M5.9 earthquake 68 km S of Adak, Alaska
A magnitude 5.9 earthquake struck 68 km S of Adak, Alaska on Thu, Jul 17, 1958, 9:59 AM GMT-11 (20:59 UTC), 25 km (16 mi) below the surface.
A larger quake followed: M6.3 100 km ESE 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
- 5.9 (Mw, moment), moderate
- Magnitude from
- ISC-GEM global catalog
- Local time
- UTC
- 1958-07-17 20:59:26 UTC
- Depth
- 25.0 km (15.5 mi), shallow
- Epicenter
- 51.256° N, 176.696° 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 |
|---|---|---|---|
| 5.86 | Mw, moment | ISC-GEM global catalog | Preferred · Final · ±0.2 |
| 6.0 | Uk | 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 iscgem884760. 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
Nearby
Within 100 km, magnitude 2.9 and up: 4 in the 60 days after this one and 2 in the 30 days before it.
After
- 5.973 km S of Adak, Alaska · 24913 days ago · 25 km deep · 16 km away
- 6.3100 km ESE of Adak, Alaska · 24885 days ago · 35 km deep · 95 km away
- 6.166 km SE of Adak, Alaska · 24883 days ago · 25 km deep · 51 km away
- 5.883 km SSE of Adak, Alaska · 24882 days ago · 15 km deep · 38 km away
Before
Earthquakes todayAlaska earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event iscgem884760 (also filed as ushis2323). Read Thu, Oct 1, 2026, 4:25 PM UTC.