August 13, 2003
Researchers at Columbia University say the West Coast could soon be facing its worst earthquake in centuries.
New research focusing on the coastal waters off Vancouver show that the area where the Juan de Fuca and North America plates overlap is almost twice the size that they thought.
Columbia's Earthquake Institute says the original estimate for the zone where the tectonic plates interlock, called Northern Cascadia, was 56 kilometres. The area is now believed to be 90 kilometres.
The known width of the zone now extends farther towards the mainland, creating an additional hazard for coastal communities.
The greater the overlap, the more friction is built up, resulting in a more powerful earthquake.
Researchers say that this locked zone could create so much energy when it finally releases that it could cause one of the largest earthquakes in history.
In fact, they say it would release 1,000 times the energy of the 2001 Seattle earthquake, which shattered windows, caused skyscrapers to sway and rattled buildings up to 350 kilometres away. The damage caused by that quake cost several billion dollars.
The Seattle quake registered only a 6.8 on the Richter Scale. Researchers say the predicted Cascadia earthquake would measure at least 9 on the Richter Scale.
If the quake is as powerful as the researchers believe, it would be the worst in the region since 1700.
http://www.canada.com/victoria/chtv/story.asp?id=8038419B-A867-4816-BD14-7F2E57923824