EARTHQUAKEM4.5

M4.5 earthquake near False Pass, Alaska

Map: the earthquake near False Pass, Alaska, with plate boundaries

A magnitude 4.5 earthquake struck 98 mi (158 km) south of False Pass, Alaska on Wednesday, October 21, 2026 at 12:03 UTC, at a depth of 13 mi (20 km), according to the U.S. Geological Survey. Shallow quakes like this one shake the surface hardest.

MagnitudeM4.5
Depth13 mi (20 km)
Time (UTC)Oct 21 12:03
Location53.43°N 163.46°W
Nearest townFalse Pass · 158 km
Energy85 tons TNT
Aftershocks M2.5+7
Tsunami flagNo
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Why here?

This earthquake struck about 29 mi (47 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 4.5 released roughly the energy of 85 tons of TNT. That is about 5.6 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 32,000,000 times more than this one.

Aftershocks

In the first 5 days after it, USGS recorded 7 smaller earthquakes of magnitude 2.5 or more within 62 mi (100 km). The largest was a magnitude 4.0 on October 22 at 21:42 UTC.

Earthquake history here

Before this earthquake, USGS had recorded 109 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 21, 2026 or earthquakes by day.

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