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Magnitude 4.6 - 55 miles SE of Nikolski
November 21, 2022 18:27:31 AKST (November 22, 2022 03:27:31 UTC)
52.3018°N 168.0794°W Depth 11.6 miles (18 km)
This event has been reviewed by a seismologist
- 62 miles (100 km) S of Mt. Recheshnoi
- 62 miles (100 km) SE of Mt. Vsevidof
- 78 miles (126 km) S of Okmok Caldera
- 83 miles (134 km) SE of Kagamil Island
- 86 miles (139 km) SE of Mt. Cleveland
- 88 miles (142 km) SE of Uliaga Island
- 91 miles (147 km) E of Herbert Island
- 92 miles (149 km) SE of Carlisle Island
- 112 miles (181 km) E of Yunaska Island
- 113 miles (183 km) S of Bogoslof Island
- 119 miles (192 km) SW of Makushin Volcano
- 127 miles (205 km) SW of Dutch
- Magnitude type: Mb2
- 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.