M3.3 earthquake 33 km N of Adak, Alaska
A magnitude 3.3 earthquake struck 33 km N of Adak, Alaska on Wed, Oct 21, 1987, 5:44 AM HADT (14:44 UTC), 33 km (21 mi) below the surface.
A larger quake followed: M4.6 64 km SSE 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
- 3.3 (ml), minor
- Local time
- UTC
- 1987-10-21 14:44:38 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 52.170° N, 176.558° 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.
- Depth from
- OPERATOR_ASSIGNED
Nearby
Within 100 km, magnitude 1.5 and up: 2 in the 60 days after this one and 5 in the 30 days before it.
After
- 4.664 km SSE of Adak, Alaska · 14210 days ago · 33 km deep · 93 km away
- 4.679 km E of Adak, Alaska · 14166 days ago · 33 km deep · 80 km away
Before
- 5.388 km E of Adak, Alaska · 14222 days ago · 64 km deep · 91 km away
- 3.773 km ESE of Adak, Alaska · 14233 days ago · 33 km deep · 90 km away
- 4.963 km SSW of Adak, Alaska · 14239 days ago · 33 km deep · 96 km away
- 4.950 km ESE of Adak, Alaska · 14239 days ago · 67 km deep · 61 km away
- 5.065 km SE of Adak, Alaska · 14242 days ago · 33 km deep · 91 km away
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Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp00039fe. Read Tue, Sep 22, 2026, 5:19 AM UTC.