161 km S of Nikolski, Alaska

Yes. A magnitude 4.0 earthquake was recorded 161 km S of Nikolski, Alaska at 05:08 UTC on 2026-10-19, 10 km deep. No felt reports to USGS yet.

2026-10-19 05:08 UTC · 10 km deep · released about 15 tons of TNT

Felt it? Tell USGS Check my area

Distance rings around the epicentre, with the nearest towns at their true direction. Not a shaking map — see the USGS ShakeMap for that.

When: 2026-10-19 05:08 UTC
Magnitude: M 4.0 (mb)
Depth: 10 km below the surface
Felt: no reports yet
Measured shaking: intensity I (ShakeMap)
Nearest mapped fault: Alaska-Aleutian subduction zone, 19 km from its surface trace — near is not the same as on
Status: Reviewed by a seismologist

USGS · last changed by USGS 3 hours ago · we first saw it 3 hours 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, people at rest would likely notice it out to about 96 km (60 mi) from the epicentre. 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.

Northridge, California 1994 M 6.7 11,000× the energy of this one
Mineral, Virginia 2011 M 5.8 500× the energy of this one
Magna, Utah 2020 M 5.7 350× the energy of this one
This earthquake M 4.0 about 15 tons of TNT
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 5.2 on 2025-06-28 — about 63 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

6.8 187 km S of Nikolski, Alaska · 42 km SW of this epicentre Nov 13, 1960
6.0 188 km SSE of Nikolski, Alaska · 27 km SSE of this epicentre Apr 19, 1957
5.6 169 km S of Nikolski, Alaska · 12 km SW of this epicentre Dec 28, 2002
5.4 159 km S of Nikolski, Alaska · 7 km W of this epicentre May 4, 1994
5.3 172 km SSE of Nikolski, Alaska · 22 km ESE of this epicentre Jan 3, 2006

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

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Aftershocks so far

No further earthquakes have been recorded within 50 km since this one.

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 15:58 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

The official USGS event page — the source of record for every value above
Did you feel it? Report it to USGS — reports go to USGS, not to us
ShakeMap for this event, when USGS has produced one

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