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Magnitude 3.5 - 56 miles SE of Unalaska
December 31, 2022 08:39:53 AKST (December 31, 2022 17:39:53 UTC)
53.1199°N 165.9921°W Depth 22.2 miles (35 km)
- 57 miles (92 km) SE of Dutch
- 65 miles (105 km) S of Akutan Pass
- 66 miles (107 km) SE of Makushin Volcano
- 71 miles (115 km) S of Akutan
- 91 miles (147 km) E of Okmok Caldera
- 101 miles (163 km) SE of Bogoslof Island
- 106 miles (171 km) E of Mt. Recheshnoi
- 111 miles (179 km) SW of Westdahl Peak
- 112 miles (181 km) E of Mt. Vsevidof
- 120 miles (194 km) E of Nikolski
- 126 miles (204 km) SW of Fisher Caldera
- Magnitude type: Ml2
- 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.