(U.S. GeologicalSurvey) - A 7.5-magnitude earthquake struck off the coast of Alaska near midnight on Friday, the U.S. Geological Survey said, prompting tsunami warnings and advisories down the coast of Alaska and Canada's British Columbia.

All tsunami warnings, watches and advisories were later canceled, the West Coast and Alaska Tsunami Warning Center (of the National Oceanic and Atmospheric Administration) said.

Initially, the USGS reported that thetremor wasa magnitude 7.7, but it later downgraded the quake's strength to 7.5.