M4.8 earthquake 69 km WNW of Adak, Alaska
A magnitude 4.8 earthquake struck 69 km WNW of Adak, Alaska on Sat, Mar 21, 1987, 5:31 AM HAST (15:31 UTC), 103 km (64 mi) below the surface.
A larger quake followed: M5.1 130 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
- 1987-03-21 15:31:51 UTC
- Depth
- 102.8 km (63.9 mi), intermediate-depth
- Epicenter
- 52.080° N, 177.582° 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.
Nearby
Within 100 km, magnitude 1.8 and up: 2 in the 60 days after this one and 3 in the 30 days before it.
After
- 5.1130 km WSW of Adak, Alaska · 14432 days ago · 33 km deep · 99 km away
- 5.126 km E of Adak, Alaska · 14422 days ago · 65 km deep · 93 km away
Before
Earthquakes todayAlaska earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp00033gv. Read Wed, Sep 30, 2026, 5:43 AM UTC.