Alaska earthquake: Tsunami warning issued after 7.8-magnitude tremor hits

Coastal communities evacuated after earlier tsunami warnings that were later cancelled

A powerful 7.8-magnitude earthquake struck the Alaskan peninsula, sending some coastal communities scrambling amid initial tsunami concerns.

The US Geological Survey (USGS) said the quake occurred at a depth of 10 km (6 miles), some 75 miles south of the city of Chignik on Wednesday morning.

There were no immediate reports of damage, and a tsunami warning issued for coastal Alaska was cancelled after a wave less than one feet tall washed-up.

The US National Tsunami Warning Center had earlier issued tsunami warnings for southern and coastal Alaska, and the Aleutian Islands, leading to some evacuations.

US National Weather service map showing tsunami alerts in place on Wednesday, now cancelled (US Department of Commerce / National Weather Service)

Schools and churches on Kodiak Island had opened their doors for evacuees, the Anchorage Daily News reported.

"We've got a high school full of people," said Larry LeDoux, superintendent of the Kodiak School District. "I've been passing out masks since the first siren sounded," he told the Daily News.

"Everything's as calm as can be. We've got probably 300, 400 people all wearing masks," he said before the warning was cancelled.

The Pacific Tsunami Warning Center announced earlier on Wednesday that “a destructive Pacific-wide tsunami is not expected and and there is no tsunami threat to Hawaii”.

A wave of less than 1 foot (30 centimeters) was later recorded in the community of Sand Point.

"I might have expected a little bit more water, but I'm happy that there wasn't," said David Hale, the senior duty scientist at the National Tsunami Warning Center in Palmer, Alaska.

Aftershock tremors around 3.9 and 5.7-magnitude were also recorded in the area, reported the USGS.

Alaska is the most actively seismic state, with more 25,000 earthquakes recorded in Alaska alone since January 1, according to Alaska University's earthquake centre.