The magnitude 7.5 quake and tsunami warning that followed caused concern in some coastal communities, with alarms sounding and people rushing to higher ground for safety.

But the Alaska Tsunami Warning Center later said the waves were too small to pose a threat, reaching just six inches above normal sea level in places such as Sitka and Port Alexander.

"Initially, in the first 15 to 20 minutes, there might have been a bit of panic," Sitka Police Chief Sheldon Schmitt told The Associated Press in a phone interview. But he said things calmed down as the town waited for the all clear.