Hakai Magazine

Coastal science and societies

The magnitude 9 earthquake that hit Japan in 2011 is an example of what’s in store for the Pacific Northwest when the next big earthquake ruptures in the Cascadia fault. Photo by Kim Kyung-Hoon/Reuters/Corbis

In the Crosshairs of Cascadia, a City Seeks Shelter From the Waves

Westport, Washington, is building the first publicly funded tsunami shelter in the United States.

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by Laura Dattaro

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Westport, Washington, is about as close to being underwater as a city can get. It’s surrounded by water on three sides: the South Bay to the east and the vast Pacific Ocean to the north and west. A land bridge just two kilometers wide connects the town to the mainland. Lurking just offshore, the Cascadia fault threatens to finish the job.

Running 1,130 kilometers from British Columbia to northern California, the Cascadia subduction zone is the fault line where the Juan de Fuca tectonic plate, the seafloor of the northeast Pacific Ocean, is forcing its way beneath North America. Stress is building, the fault is creaking, and one day the fault will rupture, releasing an earthquake of catastrophic proportions. And when it does, low-lying Westport will be in the splash zone of the tsunami that such an earthquake will no doubt spawn. It will take about 20 minutes for the water to wash over the city.

Fortunately for the residents of Westport, there will soon be a place to flee when the ground starts to shake. The city is currently constructing the United States’ first publicly funded tsunami shelter, with enough room to give a square meter of space each to 1,000 people—about half of Westport’s population.

“In the event that there’s really a big tsunami battering the coast, I think people might be willing to squeeze a little tighter,” says Tim Walsh, a geologist with the Washington State Department of Natural Resources who has been working on tsunami safety since the 1990s.

In the early 2000s, Walsh and his colleagues began to investigate if it was even possible to build a structure that could be shaken by a large quake, clobbered by a tsunami, and still “live to tell the tale.”

Work on the concept continued for years, until the 2011 Japanese earthquake and tsunami provided both a wealth of new information and rush of public awareness. In 2013, a plan was proposed to fix Westport’s aging Ocosta Elementary School and, in the process, equip it with a tsunami shelter.

Now, a new school gym is being built on a hill that’s nearly nine meters above sea level, making its roof, at nearly 17 meters elevation, one of the tallest buildings in town. Piles will support the gym from underneath in the event the foundation gives out. Stair towers at the gym’s corners will provide quick access to the roof, where students and residents can wait for the high waters to recede.

Not only will the shelter potentially “save the lives of school kids” says Walsh, it could also protect anyone else who could make it to the school in time. “It’s a real public benefit,” he says.

But at an estimated cost of US $13-million, the shelter is “a pretty significant gesture” for a tiny city with little industry, says Walsh.

It’s a gesture that’s been difficult for other communities to make, if the example of Cannon Beach, Oregon, is any indication. Just 160 kilometers south of Westport, Cannon Beach has been trying—and failing—to get the money to build a tsunami shelter for at least five years, says city planner Mark Barnes.

Cannon Beach is a long, narrow beachfront city just blocks from the Oregon Coast Highway. Almost the entire city, including the city hall and most road and water infrastructure, is in the tsunami inundation zone. That means the shelter will need to be built far from the center, requiring new roads and making construction that much more costly.

The Cannon Beach city council is actively prioritizing a tsunami shelter, Barnes says, but as of now there’s no plan for how to pay for it. Plans for construction are “years off,” Barnes says. It’s fingers crossed that the next big earthquake is years off, too.

Westport, though, will be ready. Work on the site began last November, and the shelter’s expected to be up and ready next year. After that, all that’s left is to wait.

Correction: As a point of clarification, the tsunami shelter is not a project of the City of Westport, Washington, but rather of the Ocosta School District, of which Westport is a part. The US$13 million price tag is the cost of the whole construction project, not just the tsunami shelter itself.