M4.2 earthquake 132 km WSW of Adak, Alaska
A magnitude 4.2 earthquake struck 132 km WSW of Adak, Alaska on Fri, Aug 20, 1976, 4:29 PM GMT-10 (02:29 UTC), 57 km (35 mi) below the surface.
A larger quake followed: M5.0 107 km SW of Adak, Alaska. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 4.2 (mb), light
- Local time
- UTC
- 1976-08-21 02:29:58 UTC
- Depth
- 57.0 km (35.4 mi), shallow
- Epicenter
- 51.558° N, 178.485° W
- Region
- Alaska
- 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.
- Stations used
- 11
Nearby
Within 100 km, magnitude 1.5 and up: 3 in the 60 days after this one and 3 in the 30 days before it.
After
- 5.0107 km SW of Adak, Alaska · 18287 days ago · 39 km deep · 62 km away
- 4.4157 km WSW of Adak, Alaska · 18279 days ago · 68 km deep · 27 km away
- 4.9219 km W of Adak, Alaska · 18274 days ago · 100 km deep · 99 km away
Before
Earthquakes todayAlaska earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp0000hza. Read Tue, Sep 22, 2026, 9:44 PM UTC.