M4.5 Earthquake 238 km ESE of Attu Station, Alaska — April 25, 2026
2026-04-25 05:18:45 UTC (2 hours ago)
Aftershock of the M5.1 mainshock.
On April 25, 2026 at 05:18 UTC, a magnitude 4.5 shallow crustal earthquake struck 238 km ESE of Attu Station, Alaska, at a depth of 10.0 km and coordinates 52.2239°, 176.5528°. This earthquake was detected by 90 seismic stations with good location accuracy and was assigned a USGS significance rating of 312, placing it among routine seismic activity.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.1 mainshock that occurred 21 days ago 223 km ESE of Attu Station, Alaska. Since the mainshock, the USGS has recorded 7 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
The epicenter is located in Alaska, a region characterized by Pacific Plate subduction beneath the North American Plate, producing frequent megathrust and crustal earthquakes along the Aleutian arc. The nearest mapped fault system is the Aleutian megathrust. View all earthquakes in Alaska.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
176.5528°E
Technical Information
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Common Questions
How strong was the magnitude 4.5 earthquake near Attu Station, Alaska?
The magnitude 4.5 earthquake that struck 238 km ESE of Attu Station, Alaska on April 25, 2026 at 05:18 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 52.2239°, 176.5528°, which is 238 km ESE of Attu Station, Alaska. View all earthquakes in Alaska.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.1 one earlier?
No. This magnitude 4.5 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier 223 km ESE of Attu Station, Alaska. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Has Alaska had earthquakes this big before?
The largest recorded earthquake in Alaska was the M9.2 Great Alaska earthquake of March 27, 1964. Today's magnitude 4.5 event is significantly smaller than that historical record.
What should I do after an earthquake?
If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.