|
Français | Contact Us | Help | Search | Canada Site | ||||
|
|
|
|
|
|
|
|
|
|
|
Home | Our Minister | Subject Listing | NRCan Site | |||||
               |
August 2006 Ready-to-Use News ArticlesNRCan Experts Offer Know-How on Seismic Hazardsby Carrie Stephens
VICTORIA —The majority of earthquakes in Canada occur along the coast of British Columbia. Scientists with the Geological Survey of Canada (GSC) in North Saanich record nearly 2000 earthquakes each year in Western Canada. In early 2006, the A-Channel in Victoria aired a week-long series on seismic hazards. The series featured expertise from NRCan's own research scientists, John Cassidy, Garry Rogers and research engineer, Mike Schmidt. The first episode focused on the various kinds of earthquakes that are common to the Vancouver-Victoria region. These include crustal earthquakes (0–30 km below the surface); earthquakes that occur within the ocean plate (at about 30–60 km in depth); and megathrust earthquakes, which occur every 300–800 years in the region just west of Vancouver Island. There have been 13 of these latter earthquakes in the past 6000 years (the last one occurred on January 26, 1700). Despite the reassuring fact that these enormous earthquakes are rare, John attests, "It's really the smaller earthquakes that pose much more hazard to us than the giant earthquakes. This is because they occur more frequently—decades apart, rather than centuries apart. But, of course, the giant earthquakes will affect a huge area all the way from Northern Vancouver Island to Northern California. NRCan's experts also discussed the 2004 Indian Ocean earthquake, which triggered the tsunami on Boxing Day. This earthquake was the second largest ever recorded on a seismograph and was the first of its kind in 50 years. NRCan scientists have been studying this earthquake to better understand how a similar seismic catastrophe could occur in the Vancouver region.
"We realized [after the magnitude nine Sumatra earthquake] that what happened there is virtually identical to what could happen and has happened in this region in the past. So we started looking at the plate tectonics [to see] how the plates are moving, says John. "By collecting as much information from Sumatra, Indonesia, Thailand and India, and learning about what happened there, we can apply that to this region and better understand how the ground will shake, how long the ground might shake, what the effects are in terms of areas that will drop at the time of that earthquake and areas that will rise when that giant earthquake strikes. NRCan scientists are currently using various instruments, such as satellite technology, to learn about the different types of waves that travel through the Earth and the changes in its crust. This information will, in turn, teach scientists how this type of earthquake works and how its energy is released. It will also enable scientists to develop more realistic scenarios as to what will happen when an enormous earthquake hits. Scientists are now also using several hundred international Global Positioning System (GPS) Reference Stations, which contribute data hourly to a collaborative network that allows scientists to look at plate motion around the globe. A GPS network on the west coast of Canada, the Western Canada Deformation Array, has revealed a slow landward movement towards the Northeast, which will lead to the next great Cascadia earthquake. Scientists are confident that a major earthquake will occur off the coast of Vancouver Island, but they are uncertain when it will occur.
The primary focus of NRCan's earthquake scientists is to help safeguard Canada against the threat of future earthquakes. "The research that we're doing right now will be folded into the various seismic codes used in Canada, so that buildings, bridges and pipelines are designed to withstand the shaking that we know will happen, says John. Earthquake research results in safer buildings, more resilient critical infrastructure and reduced losses in the future.
|
||||||
|
|||||||
