Quakes and the rising sea in western Canada

Canwest News Service (Canada) runs an interesting article by Richard Watts on the interaction between sea level rise and seismic activity: With global warming raising sea levels worldwide, parts of B.C. may be kept high and dry by the same geological forces that bringing earthquakes to the province, a government report says. Then again, the safety zones, where those earth-moving tectonic shifts will keep pushing the land higher out of the water, don't extend much past the west coast of Vancouver Island.

Meanwhile, other geological forces at work in the Fraser River Delta of the Lower Mainland will push the land downward, so sea levels there will become even higher. In Victoria, the geological effects will be less profound. Sea levels will likely rise anywhere between two to 94 centimetres by the end of the 21st century, due mostly to global warming.

"B.C. is a really complicated area," said Richard Thomson, physical oceanographer with Fisheries and Oceans Canada and an author of a new report examining the various factors now effecting sea levels. "Sea-level rise would be really quite simple if the land didn't move," Thomson said.

…Off the west coast of Vancouver Island, the Juan de Fuca Plate is now pushing its way under the North American Plate. This burrowing movement is pushing land levels on the west coast of the island higher, and will likely even keep pace with the rise in ocean levels there. The movement of this plate is what causes the earthquakes that regularly shake Vancouver Island. And if a big earthquake hits, then all bets are off….

Slide showing side view of the Juan de Fuca Plate, by Webber, Wikimedia Commons