The need to build such a structure was felt after the latest earthquake and tsunami that hit Japan recently. The Pacific Northwest coast is vulnerable to quakes produced by the Cascadia subduction zone, a 950-kilometer-long fault running from northern California to Vancouver, Canada.
The building would be elevated 4.5 meters off the ground and will serve as an evacuation zone for coastal residents and tourists as well as function as a new city hall. The building plans will be based partly on a 2008 Federal Emergency Management Agency (FEMA) publication Guidelines for Design of Structures for Vertical Evacuation from Tsunamis.
The Cannon Beach city hall design features concrete stilts reinforced with steel cables supporting a 900-square-meter building. Beams and concrete pilings at the base of the building will help prevent the strong waves from eroding the foundation.
The building elevation is expected to be based on tsunami inundation maps suggesting that 90% of all possible tsunamis would generate water depths of 4.5 meters at the city hall site. These assumptions might also change in the light of the recent tsunami in Japan that spawned nine-meter waves.
Funding for the building will be the next step in the process followed by hiring of architects to transform the conceptual design into a real building. The building has an estimated price tag of about $4 million, about twice as much as cost of standard construction.
