Standing Against The Wave: Anti-Tsunami Design For Houses And Communities

 @rpalmerscience
on January 23 2014 5:32 PM
tsunamisign
New designs for homes and shelters may reduce casualties from future tsunamis. Wikimedia Commons/mimigu

Washington state architect Daniel Nelson has made a house designed to stand the test of time – and, if need be, tsunamis.

Nelson’s Tsunami House stands on the waterfront, on Camano Island in Puget Sound. While it’s not indestructible, the architect recently told Smithsonian Magazine that he expects it can stand up to fast-moving tsunami waves up to eight feet high, 7.8-magnitude earthquakes, and winds up to 85 miles per hour.

Constructing a house to withstand a tsunami turns out to be an exercise in constructive judo. Rather than building massive walls around the house, the house is designed to guide water around and under it. The two main floors sit on support columns that are filled in with breakaway glass doors. If a big wave comes rolling in, the glass breaks and the water flows in under the house, through the bottom chamber and out the other side.

“If the building was a solid wall instead of columns filled in with glass doors, the whole thing could collapse under the momentum of the wave,” Nelson told Smithsonian Magazine. “We opted to enable the building to stay intact by letting the water move through along a path of least resistance.”

One of the first large tsunami shelters in the U.S. will also be built in Washington state. The Pacific Northwest coast lies near the Cascadia subduction zone, a tectonic plate boundary that could result in massive earthquakes and tsunamis someday. The odds for a 9.0 earthquake occurring in the Cascadia zone in the next 50 years are about one in 10, according to the Cascadia Region Earthquake Workgroup. A recent report from CREW [PDF] estimated that, if a tsunami struck Washington at present, the death toll could be 10,000 or more.

To take the first step in guarding against the worst, Ocosta School District voters approved a $13 million bond issue to build a tsunami-proof building in the coastal town of Westport, Wash., which lies on a peninsula jutting into the Pacific Ocean. Part of a local elementary school will be torn down and replaced by a new, fortified gym topped with a survival deck 55 feet above sea level (projections for tsunamis generally estimate a wave level of 30 feet). The shelter can house more than 1,000 people, according to the Seattle Times.

Elsewhere in the world, some builders are looking to the natural world for inspiration. An NGO called Kogami has drawn up a design for the Sumatran city of Padang that draws heavily on the model of coral reefs. The aim would be to actually grow structures with a technique called cathode accumulation, using seawater and electrical currents that would plate calcium carbonate onto an iron skeleton. Cathode accumulation could be used to build artificial reefs to act as wave barriers, but also for building shelters rasied above the waves.

Other simple ways to protect communities against tsunamis are allowing vegetation to grow, A smooth, sandy beach lets a wave roll right on in, but rougher ground disperses its fury somewhat. In Sri Lanka, villages with healthy mangrove swamps suffered significantly fewer casualties from the devastating 2004 tsunami.

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