Scientists confirm megathrust quake danger exists not only in southern B.C., but also in the north

The potential for large quakes and tsunamis off the south coast has long been known, but now scientists are confirming another theory in the north of the provin

Following years of debate, scientists can now confirm that a fault zone off B.C.’s northern coast is capable of producing powerful megathrust earthquakes, the kind that can generate tsunamis.

The findings reveal what many researchers theorized: That the Pacific Plate is partially dipping beneath the North American Plate.

This comes more than a decade after a powerful 7.8-magnitude quake struck near Haida Gwaii, on Oct. 27, 2012.

At the time, scientists were puzzled by the quake’s characteristics because it resembled activity normally seen much further south, in the Cascadia Subduction Zone off Vancouver Island and Washington State.

The 2012 quake had a thrust mechanism which was not typical of the Queen Charlotte Fault, where plates usually slide past each other horizontally.

“So not just sliding, but also going a bit under North America,” said Mladen Nedimovic, a professor of Earth and Environmental Sciences at Dalhousie University.

The research team used a state-of-the-art, 15-kilometre-long hydrophone streamer. Essentially, a very long wire with thousands of underwater microphones attached.

They then scoured the fault from northern B.C. to southern Alaska.

The breakthrough will allow researchers to better predict what types of earthquakes to expect.

“They’re both large,” Nedimovic explained. “But the ones where one plate pushes under another are the type that can produce tsunamis.”

Scientists still can’t predict exactly when a quake might hit, but the findings will help governments better prepare.

“It’s not just about saving lives, but also about protecting critical infrastructure,” he added.

The findings have been published in the journal Science Advances, and included research from Canadian and American scientists, including from Dalhousie University in Halifax.