QuakeIndex

Earthquake · reviewed by a seismologist

M 4.0mb

Rat Islands, Aleutian Islands, Alaska

Yes. A magnitude 4.0 earthquake was recorded in the Rat Islands, Aleutian Islands, Alaska at 08:47 UTC on 2026-10-07, 108 km deep.

· 108 km deep · released about 15 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Aleutians West Census Area 72 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
Magnitude
M 4.0 (mb)
Depth
108 km below the surface
Felt
no reports yet
Measured shaking
intensity I (ShakeMap)
Nearest
Aleutians West Census Area, 72 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 5 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth it was probably too small to be felt, even directly above it. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 15 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 11,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 500× the energy of this one
  3. Magna, Utah 2020 M 5.7 350× the energy of this one
  4. This earthquake M 4.0 about 15 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 32× more

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km since 2016 was M 4.2 on 2026-09-30 — about 2 times the energy of this one.

Before 2016, the USGS record lists 81 earthquakes of M5 or more within 50 km; the five largest:

  1. 8.7 1965 Western Aleutian Islands (Hawadax/Rat Islands) Earthquake · 36 km S of this epicentre
  2. 7.9 Rat Islands, Aleutian Islands, Alaska · 31 km N of this epicentre
  3. 7.8 Rat Islands, Aleutian Islands, Alaska · 48 km S of this epicentre
  4. 6.8 Rat Islands, Aleutian Islands, Alaska · 40 km S of this epicentre
  5. 6.7 275 km WSW of Adak, Alaska · 50 km ESE of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 51.5736, 178.7718. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aleutians West Census Area, AK 72 km (45 mi) NE earthquakes near Aleutians West Census Area

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

4 earthquakes have been recorded within 50 km since this one.

  1. 2.2 Rat Islands, Aleutian Islands, Alaska
  2. 4.1 Rat Islands, Aleutian Islands, Alaska
  3. 2.5 Rat Islands, Aleutian Islands, Alaska
  4. 2.6 294 km W of Adak, Alaska

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.