Tsunami fear drives building design

CORVALLIS, Ore. – An Oregon coastal town hopes to put its new City Hall on stilts and become the first U.S. city to raise a municipal building to withstand the major earthquake and tsunami that scientists say are coming sooner rather than later.

City officials and emergency workers hope the building in Cannon Beach will also raise a sense of urgency in the Pacific Northwest about the jeopardy coastal residents and visitors face.

Geological findings in recent years suggest there’s a 1 in 3 chance that in the next half century a mega-earthquake will tear apart the seafloor off the Oregon Coast.

Huge waves would surge onto coastal communities in as little as 15 minutes. There isn’t a coastwide estimate of potential lives lost and damage, but about 100,000 Oregonians live in tsunami inundation zones. Many more visit the coast.

The $4 million building the city proposes in Cannon Beach would have room for as many as 1,500 people, and could save lives.

The 2004 Sumatra tsunami, which killed almost 230,000 people, galvanized federal emergency planners and coastal communities. The National Oceanic and Atmospheric Administration sent engineers to learn what buildings withstood the earthquake – measured at magnitude 9.1 to 9.3 – and cataclysmic waves.

They found that buildings on stilts, without impediments that increased the stress of the on-rushing water, often survived, said Jenifer Rhoades, tsunami program manager for the National Weather Service. The Cannon Beach structure would be the first “vertical evacuation site” built in the United States, she said.

Japan has built several of the buildings, but they’ve never been tested.

The permanent population of Cannon Beach is about 1,700, but its beaches and art galleries draw an estimated 750,000 visitors annually.

“Imagine a July 4 weekend with an additional 200,000 people at the coast,” said James Roddey of Oregon’s geology agency. “That’s a lot of folks who don’t know what to do if the ground starts shaking.”

Emergency officials have stepped up tsunami awareness campaigns, and towns like Cannon Beach are installing signs about tsunamis, designating evacuation routes and testing sirens. Residents are being urged to hack through brambles to make paths to higher ground.

“We need things like vegetation management, so people can get to higher ground without having to fight blackberry bushes. We need footbridges across wet areas,” said Pat Corcoran, whose job as an Oregon State University extension worker is to travel the Oregon Coast urging beachfront communities to prepare for the “when,” not “if.”

Cannon Beach is working with Oregon State to design its proposed 9,800-square-foot City Hall.