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4.0MAG

LIGHT EARTHQUAKE

Rat Islands, Aleutian Islands, Alaska

USGS

A magnitude 4.0 earthquake struck Rat Islands, Aleutian Islands, Alaska on 20 Aug 2026, 02:45 UTC. The hypocentre was 10 km below the surface — shallow by seismological convention. 7 other earthquakes above our reporting threshold have been recorded within 250 km in the past 30 days.

Depth
10 km

shallow

Latitude
50.88°N

178.78°E longitude

Time
02:45 UTC

20 Aug 2026

Magnitude
M4.0

mb

EPICENTRE

View the official report

MAGNITUDE 4.0

Noticeable shaking of indoor objects. Damage is unlikely.

The scale is logarithmic: this released about 32 times the energy of a magnitude 3.0, roughly the energy of 15 tonnes of TNT.

10 KM DEEP

Shallow earthquakes release their energy close to the surface, so they are felt more strongly, and do more damage, than deeper earthquakes of the same magnitude.

NEARBY IN THE PAST 30 DAYS

7 earthquakes above our reporting threshold within 250 km of this one, the largest a magnitude 5.0.

OTHER RECENT EARTHQUAKES

M4.0 earthquake — Rat Islands, Aleutian Islands, Alaska · Quakewire