Magnitude 6.8 earthquake strikes off the coast of Canada; no tsunami threat

A magnitude 6.8 earthquake struck northwest of Canada's Vancouver Island late Sunday, according to the United States Geological Survey. It was one of a trio of earthquakes to occur in quick succession on the same fault line.

The US Geological Survey said the preliminary 6.6-magnitude earthquake was 6.8 miles deep, about 135 miles southwest of Port Hardy, a town on the northeastern end of Vancouver Island. It occurred at 10:39 p.m. local time (1:39 a.m. Monday ET), according to the USGS.

The 6.8-magnitude quake came about 35 minutes later and was centered about 12 miles closer to Port Hardy at a depth of about 6 miles, the USGS said.

An aftershock, registering a magnitude of 6.5, followed about six minutes later, the USGS said.

The USGS did not predict damage from the quakes, forecasting they would be felt only lightly. There was no tsunami threat, the Pacific Tsunami Warning Center said.

CNN meteorologist Robert Shackelford said the three earthquakes were all part of the same fault line.

"The first one, which was a 6.6 is called the foreshock. The second one, which is the main earthquake, is the strongest one. The main earthquake is followed by an aftershock, which is the one that was a 6.5. This is standard for earthquakes to happen in groups of three like this," he said.

Canada's west coast lies on the Ring of Fire, a 25,000-mile (40,000-kilometer) arc where the Pacific Plate pushes against smaller tectonic plates, creating seismic activity.