ANCHORAGE, Alaska: A magnitude-8.2 earthquake off Alaska's Kodiak Island prompted a tsunami warning for a large swath of coastal Alaska and Canada's British Columbia while the remainder of the US West Coast was under a watch.
The strong earthquake was recorded about 278km southeast of Kodiak Island early Tuesday morning. The epicentre was 10km under the seabed.
Warnings from the National Weather Service sent to cellphones in Alaska warned: "Emergency Alert. Tsunami danger on the coast. Go to high ground or move inland.''
Less-ominous tsunami watches were issued for the US west coast -- the entire coasts of California and Oregon and part of Washington state.
Kodiak officials warned residents to evacuate if they lived in low-lying areas.
People reported on social media that the quake was felt hundreds of miles away, in Anchorage.
In Alaska, authorities urged coast dwellers to seek safety.
"If you are located in this coastal area, move inland to higher ground," the Anchorage Office of Emergency Management said.
"Tsunami warnings mean that a tsunami with significant inundation is possible or is already occurring. Tsunamis are a series of waves dangerous many hours after initial arrival time. The first wave may not be the largest."