M5.6 Earthquake: 43 km NNW of Lake Minchumina, Alaska

Key context

Tectonic setting

Alaska crust and slab. Mainland Alaska has two kinds of quakes: crustal faults such as the Denali Fault (M7.9 in 2002), and quakes inside the subducting Pacific slab at 40-150 km depth, like the M7.1 Anchorage quake of 2018. Alaska has more large quakes than the rest of the United States combined.

The USGS moment tensor shows strike-slip faulting: the two sides of the fault slid sideways past each other.

At 5 km it was a very shallow quake: shallow quakes shake the ground above them hardest, so local damage depends on how close towns are.

Shaking and impact

The USGS ShakeMap estimates the strongest shaking at intensity VII on the Modified Mercalli scale (very strong).

107 people sent a "Did You Feel It?" report to USGS, with the strongest reported intensity V (moderate).

Aftershocks

This page counts quakes of M2.5 or more within 50 km after the main shock, from the USGS catalog (last checked 09:05 UTC, 29 Oct 2026): 1 aftershock so far.

Aftershocks are normal after a quake of this size. They usually become less frequent over days and weeks, but a strong aftershock can still happen, and in a few sequences a later quake is larger. No one can predict their exact time or size; follow the official agency for your area.

Earthquake history within 250 km

Since 1976, USGS lists 54 quakes of M5 or more within 250 km of this epicentre, about 1.1 a year. Since 1900 the same circle had 29 quakes of M5.6 or larger.

Official information

• Alaska Earthquake Center
• National Tsunami Warning Center
• EMSC (European-Mediterranean Seismological Centre)
• USGS event page for this quake (ShakeMap, PAGER, felt reports)
• tsunami.gov for US tsunami bulletins

Data status

USGS review status: reviewed. Magnitude type: ml. USGS last updated this event on 28 Oct 2026 at 11:17 UTC. Magnitude, depth and location can still be revised; this page keeps the same address if they change.