It is no surprise to many of you who have been following my work over the years as to one possible scenario. It is the area known as the Cascadia Subduction Zone.
I am not alone in my concern over this area, especially within the next 15 days. One of which is Bill Steele, Director of Information Services for Pacific Northwest Seismic Network (PNSN), and Public Information Officer (PIO) for the USGS earthquake related research activities.
The Cascadia Subduction Zone is located just off the coast from Northern California to Vancouver Island, British Columbia Canada. Geologists believe it has an approximate cycle of 300 years according to soil and rock samples along the Washington coastline. The last mega-thrust earthquake sent a tsunami across the Pacific hitting Japan and wiping out the southern area of the Japanese island itself. Because of the sparse development and population along the northwest coastline 300 years ago, it is difficult to say what damage was caused to the greater Seattle area.
September 16th’s magnitude 8.3 earthquake off the coast of Chile rattled the ground and triggered tsunami watches and advisories across the Pacific Ocean. “Luckily, the waves that rolled into Southern California were minor, but scientists at the Pacific Northwest Seismic Network said our turn could come at any moment.” says Steele.
“We are going to have a subduction zone earthquake and it will create a tsunami, and we do need to be ready to intelligently for that,” Steele continued. You rarely see such an adamant statement coming from the science community. There is no question of “if” – it is only “when.”
In 2001, the magnitude 6.8 Nisqually quake caused massive damage in the area. Now experts are working on an early-notification system that could provide up to four minutes of warning before the ground moves.
Seattle taxpayers are spending hundreds of millions of dollars to replace the city’s old seawall. The Seattle Department of Transportation said the old structure would likely fail and send water flooding into the city.
“We need viable evacuation option for our citizens,” said Steele. “Right now there are large areas of our coastline where there are people living that have no evacuation options.” Some progress in Washington State has been made. A new building under construction in Westport, Wash., could save at least 1,000 lives during a tsunami.
The new Ocosta Elementary School in Westport is the first of its kind. The structure utilizes something called vertical evacuation, where people could seek shelter on the rooftop to avoid the rising water.
But experts said that more work needs to be done to save as many lives as possible.