Crews in helicopters inspected power lines Saturday checking for problems caused by the largest earthquake to hit eastern Canada in more than 50 years amid reports of only minor damage and aftershocks that experts said could last several years.

The quake, which struck at 6:38 p.m. EST Friday, measured 6.0 on the Richter scale and was centered in Baie St. Paul, about 90 miles northeast of Quebec City in the West Quebec seismic zone. Seismologists calculated the quake originated 11.7 miles beneath the Earth's surface.It knocked out power and phones over much of Quebec and was also felt in Ontario and Nova Scotia. The temblor was felt in the northeastern United States from Michigan to Maine and as far south as Washington, D.C.

Even President-elect George Bush noticed the quake at his summer home in Kennebunkport, Maine where he was spending the Thanksgiving holiday weekend.

Jacques Couture, a spokesman for Quebec Hydro in Montreal, said by telephone that power failures affecting hundreds of thousands of customers on the north and south shore of the St. Lawrence River were repaired within two hours of the earthquake.

"There are lots of crews working today, but they are making an inspection to check for damage," Couture said. He said crews in helicopters were checking the huge network of transmission lines while others would check inside the system's dams for damage to electronic equipment.

In Chicoutimi, Quebec, close to the quake's epicenter, police said officials were still trying to assess damage that included three house fires and collapsed chimneys. In nearby Jonquiere, two natural gas lines caught fire but the flames were quickly controlled and no injuries were reported.

Quebec City chief engineer Claude Vincent said the quake caused "a few cracks in the walls" of buildings there.

Janet Drysdale, another seismologist with the Geological Survey, said the aftershocks could continue as long as two years.

"We would expect at least one with a magnitude of 5.0 on the Richter scale, a couple of 4.0s, two 3.0s and numerous little wee ones," Drysdale said.