Pacific Northwest deemed unprepared for Cascadia Subduction Zone megaquake or tsunami
By Tim Fought and Alicia Chang
CANNON BEACH, Ore. – When the big one hits the Pacific Northwest, the best place to escape the wall of water moving at jetliner speed from 50 miles off the coast may be a City Hall on stilts.
Once the ground finishes two to four minutes of lurching and shaking, residents and tourists in Cannon Beach would flock to the refuge on concrete columns 14 feet above the waves racing beneath.
They would … if the refuge gets built. There’s nothing like it from Northern California to British Columbia and, so far, no money for anything like it.
It’s an example of how underprepared the West Coast is for an earthquake and tsunami on the scale of what happened in Japan.
Scientists say it’s inevitable that an offshore seismic menace called the Cascadia Subduction Zone will one day unleash a megaquake. The last time it happened was 300 years ago when a magnitude-9 shaker spawned enormous ocean waves that slammed into the West Coast and damaged Japanese fishing villages.
Mindful of the risks of waves as high as 60 feet, communities in the Pacific Northwest have worked on their defenses, installing sirens to warn of dangerous waves, posting hazard signs to mark inundation zones, designating evacuation routes and holding evacuation drills.
Scientists in the Pacific Northwest hadn’t understood the geology and the threat it poses until recent decades when they discovered evidence of big quakes near the coast over the last 10,000 years.