Calgary, a prairie city far from any nearby fault lines, felt an unfamiliar sensation early Tuesday evening — an earthquake.
A 6.5 magnitude quake occurred at a depth of 10 kilometres near Challis, Idaho, at 5:52 p.m. MT, and was felt in Calgary just a few minutes later.
The epicentre of the quake was nearly 700 kilometres southwest of Calgary.
Some residents were quick to react to their buildings trembling on social media.
My apartment (on 17th floor of my building) felt really wobbly for a few seconds there. Was there an earthquake? Does Calgary get earthquakes? <a href=”https://twitter.com/hashtag/yyc?src=hash&ref_src=twsrc%5Etfw”>#yyc</a> <a href=”https://twitter.com/hashtag/earthquake?src=hash&ref_src=twsrc%5Etfw”>#earthquake</a> <a href=”https://twitter.com/hashtag/calgary?src=hash&ref_src=twsrc%5Etfw”>#calgary</a>
My mom just called from work (Foothills Hospital) claiming they just felt the building move like an earthquake. Anyone feel anything? <a href=”https://twitter.com/hashtag/YYC?src=hash&ref_src=twsrc%5Etfw”>#YYC</a>
Tom Sampson, chief of the Calgary Emergency Management Agency, tweeted that the lights swayed in the city’s emergency operations centre — where his team has been busy since the city declared a state of local emergency to respond to the COVID-19 crisis.
John Cassidy, a seismologist with Natural Resources Canada, said the earthquake was a large one, and was felt in southern B.C., Montana and Utah as well.
“The shaking in Canada is not particularly strong, it certainly isn’t damaging shaking, but it certainly was noticeable by many people,” he said.
“At great distances, typically what you feel are what we call surface waves. These are almost like waves on the ocean … those waves are relatively slow, and they are the kind of waves that can get high buildings shaking, so high rises will tend to sway back and forth during these types of earthquakes.”
Cassidy said it’s been more than a decade since Idaho last experienced a quake of this size, but its not extremely unusual for the region. He said globally, there are about 120 earthquakes of that size each year.
Incredible to believe but we noted the lights sway slightly in the EOC. <a href=”https://twitter.com/hashtag/YYC?src=hash&ref_src=twsrc%5Etfw”>#YYC</a> <a href=”https://twitter.com/hashtag/Earthquake?src=hash&ref_src=twsrc%5Etfw”>#Earthquake</a> <a href=”https://t.co/uaTsSpHWTd”>pic.twitter.com/uaTsSpHWTd</a>
The police department in Boise, Idaho tweeted that there were no immediate reports of damage or injuries.
A 4.6-magnitude aftershock happened at 6:27 p.m. MT, according to the United States Geological Survey.
The last time Calgarians felt a large earthquake was in 2017, when a 5.8-magnitude quake shook Montana.
While more than 1,000 earthquakes happen in Western Canada each year, the majority happen along the Pacific Coast, with the quakes sharply reducing in intensity and frequency east of the Rockies.