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Magnitude 2.2 - 61 miles SW of Seguam Island
May 21, 2023 11:38:01 AKDT (May 21, 2023 19:38:01 UTC)
51.5193°N 173.0736°W Depth 16.4 miles (26 km)
This event has been reviewed by a seismologist
- 67 miles (108 km) SE of Atka
- 73 miles (118 km) SW of Amukta Pass
- 79 miles (128 km) SW of Amukta Pass
- 88 miles (142 km) SE of Mt. Sergief
- 100 miles (162 km) SE of Koniuji Island
- 105 miles (170 km) E of Atka Pass
- 110 miles (178 km) SW of Chagulak Island
- 114 miles (184 km) E of Kasatochi Island
- 127 miles (205 km) SW of Yunaska Island
- 135 miles (218 km) E of Great Sitkin Island
- 152 miles (246 km) SW of Herbert 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.