M4.9 earthquake 86 km S of Adak, Alaska
A magnitude 4.9 earthquake struck 86 km S of Adak, Alaska on Tue, Jun 23, 1987, 12:21 PM HADT (21:21 UTC), 33 km (21 mi) below the surface.
A larger quake followed: M5.0 97 km S 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
- 4.9 (mb), light
- Local time
- UTC
- 1987-06-23 21:21:26 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 51.099° N, 176.564° 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 1.9 and up: 7 in the 60 days after this one and 6 in the 30 days before it.
After
- 4.588 km S of Adak, Alaska · 14335 days ago · 33 km deep · 3 km away
- 4.0100 km S of Adak, Alaska · 14329 days ago · 33 km deep · 15 km away
- 4.588 km S of Adak, Alaska · 14329 days ago · 33 km deep · 9 km away
- 4.784 km S of Adak, Alaska · 14329 days ago · 33 km deep · 8 km away
- 5.097 km S of Adak, Alaska · 14329 days ago · 33 km deep · 14 km away
- 4.583 km S of Adak, Alaska · 14329 days ago · 33 km deep · 4 km away
- 4.1110 km SSE of Adak, Alaska · 14307 days ago · 33 km deep · 44 km away
Before
- 4.386 km SSE of Adak, Alaska · 14344 days ago · 33 km deep · 35 km away
- 5.036 km SE of Adak, Alaska · 14358 days ago · 58 km deep · 66 km away
- 4.982 km SW of Adak, Alaska · 14358 days ago · 33 km deep · 67 km away
- 5.570 km WSW of Adak, Alaska · 14358 days ago · 33 km deep · 82 km away
- 3.697 km SSE of Adak, Alaska · 14363 days ago · 33 km deep · 34 km away
- 4.397 km ESE of Adak, Alaska · 14364 days ago · 33 km deep · 100 km away
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Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp000360x. Read Tue, Sep 22, 2026, 11:35 AM UTC.