Alaska earthquakes

M4.8 earthquake 47 km NNW of Atka, Alaska

A magnitude 4.8 earthquake struck 47 km NNW of Atka, Alaska on Thu, Dec 28, 2017, 4:58 AM HAST (14:58 UTC), 182 km (113 mi) below the surface.

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The earthquake

Magnitude: 4.8 (mb, body-wave), light
Magnitude from: USGS National Earthquake Information Center
Local time: Thu, Dec 28, 2017, 4:58 AM HAST
UTC: 2017-12-28 14:58:42 UTC
Depth: 182.1 km (113.2 mi), intermediate-depth
Epicenter: 52.584° N, 174.488° W
Region: Alaska
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
4.8	mb, body-wave	USGS National Earthquake Information Center	Preferred · Reviewed · ±0.033 · 283 stations
4.8	mb, body-wave	Alaska Earthquake Center	Preliminary
5.1	mb, body-wave	NOAA National Tsunami Warning Center	Reviewed · 37 stations

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.

Did you feel it?

No one has reported feeling this quake to the USGS.

How well it is located

Reviewed by a seismologist.

Location uncertainty: About 7.3 km horizontally, 4.6 km in depth
Magnitude uncertainty: ±0.03
Depth from: From location
Station coverage gap: 54°
Stations used: 347

Nearby

Within 100 km, magnitude 1.8 and up: 56 in the 60 days after this one and 23 in the 30 days before it.

After

Before

Earthquakes today Alaska earthquakes Live radar here

Sources

From the USGS Earthquake Hazards Program and its partner networks, event us1000bx6m (also filed as ak017gmx87yn, ak17718504, at00p1oexu). Read Fri, Oct 2, 2026, 2:23 AM UTC.