4.9 magnitude earthquake strikes northwest of Pemberton

A 4.9 magnitude earthquake struck the west coast of B.C. on Sunday afternoon, approximately 137 kilometres northwest of Pemberton.

The earthquake, which happened around 3:30 p.m., could be felt on northern and central Vancouver Island, the Sunshine Coast and parts of Greater Vancouver.

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A lot of folks Downtown and in the West End saying they felt something shake in the last 30 mins.

— drex (@drex) December 17, 2023

John Cassidy, a seismologist with Natural Resources Canada, says people over a “very wide region” of the province have reported feeling the earthquake.

Cassidy said the quake was felt as far away as Kelowna, more than 350 kilometres from the quake’s epicentre.

Cassidy says seismic events in that part of the province are “relatively rare,” with the last quake in the area around the same magnitude hitting in 2017. He says Sunday’s quake wasn’t a complete surprise since the province’s coastal areas are an active earthquake zone, but the largest and most frequent earthquakes occur offshore.

“For this size of an earthquake, aftershocks are expected,” Cassidy said. “In fact we are recording a number of small aftershocks at this time. So the largest that we’ve seen so far is about a 2.6 magnitude.”

Cassidy said aftershocks can happen hours or even days after such quakes, but tend to drop off in frequency “as time goes on.”

There have been no reports of damage or injuries so far.

Earlier this month, a magnitude 3.1 earthquake was felt in parts of the B.C.’s Okanagan region.

B.C.’s earthquake and tsunami guide says there are an average of 3,000 quakes reported in the province every year.

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The guide says most of them are too small to be felt, but tremors strong enough to cause structural damage typically happen once every 10 years.

However, B.C. is at risk from what is often called “the big one” — a megathrust temblor that could occur offshore where the Juan de Fuca tectonic plate is being forced under the North American plate — as well as from fault lines that run through the Pacific Northwest.

— With files from The Canadian Press and Glenda Luymes