The U.S. Geological Survey said that the magnitude-7.2 struck at 11:30 p.m. Tuesday and was centered about 125 miles (200 kilometers) west of Adak in the island chain.
There were no reports of any injuries or damage and a dispatcher with the Anchorage Police Department said he did not feel the quake, some 1,300 miles (2,100 kilometers) away.
The Aleutian Islands extend southwestward from Alaska into the northern Pacific Ocean and include more than 300 islands.
A tsunami warning was canceled early Wednesday for Alaska's coasts after officials determined waves from the earthquake posed no widespread destructive threat.
The earth's most active seismic feature, the circum-Pacific seismic belt, brushes Alaska and the Aleutian Islands.
The Andreanof Island sustained a magnitude 8.8 earthquake in March 1957 that caused very severe damage on Adak and Unimak Islands. A damaging tsunami was generated, and a wall of water 40 feet (12 meters) high smashed the coastline of Scotch Cap on Unimak Island. Sand Bay, near Adak, reported 26-foot (8-meter) waves inundated its shores.
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