314 years ago Sunday, a megathrust earthquake devastated the region … ready for another?
Posted by James Smith on January 29, 2014
Digging into the soil at the Effingham Inlet in British Columbia, Canadian scientists have confirmed that a city-destroying megathrust earthquake in the Northwest is due.
January 28, 2014 | By Jake Ellison
Never missing the opportunity to scare the living daylights out of us, earthquake experts in Washington remind us that this past Sunday was the 314th anniversary of the last megathrust quake in the Cascadia Subduction Zone that would have wiped out a big part of Seattle and the infrastructure of the region had we all been there.
And we are due for another one.
So, the Cascadia Region Earthquake Workgroup has updated its scenario document for what that magnitude of quake would do to us now.
THE CASCADIA SUBDUCTION ZONE: The geography of northern California, Oregon, Washington, and southern British Columbia is shaped by the Cascadia subduction zone, where the North American Plate collides with a number of smaller plates: the largest of these is the Juan de Fuca Plate, flanked by the Explorer Plate to the north and the Gorda plate to the south. These smaller plates “subduct” (descend) beneath the North American Plate as they converge along a 700-mile long (1,130 km) boundary. A large portion of the boundary between the subducting and overriding plates resists the convergent motion, until this part of the boundary breaks in a great earthquake. Above: Schematic view of the source area for the largest Cascadia earthquakes. (Image adapted from U.S. Geological Survey Professional Paper 1707 (page 8), Atwater et al., http://pubs.usgs.gov/pp/pp1707/)
The group said in the news release:
The very advances that are the foundations of our modern communities create vulnerability along with convenience said Michael Kubler, Cascadia Region Earthquake Workgroup (CREW) President. The revised Cascadia scenario is a crucial tool for regional leaders to use in developing policies and plans for the next earthquake. Events over the last few years have expanded our understanding of earthquake science and the hazards faced by our region from a future Cascadia Subduction Zone earthquake.
For a bit more background, here’s some of the story we wrote last summer proclaiming … Canadian study confirms megathrust earthquake is due in NW:
Digging into the soil at the Effingham Inlet in British Columbia, Canadian scientists have confirmed that a city-destroying megathrust earthquake in the Northwest is due.
The Cascadia Subduction Zone running the length of the coast from northern Vancouver Island down to California last slipped and shook the surface of the Earth 300 years ago, and that was just the latest of 22 such quakes in the past 11,000 years.
The scientists, whose work is published in the latest Canadian Journal of Earth Sciences, used a new aging model for identifying and dating disturbed sedimentary layers in a core raised from the inlet.
The disturbances appear to have been caused by large and megathrust earthquakes that have occurred over the past 11,000 years, According to a science news site run by the American Association for the Advancement of Science.
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