VANCOUVER — Like many on Friday, Simon Fraser University earthquake expert John Clague watched with a mixture of fascination and horror as Japan struggled to cope with the devastation caused by an 8.9-magnitude earthquake that sparked an equally destructive tsunami that has left thousands dead or missing.

While the images of burning buildings and floating cars were impressive, it was something else, a little closer to home, that kept the professor of Earth sciences monitoring the headlines throughout the day.

What if the Big One hit here?

Like Japan, the West Coast of B.C. rests on a subduction zone — in this case the Cascadia Subduction Zone — the physical convergence of two tectonic plates that sees one plate, an oceanic plate, submerge under the other, either another oceanic plate or a continental plate.

The result is a highly unstable geographical area that features volcanoes, earthquakes and mountain ranges. The entire Pacific region is lined with these subduction zones, earning it the nickname the Ring of Fire.

The Cascadia Subduction Zone sits a few hundred kilometres off the coast of B.C. and stretches from the middle of Vancouver Island to Northern California. It marks the convergence of the submerging Juan de Fuca plate and the North American Plate. Movement here could produce an earthquake with a magnitude of 9.0 or greater.

Given their geographical similarities, what was happening in Japan Friday easily could serve as a carbon copy for what would happen in areas along the West Coast, in particular Vancouver and Victoria, should there be major movement along the Cascadia subduction.

While Vancouver Island should protect Vancouver from the brunt of the ensuing tsunami — which will be moving at speeds of 700 kilometres an hour, the equivalent of a jet — the devastation will still be catastrophic.

The question then, is how long before the Big One strikes?

“We can’t predict when the next one will occur,” said Clague. “But I would say that they are inevitable. We will experience one and what I’m most interested in is that this earthquake is a perfect analog for what we would expect to see on our coast.”

Clague said geographical evidence suggests there is major movement along the Cascadia subduction about every 400- 500 years, the last rupture occurring in about 1700 AD. The ensuing earthquake, estimated to be comparable to Thursday’s, is believed to have triggered a tsunami that struck Japan.

Should there be an earthquake, residents along B.C.’s coast likely would have 15 to 20 minutes to find high ground before the tsunami hit.

Clague said the amount of energy released during Japan’s 8.9 quake could be compared to the eruption of Mount St. Helens in 1980, or just slightly less than the annual energy consumption of the United States. Based on similar earthquakes in the past, the number of expected aftershocks could be in the thousands, he added.

Clague said there is likely no link between the earthquake in Japan to New Zealand’s 6.3 quake last month, although there is some recent research that suggests that there could be a relationship between earthquakes in different parts of the world.

“Normally, we would say there’s no relation,” he said. “But there is some research that is being done that suggests there could be some subtle linkages.”

Vancouver Province

— with files from Postmedia

colivier@theprovince.com

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