(CNN) — A tsunami advisory has been issued for coastal Alaska following a magnitude 7.9 earthquake located about 15 miles from Little Sitkin Island, Alaska.
The quake had a depth of 71 miles and was expected to produce a “modest” tsunami, according to the Pacific Tsunami Warning Center.
The advisory was in effect for the Aleutian Islands from Nikolski, Alaska, west to Attu and east to Unimak Pass. The tsunami center warned residents to stay off the beach.
The town of Adak evacuated its 150 residents to a shelter about 600 feet above sea level, City Manager Layton Lockett told CNN.
There were no initial reports of damage in Adak or on Shemya Island, said Ian Dickson, website manager for the Alaska Earthquake Information Center.
Dickson said there were 17 measurable aftershocks in the two hours after the quake.
First estimates put the quake at magnitude 8.0, and prompted a tsunami warning. The strength was subsequently set by the U.S. Geological Survey at 7.9 magnitude and the tsunami warning was scaled back to an advisory.