Whitehorse Daily Star

Aftershocks still being felt in Whitehorse

No, that wasn’t your imagination....

By Stephanie Waddell on May 4, 2017

No, that wasn’t your imagination....

Anyone thinking he or she was once again on shaky ground Wednesday evening was right.

Aftershocks from the two major earthquakes felt throughout the territory early Monday morning have continued since, with many feeling a shake measuring 4.6 last night.

The first earthquake on Monday that awoke many Yukoners at 5:31 a.m. measured 6.2 at the epicentre in the mountains between the South Klondike Highway and the Haines Highway.

Then, less than two hours later, at 7:18, another 6.3 quake was felt. Its epicentre was 66 kilometers northwest of Klukwan, Alaska, which sits along the Haines Highway.

Aftershocks continued to be felt throughout the day on Monday. Things seemed to settle a bit Tuesday and into Wednesday evening, until shortly before 8:30 p.m.

That’s when a number of Yukoners took to social media. Some wondered if they had really just felt another tremblor, or if it was their imagination taking over from Monday’s events.

Others were more certain they had indeed felt another temblor.

It wasn’t long before links and screen shots were being posted and shared from geological websites showing the 4.6 shake at 8:13 p.m. recorded 40 miles northwest of Klukwan – dispelling any confusion that the shake had been imagined.

It’s the largest of several seismic events in the area recorded yesterday and among an even longer list of after shocks that have been ongoing since Monday’s two quakes.

The University of Alaska Fairbanks’ earthquake centre website shows it had a depth of 12 miles. Further after shocks have continued.

Maurice Colpron is the head of the bedrock geology section of the Yukon Geological Survey.

This morning, he explained the aftershocks – including the one felt last night – are a readjusting of the tectonic plates after the two major earthquakes.

“It’s nothing unusual,” Colpron said.

The number of aftershocks has fallen in the days following the large quakes. “It will diminish with time.”

It’s unknown, though, exactly how long it will take before the aftershocks will end.

Following Monday’s quake, the Yukon Geological Survey released a video where Colpron explained the two temblors:

“These earthquakes appear because there was a build-up of energy around the Denali, Duke River fault systems, and yesterday we just had a sudden release of that energy.

“So that energy builds over time. As the tectonic plates pass each other, you’ll have a lock-up and build-up of energy which will be released in these dramatic events.”

The aftershocks come as fault lines readjust to the changes from the earthquake.

In the meantime, officials are still dealing with the quakes’ aftermath.

The Yukon government is continuing its assessment of the Ross River School, which has been closed since the earthquake, over concerns around possible structural damage. Field trips for students have been organized for the remainder of the week.

Meanwhile, Natalia Martinez, a 37-year-old mountain climber from Argentina, remains stranded on Mount Logan in Kluane Natunal Park after the earthquakes triggered avalanches.

Helicopters have been unable to reach her due to a storm, but the climber remains in close contact with Parks Canada as she waits out the storm.

Her partner, who’s in Whistler, B.C., has told national media outlets Martinez is tired, but safe and well-supplied.

It’s hoped she can be plucked off the mountain on Friday, but plans are weather-dependent.

Comments (5)

Up 0 Down 0

seismiccreep on May 10, 2017 at 3:09 pm

The last big shaker to hit Whitehorse and Yukon sometime in the 90's, I was on the old Canadian Tire roof across the parking lot from Independent Grocers after the fact. I noticed a crack in the roofing that went from one end of the roof to the other. I followed it to the edge of the roof and noticed the crack continued right across the parking lot.

Are there any undetected faults waiting for the next shaker? Get up on the roofs, check the parking lots, For professional advice call Shaky Jake, Earthquake Specialists, Skid Row, Tagish.

Up 4 Down 4

Sorry... on May 5, 2017 at 4:50 pm

Sorry north_of_60 but your comment is only partially accurate and somewhat misleading...Seismology is a heck of a lot more complicated than that.

Remotely triggered and doublet earthquakes are two examples... Throw in some postseismic stress transfer and stress feedback between intra-plate faulting and far-field tectonics... the list goes on...

Stay thirsty for knowledge, my friends.
Regards,
The most uninteresting man in the world.

Up 9 Down 9

north_of_60 on May 4, 2017 at 11:07 pm

Many small quakes are good news. Plates are constantly moving at about the rate our fingernails grow. Small quakes are the sign of continual adjustments. If it gets totally 'quiet' for long periods, then we have reasons for concern.

Up 16 Down 24

ralpH on May 4, 2017 at 3:19 pm

Just YTG employees vibrating from the budget numbers that has to be at least a 3 on the richter lol

Up 13 Down 22

ralpH on May 4, 2017 at 3:18 pm

Just repercussions from the budget numbers. All YTG employees are vibrating lol

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