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Magnitude 3.8 - 106 miles S of Adak
January 10, 2023 23:23:18 AKST (January 11, 2023 08:23:18 UTC)
50.3826°N 177.1929°W Depth 20.6 miles (33 km)
- 106 miles (171 km) S of Bobrof Island
- 107 miles (173 km) S of Kanaga Volcano
- 109 miles (176 km) S of Mt. Moffett
- 112 miles (181 km) S of Tanaga Volcano
- 114 miles (184 km) S of Mt. Adagdak
- 119 miles (192 km) SE of Mt. Gareloi
- 125 miles (202 km) S of Great Sitkin Island
- 137 miles (222 km) SW of Atka Pass
- 143 miles (231 km) SW of Kasatochi Island
- 151 miles (244 km) SW of Mt. Sergief
- 155 miles (251 km) SW of Koniuji Island
- 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.