California earthquakes

M1.5 earthquake 5 km SW of Ridgemark, California

A magnitude 1.5 earthquake struck 5 km SW of Ridgemark, California on Sat, Feb 18, 1978, 6:18 PM PST (02:18 UTC), 9 km (6 mi) below the surface.

A larger quake followed: M3.1 9 km SSE of San Juan Bautista, 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
1978-02-19 02:18:14 UTC
Depth
8.9 km (5.6 mi), shallow
Epicenter
36.784° N, 121.416° 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, 0.6 km in depth
Magnitude uncertainty
±0.27
Depth from
From location
Station coverage gap
53°
Stations used
23

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 112 in the 60 days after this one and 69 in the 30 days before it.

After

  1. 1.624 km NE of Greenfield, California · 17758 days ago · 7 km deep · 46 km away
  2. 1.6Northern California · 17758 days ago · 5 km deep · 29 km away
  3. 1.71 km W of Cambrian Park, California · 17757 days ago · 8 km deep · 71 km away
  4. 2.44 km N of Morgan Hill, California · 17756 days ago · 6 km deep · 48 km away
  5. 1.84 km N of Morgan Hill, California · 17756 days ago · 5 km deep · 48 km away
  6. 1.821 km NNE of Soledad, California · 17756 days ago · 8 km deep · 29 km away
  7. 2.27 km S of Livermore, California · 17755 days ago · 8 km deep · 97 km away
  8. 1.625 km SE of Tres Pinos, California · 17755 days ago · 7 km deep · 32 km away
  9. 1.722 km NE of San Ardo, California · 17755 days ago · 7 km deep · 90 km away
  10. 2.827 km W of Three Rocks, California · 17754 days ago · 8 km deep · 70 km away
  11. 2.216 km N of Morgan Hill, California · 17754 days ago · 6 km deep · 59 km away
  12. 1.54 km SE of Tres Pinos, California · 17754 days ago · 8 km deep · 13 km away
  13. 2.423 km NNE of San Lucas, California · 17753 days ago · 5 km deep · 71 km away
  14. 2.78 km SSE of San Juan Bautista, California · 17753 days ago · 7 km deep · 7 km away
  15. 1.737 km SSW of South Dos Palos, California · 17752 days ago · 7 km deep · 51 km away
  16. 1.737 km SSW of South Dos Palos, California · 17752 days ago · 6 km deep · 51 km away
  17. 1.6Northern California · 17751 days ago · 2 km deep · 62 km away
  18. 2.51 km NE of Hollister, California · 17751 days ago · 8 km deep · 9 km away
  19. 1.61 km ENE of Hollister, California · 17751 days ago · 8 km deep · 9 km away
  20. 1.7Central California · 17750 days ago · 11 km deep · 50 km away
  21. 2.0Central California · 17750 days ago · 7 km deep · 98 km away
  22. 1.7Central California · 17750 days ago · 5 km deep · 17 km away
  23. 2.4Central California · 17749 days ago · 8 km deep · 46 km away
  24. 2.723 km ENE of San Lucas, California · 17749 days ago · 8 km deep · 85 km away
  25. 2.42 km WSW of San Juan Bautista, California · 17748 days ago · 7 km deep · 15 km away
  26. 2.17 km NE of San Martin, California · 17747 days ago · 1 km deep · 41 km away
  27. 1.621 km NE of Soledad, California · 17746 days ago · 4 km deep · 32 km away
  28. 1.59 km ENE of Milpitas, CA · 17746 days ago · 7 km deep · 84 km away
  29. 2.422 km ENE of Soledad, California · 17745 days ago · 4 km deep · 42 km away
  30. 2.622 km ENE of Soledad, California · 17745 days ago · 5 km deep · 42 km away
  31. 1.922 km ENE of Soledad, California · 17745 days ago · 5 km deep · 42 km away
  32. 1.631 km NE of Soledad, California · 17745 days ago · 6 km deep · 40 km away
  33. 1.921 km NE of Soledad, California · 17745 days ago · 7 km deep · 30 km away
  34. 2.16 km S of Sunol, California · 17744 days ago · 8 km deep · 94 km away
  35. 1.624 km NE of Greenfield, California · 17743 days ago · 5 km deep · 52 km away
  36. 1.88 km SSE of San Juan Bautista, California · 17743 days ago · 7 km deep · 7 km away
  37. 2.211 km S of Tres Pinos, California · 17742 days ago · 3 km deep · 15 km away
  38. 2.0Northern California · 17740 days ago · 6 km deep · 73 km away
  39. 1.922 km ENE of Soledad, California · 17739 days ago · 4 km deep · 39 km away
  40. 2.222 km ENE of Soledad, California · 17739 days ago · 4 km deep · 39 km away
  41. 2.37 km SE of Alum Rock, California · 17739 days ago · 3 km deep · 67 km away
  42. 2.124 km ENE of Soledad, California · 17739 days ago · 2 km deep · 44 km away
  43. 1.64 km SW of Ridgemark, California · 17738 days ago · 7 km deep · 2 km away
  44. 2.57 km NE of Interlaken, California · 17738 days ago · 11 km deep · 33 km away
  45. 1.523 km ENE of Soledad, California · 17738 days ago · 4 km deep · 42 km away
  46. 1.627 km NE of Soledad, California · 17737 days ago · 5 km deep · 34 km away
  47. 2.43 km ESE of Lexington Hills, California · 17737 days ago · 12 km deep · 62 km away
  48. 2.010 km ESE of Sunol, California · 17736 days ago · 7 km deep · 91 km away
  49. 1.83 km ESE of Lexington Hills, California · 17736 days ago · 11 km deep · 62 km away
  50. 2.624 km NE of Greenfield, California · 17736 days ago · 2 km deep · 47 km away
  51. 1.724 km NE of Greenfield, California · 17736 days ago · 5 km deep · 48 km away
  52. 2.115 km E of Seven Trees, California · 17736 days ago · 6 km deep · 60 km away
  53. 2.321 km NW of Diablo Grande, California · 17735 days ago · 4 km deep · 81 km away
  54. 2.824 km NE of Greenfield, California · 17734 days ago · 3 km deep · 48 km away
  55. 1.724 km NE of Greenfield, California · 17734 days ago · 3 km deep · 49 km away
  56. 2.16 km NE of Ridgemark, California · 17733 days ago · 6 km deep · 12 km away
  57. 1.925 km ENE of Greenfield, California · 17732 days ago · 6 km deep · 54 km away
  58. 2.69 km SE of Sunol, California · 17732 days ago · 2 km deep · 91 km away
  59. 1.83 km SW of Loyola, California · 17730 days ago · 5 km deep · 87 km away
  60. 1.724 km NE of Greenfield, California · 17730 days ago · 5 km deep · 49 km away

The first 60 of 112.

Before

  1. 3.016 km SSE of Tres Pinos, California · 17758 days ago · 3 km deep · 20 km away
  2. 1.510 km NNW of Hollister, California · 17758 days ago · 7 km deep · 17 km away
  3. 2.320 km SSE of Tres Pinos, California · 17759 days ago · 5 km deep · 25 km away
  4. 2.312 km N of Morgan Hill, California · 17760 days ago · 4 km deep · 55 km away
  5. 2.05 km NNW of East Foothills, California · 17760 days ago · 2 km deep · 81 km away
  6. 2.315 km E of Seven Trees, California · 17761 days ago · 4 km deep · 60 km away
  7. 1.825 km NE of King City, California · 17761 days ago · 2 km deep · 59 km away
  8. 1.629 km ENE of Soledad, California · 17763 days ago · 9 km deep · 42 km away
  9. 1.612 km N of Morgan Hill, California · 17763 days ago · 3 km deep · 55 km away
  10. 1.85 km SW of Gilroy, California · 17764 days ago · 3 km deep · 27 km away
  11. 1.620 km SSE of Tres Pinos, California · 17767 days ago · 5 km deep · 24 km away
  12. 1.523 km E of Tres Pinos, California · 17767 days ago · 2 km deep · 32 km away
  13. 1.811 km SW of Soledad, California · 17767 days ago · 6 km deep · 48 km away
  14. 1.920 km SSE of Tres Pinos, California · 17767 days ago · 5 km deep · 25 km away
  15. 1.915 km SW of Soledad, California · 17768 days ago · 9 km deep · 53 km away
  16. 2.07 km ENE of Interlaken, California · 17768 days ago · 0 km deep · 30 km away
  17. 1.611 km ESE of Livermore, California · 17768 days ago · 7 km deep · 96 km away
  18. 2.811 km ESE of Livermore, California · 17768 days ago · 8 km deep · 97 km away
  19. 2.112 km ESE of Livermore, California · 17768 days ago · 8 km deep · 96 km away
  20. 2.34 km WNW of San Juan Bautista, California · 17768 days ago · 7 km deep · 17 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1039003. Read Sat, Oct 3, 2026, 8:54 AM UTC.