Magnitude 3.6 - 38 miles W of Seguam Island

February 7, 2023 03:41:59 AKST (February 7, 2023 12:41:59 UTC)
52.1249°N 173.298°W Depth 113.7 miles (184 km)

This event has been reviewed by a seismologist

39 miles (63 km) E of Atka
57 miles (92 km) W of Amukta Pass
59 miles (95 km) SW of Amukta Pass
70 miles (113 km) E of Mt. Sergief
78 miles (126 km) E of Koniuji Island
89 miles (144 km) E of Atka Pass
94 miles (152 km) E of Kasatochi Island
96 miles (155 km) W of Chagulak Island
115 miles (186 km) W of Yunaska Island
120 miles (194 km) E of Great Sitkin Island
140 miles (226 km) E of Mt. Adagdak
307 miles (497 km) W of Dutch

Magnitude type: M_l²
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.