(Reuters) - A powerful earthquake with a magnitude of 7.7 hit Canada's Pacific coast province of British Columbia late Saturday, setting off a small tsunami, but there were no immediate reports of damage, officials said. The U.S. Geological Survey said an earthquake with a 7.7 magnitude hit the province, centered 123 miles south-southwest of Prince Rupert at a depth of 6.2 miles, the USGS said.