ATKA, ALASKA / RankWire.AI / – A magnitude 5.0 earthquake struck southeast of Atka in Alaska’s Aleutian Islands late Saturday. The Alaska Earthquake Center recorded the quake at 7:36 p.m. Alaska Daylight Time on August 8. That corresponded to 03:36 UTC on August 9. The epicenter was about 48 miles, or 77 kilometers, southeast of Atka. Seismologists placed the earthquake at a depth of about 10.6 miles, or 17 kilometers.
The reviewed event occurred at coordinates 51.8286 degrees north and 173.2496 degrees west. Seismologists classified its magnitude as a local magnitude measurement of 5.0. The earthquake occurred in a remote part of the Aleutian chain, far from Alaska’s largest population centers. Atka lies on Atka Island in the western portion of the state. The community sits within a region where earthquakes occur frequently because of major tectonic forces beneath the North Pacific.
The earthquake’s recorded location also placed it 48 miles southwest of Seguam Island. It was about 64 miles southwest of Amukta Pass and 74 miles east of Mount Sergief. Other nearby geographic points include Koniuji Island, Kasatochi Island and Great Sitkin Island. The seismic record showed a relatively shallow event compared with deeper earthquakes that also occur beneath the Aleutians. The reviewed data provided the main measurements for the magnitude 5.0 Alaska earthquake.
Aleutian region remains highly active
The Aleutian Arc forms one of Alaska’s most active earthquake zones. The Pacific Plate moves beneath the North American Plate along this long boundary. Scientists call that process subduction. It produces earthquakes at different depths across the region and contributes to Alaska’s high level of seismic activity. The Aleutian Islands experience thousands of earthquakes each year. Monitoring networks across the state track these events and provide updated locations, magnitudes and depths after scientists review the incoming seismic data.
Alaska has experienced some of the strongest earthquakes recorded in modern history. The Aleutian region has also produced several major earthquakes since 1900. They include a magnitude 8.6 event in the Andreanof Islands in 1957. A magnitude 8.7 earthquake struck the Rat Islands in 1965. Large earthquakes also occurred in the Andreanof Islands in 1986 and 1996. Those historical events reflect the sustained seismic activity along the plate boundary that extends beneath the Aleutian chain.
Monitoring continues across Alaska
Earthquakes in the Aleutians can originate from several geological settings. Some occur along the main boundary where the Pacific and North American plates meet. Others develop deeper within the descending Pacific Plate. Shallow earthquakes can also occur within the crust of the overriding plate. The U.S. Geological Survey maintains national earthquake information alongside regional seismic networks. These systems help scientists review earthquake measurements and provide standardized information about events across Alaska and other parts of the United States.
The latest magnitude 5.0 earthquake adds to the regular seismic activity recorded around the Aleutian Islands. The Alaska Earthquake Center operates a statewide network that monitors ground motion from earthquakes and other seismic events. Its reviewed record confirms the August 8 local-time event southeast of Atka at a depth of 17 kilometers. The center also monitors earthquakes across remote areas where population centers are widely separated. That coverage allows specialists to locate and assess earthquakes throughout Alaska’s extensive and highly active seismic regions.