M5.7 earthquake 204 km WNW of Adak, Alaska
A magnitude 5.7 earthquake struck 204 km WNW of Adak, Alaska on Thu, Feb 8, 2018, 1:04 AM HAST (11:04 UTC), 211 km (131 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.7 (Mww, W-phase moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 2018-02-08 11:04:01 UTC
- Depth
- 211.4 km (131.4 mi), intermediate-depth
- Epicenter
- 52.592° N, 179.384° W
- Region
- Alaska
- Felt reports
- 2
- Strongest shaking
- III, weak shaking
- PAGER alert
- Green
- Tsunami flag
- Yes: a large quake in an oceanic region
- 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 |
|---|---|---|---|
| 5.7 | Mww, W-phase moment | USGS National Earthquake Information Center | Preferred · Reviewed · ±0.038 · 68 stations |
| 5.78 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.8 | Mw, moment | Alaska Earthquake Center | Preliminary |
| 5.7 | Mwb, body-wave moment | USGS National Earthquake Information Center | Moment tensor · Reviewed |
Tsunami
The USGS flags a quake this large in an oceanic region. The flag does not mean a tsunami happened; the tsunami warning centers decide that, and their messages are below when they issued any.
Current tsunami warnings: tsunami.gov. Warnings in force in the US also appear on our alerts pages.
Shaking
The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.
- Strongest estimated
- III, weak shaking
- Peak ground acceleration
- 96.0% of gravity
- Peak ground velocity
- 0.5 cm/s
- Map
- Automatic
Did you feel it?
2 people reported to the USGS what they felt; the strongest reported shaking was IV, light shaking.
Estimated impact
The USGS PAGER system estimates deaths and economic losses from the shaking and the population and buildings exposed to it.
- Alert level
- Green: little or no damage or loss of life expected
| Range | Chance |
|---|---|
| Under 1 | 69% |
| 1 to 10 | 29% |
| 10 to 100 | 2% |
| 100 to 1,000 | Under 1% |
| 1,000 to 10,000 | Under 1% |
| 10,000 to 100,000 | Under 1% |
| 100,000 to 10,000,000 | Under 1% |
| Range, million USD | Chance |
|---|---|
| Under 1 | 65% |
| 1 to 10 | 30% |
| 10 to 100 | 4% |
| 100 to 1,000 | Under 1% |
| 1,000 to 10,000 | Under 1% |
| 10,000 to 100,000 | Under 1% |
| 100,000 to 10,000,000 | Under 1% |
Fault motion and ground failure
How the rock slipped, from the moment tensor, and the USGS estimate of landslides and liquefaction.
- Faulting
- Strike-slip
- Moment magnitude
- 5.7 Mww
- Nodal plane 1
- Strike 211°, dip 23°, rake 5°
- Nodal plane 2
- Strike 116°, dip 88°, rake 113°
How well it is located
Reviewed by a seismologist.
- Location uncertainty
- About 6.7 km horizontally, 3.3 km in depth
- Magnitude uncertainty
- ±0.04
- Depth from
- From location
- Station coverage gap
- 16°
- Stations used
- 227
Nearby
Within 100 km, magnitude 2.7 and up: 6 in the 60 days after this one and 3 in the 30 days before it.
After
- 2.8Andreanof Islands, Aleutian Islands, Alaska · 3158 days ago · 118 km deep · 90 km away
- 3.0175 km W of Adak, Alaska · 3156 days ago · 236 km deep · 63 km away
- 2.8200 km W of Adak, Alaska · 3139 days ago · 123 km deep · 87 km away
- 3.8220 km W of Adak, Alaska · 3109 days ago · 177 km deep · 79 km away
- 2.7230 km W of Adak, Alaska · 3109 days ago · 196 km deep · 69 km away
- 2.8187 km W of Adak, Alaska · 3107 days ago · 217 km deep · 69 km away
Before
Earthquakes todayAlaska earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event us2000cysh (also filed as ak18413736, ak0181soj60t, at00p3tw2j, iscgem616640797). Read Fri, Oct 2, 2026, 7:08 AM UTC.