M1.5 earthquake 4 km WSW of Cobb, California

Magnitude

1.5 (Md, duration), micro

Magnitude from

Northern California Seismic System

Local time

Mon, Mar 28, 1977, 12:24 PM PST

UTC

1977-03-28 20:24:05 UTC

Depth

1.1 km (0.7 mi), shallow

Epicenter

38.801° N, 122.768° W

Region

California

Tsunami flag

No

Status

Reviewed by a seismologist

Location uncertainty

About 0.4 km horizontally, 0.5 km in depth

Magnitude uncertainty

±0.12

Depth from

From location

Station coverage gap

96°

Stations used

9

• Cobb, CaliforniaPopulation 1,778. Forecast5 kmWSW
• Clearlake, CaliforniaPopulation 15,182. Forecast21 kmSW
• Santa Rosa, CaliforniaPopulation 178,127. Forecast40 kmN
• Los Angeles, CaliforniaPopulation 3,820,914. Forecast665 kmNW

After

1. 1.77 km W of Cobb, CaliforniaMon, Mar 28, 2:43 PM PST · 18085 days ago · 1 km deep · 5 km away
2. 2.13 km ENE of Windsor, CaliforniaMon, Mar 28, 7:18 PM PST · 18085 days ago · 5 km deep · 26 km away
3. 1.87 km ESE of Geyserville, CaliforniaTue, Mar 29, 4:28 AM PST · 18084 days ago · 6 km deep · 15 km away
4. 2.58 km W of Cobb, CaliforniaTue, Mar 29, 11:14 AM PST · 18084 days ago · 0 km deep · 5 km away
5. 3.026 km N of Potter Valley, CaliforniaSun, Apr 3, 2:20 AM PST · 18079 days ago · 11 km deep · 89 km away
6. 1.86 km W of Cobb, CaliforniaSun, Apr 3, 7:22 AM PST · 18079 days ago · 3 km deep · 4 km away
7. 1.66 km W of Cobb, CaliforniaWed, Apr 6, 8:40 AM PST · 18076 days ago · 3 km deep · 4 km away
8. 1.97 km WSW of Kenwood, CaliforniaFri, Apr 8, 7:33 AM PST · 18074 days ago · 9 km deep · 47 km away
9. 2.07 km WSW of Kenwood, CaliforniaFri, Apr 8, 8:27 AM PST · 18074 days ago · 10 km deep · 47 km away
10. 1.74 km WSW of Cobb, CaliforniaFri, Apr 8, 10:48 PM PST · 18074 days ago · 3 km deep · 1 km away
11. 2.37 km WSW of Cobb, CaliforniaSat, Apr 9, 2:08 PM PST · 18073 days ago · -1 km deep · 3 km away
12. 1.78 km WSW of Cobb, CaliforniaMon, Apr 11, 6:50 AM PST · 18071 days ago · 3 km deep · 4 km away
13. 2.38 km ESE of Hopland, CaliforniaWed, Apr 13, 9:08 AM PST · 18069 days ago · 7 km deep · 27 km away
14. 2.04 km WNW of Cobb, CaliforniaSat, Apr 16, 2:37 PM PST · 18066 days ago · 3 km deep · 3 km away
15. 1.53 km N of Healdsburg, CaliforniaMon, Apr 18, 7:32 PM PST · 18064 days ago · 5 km deep · 20 km away
16. 1.93 km ESE of Hopland, CaliforniaSat, Apr 23, 7:37 PM PST · 18059 days ago · 5 km deep · 32 km away
17. 2.56 km W of Cobb, CaliforniaMon, Apr 25, 7:25 PM PDT · 18057 days ago · 4 km deep · 3 km away
18. 1.94 km WSW of Cobb, CaliforniaTue, Apr 26, 7:35 AM PDT · 18056 days ago · 2 km deep · 1 km away
19. 1.94 km S of Crockett, CaliforniaSat, Apr 30, 10:31 PM PDT · 18052 days ago · 9 km deep · 100 km away
20. 1.64 km WSW of Cobb, CaliforniaSat, Apr 30, 11:09 PM PDT · 18052 days ago · 1 km deep · 1 km away
21. 1.62 km SE of Clear Lake Riviera, CaliforniaMon, May 2, 1:08 AM PDT · 18051 days ago · 1 km deep · 17 km away
22. 1.84 km WSW of Cobb, CaliforniaMon, May 2, 11:23 AM PDT · 18050 days ago · 1 km deep · 1 km away
23. 1.61 km NNW of Geyserville, CaliforniaFri, May 6, 6:55 PM PDT · 18046 days ago · 5 km deep · 15 km away
24. 1.68 km WSW of Cobb, CaliforniaMon, May 16, 2:42 AM PDT · 18037 days ago · 3 km deep · 4 km away
25. 1.99 km S of Calistoga, CaliforniaWed, May 25, 9:09 AM PDT · 18027 days ago · 7 km deep · 38 km away
26. 1.919 km NE of Upper Lake, CaliforniaFri, May 27, 5:22 AM PDT · 18025 days ago · 12 km deep · 56 km away

Before

1. 2.42 km ESE of Princeton, CaliforniaSun, Mar 27, 7:49 PM PST · 18086 days ago · 22 km deep · 94 km away
2. 2.32 km ESE of Boonville, CaliforniaSun, Mar 27, 11:01 AM PST · 18086 days ago · 8 km deep · 54 km away
3. 2.95 km NNE of Penngrove, CaliforniaSun, Mar 27, 3:24 AM PST · 18086 days ago · 7 km deep · 52 km away
4. 3.33 km W of Moskowite Corner, CaliforniaSat, Mar 26, 11:13 AM PST · 18087 days ago · 7 km deep · 61 km away
5. 2.22 km ENE of Calpella, CaliforniaFri, Mar 25, 7:35 AM PST · 18088 days ago · 5 km deep · 60 km away
6. 1.68 km WSW of Cobb, CaliforniaThu, Mar 24, 7:23 PM PST · 18089 days ago · 3 km deep · 4 km away
7. 2.26 km S of Moskowite Corner, CaliforniaThu, Mar 24, 2:39 AM PST · 18089 days ago · 12 km deep · 68 km away
8. 2.46 km W of Cobb, CaliforniaWed, Mar 23, 1:10 PM PST · 18090 days ago · 3 km deep · 4 km away
9. 2.421 km NNE of Upper Lake, CaliforniaWed, Mar 23, 12:39 PM PST · 18090 days ago · 8 km deep · 61 km away
10. 2.06 km S of Calistoga, CaliforniaTue, Mar 22, 11:05 PM PST · 18091 days ago · 5 km deep · 35 km away
11. 2.18 km WSW of Cobb, CaliforniaTue, Mar 22, 5:06 PM PST · 18091 days ago · 4 km deep · 4 km away
12. 1.75 km WSW of Cobb, CaliforniaMon, Mar 21, 2:39 PM PST · 18092 days ago · 4 km deep · 2 km away
13. 1.86 km W of Cobb, CaliforniaMon, Mar 21, 1:48 AM PST · 18093 days ago · 3 km deep · 3 km away
14. 1.96 km W of Cobb, CaliforniaSun, Mar 20, 11:46 PM PST · 18093 days ago · 2 km deep · 3 km away
15. 2.40 km WSW of Larkfield-Wikiup, CaliforniaSat, Mar 19, 6:16 AM PST · 18094 days ago · 2 km deep · 32 km away
16. 2.721 km NNE of Upper Lake, CaliforniaSat, Mar 19, 4:37 AM PST · 18094 days ago · 10 km deep · 58 km away
17. 1.96 km W of Cobb, CaliforniaFri, Mar 18, 9:14 AM PST · 18095 days ago · 3 km deep · 3 km away
18. 1.98 km W of Saint Helena, CaliforniaFri, Mar 18, 7:18 AM PST · 18095 days ago · 7 km deep · 38 km away
19. 1.84 km WSW of Cobb, CaliforniaTue, Mar 15, 5:11 PM PST · 18098 days ago · 1 km deep · 0 km away
20. 1.74 km WSW of Cobb, CaliforniaTue, Mar 15, 4:58 PM PST · 18098 days ago · 1 km deep · 1 km away

From the USGS Earthquake Hazards Program and its partner networks, event nc1034572. Read Fri, Oct 2, 2026, 9:26 PM UTC.