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Magnitude 2.6 - 94 miles S of Nikolski
May 21, 2023 19:43:17 AKDT (May 22, 2023 03:43:17 UTC)
51.5771°N 168.7793°W Depth 6.2 miles (10 km)
This event has been reviewed by a seismologist
- 99 miles (160 km) SE of Herbert Island
- 99 miles (160 km) SE of Mt. Cleveland
- 105 miles (170 km) SE of Kagamil Island
- 106 miles (171 km) SE of Carlisle Island
- 107 miles (173 km) S of Mt. Vsevidof
- 109 miles (176 km) S of Mt. Recheshnoi
- 109 miles (176 km) SE of Yunaska Island
- 111 miles (179 km) SE of Uliaga Island
- 122 miles (197 km) SE of Chagulak Island
- 131 miles (212 km) S of Okmok Caldera
- 147 miles (238 km) E of Amukta Pass
- 186 miles (301 km) SW of Dutch
- 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.