M5.7 earthquake 100 km SSE of Old Harbor, Alaska
A magnitude 5.7 earthquake struck 100 km SSE of Old Harbor, Alaska on Fri, Apr 8, 1966, 12:10 PM GMT-10 (22:10 UTC), 31 km (19 mi) below the surface.
A larger quake followed: M6.1 36 km ESE of Akhiok, Alaska. This one was a foreshock.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.7 (Mw, moment), moderate
- Magnitude from
- ISC-GEM global catalog
- Local time
- UTC
- 1966-04-08 22:10:58 UTC
- Depth
- 30.5 km (19.0 mi), shallow
- Epicenter
- 56.422° N, 152.481° W
- Region
- Alaska
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
Magnitude estimates
Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.
| Mag. | Scale | Computed by | Notes |
|---|---|---|---|
| 5.68 | Mw, moment | ISC-GEM global catalog | Preferred · Final · ±0.2 |
| 5.0 | mb, body-wave | USGS historic United States catalog | Final |
What happened
The USGS’s account of the effects of this earthquake.
Maximum observed Modified Mercalli Intensity (MMI) I
From the USGS event page for iscgem848226. U.S. Geological Survey text and figures are in the public domain.
Did you feel it?
No one has reported feeling this quake to the USGS.
How well it is located
Reviewed by a seismologist.
- Magnitude uncertainty
- ±0.20
- Depth from
- From location
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.7 and up: 4 in the 60 days after this one and 0 in the 30 days before it.
After
- 5.594 km SSE of Old Harbor, Alaska · 22091 days ago · 22 km deep · 6 km away
- 5.8103 km SE of Old Harbor, Alaska · 22089 days ago · 25 km deep · 22 km away
- 6.136 km ESE of Akhiok, Alaska · 22085 days ago · 35 km deep · 83 km away
- 5.436 km SSW of Chiniak, Alaska · 22078 days ago · 22 km deep · 97 km away
Earthquakes todayAlaska earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event iscgem848226 (also filed as ushis2886). Read Fri, Oct 2, 2026, 2:10 PM UTC.