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Magnitude 4.8 - 28 miles NE of Uliaga Island
January 21, 2023 18:27:43 AKST (January 22, 2023 03:27:43 UTC)
53.3607°N 169.3059°W Depth 69.5 miles (112 km)
This event has been reviewed by a seismologist
- 30 miles (48 km) NE of Kagamil Island
- 30 miles (48 km) NW of Mt. Vsevidof
- 35 miles (56 km) NW of Mt. Recheshnoi
- 35 miles (56 km) NW of Nikolski
- 45 miles (72 km) NE of Carlisle Island
- 46 miles (74 km) NE of Mt. Cleveland
- 48 miles (77 km) W of Okmok Caldera
- 54 miles (87 km) NE of Herbert Island
- 65 miles (105 km) SW of Bogoslof Island
- 77 miles (124 km) NE of Yunaska Island
- 94 miles (152 km) NE of Chagulak Island
- 120 miles (194 km) W 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.