WASHINGTON, July 22 — A 7.8-magnitude earthquake struck off the Alaskan peninsula, triggering a tsunami warning for areas within 300 kilometres of the epicentre.

The shallow quake hit at 0612 GMT today about 800 km southwest of Anchorage, and around 100 km south-southeast of the remote settlement of Perryville, the US Geological Survey said.

"Based on the preliminary earthquake parameters ... hazardous tsunami waves are possible for coasts located within 300 km of the earthquake epicentre, the Pacific Tsunami Warning Center said.

A tsunami warning was in effect for the Alaskan peninsula and south Alaska.

"For other US and Canadian Pacific coasts in North America, the level of tsunami danger is being evaluated.”

The quake was felt hundreds of miles away.

"Bed and curtains were going. Felt like a very long quake!” one witness in Homer, Alaska, 640 km from the epicentre, said on the quake monitoring website msc-csem.org.

Alaska is part of the seismically active Pacific Ring of Fire.

Alaska was hit by a 9.2-magnitude earthquake in March 1964, the strongest ever recorded in North America. It devastated Anchorage and unleashed a tsunami that slammed the Gulf of Alaska, the US west coast, and Hawaii.

More than 250 people were killed by the quake and the tsunami. — AFP