M0.5 Earthquake near Atka, Alaska — 31 July 2026
A micro earthquake of magnitude 0.5 was recorded near Atka, Alaska on , with an epicentre 23 km north-northeast of Atka, at a focal depth of 8.4 km.
Time (UTC): 2026-07-31 18:07:49
Time (your timezone): —
Magnitude: 0.5 (micro)
Focal depth: 8.4 km (shallow)
Epicentre: 52.3940, -174.0940
Location: 23 km NNE of Atka, Alaska
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 0.5 earthquake radiates roughly 0.10 kg of TNT equivalent in seismic energy.
The USGS assigns this earthquake a significance score of 4, 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.
Where was the epicentre?
The epicentre was located at 52.3940, -174.0940 — 23 km north-northeast of Atka. The closest other recorded event was a magnitude 0.2 earthquake 6 km west-southwest of here on 30 July 2026.
Why the 8 km depth matters
At 8 km this was a shallow earthquake. Shallow events release their energy close to the surface, so for a given magnitude they produce noticeably stronger shaking — and more damage — than deeper ones. Roughly three quarters of all earthquakes worldwide occur at shallow depths.
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 shallow focus makes stronger surface shaking more likely than for a deeper event of the same magnitude.
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 M0.5 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
2 further earthquakes have been recorded within about 150 km of the epicentre in the 1 day since this event, the largest of them magnitude 4.9.
75 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.8 event near Atka on 26 July 2026. This M0.5 event released about 77.6 million times less energy than that event.
How long aftershock sequences last, and how large they get →
Where this event sits in the record
This earthquake is part of the July 2026 worldwide record. Browse the full monthly archive to compare periods.
Nearest recorded earthquakes to this epicentre
- M0.2 earthquake near Atka, Alaska — (6 km WSW)
- M0.4 earthquake near Atka, Alaska — (8 km SSE)
- M0.2 earthquake near Atka, Alaska — (10 km SSW)
- M1.0 earthquake near Atka, Alaska — (11 km SSW)
- M0.5 earthquake near Atka, Alaska — (11 km SSW)
- M0.1 earthquake near Atka, Alaska — (12 km SSW)
- M0.5 earthquake near Atka, Alaska — (12 km SSW)
- M1.1 earthquake near Atka, Alaska — (16 km SE)
- M2.2 earthquake near Atka, Alaska — (37 km SW)
- M2.2 earthquake near Atka, Alaska — (37 km SSW)
Other magnitude 0 earthquakes worldwide
Questions about this earthquake
How strong is a magnitude 0.5 earthquake?
Micro earthquakes are almost never felt at the surface and are recorded only by seismographs. A magnitude 0.5 earthquake radiates roughly 0.10 kg of TNT equivalent in seismic energy.
How deep was the earthquake near Atka?
At 8 km this was a shallow earthquake. Shallow events release their energy close to the surface, so for a given magnitude they produce noticeably stronger shaking — and more damage — than deeper ones. Roughly three quarters of all earthquakes worldwide occur at shallow depths.
Was the M0.5 earthquake near Atka felt?
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 shallow focus makes stronger surface shaking more likely than for a deeper event of the same magnitude.
What does the USGS tsunami field mean for this event?
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 M0.5 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.
Have there been aftershocks?
2 further earthquakes have been recorded within about 150 km of the epicentre in the 1 day since this event, the largest of them magnitude 4.9.
How often do earthquakes happen near Atka?
75 earthquakes of magnitude 4 or above have been logged within roughly 200 km of this epicentre in our catalogue. The strongest was a magnitude 5.8 event near Atka on 26 July 2026. This M0.5 event released about 77.6 million times less energy than that event.