, California · 17544 days ago · 4 km deep · 17 km away
  20. 2.9Central California · 17544 days ago · 5 km deep · 17 km away
  21. 2.010 km S of Tres Pinos, California · 17544 days ago · 4 km deep · 16 km away
  22. 3.0Central California · 17544 days ago · 4 km deep · 16 km away
  23. 2.011 km S of Tres Pinos, California · 17544 days ago · 4 km deep · 17 km away
  24. 2.39 km NE of San Martin, California · 17543 days ago · 7 km deep · 40 km away
  25. 1.610 km SSW of Tres Pinos, California · 17542 days ago · 12 km deep · 17 km away
  26. 1.817 km SSE of Tres Pinos, California · 17542 days ago · 8 km deep · 23 km away
  27. 2.19 km S of Tres Pinos, California · 17542 days ago · 4 km deep · 16 km away
  28. 2.38 km SSE of Tres Pinos, California · 17541 days ago · 5 km deep · 15 km away
  29. 3.28 km NE of Interlaken, California · 17541 days ago · 4 km deep · 36 km away
  30. 1.69 km SSE of Tres Pinos, California · 17541 days ago · 5 km deep · 15 km away
  31. 1.88 km NE of Interlaken, California · 17541 days ago · 4 km deep · 36 km away
  32. 1.89 km NW of Hollister, California · 17540 days ago · 4 km deep · 16 km away
  33. 2.89 km NNW of Hollister, California · 17540 days ago · 6 km deep · 15 km away
  34. 1.522 km ENE of Soledad, California · 17539 days ago · 5 km deep · 43 km away
  35. 2.29 km NNW of Hollister, California · 17539 days ago · 6 km deep · 15 km away
  36. 1.78 km NNW of Hollister, California · 17539 days ago · 4 km deep · 14 km away
  37. 2.99 km S of Tres Pinos, California · 17539 days ago · 4 km deep · 16 km away
  38. 1.59 km S of Tres Pinos, California · 17539 days ago · 4 km deep · 16 km away
  39. 1.623 km NNE of San Lucas, California · 17539 days ago · 6 km deep · 70 km away
  40. 2.510 km S of Tres Pinos, California · 17539 days ago · 4 km deep · 16 km away
  41. 2.021 km NE of Soledad, California · 17538 days ago · 3 km deep · 34 km away
  42. 1.99 km S of Tres Pinos, California · 17537 days ago · 4 km deep · 16 km away
  43. 1.99 km S of Tres Pinos, California · 17537 days ago · 4 km deep · 16 km away
  44. 1.99 km NNW of Hollister, California · 17537 days ago · 5 km deep · 15 km away
  45. 1.63 km W of Hollister, California · 17536 days ago · 4 km deep · 11 km away
  46. 1.9Central California · 17536 days ago · 4 km deep · 16 km away
  47. 1.59 km NNW of Hollister, California · 17536 days ago · 5 km deep · 15 km away
  48. 1.510 km S of Tres Pinos, California · 17536 days ago · 4 km deep · 17 km away
  49. 1.522 km ENE of San Lucas, California · 17536 days ago · 5 km deep · 83 km away
  50. 2.93 km ENE of East Foothills, California · 17536 days ago · 1 km deep · 74 km away
  51. 1.54 km N of Aromas, California · 17534 days ago · 4 km deep · 32 km away
  52. 1.64 km NE of Day Valley, California · 17533 days ago · 12 km deep · 51 km away
  53. 2.016 km E of Seven Trees, California · 17532 days ago · 7 km deep · 59 km away
  54. 1.78 km SSW of Tres Pinos, California · 17532 days ago · 2 km deep · 15 km away
  55. 1.56 km WSW of Gilroy, California · 17531 days ago · 4 km deep · 33 km away
  56. 2.48 km ESE of East Foothills, California · 17531 days ago · 1 km deep · 68 km away
  57. 1.521 km NE of Soledad, California · 17531 days ago · 7 km deep · 33 km away
  58. 2.88 km E of Gilroy, California · 17530 days ago · 4 km deep · 22 km away
  59. 1.76 km WSW of Gilroy, California · 17530 days ago · 7 km deep · 34 km away
  60. 1.814 km SSE of Tres Pinos, California · 17530 days ago · 4 km deep · 20 km away

The first 60 of 164.

Before

  1. 2.25 km SE of Alum Rock, California · 17546 days ago · 3 km deep · 69 km away
  2. 2.36 km E of East Foothills, California · 17546 days ago · 7 km deep · 71 km away
  3. 1.89 km S of Tres Pinos, California · 17547 days ago · 4 km deep · 16 km away
  4. 1.79 km S of Tres Pinos, California · 17547 days ago · 4 km deep · 16 km away
  5. 2.19 km S of Tres Pinos, California · 17547 days ago · 3 km deep · 16 km away
  6. 1.99 km S of Tres Pinos, California · 17547 days ago · 4 km deep · 16 km away
  7. 3.210 km S of Tres Pinos, California · 17547 days ago · 4 km deep · 16 km away
  8. 1.510 km S of Tres Pinos, California · 17548 days ago · 3 km deep · 16 km away
  9. 1.627 km NE of Soledad, California · 17548 days ago · 9 km deep · 34 km away
  10. 1.929 km SE of Big Sur, California · 17549 days ago · 10 km deep · 90 km away
  11. 2.26 km E of East Foothills, California · 17550 days ago · 7 km deep · 71 km away
  12. 1.610 km S of Tres Pinos, California · 17552 days ago · 3 km deep · 17 km away
  13. 2.46 km ENE of Seven Trees, California · 17552 days ago · 5 km deep · 67 km away
  14. 3.410 km S of Tres Pinos, California · 17552 days ago · 4 km deep · 16 km away
  15. 2.310 km S of Tres Pinos, California · 17552 days ago · 3 km deep · 16 km away
  16. 2.35 km ENE of Aromas, California · 17553 days ago · 8 km deep · 26 km away
  17. 1.63 km NE of Tres Pinos, California · 17553 days ago · 8 km deep · 3 km away
  18. 1.81 km SE of East Foothills, California · 17554 days ago · 5 km deep · 73 km away
  19. 1.623 km NE of King City, California · 17554 days ago · 2 km deep · 65 km away
  20. 1.86 km NE of Ridgemark, California · 17554 days ago · 5 km deep · 2 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1042333. Read Wed, Sep 30, 2026, 10:47 AM UTC.