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Magnitude 4.6 - 73 miles SW of Buldir Is
January 4, 2023 02:06:17 AKST (January 4, 2023 11:06:17 UTC)
51.6860°N 174.6020°E Depth 10.5 miles (17 km)
This event has been reviewed by a seismologist
- 73 miles (118 km) SW of Buldir Island
- 74 miles (119 km) S of Shemya Is
- 104 miles (168 km) SE of Attu
- 131 miles (212 km) W of Kiska Volcano
- 152 miles (246 km) W of Segula Peak
- 160 miles (259 km) W of Davidof Island
- 163 miles (264 km) W of Little Sitkin Pass
- 189 miles (306 km) W of Amchitka
- 214 miles (346 km) W of Semisopochnoi Island
- 283 miles (458 km) W of Mt. Gareloi
- 310 miles (502 km) W of Tanaga Volcano
- Magnitude type: Mb2
- 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.