M 4.2 Earthquake 157 km WSW of Adak, Alaska

Source: USGS · Alaska

A magnitude 4.2 earthquake was recorded by USGS near 157 km WSW of Adak. On the USGS Earthquake Hazards Program scale, M4.2 is classified "Light". Among the 1,712 earthquake reports Areazine has published, this M4.2 event ranks stronger than 49% of them (rank #849 by magnitude).

Read this earthquake report in 30 seconds

Magnitude
M 4.2
USGS class
Light
Location
157 km WSW of Adak
Archive rank
#849 of 1,712
Source
USGS
Published
September 13, 2026
LIGHT

Stronger than 49% of the 1,712 earthquake reports in Areazine's archive, weaker than 848 others.

Record status: a snapshot from USGS, not a final record. Check USGS's own event page for aftershocks and any later revision to the magnitude shown here.

What Happened

A M 4.2 ml earthquake occurred at 2026-09-12 12:48:41 UTC (reviewed by USGS) with an epicenter at 51.118°N, 178.556°W. The event was located 157 km WSW of Adak, Alaska, at a depth of 18.6 km, which classifies as shallow (less than 20 km).

Location Details

The earthquake was centered 157 km west-southwest of Adak, Alaska, at coordinates 51.118 latitude, -178.556 longitude. The shallow depth of 18.6 km means the event occurred in the upper crust.

Impact Assessment

No felt reports were recorded. The maximum modified Mercalli intensity was estimated at 3.485. There was no tsunami advisory (tsunami flag: 0) and no alert level issued.

What You Should Know

Earthquakes of this magnitude are classified as light and are often felt but rarely cause damage. Residents in the region should be aware of the possibility of aftershocks and follow standard earthquake safety practices such as drop, cover, and hold on during shaking.

Source

https://earthquake.usgs.gov/earthquakes/eventpage/aka2026sddwmu (USGS)

Original source: USGS Official Notice ↗

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Elsewhere in the country: similar length or severity timing 8

Two Areazine-derived peer sets for this USGS earthquake report: nearest notices by body length and by same severity near the same agency date. Peers come from other categories so they are not the same-feed Related list above.

What People Ask

Questions readers often have about this USGS earthquake report.

What magnitude was this earthquake?
A magnitude 4.2 ml earthquake struck 157 km west-southwest of Adak, Alaska, at a depth of 18.6 km.
How should a magnitude 4.2 ("Light") event be understood?
The USGS classifies M4.2 as "Light" on its Earthquake Hazards Program scale. Events in this range are often felt near the epicenter and can cause minor damage to vulnerable structures, though widespread damage is uncommon.
Is this earthquake stronger or weaker than others in the archive?
This is the #849 strongest of the 1,712 earthquake reports in Areazine's archive by magnitude, stronger than 49% of them and weaker than 848 others.
Was Adak likely to feel this earthquake?
This event was centered 157 km WSW of Adak. Shaking intensity falls off sharply with distance from the epicenter and depends on depth and local geology, so check the USGS "Did You Feel It?" report for this event for real felt-shaking data rather than assuming from magnitude and distance alone.