M1.8 earthquake 8 km WSW of Cobb, California

Magnitude

1.8 (Md, duration), micro

Magnitude from

Northern California Seismic System

Local time

Fri, Aug 27, 1976, 6:27 PM PDT

UTC

1976-08-28 01:27:09 UTC

Depth

4.0 km (2.5 mi), shallow

Epicenter

38.798° N, 122.810° W

Region

California

Tsunami flag

No

Status

Reviewed by a seismologist

Location uncertainty

About 0.2 km horizontally, 0.4 km in depth

Magnitude uncertainty

±0.12

Depth from

From location

Station coverage gap

52°

Stations used

22

• Cobb, CaliforniaPopulation 1,778. Forecast8 kmWSW
• Healdsburg, CaliforniaPopulation 11,742. Forecast21 kmNNE
• Santa Rosa, CaliforniaPopulation 178,127. Forecast41 kmNNW
• Los Angeles, CaliforniaPopulation 3,820,914. Forecast667 kmNW

After

1. 1.81 km S of Sea Ranch, CaliforniaSat, Aug 28, 6:15 AM PDT · 18299 days ago · 1 km deep · 57 km away
2. 1.76 km WSW of Cobb, CaliforniaSun, Aug 29, 12:07 PM PDT · 18297 days ago · 1 km deep · 2 km away
3. 2.417 km W of Stonyford, CaliforniaSun, Aug 29, 5:59 PM PDT · 18297 days ago · 11 km deep · 62 km away
4. 1.59 km W of Cobb, CaliforniaMon, Aug 30, 12:20 AM PDT · 18297 days ago · 0 km deep · 2 km away
5. 1.6Northern CaliforniaMon, Aug 30, 8:50 PM PDT · 18296 days ago · 3 km deep · 3 km away
6. 1.96 km WSW of Cobb, CaliforniaMon, Aug 30, 9:21 PM PDT · 18296 days ago · -1 km deep · 2 km away
7. 2.421 km NNE of Upper Lake, CaliforniaTue, Aug 31, 10:03 PM PDT · 18295 days ago · 4 km deep · 62 km away
8. 1.93 km E of Larkfield-Wikiup, CaliforniaWed, Sep 1, 3:28 AM PDT · 18295 days ago · 8 km deep · 33 km away
9. 2.112 km NNE of Angwin, CaliforniaFri, Sep 3, 12:26 PM PDT · 18292 days ago · 11 km deep · 41 km away
10. 2.720 km WSW of Stonyford, CaliforniaSat, Sep 4, 3:52 AM PDT · 18292 days ago · 12 km deep · 57 km away
11. 1.79 km WNW of Cobb, CaliforniaSat, Sep 4, 6:22 PM PDT · 18291 days ago · -1 km deep · 8 km away
12. 2.02 km ENE of Clear Lake Riviera, CaliforniaSat, Sep 4, 8:36 PM PDT · 18291 days ago · 4 km deep · 21 km away
13. 1.84 km WNW of Clearlake, CaliforniaSat, Sep 4, 8:36 PM PDT · 18291 days ago · 6 km deep · 22 km away
14. 1.72 km ESE of Clear Lake Riviera, CaliforniaSat, Sep 4, 8:39 PM PDT · 18291 days ago · 7 km deep · 19 km away
15. 1.82 km NE of Clear Lake Riviera, CaliforniaSat, Sep 4, 8:41 PM PDT · 18291 days ago · 3 km deep · 21 km away
16. 1.93 km NE of Clear Lake Riviera, CaliforniaSun, Sep 5, 12:31 AM PDT · 18291 days ago · 3 km deep · 22 km away
17. 1.62 km ENE of Clear Lake Riviera, CaliforniaSun, Sep 5, 12:40 AM PDT · 18291 days ago · 4 km deep · 21 km away
18. 1.62 km NE of Clear Lake Riviera, CaliforniaSun, Sep 5, 2:03 AM PDT · 18291 days ago · 3 km deep · 21 km away
19. 1.72 km ENE of Clear Lake Riviera, CaliforniaSun, Sep 5, 3:09 AM PDT · 18291 days ago · 4 km deep · 21 km away
20. 2.58 km E of Larkfield-Wikiup, CaliforniaSun, Sep 5, 7:30 AM PDT · 18291 days ago · 4 km deep · 34 km away
21. 1.72 km ESE of Clear Lake Riviera, CaliforniaWed, Sep 8, 2:37 AM PDT · 18288 days ago · 1 km deep · 20 km away
22. 1.54 km WSW of Cobb, CaliforniaWed, Sep 8, 9:02 PM PDT · 18287 days ago · 4 km deep · 3 km away
23. 2.84 km SW of Green Valley, CaliforniaThu, Sep 9, 4:42 AM PDT · 18287 days ago · 7 km deep · 84 km away
24. 1.77 km WSW of Cobb, CaliforniaSat, Sep 11, 1:56 PM PDT · 18284 days ago · 2 km deep · 1 km away
25. 2.14 km WSW of Cobb, CaliforniaSat, Sep 11, 4:13 PM PDT · 18284 days ago · -1 km deep · 3 km away
26. 1.96 km E of Santa Rosa, CaliforniaSat, Sep 11, 4:15 PM PDT · 18284 days ago · 10 km deep · 44 km away
27. 2.07 km WSW of Cobb, CaliforniaSat, Sep 11, 9:51 PM PDT · 18284 days ago · 1 km deep · 1 km away
28. 1.73 km NNW of Clear Lake Riviera, CaliforniaSun, Sep 12, 7:08 AM PDT · 18284 days ago · 2 km deep · 22 km away
29. 2.013 km NNE of Angwin, CaliforniaMon, Sep 13, 11:11 PM PDT · 18282 days ago · 12 km deep · 40 km away
30. 2.311 km E of Potter Valley, CaliforniaTue, Sep 14, 4:40 AM PDT · 18282 days ago · 3 km deep · 61 km away
31. 2.95 km NE of Santa Rosa, CaliforniaWed, Sep 15, 11:04 AM PDT · 18281 days ago · 8 km deep · 37 km away
32. 1.78 km W of Cobb, CaliforniaWed, Sep 15, 5:03 PM PDT · 18280 days ago · 0 km deep · 2 km away
33. 3.032 km NNE of Potter Valley, CaliforniaFri, Sep 17, 4:09 AM PDT · 18279 days ago · 15 km deep · 86 km away
34. 2.114 km SE of Sea Ranch, CaliforniaSun, Sep 19, 3:41 AM PDT · 18277 days ago · 7 km deep · 52 km away
35. 1.66 km W of Cobb, CaliforniaMon, Sep 20, 2:51 AM PDT · 18276 days ago · -1 km deep · 2 km away
36. 1.96 km W of Cobb, CaliforniaMon, Sep 20, 11:05 PM PDT · 18275 days ago · 4 km deep · 2 km away
37. 1.67 km W of Cobb, CaliforniaTue, Sep 21, 12:12 PM PDT · 18274 days ago · 0 km deep · 3 km away
38. 2.46 km W of Cobb, CaliforniaWed, Sep 22, 4:23 PM PDT · 18273 days ago · 3 km deep · 2 km away
39. 2.56 km NNE of Penngrove, CaliforniaFri, Sep 24, 2:24 AM PDT · 18272 days ago · 7 km deep · 52 km away
40. 2.24 km SW of Cobb, CaliforniaSat, Sep 25, 10:45 PM PDT · 18270 days ago · 0 km deep · 4 km away
41. 1.67 km WSW of Cobb, CaliforniaSun, Sep 26, 8:31 AM PDT · 18270 days ago · 3 km deep · 1 km away
42. 1.68 km W of Cobb, CaliforniaSun, Sep 26, 5:18 PM PDT · 18269 days ago · -1 km deep · 2 km away
43. 1.94 km WSW of Cobb, CaliforniaSun, Sep 26, 7:00 PM PDT · 18269 days ago · 2 km deep · 4 km away
44. 1.57 km WSW of Cobb, CaliforniaSun, Sep 26, 11:14 PM PDT · 18269 days ago · 2 km deep · 1 km away
45. 1.87 km W of Cobb, CaliforniaMon, Sep 27, 10:02 PM PDT · 18268 days ago · 3 km deep · 1 km away
46. 2.318 km WSW of Stonyford, CaliforniaMon, Sep 27, 10:51 PM PDT · 18268 days ago · 11 km deep · 59 km away
47. 1.56 km W of Cobb, CaliforniaTue, Sep 28, 8:00 AM PDT · 18268 days ago · 3 km deep · 3 km away
48. 1.610 km WSW of Cobb, CaliforniaTue, Sep 28, 1:38 PM PDT · 18267 days ago · 3 km deep · 3 km away
49. 2.33 km NE of Santa Rosa, CaliforniaWed, Sep 29, 10:21 AM PDT · 18267 days ago · 9 km deep · 39 km away
50. 1.95 km WSW of Cobb, CaliforniaWed, Sep 29, 11:52 PM PDT · 18266 days ago · 0 km deep · 2 km away
51. 1.96 km WSW of Cobb, CaliforniaSat, Oct 2, 10:30 AM PDT · 18264 days ago · 1 km deep · 2 km away
52. 2.118 km SW of Stonyford, CaliforniaSun, Oct 3, 2:34 PM PDT · 18262 days ago · 9 km deep · 52 km away
53. 1.84 km WSW of Cobb, CaliforniaSun, Oct 3, 6:42 PM PDT · 18262 days ago · 1 km deep · 4 km away
54. 1.84 km WSW of Cobb, CaliforniaSun, Oct 3, 6:42 PM PDT · 18262 days ago · 1 km deep · 4 km away
55. 2.08 km W of Cobb, CaliforniaSun, Oct 3, 7:17 PM PDT · 18262 days ago · 0 km deep · 2 km away
56. 1.76 km W of Cobb, CaliforniaSun, Oct 3, 7:46 PM PDT · 18262 days ago · 3 km deep · 3 km away
57. 1.64 km WSW of Cobb, CaliforniaMon, Oct 4, 10:22 PM PDT · 18261 days ago · 1 km deep · 4 km away
58. 1.71 km NE of Clear Lake Riviera, CaliforniaTue, Oct 5, 10:49 AM PDT · 18261 days ago · 0 km deep · 21 km away
59. 2.38 km W of Healdsburg, CaliforniaWed, Oct 6, 3:48 PM PDT · 18259 days ago · 0 km deep · 24 km away
60. 1.77 km W of Cobb, CaliforniaWed, Oct 6, 5:14 PM PDT · 18259 days ago · -1 km deep · 1 km away

The first 60 of 82.

Before

1. 2.49 km E of Hidden Valley Lake, CaliforniaThu, Aug 26, 10:56 PM PDT · 18300 days ago · 8 km deep · 32 km away
2. 1.85 km WSW of Cobb, CaliforniaThu, Aug 26, 2:10 PM PDT · 18300 days ago · 0 km deep · 2 km away
3. 1.610 km N of Cloverdale, CaliforniaThu, Aug 26, 6:50 AM PDT · 18301 days ago · 3 km deep · 21 km away
4. 1.57 km WSW of Cobb, CaliforniaWed, Aug 25, 8:21 AM PDT · 18302 days ago · 1 km deep · 0 km away
5. 2.49 km W of Cobb, CaliforniaWed, Aug 25, 8:13 AM PDT · 18302 days ago · 0 km deep · 2 km away
6. 1.74 km WSW of Cobb, CaliforniaTue, Aug 24, 9:57 AM PDT · 18303 days ago · 2 km deep · 4 km away
7. 1.68 km WSW of Cobb, CaliforniaTue, Aug 24, 8:35 AM PDT · 18303 days ago · -1 km deep · 1 km away
8. 1.88 km WSW of Cobb, CaliforniaTue, Aug 24, 8:35 AM PDT · 18303 days ago · 0 km deep · 1 km away
9. 2.27 km WSW of Cobb, CaliforniaSat, Aug 21, 8:37 PM PDT · 18305 days ago · 1 km deep · 0 km away
10. 1.54 km ENE of Clear Lake Riviera, CaliforniaSat, Aug 21, 7:42 AM PDT · 18306 days ago · 3 km deep · 22 km away
11. 1.58 km WSW of Cobb, CaliforniaSat, Aug 21, 1:33 AM PDT · 18306 days ago · 4 km deep · 0 km away
12. 1.66 km W of Cobb, CaliforniaFri, Aug 20, 3:45 PM PDT · 18306 days ago · 2 km deep · 2 km away
13. 1.53 km SSE of Lower Lake, CaliforniaFri, Aug 20, 2:22 PM PDT · 18306 days ago · 6 km deep · 20 km away
14. 1.67 km W of Cobb, CaliforniaFri, Aug 20, 11:59 AM PDT · 18306 days ago · 1 km deep · 2 km away
15. 1.61 km SE of Clear Lake Riviera, CaliforniaFri, Aug 20, 11:33 AM PDT · 18306 days ago · 0 km deep · 19 km away
16. 1.66 km W of Cobb, CaliforniaFri, Aug 20, 7:28 AM PDT · 18307 days ago · 3 km deep · 3 km away
17. 1.77 km WSW of Cobb, CaliforniaWed, Aug 18, 7:13 PM PDT · 18308 days ago · 0 km deep · 1 km away
18. 1.88 km WSW of Cobb, CaliforniaWed, Aug 18, 4:30 PM PDT · 18308 days ago · 0 km deep · 1 km away
19. 3.02 km ESE of Clear Lake Riviera, CaliforniaMon, Aug 16, 3:48 PM PDT · 18310 days ago · 1 km deep · 19 km away
20. 2.23 km ESE of Clear Lake Riviera, CaliforniaMon, Aug 16, 3:09 PM PDT · 18310 days ago · 2 km deep · 19 km away

From the USGS Earthquake Hazards Program and its partner networks, event nc1031225. Read Sun, Oct 4, 2026, 5:49 AM UTC.