EARTHQUAKEM5.5

M5.5 earthquake near Aleneva, Alaska

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

A magnitude 5.5 earthquake struck 57 mi (92 km) north-northwest of Aleneva, Alaska on Tuesday, October 6, 2026 at 18:34 UTC, at a depth of 54 mi (88 km), according to the U.S. Geological Survey. At this intermediate depth, shaking spreads out before it reaches the surface.

USGS’s PAGER impact estimate is GREEN: little or no damage expected.

342 people reported feeling it to USGS “Did You Feel It?”.

MagnitudeM5.5
Depth54 mi (88 km)
Time (UTC)Oct 6 18:34
Location58.80°N 153.61°W
Nearest townAleneva · 92 km
Energy3 kilotons TNT
Aftershocks M2.5+2
Tsunami flagNo
PAGER alertGREEN
Felt reports342
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Why here?

This earthquake struck 88 km (54 mi) down, about 192 mi (309 km) from the nearest plate boundary on the surface. Quakes this deep happen inside old ocean plate that has sunk far into the mantle at a subduction zone, long after it dove beneath its neighbor. Their great depth spreads the shaking over a wide area but usually keeps it gentle at the surface.

The red lines on the map are plate boundaries.

What kind of fault?

USGS’s analysis of the seismic waves shows it was a strike-slip earthquake: the two sides of the fault slid past each other sideways, like California’s San Andreas Fault.

Shaking and impact

The strongest shaking USGS estimates was intensity 4 on the Modified Mercalli scale: light. USGS’s PAGER system estimates it most likely caused no deaths (95 percent probability). Early estimates are revised as reports come in.

How strong was it?

Magnitude is logarithmic: each whole step releases about 32 times more energy. This magnitude 5.5 released roughly the energy of 3 kilotons of TNT. That is about 178 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 1,000,000 times more than this one.

Aftershocks

In the first 19 days after it, USGS recorded 2 smaller earthquakes of magnitude 2.5 or more within 62 mi (100 km). The largest was a magnitude 2.7 on October 20 at 18:12 UTC.

Earthquake history here

Before this earthquake, USGS had recorded 82 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 6, 2026 or earthquakes by day.

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