Magnitude 2.3 - 28 miles SE of Akutan

May 20, 2023 17:55:40 AKDT (May 21, 2023 01:55:40 UTC)
53.8947°N 165.2054°W Depth 25.1 miles (40 km)

This event has been reviewed by a seismologist

38 miles (61 km) E of Akutan Pass
48 miles (77 km) SW of Westdahl Peak
54 miles (87 km) E of Dutch
54 miles (87 km) E of Unalaska
63 miles (102 km) SW of Fisher Caldera
70 miles (113 km) E of Makushin Volcano
78 miles (126 km) SW of Shishaldin Volcano
85 miles (137 km) SW of Isanotski Peaks
90 miles (145 km) SW of Roundtop Mountain
98 miles (158 km) SW of False Pass
115 miles (186 km) E of Bogoslof Island

Magnitude type: M_l²
Event type: earthquake

Tectonic Setting of the Aleutian Islands

The world's largest earthquakes originate along convergent plate boundaries such as the Aleutian megathrust. Starting in 1938, a series of three great earthquakes ruptured the subduction zone along its entire length from the Alaska Peninsula to the western Aleutians with the exception of a small gap near the Shumagin Islands. The sequence began with a M8.2 earthquake southwest of Kodiak Island. A M8.6 in the Andreanof Islands followed in 1957, and the sequence concluded with the Rat Islands M8.7 in 1965. The Shumagin Gap still has not ruptured, but GPS observations suggest that little strain has built up in this region.

Another notable source of seismicity in the arc are the intermediate depth earthquakes within the subducting Pacific Plate, known as the Wadati-Benioff zone. The largest recorded earthquake of this kind was the 2014 M7.9 Little Sitkin event. Shallow earthquakes associated with volcano processes and crustal faults within the overriding North American plate occur regularly and may produce vigorous aftershock or swarm-like sequences.