More than 100 aftershocks had shivered across the Alaska Panhandle, southern Yukon and parts of northwestern British Columbia by early Tuesday following two powerful earthquakes a day earlier, but seismologists say while people need to be prepared, it isn't time to be alarmed.

The U.S. Geological Survey reported the aftershocks, including at least a dozen Tuesday morning, came in the wake of the 6.2 and 6.3 magnitude earthquakes Monday that were centred west of Skagway, Alaska.

The quakes were felt as far away as Whitehorse and Ross River, which is more than 300 kilometres away.

Earthquake map

The earthquake hit about 85 kilometres northwest of Skagway, Alaska, near B.C./Yukon border. (CBC)

Earthquakes Canada also reported a 4.5 magnitude quake jolted the Carcross region, about 75 kilometres south of Whitehorse on Tuesday morning.

Earthquake seismologist Alison Bird of the Geological Survey of Canada said continued shaking is expected.

"It's sort of a swarm of activity, there seems to be some intense earthquakes," she said. "It's fairly normal to have this sort of thing. This is an area that gets a lot of earthquakes anyway, but sometimes it sort of flares up in sudden activity."

Whitehorse earthquake

Debris is sent tumbling down Whitehorse's clay cliffs. Whitehorse resident Angie Dickson took this photo after the second earthquake hit at 7:20 a.m. PT. (Angie Dickson)

Powerful earthquakes almost always spawn aftershocks that can continue for years, she said, adding that the level of seismic activity in the Haida Gwaii region of B.C. remains elevated, five years after a magnitude 7.8 quake there.

Following Monday's earthquakes, the Yukon government issued messages via Twitter confirming that the school in Ross River, about 200 kilometres northeast of Whitehorse, remained closed as engineers checked for safety.

The four-storey Lynn Building in downtown Whitehorse was also closed after being evacuated Monday when large cracks were spotted in its foundation but other structures, as well as the clay cliffs overlooking downtown Whitehorse had been checked and declared safe.

"It is a good reminder that we can have large earthquakes in that area and they can get much larger than this, so people up there tend to be prepared for that sort of thing," said Bird.