Magnitude 5.2 - 63 miles NW of Seguam Island
October 27, 2020 20:13:41 AKDT (October 28, 2020 04:13:41 UTC)
53.0552°N 173.3519°W Depth 156.7 miles (254 km)
This event has been reviewed by a seismologist
- 69 miles (111 km) NW of Amukta Pass
- 70 miles (113 km) NE of Atka
- 75 miles (121 km) NW of Amukta Pass
- 94 miles (152 km) NE of Koniuji Island
- 96 miles (155 km) NE of Mt. Sergief
- 98 miles (158 km) W of Chagulak Island
- 109 miles (176 km) NE of Kasatochi Island
- 112 miles (181 km) NE of Atka Pass
- 115 miles (186 km) W of Yunaska Island
- 135 miles (218 km) NE of Great Sitkin Island
- 136 miles (220 km) W of Herbert Island
- 287 miles (465 km) W of Dutch
- Magnitude type: Ml2
- Event type: earthquake
Tectonic Setting of the Aleutian Islands
The Aleutian Arc marks the region where the Pacific Plate subducts into the mantle beneath the North American Plate. It is a seismically active region, evidenced by the thousands of earthquakes occurring each year. Since 1900, this region has hosted several major megathrust earthquakes, including the 1957 M8.6 in the Andreanof Islands, the 1965 M8.7 in the Rat Islands, the 1986 M7.9 and the 1996 M7.9 in the Andreanof Islands, and the 2003 M7.8 in the Rat Islands. Together they have ruptured the entire length of the megathrust boundary in this region. Another notable source of seismicity in the arc is the zone 6-9 miles (10-15 km) wide of intermediate-depth earthquakes within the subducting Pacific Plate, known as the Wadati-Benioff Zone. The largest recorded intermediate-depth earthquake in this region was the 2014 M7.9 Little Sitkin event. A third source of seismicity in this region are shallow earthquakes associated with volcanic processes and crustal faults within the overriding North American Plate. They occur regularly and may produce vigorous aftershock or swarm-like sequences.