[Vulcan]

Here's another view of the earthquake danger on the BC mainland.

The threat of the “Big One” looms large for residents up and down the Pacific coast. These quakes happen below the ocean floor off the west coast of Vancouver Island where the Juan de Fuca plate is slowly being forced beneath the North American plate.

However, Dr. Steve Earle, chair of the earth science department at Vancouver Island University, said it isn’t these expected earthquakes that we should worry about the most. Rather, it is the more unexpected ones, like the 1946 earthquake located somewhere on the Forbidden Plateau on Vancouver Island, that are cause for thought. It holds the distinction of being Canada’s largest recorded on-shore earthquake. At a magnitude of 7.3 it rocked Powell River and was felt as far north as Prince Rupert and as far south as Portland, Oregon.

“I think there’s reason to be more worried about an earthquake like the 1946 one than big subduction zone earthquakes for a couple of reasons,” said Earle. “It’s more likely to happen sooner, although we don’t know what kind of interval there is between those kinds of earthquakes. It’s likely that it’s shorter than the interval for the big earthquakes.

“The other reason is that it would be a lot closer in distance across land, and also it would be a shallower earthquake,” he said. “It’s likely to have more of an impact on Vancouver Island, Powell River and even the Lower Mainland than a really big earthquake.”

http://www.prpeak.com/articles/2012/...2389642481.txt