http://www.theglobeandmail.com/servlet/story/RTGAM.20050914.wxtremor14/BNStory/National/"Southern Vancouver Island is sort of sliding towards the west right now. We're moving towards Japan," said John Cassidy, a seismologist with Natural Resource Canada at the Pacific Geoscience Centre near Sidney, B.C. "It's a very small amount. We've moved about three millimetres to the west over the past couple of days."
The event, known as an episodic tremor and slip, is a predictable, cyclical phenomenon that is adding pressure to a zone where the Juan de Fuca Plate and the North American Plate are locked, just off Vancouver Island. While the two plates are slipping in some areas, in another they remained locked. That locked zone is where the next megathrust earthquake is expected to come from when it suddenly releases.
Mr. Cassidy said a slip event occurs every 14 months, and when it does, scientists believe the chance of an earthquake the size that triggered the Asia tsunamis increases.
One researcher has likened the event to going up a step on a staircase, at the top of which sits a megathrust earthquake. But nobody knows where the top is or where we are on the staircase.