California earthquakes

M1.7 earthquake 7 km W of Cobb, California

A magnitude 1.7 earthquake struck 7 km W of Cobb, California on Mon, Mar 28, 1977, 2:43 PM PST (22:43 UTC), 1 km (0 mi) below the surface.

A larger quake followed: M3.0 26 km N of Potter Valley, California. This one was a foreshock.

Cobb 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, duration), micro
Magnitude from
Northern California Seismic System
Local time
UTC
1977-03-28 22:43:18 UTC
Depth
0.6 km (0.4 mi), shallow
Epicenter
38.823° N, 122.813° 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, 0.5 km in depth
Magnitude uncertainty
±0.17
Depth from
From location
Station coverage gap
84°
Stations used
14

Nearest places

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

Nearby

Within 100 km, magnitude 1.5 and up: 24 in the 60 days after this one and 43 in the 30 days before it.

After

  1. 2.13 km ENE of Windsor, California · 18085 days ago · 5 km deep · 29 km away
  2. 1.87 km ESE of Geyserville, California · 18085 days ago · 6 km deep · 16 km away
  3. 2.58 km W of Cobb, California · 18084 days ago · 0 km deep · 2 km away
  4. 3.026 km N of Potter Valley, California · 18080 days ago · 11 km deep · 85 km away
  5. 1.86 km W of Cobb, California · 18079 days ago · 3 km deep · 1 km away
  6. 1.66 km W of Cobb, California · 18076 days ago · 3 km deep · 1 km away
  7. 1.97 km WSW of Kenwood, California · 18074 days ago · 9 km deep · 51 km away
  8. 2.07 km WSW of Kenwood, California · 18074 days ago · 10 km deep · 51 km away
  9. 1.74 km WSW of Cobb, California · 18074 days ago · 3 km deep · 4 km away
  10. 2.37 km WSW of Cobb, California · 18073 days ago · -1 km deep · 2 km away
  11. 1.78 km WSW of Cobb, California · 18071 days ago · 3 km deep · 3 km away
  12. 2.38 km ESE of Hopland, California · 18069 days ago · 7 km deep · 22 km away
  13. 2.04 km WNW of Cobb, California · 18066 days ago · 3 km deep · 3 km away
  14. 1.53 km N of Healdsburg, California · 18064 days ago · 5 km deep · 21 km away
  15. 1.93 km ESE of Hopland, California · 18059 days ago · 5 km deep · 27 km away
  16. 2.56 km W of Cobb, California · 18057 days ago · 4 km deep · 2 km away
  17. 1.94 km WSW of Cobb, California · 18056 days ago · 2 km deep · 4 km away
  18. 1.64 km WSW of Cobb, California · 18052 days ago · 1 km deep · 4 km away
  19. 1.62 km SE of Clear Lake Riviera, California · 18051 days ago · 1 km deep · 16 km away
  20. 1.84 km WSW of Cobb, California · 18050 days ago · 1 km deep · 4 km away
  21. 1.61 km NNW of Geyserville, California · 18046 days ago · 5 km deep · 14 km away
  22. 1.68 km WSW of Cobb, California · 18037 days ago · 3 km deep · 2 km away
  23. 1.99 km S of Calistoga, California · 18027 days ago · 7 km deep · 42 km away
  24. 1.919 km NE of Upper Lake, California · 18026 days ago · 12 km deep · 54 km away

Before

  1. 1.54 km WSW of Cobb, California · 18085 days ago · 1 km deep · 5 km away
  2. 2.42 km ESE of Princeton, California · 18086 days ago · 22 km deep · 95 km away
  3. 2.32 km ESE of Boonville, California · 18086 days ago · 8 km deep · 50 km away
  4. 2.95 km NNE of Penngrove, California · 18087 days ago · 7 km deep · 55 km away
  5. 3.33 km W of Moskowite Corner, California · 18087 days ago · 7 km deep · 66 km away
  6. 2.22 km ENE of Calpella, California · 18088 days ago · 5 km deep · 56 km away
  7. 1.68 km WSW of Cobb, California · 18089 days ago · 3 km deep · 2 km away
  8. 2.26 km S of Moskowite Corner, California · 18090 days ago · 12 km deep · 72 km away
  9. 2.46 km W of Cobb, California · 18090 days ago · 3 km deep · 1 km away
  10. 2.421 km NNE of Upper Lake, California · 18090 days ago · 8 km deep · 58 km away
  11. 2.06 km S of Calistoga, California · 18091 days ago · 5 km deep · 39 km away
  12. 2.18 km WSW of Cobb, California · 18091 days ago · 4 km deep · 3 km away
  13. 1.75 km WSW of Cobb, California · 18092 days ago · 4 km deep · 3 km away
  14. 1.86 km W of Cobb, California · 18093 days ago · 3 km deep · 1 km away
  15. 1.96 km W of Cobb, California · 18093 days ago · 2 km deep · 2 km away
  16. 2.40 km WSW of Larkfield-Wikiup, California · 18095 days ago · 2 km deep · 35 km away
  17. 2.721 km NNE of Upper Lake, California · 18095 days ago · 10 km deep · 56 km away
  18. 1.96 km W of Cobb, California · 18095 days ago · 3 km deep · 1 km away
  19. 1.98 km W of Saint Helena, California · 18095 days ago · 7 km deep · 42 km away
  20. 1.84 km WSW of Cobb, California · 18098 days ago · 1 km deep · 4 km away

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Sources

From the USGS Earthquake Hazards Program and its partner networks, event nc1034573. Read Sat, Oct 3, 2026, 1:56 AM UTC.