Earthquake.now

M1.9 Earthquake near Adak, United States — 28 August 2026

A micro earthquake of magnitude 1.9 was recorded near Adak, United States on , with an epicentre 19 km south-southwest of Adak, at a focal depth of 88.7 km. It ranked as the 1688th strongest of 7793 earthquakes recorded in the United States in the preceding 30 days.

1.9 Micro

Time (UTC): 2026-08-28 04:38:18

Time (your timezone): —

Magnitude: 1.9 (micro)

Focal depth: 88.7 km (intermediate)

Epicentre: 51.7200, -176.7540

Location: 19 km SSW 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?

Micro earthquakes are almost never felt at the surface and are recorded only by seismographs.

A magnitude 1.9 earthquake radiates roughly 11 kg of TNT equivalent in seismic energy.

The USGS assigns this earthquake a significance score of 56, 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 16:51 local solar time at the epicentre, during the afternoon.

This event was deeper than 97% of the 152,533 earthquakes recorded in the United States in our catalogue and stronger than 80% of them.

Where was the epicentre?

The epicentre was located at 51.7200, -176.7540 — 19 km south-southwest of Adak. The closest other recorded event was a magnitude 1.7 earthquake 6 km southeast of here on 23 August 2026.

The nearest other settlement in our records is Adak (241 km south-southwest).

Why the 89 km depth matters

At 89 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, events this small are usually detected by instruments rather than people. 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 M1.9 it falls below the magnitude 6.5 threshold that generally applies before a submarine earthquake displaces enough water to generate a damaging tsunami; 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

7 further earthquakes have been recorded within about 150 km of the epicentre in the 4 days since this event, the largest of them magnitude 3.5.

109 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 6.2 event near Adak on 21 March 2025. This M1.9 event released about 2.8 million times less energy than that event.

568 earthquakes have been recorded within 100 km of this epicentre in the past year, 83 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 August 2026 worldwide record, and of earthquakes in the United States during August 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 1 earthquakes worldwide

Questions about this earthquake

How strong was the earthquake near Adak?

It measured magnitude 1.9 — a micro earthquake. A magnitude 1.9 earthquake radiates roughly 11 kg of TNT equivalent in seismic energy.

How deep was the earthquake near Adak?

The focus was 89 km below the surface, which counts as intermediate.

Was the Adak earthquake felt at the surface?

At magnitude 1.9 and a focal depth of 89 km, the depth spreads the energy out, so shaking is weaker overhead but reaches further.

When did the earthquake near Adak happen?

28 August 2026 at 04:38 UTC.

Was there a tsunami?

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

Have there been aftershocks?

7 further earthquakes have been recorded within about 150 km of the epicentre in the 4 days since this event, the largest of them magnitude 3.5.

How often do earthquakes happen near Adak?

109 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 6.2 event near Adak on 21 March 2025. This M1.9 event released about 2.8 million times less energy than that event.