The temblor at 2041 GMT was followed by more than 30 aftershocks ranging from magnitude 5.1 to 3.3 over the next three hours, according to the US Geological Survey.

The epicenter was about 155 miles (248 kilometers) west of Whitehorse, the capital of Canada's Yukon, and 230 miles northwest of Alaska's capital Juneau.

In Yakutat, Alaska, near the epicenter, police chief Theo Capes told AFP there were no injuries or damages reported from the quake that "lasted surprisingly long, 15 to 20 seconds."

There was no threat of a tsunami, according to the US Tsunami Warning System.