VANCOUVER - A new study says the Pacific coast has experienced 22 major earthquakes over the last 11,000 years, and is due for another.
The study looked at sediment disturbance in Effingham Inlet, on the west coast of Vancouver Island.
Study author Audrey Dallimore, of Royal Roads University, says researchers using state-of-the-art radiocarbon dating determined the last so-called megathrust earthquake in the zone that stretches from northern Vancouver Island down to California happened more than 3,000 years ago.
The world's largest earthquakes are all megathrust earthquakes, which occur when there is a slip along the fault between a subducting and overriding tectonic plate.
There has never been a megathrust earthquake along the west coast in the written history of Canada, but the study found that megathrust earthquakes occur about every 500 years in the region, although they can stretch out for up to 1,000 years.
"The last megathrust earthquake originating from the Cascadia subduction zone occurred in 1700 AD. Therefore, we are now in the risk zone of another earthquake," Dallimore said in a statement.
"Even though it could be tomorrow or perhaps even centuries before it occurs, paleoseismic studies such as this one can help us understand the nature and frequency of rupture along the (zone), and help Canadian coastal communities to improve their hazard assessments and emergency preparedness plans."
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