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Magnitude 2.2 - 42 miles S of Mt. Gareloi
May 20, 2023 16:07:24 AKDT (May 21, 2023 00:07:24 UTC)
51.1949°N 178.9423°W Depth 14.7 miles (23 km)
This event has been reviewed by a seismologist
- 59 miles (95 km) SW of Tanaga Volcano
- 81 miles (131 km) SW of Bobrof Island
- 82 miles (132 km) SE of Semisopochnoi Island
- 92 miles (149 km) E of Amchitka
- 92 miles (149 km) SW of Kanaga Volcano
- 107 miles (173 km) SW of Mt. Moffett
- 109 miles (176 km) SW of Adak
- 115 miles (186 km) SW of Mt. Adagdak
- 126 miles (204 km) SE of Little Sitkin Pass
- 128 miles (207 km) SE of Davidof Island
- 135 miles (218 km) SW of Great Sitkin 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.