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Five others could not be reliably assessed.

SFU professor John Clague, an authority on environmental earth sciences, says there are multiple potential scenarios for an earthquake in the Metro Vancouver area — but it’s unclear when a quake will come, where it will be centred and how strong it will be.

“We’ve never had a damaging earthquake in Vancouver, so there’s a kind of reluctance to think they might occur,” said Clague. “But they will. It’s just a question of when.”

“The Big One” — an earthquake of magnitude 9.0 or higher on the Richter scale, which occurs roughly once every 500 years in the Pacific Northwest — would begin off the coast of Vancouver island but could still cause the ground to roll and liquefy in Metro Vancouver, Clague says, which could seriously damage tall buildings.

There’s also the potential for a smaller 7.0 “shallow” quake caused by a fault line, like the 6.3 Christchurch earthquake in 2011 that killed 185 people and caused about $30 billion in damages in 10 seconds.

In a statement to Postmedia, chief facilities officer Larry Waddell argued the 2017 assessment was based off the model earthquake used in the 2015 National Building Code, which he called a “very rare event,” stressing a collapse is unlikely.

Clague agreed it’s unlikely a quake will be direct, but recommends planning for the worst-case scenario.

“You have to think about a worst-case scenario, but the most likely scenario is that we’re going to be dinged by an earthquake that’s far enough away that the buildings remain standing but are seriously damaged,” he said.