M4.8 earthquake 154 km WSW of Adak, Alaska
A magnitude 4.8 earthquake struck 154 km WSW of Adak, Alaska on Fri, Jul 31, 1987, 6:21 PM HADT (03:21 UTC), 33 km (21 mi) below the surface.
A larger quake followed: M5.0 177 km WSW 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
- 4.8 (mb), light
- Local time
- UTC
- 1987-08-01 03:21:54 UTC
- Depth
- 33.0 km (20.5 mi), shallow
- Epicenter
- 51.290° N, 178.662° 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 1.8 and up: 4 in the 60 days after this one and 3 in the 30 days before it.
After
- 5.0177 km WSW of Adak, Alaska · 14286 days ago · 33 km deep · 23 km away
- 4.3248 km WSW of Adak, Alaska · 14274 days ago · 33 km deep · 94 km away
- 4.4147 km WSW of Adak, Alaska · 14256 days ago · 33 km deep · 30 km away
- 4.7145 km WSW of Adak, Alaska · 14250 days ago · 33 km deep · 13 km away
Before
Earthquakes todayAlaska earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp000374e. Read Tue, Sep 22, 2026, 9:17 PM UTC.