The 2.2 magnitude earthquake that shook Salmon Arm residents on Saturday, March 2 was a mere ripple compared to past quakes that have rattled the Southern Interior.
The most powerful quake to hit the region shook the ground on Feb. 4, 1918. The epicentre of the 6.0 magnitude quake was near the current location of the community of Mica Creek, approximately 150 kilometres north of Revelstoke.
Although the quake’s centre was in a remote area on the west slope of the Rocky Mountains, earthquake seismologist Taimi Mulder said it would have made its presence known far and wide.
Mulder, who works for the Geological Survey of Canada, a division of Natural Resources Canada, said people in the Okangan and Shuswap definitely would have felt the quake.
“When you’re further away the high frequencies attenuate and you get longer lower frequencies. It gets to feel a little bit more like a rolling motion,”
Mulder said at 150 kilometres from an earthquake the size of the one that hit in 1918, people definitely would have experienced rattling dishes and swaying chandeliers in their homes. Closer to the quake, high frequency shaking would have been felt for between 15 and 30 seconds.
Based on current building codes, damage to structures begins happening at a 5.5 magnitude or more. Mulder said damage caused by a quake of this strength would have been localized to an area 10 to 20 kilometres from the epicentre.
A 5.0 magnitude quake, the second most powerful to hit the region, was recorded southwest of Kamloops near Lytton on Sept. 22 1926.
The most powerful quake since the turn of the century was recorded on Aug. 17, 2002, with a magnitude of 4.5. Its epicentre was less than 100 km due west of Kelowna.
The most recent quake to make Earthquakes Canada’s top 10 list for the region took place on Sept. 10, 2016. The 4.1 magnitude quake’s epicentre was south-east of Penticton. The Penticton Western News reported the quake shook the ground at 9:16 a.m., originating from an epicentre 21 km north-east of Osoyoos and five kilometres deep.