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Magnitude 5.1 - 124 miles S of Seguam Island
January 26, 2023 07:41:40 AKST (January 26, 2023 16:41:40 UTC)
50.5350°N 172.671°W Depth 4.1 miles (6 km)
This event has been reviewed by a seismologist
- 129 miles (209 km) S of Amukta Pass
- 132 miles (214 km) SE of Atka
- 136 miles (220 km) S of Amukta Pass
- 144 miles (233 km) SE of Mt. Sergief
- 155 miles (251 km) SW of Chagulak Island
- 156 miles (252 km) SE of Atka Pass
- 158 miles (256 km) SE of Koniuji Island
- 167 miles (270 km) SE of Kasatochi Island
- 168 miles (272 km) SW of Yunaska Island
- 182 miles (295 km) SE of Great Sitkin Island
- 188 miles (304 km) SW of Herbert Island
- Magnitude type: Mww2
- 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.