Earthquake.now

M4.2 Earthquake near Adak, United States — 30 September 2026

A light earthquake of magnitude 4.2 was recorded near Adak, United States on , with an epicentre 286 km west of Adak, at a focal depth of 119.2 km. It ranked as the 58th strongest of 7086 earthquakes recorded in the United States in the preceding 30 days.

4.2 Light

Time (UTC): 2026-09-30 19:10:09

Time (your timezone): —

Magnitude: 4.2 (light)

Focal depth: 119.2 km (intermediate)

Epicentre: 51.8805, 179.2120

Location: 286 km W of Adak, Alaska

Country: United States

USGS link to NOAA tsunami information: Not linked

Review status: Reviewed

Source: USGS event page

How strong was this earthquake?

Light earthquakes are widely felt near the epicentre and can rattle windows, dishes and hanging objects. Damage is uncommon and usually limited to cracked plaster or fallen loose items.

A magnitude 4.2 earthquake radiates roughly 30 tons of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 271, which is below the USGS threshold of more than 600 for its significant-earthquake list. The ranking combines magnitude with available Did You Feel It responses and PAGER alert level; it is not a direct measurement of damage.

What the magnitude scale actually measures →

When it happened locally

That is about 07:06 local solar time at the epicentre, around dawn.

This event was deeper than 99% of the 159,525 earthquakes recorded in the United States in our catalogue and stronger than 100% of them.

Where was the epicentre?

The epicentre was located at 51.8805, 179.2120 — 286 km west of Adak. The closest other recorded event was a magnitude 1.1 earthquake 22 km east of here on 18 September 2026.

The nearest other settlements in our records are Aleutians West (56 km southwest), Adak (104 km south) and Attu Station (131 km west).

Why the 119 km depth matters

At 119 km this was an intermediate-depth earthquake. Energy from events at this depth spreads out before it reaches the surface, which usually means weaker shaking near the epicentre than a shallow quake of the same magnitude, but shaking felt across a wider area.

This catalogue does not ingest eyewitness responses, so it cannot confirm where this earthquake was felt. Based on magnitude alone, an event this size is often felt across the surrounding area. Its intermediate depth normally reduces peak shaking near the epicentre compared with a shallow event of the same magnitude.

Read more on how focal depth changes what you feel →

What does the tsunami information flag mean?

The USGS record does not carry a link to NOAA tsunami information. That field is not an all-clear and does not state whether a tsunami occurred. In this case, a damaging tsunami would be less likely because at M4.2 it falls below the magnitude 6.5 threshold that generally applies before a submarine earthquake displaces enough water to generate a damaging tsunami; its 119 km focal depth is too great to deform the sea floor significantly; it occurred inland rather than beneath the sea floor. For an active coastal alert, use tsunami.gov or your local warning authority.

How earthquakes generate tsunamis, and what the alert levels mean →

Aftershocks and local seismic history

No further earthquakes have been recorded within about 150 km of the epicentre in the 2 hours since this event.

54 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.9 event near Adak on 28 August 2025. This M4.2 event released about 355 times less energy than that event.

213 earthquakes have been recorded within 100 km of this epicentre in the past year, 26 of them in the past 30 days.

How long aftershock sequences last, and how large they get →

Where this event sits in the record

This earthquake is part of the September 2026 worldwide record, and of earthquakes in the United States during September 2026. Browse the full monthly archive to compare periods.

Nearest recorded earthquakes to this epicentre

Other recent earthquakes in the United States

All recorded earthquakes in the United States →

Other magnitude 4 earthquakes worldwide

All magnitude 4 earthquakes →

Questions about this earthquake

How strong was the earthquake near Adak?

It measured magnitude 4.2 — a light earthquake. A magnitude 4.2 earthquake radiates roughly 30 tons of TNT equivalent in seismic energy.

How deep was the earthquake near Adak?

The focus was 119 km below the surface, which counts as intermediate.

Was the Adak earthquake felt at the surface?

At magnitude 4.2 and a focal depth of 119 km, the depth spreads the energy out, so shaking is weaker overhead but reaches further.

When did the earthquake near Adak happen?

30 September 2026 at 19:10 UTC.

Was there a tsunami?

No. The USGS record carries no tsunami-information link for this event.

Have there been aftershocks?

No further earthquakes have been recorded within about 150 km of the epicentre in the 2 hours since this event.

How often do earthquakes happen near Adak?

54 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.9 event near Adak on 28 August 2025. This M4.2 event released about 355 times less energy than that event.