* Quake hits Haida Gwaii region
* Tsunami warning issued, though no major wave seen
* Provincial officials say no reports of major damage
* Communities evacuated on Haida Gwaii islands, northwest (Adds information from Emergency Management B.C. conference call)
By Jeffrey Hodgson
Oct 27 (Reuters) - A powerful earthquake with a magnitude of 7.7 hit Canada's Pacific coastal province of British Columbia late Saturday, setting off a small tsunami, but there were no immediate reports of injuries or damage, officials said.
The U.S. Geological Survey said an earthquake with a 7.7 magnitude had hit the province, centered 123 miles (198 km) south-southwest of Prince Rupert at a depth of 6.2 miles (10 km).
Earthquakes Canada said the quake in the Haida Gwaii region has been followed by numerous aftershocks as large as 4.6 and said a small tsunami has been recorded by a deep ocean pressure sensor.
"It was felt across much of north-central B.C., including Haida Gwaii, Prince Rupert, Quesnel, and Houston. There have been no reports of damage at this time," the agency said in a statement on its website.
Officials with Emergency Management B.C. said in a conference call that while power supply had been hit in some areas, there was no major damage reported.
Some communities on the Haida Gwaii islands, as well as Port Edward in the northwest of the province were being evacuated as a precaution.
The provincial agency issued a tsunami warning for the north coast and Haida Gwaii, as well as for central coast communities like Bella Coola, Bella Bella and Shearwater.
A tsunami advisory was also issued for the outer west coast and part of the south coast of Vancouver Island. Officials said a lower-level advisory has been declared because of potentially strong currents and waves. It urged residents to stay away from beaches and shorelines until further notice.
The quake was not felt in the larger cities of Victoria or Vancouver in the south, a resident in each city told Reuters.
The Pacific Tsunami Warning Center said no destructive tsunami was expected from the quake but the West Coast-Alaska Tsunami Warning Center issued a warning for coastal sections of British Columbia and Alaska. (With additional reporting by Will Dunham, Nicole Mordant and Jennifer Kwan; Editing by Andrew Osborn)