A Natural Resources Canada seismologist says there is a one in 10 chance of a megathrust earthquake off the B.C. coast in the next 50 years
Photo Credit: CBC

Pacific megathrust earthquake: rip open the Earth

Is this “the big one” coming?  Maybe,… or maybe just one of the “big ones” –plural, that may wreak havoc on the west coast of North America.

An expert is warning a megathrust earthquake is in the works off Vancouver Island on Canada’s west coast. She says the epicentre will be not far from Pachena Bay on the Pacific side of the island

A similar megathrust quake on Boxing Day 2011 in the Indian Ocean resulted in a tsunami that killed over 220,000 people.

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The huge Indian Ocean tsunami of 2004 rolling in as bathers begin to realize the danger. The flood killed over 200,000 people. © submitted by Christine Lang

Alison Bird, a Victoria-area Natural Resources Canada seismologist says the Cascadia subduction zone off the west coast of Vancouver Island has two tectonic plates locked together and which have been slowly building pressure for hundreds of years.

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Red dot indicates Pachena Bay near the Pacific Rim National Park on Vancouver island off Canada’s west coast © goolge

Rip open the earth like a zipper” Moran

She says scientists have evidence of  a massive magnitude 9 quake and tsunami on January 26, 1700 along the Cascadia zone some 1000km in length. It resulted in tremendous shaking and a subsequent tsunami that swept away the entire village at Pachena Bay, and others all along the west coast.

University of Victoria ocean engineer Kate Moran headed the first research team into the Indian Ocean area following the Boxing Day earthquake and tsunami. She described the events in 1700 and 2004 as ripping open the earth’s zipper.

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In this graphic, provided by CBC metereologist Johanna Wagstaffe, the Juan de Fuca plate is moving toward and riding under the North America plate The red circle around TOfino is about 70 km notthe (by air) from Pahena Bay © CBC

A one in ten chance of a megaquake in the next 50 years

The event is known in aboriginal oral history and artwork from  Vancouver Island to northern California.

Scientists in 1990 determined that it was that same quake in 1700 that caused a giant tsunami the height of a four story building which hit Japan nine hours later, on January 27, causing massive destruction there.

Scientists say there have been 13 great quakes in the last 6000 years.

Alison Bird says there’s a one in ten chance a megaquake will occur in the next 50 years.  If that happens, people on the west coast of the island would have about 20 minutes to get to high ground.

A 5.5 magnitude quake was felt in August of 2013 off the coast of north Vancouver Island, along the Nootka fault line, shaking people awake at 6.20 am, but caused no major damage.

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(with files from Dirk Meissner Canadian Press)

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