California earthquakes

M1.7 earthquake 8 km ESE of Blackhawk, California

A magnitude 1.7 earthquake struck 8 km ESE of Blackhawk, California on Sun, Apr 19, 1981, 10:59 PM PST (06:59 UTC), 7 km (4 mi) below the surface.

A larger quake followed: M1.9 4 km ESE of Interlaken, California. This one was a foreshock.

Blackhawk 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
1.7 (md), micro
Local time
UTC
1981-04-20 06:59:22 UTC
Depth
6.7 km (4.2 mi), shallow
Epicenter
37.798° N, 121.818° 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
±0.17
Depth from
From location
Station coverage gap
54°
Stations used
20

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 80 in the 60 days after this one and 32 in the 30 days before it.

After

  1. 1.94 km ESE of Interlaken, California · 16590 days ago · 10 km deep · 96 km away
  2. 1.97 km SE of Sunol, California · 16590 days ago · 5 km deep · 28 km away
  3. 1.72 km NW of Orinda, California · 16589 days ago · 11 km deep · 35 km away
  4. 1.82 km NNW of Brentwood, California · 16588 days ago · 0 km deep · 20 km away
  5. 1.68 km SSW of Antioch, California · 16588 days ago · 0 km deep · 15 km away
  6. 1.67 km NNE of East Foothills, California · 16586 days ago · 11 km deep · 41 km away
  7. 4.18 km N of Day Valley, California · 16586 days ago · 13 km deep · 76 km away
  8. 2.616 km N of Morgan Hill, California · 16584 days ago · 6 km deep · 60 km away
  9. 1.77 km W of Mountain House, California · 16582 days ago · 9 km deep · 17 km away
  10. 1.82 km S of Rancho Calaveras, California · 16582 days ago · 38 km deep · 91 km away
  11. 1.69 km ESE of East Foothills, California · 16582 days ago · 8 km deep · 50 km away
  12. 2.29 km ESE of East Foothills, California · 16582 days ago · 8 km deep · 50 km away
  13. 1.78 km W of Gilroy, California · 16580 days ago · 7 km deep · 89 km away
  14. 2.03 km SW of Broadmoor, California · 16578 days ago · 7 km deep · 62 km away
  15. 1.66 km WSW of Pescadero, California · 16578 days ago · 6 km deep · 85 km away
  16. 1.58 km NE of Gilroy, California · 16577 days ago · 3 km deep · 88 km away
  17. 1.7Northern California · 16575 days ago · 9 km deep · 85 km away
  18. 2.714 km E of East Foothills, California · 16573 days ago · 6 km deep · 51 km away
  19. 1.89 km ENE of Gilroy, California · 16572 days ago · 8 km deep · 91 km away
  20. 2.420 km SW of Diablo Grande, California · 16572 days ago · 72 km deep · 64 km away
  21. 1.79 km E of Gilroy, California · 16571 days ago · 8 km deep · 92 km away
  22. 2.82 km ENE of San Leandro, California · 16570 days ago · 11 km deep · 28 km away
  23. 1.70 km NNW of Concord, California · 16570 days ago · 13 km deep · 28 km away
  24. 1.611 km ESE of East Foothills, California · 16569 days ago · 7 km deep · 53 km away
  25. 2.29 km ENE of Gilroy, California · 16568 days ago · 9 km deep · 90 km away
  26. 1.611 km E of Blackhawk, California · 16566 days ago · 11 km deep · 5 km away
  27. 1.63 km NNE of Union City, California · 16566 days ago · 7 km deep · 25 km away
  28. 1.913 km N of Morgan Hill, California · 16566 days ago · 3 km deep · 63 km away
  29. 1.910 km SW of Brentwood, California · 16566 days ago · 19 km deep · 8 km away
  30. 1.710 km SSW of Brentwood, California · 16566 days ago · 21 km deep · 8 km away
  31. 1.811 km SW of Brentwood, California · 16565 days ago · 20 km deep · 7 km away
  32. 2.110 km ESE of East Foothills, California · 16565 days ago · 7 km deep · 51 km away
  33. 3.011 km ESE of Gilroy, California · 16564 days ago · 6 km deep · 98 km away
  34. 3.00 km ESE of North Gate, California · 16563 days ago · 12 km deep · 19 km away
  35. 1.815 km E of Seven Trees, California · 16563 days ago · 5 km deep · 58 km away
  36. 1.511 km ESE of Gilroy, California · 16563 days ago · 5 km deep · 98 km away
  37. 1.512 km E of Angwin, California · 16562 days ago · 5 km deep · 98 km away
  38. 2.011 km ESE of Gilroy, California · 16561 days ago · 5 km deep · 98 km away
  39. 1.60 km W of Broadmoor, California · 16561 days ago · 11 km deep · 61 km away
  40. 1.81 km NW of Emerald Lake Hills, California · 16560 days ago · 3 km deep · 54 km away
  41. 2.59 km NE of Gilroy, California · 16558 days ago · 9 km deep · 85 km away
  42. 2.55 km SW of Gilroy, California · 16558 days ago · 8 km deep · 94 km away
  43. 1.83 km E of Union City, California · 16557 days ago · 7 km deep · 27 km away
  44. 1.815 km SE of Livermore, California · 16556 days ago · 2 km deep · 29 km away
  45. 2.78 km NNE of East Foothills, California · 16555 days ago · 7 km deep · 39 km away
  46. 1.50 km SE of North Gate, California · 16555 days ago · 10 km deep · 19 km away
  47. 1.79 km NE of Gilroy, California · 16555 days ago · 8 km deep · 87 km away
  48. 1.99 km ENE of Gilroy, California · 16555 days ago · 8 km deep · 91 km away
  49. 2.26 km ENE of East Foothills, California · 16555 days ago · 9 km deep · 45 km away
  50. 1.66 km ENE of East Foothills, California · 16555 days ago · 9 km deep · 45 km away
  51. 2.46 km NE of East Foothills, California · 16554 days ago · 7 km deep · 43 km away
  52. 2.45 km S of Gilroy, California · 16554 days ago · 7 km deep · 96 km away
  53. 1.94 km SSW of Lagunitas-Forest Knolls, California · 16553 days ago · 0 km deep · 80 km away
  54. 2.211 km SW of Brentwood, California · 16551 days ago · 19 km deep · 7 km away
  55. 1.611 km ESE of East Foothills, California · 16551 days ago · 7 km deep · 52 km away
  56. 1.810 km SW of Brentwood, California · 16550 days ago · 15 km deep · 7 km away
  57. 1.55 km E of Fremont, California · 16550 days ago · 8 km deep · 29 km away
  58. 1.63 km NE of Day Valley, California · 16549 days ago · 3 km deep · 82 km away
  59. 1.64 km SSE of Fairview, California · 16549 days ago · 3 km deep · 26 km away
  60. 2.315 km SE of Livermore, California · 16547 days ago · 2 km deep · 29 km away

The first 60 of 80.

Before

  1. 1.713 km N of Hollister, California · 16594 days ago · 7 km deep · 100 km away
  2. 1.822 km SE of Livermore, California · 16597 days ago · 2 km deep · 35 km away
  3. 1.65 km ENE of San Martin, California · 16597 days ago · 3 km deep · 81 km away
  4. 1.610 km E of Gilroy, California · 16598 days ago · 8 km deep · 94 km away
  5. 1.60 km W of Moskowite Corner, California · 16599 days ago · 16 km deep · 79 km away
  6. 1.814 km E of Seven Trees, California · 16600 days ago · 1 km deep · 57 km away
  7. 3.410 km NNE of Livermore, California · 16600 days ago · 13 km deep · 8 km away
  8. 1.74 km NE of Blackhawk, California · 16601 days ago · 5 km deep · 7 km away
  9. 1.912 km N of Livermore, California · 16604 days ago · 10 km deep · 6 km away
  10. 1.53 km NNE of Pleasanton, California · 16605 days ago · 14 km deep · 12 km away
  11. 1.53 km WSW of Campbell, California · 16605 days ago · 4 km deep · 60 km away
  12. 1.58 km E of East Foothills, California · 16605 days ago · 8 km deep · 49 km away
  13. 1.74 km W of Westley, California · 16606 days ago · 8 km deep · 58 km away
  14. 1.59 km NE of Gilroy, California · 16607 days ago · 8 km deep · 86 km away
  15. 1.616 km SSE of Livermore, California · 16607 days ago · -1 km deep · 30 km away
  16. 1.62 km NW of Bonny Doon, California · 16608 days ago · 12 km deep · 88 km away
  17. 1.96 km S of Sunol, California · 16609 days ago · 9 km deep · 30 km away
  18. 1.68 km NE of San Martin, California · 16610 days ago · 6 km deep · 78 km away
  19. 2.112 km NNW of Hollister, California · 16612 days ago · 4 km deep · 99 km away
  20. 1.515 km SSE of Livermore, California · 16614 days ago · 2 km deep · 29 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1062773. Read Tue, Sep 22, 2026, 10:27 PM UTC.