There has been a 'swarm' of 200 or so earthquakes hundreds of kilometres off B.C.'s coast in the last 36 to 48 hours, but a Canadian seismologist says it's considered "business as usual."
Andrew Schaeffer, an earthquake seismologist with Natural Resources Canada, said over the last few days there have been a number of earthquakes that have occurred about 150 to 200 kilometres southwest off Vancouver Island. He said the earthquakes are happening in an intersection area between the Juan de Fuca spreading ridge: the Sovanco fracture zone and the Nootka fault zone.
On Wednesday, the United States Geological Survey listed about five earthquakes, ranging from 4- to 4.7-magnitude, in a little more than two hours.
He said Natural Resources Canada has located about 200 or so earthquakes in recent days, but there have been many more even smaller ones that are just too far offshore. On Friday morning (July 5), there were a few magnitude-five earthquakes.
Earthquakes Canada's most recent is a 5.2-magnitude earthquake, about 225 kilometres southwest of Port Alice.
"This is an area of Vancouver Island that is very commonly seismically active. It'll have magnitude twos and threes all the time, and every once in a while, we'll see a swarm, like this where we see a swarm like this where we start to get some fours and fives."
Schaeffer said those magnitude-fours and fives will happen in close succession, but he added it's "still completely normal."
"We would consider this business as usual for this portion off the west coast of Vancouver Island."
The earthquakes that happen in this area are "quite shallow, but they are not the type of earthquake that produces tsunamis," he said. They're also not particularly related to the Cascadia subduction zone.
Schaeffer added it's not uncommon to get a few swarms like this in a year.
"While the larger earthquakes like this in this area kind of pique our interest, fortunately these types, they're not damaging to people or infrastructure because of how offshore they are," he said.
"But they just serve as a good and constant reminder that we do live in a tectonically active region, and it's a reminder to just be ready because we have the potential for others."
