by Andru McCracken
Something shook Valemount, Cedarside and Tete Jaune for 10 seconds four days before Christmas, and after some scrutiny it is believed to be an earthquake.
The quake’s epicentre was at the head of Kinbasket Reservoir just nine kilometers from the Village of Valemount. Other potential causes haven’t been ruled out, but for now, the Geological Survey of Canada has deemed it a quake.
On December 21, Darren Heaps was at home on the computer when he noticed his pellet stove rattle, and then dishes on the rack rattle too.
“We just had an earthquake!” wrote Heaps at 12:37 pm.
When Lorna Griffin first heard it, it was loud.
“I thought Bob had blown something up at the campground. It kept on long enough I thought, ‘Should I get out of the house?’”
Griffin said it knocked some pictures off the wall.
“I’ve never felt anything like it before,” she said.
People took to social media to air theories of the shake: some said it was CN or highways blasting for avalanche control, but Lorna figured there is little chance a blast heard in Valemount could also be felt in Tete Jaune.
When the Goat phoned Taimi Mulder, Earthquake Seismologist for Geological Survey of Canada – Natural Resources Canada, and explained accounts of the shudder, at first she was sure it was not an earthquake.
“If it shook for 10 seconds the magnitude would have lit up all of Canada and our seismic network,” said Mulder. “There is no way we would ever miss that.”
Mulder said an usual suspect would be something breaking the sound barrier in the vicinity, like a military aircraft breaking the sound barrier or possibly an asteroid, which can often go undetected during the day.
The reason she was sure it wasn’t an earthquake was because a duration that long requires a significant shake, magnitude 4 or more. According to Mulder there are 150 to 200 instruments detecting seismic activity across BC, one as close as Blue River.
But Mulder promised to re-check the data after our initial interview to see if anything had been detected.
That’s when she discovered there had been a shallow earthquake near the tip of Kinbasket Lake measuring 3.1 on the Richter Scale.
She said she might be out by a few kilometers, but geologically-inclined explorers may find evidence of the quake near that location, including a surface rupture. (For keeners, the GPS coordinates are 52.7669 -119.1735)
“It’s not very deep at all,” said Mulder.
Mulder classified the movement as an earthquake, but left the door open to other possibilities, blasting in a gravel pit or a mine in the area could produce a similar impact.
Mulder said the closest working seismic instrument at that time was 150 km away.
She said a 3.1 magnitude earthquake shouldn’t cause damage.
“You’d feel it, but that’s it,” she said.
Heaps said it was his first earthquake despite living in the mountains his whole life.
“I was waiting to feel another tremor, but there were no more,” he said.