HONOLULU - A 6.3 magnitude earthquake struck the coast of western Canada, several hours after a powerful temblor nearby sparked a tsunami warning and sent Hawaiians scrambling, US seismologists said Sunday.
The quake hit at 1854 GMT Sunday at a depth of 5.1 miles (8.2 kilometers) in Canada's Queen Charlotte Islands region north of Vancouver, the US Geological Survey said.
There were no immediate reports of damage or tsunami alerts.
It followed a powerful 7.7 magnitude earthquake off the coast overnight, which triggered a tsunami warning that emptied restaurants, bars and theaters in Hawaii and sent rattled residents fleeing beach areas.
But only relatively small waves rolled to shore on the island of Oahu, and the US Tsunami Warning Center later issued an advisory saying the worst was over.
The first quake struck at 0304 GMT Sunday, prompting an initial warning from the Hawaii-based Pacific Tsunami Warning Center.
The center eventually issued an all-clear, but warned that sea level changes and strong currents could still occur and present a hazard for swimmers and boaters.
The Queen Charlotte Islands, also known by their indigenous name of Haida Gwaii, comprise about 150 islands located north of Canada's Vancouver Island.
Only about 5,000 people live on the islands, about 45 percent of them indigenous Haida people.
Natural Resources Canada said in a statement that the first quake caused no damage, but was felt across much of north-central British Columbia.
Gerard Fryer, a senior geophysicist with the Pacific Tsunami Warning Center, said quakes exceeding magnitude 7.0 should not be taken lightly.
"A 7.7 is a big, hefty earthquake. It's not something you can ignore," he told CNN International.
He said it had struck partly under an island, but mostly under shallow water.
"I think we have to be thankful it happened where it did," Fryer said.
"If that were a heavily populated area, it would have caused significant damage."