M5.8 Earthquake near Adak, Alaska — 09 May 2026
A moderate earthquake of magnitude 5.8 was recorded near Adak, Alaska on , with an epicentre 292 km west-southwest of Adak, at a focal depth of 26.5 km.
Time (UTC): 2026-05-09 04:42:23
Time (your timezone): —
Magnitude: 5.8 (moderate)
Focal depth: 26.5 km (shallow)
Epicentre: 51.0818, 179.3490
Location: 292 km WSW of Adak, Alaska
USGS link to NOAA tsunami information: Not linked
Review status: Reviewed
Source: USGS event page
How strong was this earthquake?
Moderate earthquakes can damage poorly built or unreinforced structures near the epicentre, while well-engineered buildings typically escape serious harm. Shaking is often strong enough to wake sleeping residents over a wide area.
A magnitude 5.8 earthquake radiates roughly 7,558 tons of TNT equivalent in seismic energy.
The USGS assigns this earthquake a significance score of 518, 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 51.0818, 179.3490 — 292 km west-southwest of Adak. The closest other recorded event was a magnitude 4.1 earthquake 24 km east of here on 20 June 2026.
Why the 26 km depth matters
At 26 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, an event this size can be felt widely and may cause minor local damage. 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 M5.8 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
5 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 4.4.
47 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 M5.8 event released about 1.4 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 May 2026 worldwide record. Browse the full monthly archive to compare periods.
Nearest recorded earthquakes to this epicentre
- M4.1 earthquake near Adak, Alaska — (24 km E)
- M3.8 earthquake near Adak, Alaska — (25 km E)
- M2.3 earthquake near Adak, Alaska — (34 km N)
- M3.1 earthquake near Adak, Alaska — (37 km ENE)
- M2.9 earthquake near Rat Islands, Aleutian Islands, Alaska — (54 km NW)
- M2.8 earthquake near Adak, Alaska — (56 km NNE)
- M3.4 earthquake near Adak, Alaska — (56 km NNE)
- M2.2 earthquake near Rat Islands, Aleutian Islands, Alaska — (62 km NNW)
- M1.9 earthquake near Rat Islands, Aleutian Islands, Alaska — (65 km NW)
- M3.1 earthquake near Rat Islands, Aleutian Islands, Alaska — (69 km NNW)
Other magnitude 5 earthquakes worldwide
- M5.6 earthquake near Port McNeill, Canada —
- M5.5 earthquake near Mutsu, Japan —
- M5.6 earthquake near San Fernando, Peru —
- M5.9 earthquake near Colonia, Micronesia —
- M5.8 earthquake near Kermadec Islands region —
- M5.9 earthquake near Kermadec Islands region —
- M5.6 earthquake near Pacific-Antarctic Ridge —
- M5.6 earthquake near Tsunagi, Japan —
Questions about this earthquake
How strong is a magnitude 5.8 earthquake?
Moderate earthquakes can damage poorly built or unreinforced structures near the epicentre, while well-engineered buildings typically escape serious harm. Shaking is often strong enough to wake sleeping residents over a wide area. A magnitude 5.8 earthquake radiates roughly 7,558 tons of TNT equivalent in seismic energy.
How deep was the earthquake near Adak?
At 26 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 M5.8 earthquake near Adak felt?
This catalogue does not ingest eyewitness responses, so it cannot confirm where this earthquake was felt. Based on magnitude alone, an event this size can be felt widely and may cause minor local damage. 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 M5.8 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?
5 further earthquakes have been recorded within about 150 km of the epicentre in the seven days after this event, the largest of them magnitude 4.4.
How often do earthquakes happen near Adak?
47 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 M5.8 event released about 1.4 times less energy than that event.