Authorities say there is no risk of a local tsunami.
The USGS National Earthquake Information Centre later changed the scale of the quake to 6.6.
People from as far away as Kelowna, B.C., nearly a thousand kilometres to the east, reported feeling the earthquake. So far more than 400 people have reported feeling the earthquake to the U.S. Geological Survey.
In downtown Vancouver some residents in high rises said they felt their building or chandeliers sway.
There are currently no reports of damage or injury.
There have been two aftershocks, one of magnitude 5 and a smaller one at magnitude 4.
The USGS says aftershocks are normal for a quake of this magnitude.
Secondary shockwaves are usually less violent, but could cause structural damage to any structures weakened during the initial earthquake.
MAP: Port Alice, B.C.