M1.5 earthquake 9 km WSW of Cobb, California

Magnitude

1.5 (md), micro

Local time

Tue, Dec 20, 1983, 7:04 AM PST

UTC

1983-12-20 15:04:07 UTC

Depth

1.4 km (0.8 mi), shallow

Epicenter

38.797° N, 122.824° W

Region

California

Tsunami flag

No

Status

Reviewed by a seismologist

Location uncertainty

About 0.3 km horizontally, 0.5 km in depth

Magnitude uncertainty

±0.28

Depth from

From location

Station coverage gap

90°

Stations used

13

• Cobb, CaliforniaPopulation 1,778. Forecast9 kmWSW
• Healdsburg, CaliforniaPopulation 11,742. Forecast21 kmN
• Santa Rosa, CaliforniaPopulation 178,127. Forecast41 kmNNW
• Los Angeles, CaliforniaPopulation 3,820,914. Forecast668 kmNW

After

1. 3.17 km W of Cobb, CaliforniaTue, Dec 20, 11:37 AM PST · 15625 days ago · 1 km deep · 2 km away
2. 1.76 km W of Cobb, CaliforniaTue, Dec 20, 5:56 PM PST · 15625 days ago · 3 km deep · 3 km away
3. 2.928 km WNW of Stonyford, CaliforniaWed, Dec 21, 4:16 AM PST · 15624 days ago · 4 km deep · 76 km away
4. 1.625 km NNE of Potter Valley, CaliforniaWed, Dec 21, 4:25 AM PST · 15624 days ago · 5 km deep · 83 km away
5. 1.66 km W of Cobb, CaliforniaWed, Dec 21, 4:34 AM PST · 15624 days ago · 3 km deep · 4 km away
6. 1.54 km NW of Redwood Valley, CaliforniaThu, Dec 22, 3:52 PM PST · 15623 days ago · 7 km deep · 66 km away
7. 1.84 km S of Cobb, CaliforniaThu, Dec 22, 7:28 PM PST · 15623 days ago · 1 km deep · 8 km away
8. 1.711 km NE of Healdsburg, CaliforniaFri, Dec 23, 1:31 AM PST · 15623 days ago · 5 km deep · 15 km away
9. 1.56 km W of Cobb, CaliforniaFri, Dec 23, 5:54 AM PST · 15622 days ago · 3 km deep · 4 km away
10. 2.47 km W of Cobb, CaliforniaFri, Dec 23, 10:24 AM PST · 15622 days ago · 2 km deep · 3 km away
11. 2.25 km WSW of Cobb, CaliforniaFri, Dec 23, 12:57 PM PST · 15622 days ago · 0 km deep · 3 km away
12. 2.36 km WSW of Cobb, CaliforniaFri, Dec 23, 12:58 PM PST · 15622 days ago · 0 km deep · 3 km away
13. 1.97 km WSW of Cobb, CaliforniaSat, Dec 24, 1:12 AM PST · 15622 days ago · 0 km deep · 2 km away
14. 2.26 km W of Cobb, CaliforniaSat, Dec 24, 4:32 PM PST · 15621 days ago · 3 km deep · 3 km away
15. 1.58 km WSW of Cobb, CaliforniaSun, Dec 25, 11:00 AM PST · 15620 days ago · 3 km deep · 1 km away
16. 1.56 km WSW of Cobb, CaliforniaSun, Dec 25, 8:56 PM PST · 15620 days ago · 1 km deep · 3 km away
17. 1.66 km W of Cobb, CaliforniaMon, Dec 26, 1:12 PM PST · 15619 days ago · 3 km deep · 4 km away
18. 2.26 km W of Cobb, CaliforniaTue, Dec 27, 9:21 AM PST · 15618 days ago · 3 km deep · 3 km away
19. 1.88 km WSW of Cobb, CaliforniaTue, Dec 27, 10:34 AM PST · 15618 days ago · 1 km deep · 1 km away
20. 1.66 km WSW of Cobb, CaliforniaTue, Dec 27, 10:49 AM PST · 15618 days ago · 4 km deep · 3 km away
21. 2.37 km W of Cobb, CaliforniaTue, Dec 27, 11:57 AM PST · 15618 days ago · 0 km deep · 4 km away
22. 1.77 km W of Cobb, CaliforniaTue, Dec 27, 2:38 PM PST · 15618 days ago · 1 km deep · 4 km away
23. 2.013 km WSW of Esparto, CaliforniaTue, Dec 27, 8:57 PM PST · 15618 days ago · 8 km deep · 61 km away
24. 2.47 km WSW of Cobb, CaliforniaWed, Dec 28, 6:04 AM PST · 15617 days ago · 1 km deep · 2 km away
25. 2.16 km S of Clear Lake Riviera, CaliforniaWed, Dec 28, 7:18 AM PST · 15617 days ago · -1 km deep · 14 km away
26. 1.75 km WSW of Cobb, CaliforniaWed, Dec 28, 8:40 AM PST · 15617 days ago · -1 km deep · 4 km away
27. 2.57 km W of Cobb, CaliforniaWed, Dec 28, 3:58 PM PST · 15617 days ago · 2 km deep · 2 km away
28. 1.712 km N of Brooktrails, CaliforniaThu, Dec 29, 10:23 AM PST · 15616 days ago · 6 km deep · 97 km away
29. 2.16 km ENE of Willits, CaliforniaThu, Dec 29, 5:27 PM PST · 15616 days ago · 3 km deep · 80 km away
30. 1.69 km WSW of Cobb, CaliforniaFri, Dec 30, 12:36 PM PST · 15615 days ago · 2 km deep · 1 km away
31. 1.610 km SE of Boonville, CaliforniaSat, Dec 31, 12:04 AM PST · 15615 days ago · 2 km deep · 43 km away
32. 1.56 km WSW of Cobb, CaliforniaSat, Dec 31, 1:41 AM PST · 15615 days ago · 0 km deep · 3 km away
33. 2.06 km SW of Glen Ellen, CaliforniaSat, Dec 31, 11:28 AM PST · 15614 days ago · 9 km deep · 56 km away
34. 2.28 km WSW of Cobb, CaliforniaSun, Jan 1, 4:39 AM PST · 15613 days ago · 4 km deep · 1 km away
35. 1.77 km W of North Lakeport, CaliforniaSun, Jan 1, 5:27 AM PST · 15613 days ago · 12 km deep · 35 km away
36. 1.67 km WSW of Cobb, CaliforniaSun, Jan 1, 10:36 PM PST · 15613 days ago · 1 km deep · 2 km away
37. 1.86 km W of Cobb, CaliforniaMon, Jan 2, 1:53 AM PST · 15613 days ago · 3 km deep · 3 km away
38. 2.213 km NNE of Angwin, CaliforniaMon, Jan 2, 11:23 AM PST · 15612 days ago · -1 km deep · 40 km away
39. 1.56 km W of Cobb, CaliforniaTue, Jan 3, 11:43 AM PST · 15611 days ago · 3 km deep · 3 km away
40. 1.67 km WSW of Cobb, CaliforniaWed, Jan 4, 7:19 AM PST · 15610 days ago · 2 km deep · 2 km away
41. 2.56 km SW of Glen Ellen, CaliforniaWed, Jan 4, 12:16 PM PST · 15610 days ago · 7 km deep · 56 km away
42. 1.67 km W of Cobb, CaliforniaWed, Jan 4, 2:05 PM PST · 15610 days ago · 3 km deep · 3 km away
43. 2.66 km SW of Cobb, CAThu, Jan 5, 2:28 PM PST · 15609 days ago · 1 km deep · 4 km away
44. 3.07 km W of Cobb, CaliforniaThu, Jan 5, 3:33 PM PST · 15609 days ago · 3 km deep · 3 km away
45. 1.77 km W of Cobb, CaliforniaThu, Jan 5, 4:29 PM PST · 15609 days ago · 3 km deep · 2 km away
46. 1.58 km WNW of Comptche, CaliforniaThu, Jan 5, 7:45 PM PST · 15609 days ago · 1 km deep · 92 km away
47. 2.17 km W of Cobb, CaliforniaThu, Jan 5, 7:50 PM PST · 15609 days ago · 3 km deep · 3 km away
48. 1.77 km WSW of Cobb, CaliforniaFri, Jan 6, 2:49 AM PST · 15609 days ago · 0 km deep · 1 km away
49. 1.86 km W of Cobb, CaliforniaFri, Jan 6, 8:42 PM PST · 15608 days ago · 3 km deep · 4 km away
50. 2.014 km NNW of Moskowite Corner, CaliforniaSat, Jan 7, 4:23 AM PST · 15607 days ago · 2 km deep · 55 km away
51. 2.017 km ENE of Potter Valley, CaliforniaSun, Jan 8, 11:56 AM PST · 15606 days ago · 7 km deep · 65 km away
52. 1.63 km ESE of Larkfield-Wikiup, CaliforniaSun, Jan 8, 12:04 PM PST · 15606 days ago · 8 km deep · 34 km away
53. 1.77 km WSW of Cobb, CaliforniaSun, Jan 8, 3:52 PM PST · 15606 days ago · 1 km deep · 2 km away
54. 2.26 km W of Cobb, CaliforniaSun, Jan 8, 10:13 PM PST · 15606 days ago · 3 km deep · 4 km away
55. 1.65 km NW of Napa, CaliforniaMon, Jan 9, 3:51 AM PST · 15605 days ago · 11 km deep · 67 km away
56. 1.78 km W of Cobb, CaliforniaMon, Jan 9, 11:30 AM PST · 15605 days ago · 8 km deep · 3 km away
57. 1.77 km W of Cobb, CaliforniaMon, Jan 9, 11:50 AM PST · 15605 days ago · 3 km deep · 3 km away
58. 2.6Northern CaliforniaMon, Jan 9, 4:36 PM PST · 15605 days ago · -1 km deep · 1 km away
59. 1.65 km SSW of Calistoga, CaliforniaTue, Jan 10, 8:00 AM PST · 15604 days ago · 6 km deep · 34 km away
60. 1.715 km NE of Angwin, CaliforniaTue, Jan 10, 9:17 PM PST · 15604 days ago · 20 km deep · 44 km away

The first 60 of 162.

Before

1. 1.823 km ENE of Potter Valley, CaliforniaMon, Dec 19, 7:58 AM PST · 15626 days ago · 14 km deep · 67 km away
2. 1.76 km WSW of Cobb, CaliforniaMon, Dec 19, 5:11 AM PST · 15626 days ago · 3 km deep · 3 km away
3. 1.87 km WSW of Cobb, CaliforniaMon, Dec 19, 1:09 AM PST · 15627 days ago · 0 km deep · 2 km away
4. 1.83 km E of Santa Rosa, CaliforniaSun, Dec 18, 9:36 PM PST · 15627 days ago · 8 km deep · 42 km away
5. 2.06 km WSW of Cobb, CaliforniaSun, Dec 18, 3:58 PM PST · 15627 days ago · 2 km deep · 3 km away
6. 1.99 km WSW of Cobb, CaliforniaSat, Dec 17, 6:02 AM PST · 15628 days ago · 1 km deep · 0 km away
7. 1.77 km WSW of Cobb, CaliforniaFri, Dec 16, 9:03 PM PST · 15629 days ago · 1 km deep · 2 km away
8. 1.65 km SW of Cobb, CaliforniaFri, Dec 16, 3:01 PM PST · 15629 days ago · 0 km deep · 5 km away
9. 2.13 km SE of Clear Lake Riviera, CaliforniaThu, Dec 15, 4:07 AM PST · 15630 days ago · 2 km deep · 20 km away
10. 2.42 km SE of Clear Lake Riviera, CaliforniaThu, Dec 15, 2:47 AM PST · 15631 days ago · 1 km deep · 19 km away
11. 1.58 km SW of Calistoga, CaliforniaThu, Dec 15, 2:40 AM PST · 15631 days ago · 6 km deep · 35 km away
12. 2.213 km ESE of Angwin, CaliforniaThu, Dec 15, 12:08 AM PST · 15631 days ago · -1 km deep · 53 km away
13. 1.55 km WSW of Cobb, CaliforniaWed, Dec 14, 10:09 PM PST · 15631 days ago · 1 km deep · 4 km away
14. 2.08 km WSW of Cobb, CaliforniaWed, Dec 14, 5:52 PM PST · 15631 days ago · 1 km deep · 0 km away
15. 1.56 km W of Cobb, CaliforniaWed, Dec 14, 6:51 AM PST · 15631 days ago · 3 km deep · 4 km away
16. 1.79 km ESE of Hidden Valley Lake, CaliforniaTue, Dec 13, 11:02 PM PST · 15632 days ago · 6 km deep · 32 km away
17. 2.07 km WSW of Cobb, CaliforniaTue, Dec 13, 11:42 AM PST · 15632 days ago · 0 km deep · 2 km away
18. 3.17 km W of Cobb, CaliforniaTue, Dec 13, 12:39 AM PST · 15633 days ago · 0 km deep · 2 km away
19. 1.88 km NE of Willits, CaliforniaMon, Dec 12, 9:19 PM PST · 15633 days ago · 7 km deep · 83 km away
20. 1.87 km WSW of Cobb, CaliforniaMon, Dec 12, 5:20 PM PST · 15633 days ago · 1 km deep · 1 km away

From the USGS Earthquake Hazards Program and its partner networks, event nc1108764. Read Wed, Sep 30, 2026, 10:44 PM UTC.