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Magnitude 3.8 - 121 miles S of Mt. Gareloi
December 29, 2022 10:25:31 AKST (December 29, 2022 19:25:31 UTC)
50.0797°N 179.4098°W Depth 2.6 miles (4 km)
- 122 miles (197 km) SE of Amchitka
- 136 miles (220 km) S of Semisopochnoi Island
- 136 miles (220 km) SW of Tanaga Volcano
- 152 miles (246 km) SW of Bobrof Island
- 161 miles (261 km) SW of Kanaga Volcano
- 161 miles (261 km) SE of Little Sitkin Pass
- 163 miles (264 km) SE of Davidof Island
- 171 miles (277 km) SE of Segula Peak
- 172 miles (278 km) SW of Adak
- 173 miles (280 km) SW of Mt. Moffett
- 180 miles (291 km) SW of Mt. Adagdak
- 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.