An earthquake measuring 8.0 on the Richter scale jolted 24 km southeast of Little Sitkin Island, Alaska on Monday, the U.S. Geological Survey (USGS) said, Xinhua reported.
The epicenter, with a depth of 114.4 km, was initially determined to be at 51.7968 degrees north latitude and 178.7591 degrees east longitude, the USGS said.
The National Tsunami Warning Center in Palmer, Alaska, issued a tsunami warning covering Alaska coastal areas from Nikolski to Attu, on the Aleutian Islands.
The level of tsunami danger was being evaluated for other U.S. and Canadian Pacific coasts, the center added.
So far, there were no immediate reports of damage.