The tsunami warning was lifted without incident a short time later. There were no immediate reports of any deaths or serious injuries.
The U.S. Geological Survey said the first and more powerful quake was centered about 7 miles (12 kilometers) north of Anchorage, Alaska's largest city, with a population of about 300,000. People ran from their offices or took cover under desks.
Alaska earthquake: Home surveillance video shows 20 seconds of chaos as quake hits Palmer