EARTHQUAKEM4.3

M4.3 earthquake near Akutan, Alaska

Map: the earthquake near Akutan, Alaska, with plate boundaries

First reported as magnitude 4.5, the earthquake has since been revised to 4.3 by the US Geological Survey. Early estimates come within minutes from the first seismic stations; the reviewed figure takes in many more.

A magnitude 4.3 earthquake struck 50 mi (81 km) south-southeast of Akutan, Alaska on Sunday, October 25, 2026 at 07:45 UTC, at a depth of 22 mi (35 km), according to the U.S. Geological Survey. Shallow quakes like this one shake the surface hardest.

MagnitudeM4.3
Depth22 mi (35 km)
Time (UTC)Oct 25 07:45
Location53.49°N 165.19°W
Nearest townAkutan · 81 km
Energy43 tons TNT
Aftershocks M2.5+0
Tsunami flagNo
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Why here?

This earthquake struck about 64 mi (103 km) from the boundary between the North American and Pacific plates. Most earthquakes happen along plate boundaries like this one, where the pieces of Earth’s outer shell collide, pull apart or grind past each other. Stress builds up over years until the rock suddenly slips.

The red lines on the map are plate boundaries.

How strong was it?

Magnitude is logarithmic: each whole step releases about 32 times more energy. This magnitude 4.3 released roughly the energy of 43 tons of TNT. That is about 2.8 times the energy of a magnitude 4.0, a quake people nearby feel but that rarely causes damage. The strongest earthquake ever recorded, magnitude 9.5 in Chile in 1960, released about 63,000,000 times more than this one.

Aftershocks

In the first 21 hours after it, USGS recorded no smaller earthquakes of magnitude 2.5 or more within 62 mi (100 km).

Earthquake history here

Before this earthquake, USGS had recorded 133 earthquakes of magnitude 6 or larger within 300 km (186 mi) since 1900. The strongest:

Official details, updates and the shaking map: USGS event page.

See every earthquake on October 25, 2026 or earthquakes by day.

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