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Magnitude 4.0 - 22 miles SW of Amchitka
February 10, 2023 20:09:32 AKST (February 11, 2023 05:09:32 UTC)
51.3753°N 178.5626°E Depth 28.3 miles (45 km)
This event has been reviewed by a seismologist
- 41 miles (66 km) S of Little Sitkin Pass
- 42 miles (68 km) S of Davidof Island
- 48 miles (77 km) SE of Segula Peak
- 60 miles (97 km) SW of Semisopochnoi Island
- 65 miles (105 km) SE of Kiska Volcano
- 117 miles (189 km) W of Mt. Gareloi
- 131 miles (212 km) SE of Buldir Is
- 131 miles (212 km) SE of Buldir Island
- 146 miles (236 km) W of Tanaga Volcano
- 175 miles (283 km) W of Bobrof Island
- 187 miles (303 km) W of Kanaga Volcano
- 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.