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December 14, 2009

Making Waves, Saving Lives


Making waves provides insight into nature's most destructive forces

The horrifying tsunami that struck Southeast Asia in 2004 changed a lot of things for the engineers who study those natural disasters.

"Before 2004, tsunami research was really a niche area," says civil engineering Professor Dan Cox, director of the O.H. Hinsdale Wave Research Laboratory (HWRL) at Oregon State University. HWRL is part of the National Science Foundation's (NSF) Network for Earthquake Engineering Simulation (NEES) program.

"People really didn't know much about it. In fact, the word 'tsunami' wasn't very commonly used. When we gave tours before 2004, we were still explaining what a tsunami is, and why it's important to do the research," says Cox.

The amateur videos of the deadly 2004 tsunami captured by people on the beaches of Thailand, Indonesia, Sri Lanka and India provided images that would help coastal researchers around the world. More than 200,000 people were killed in that disaster, when waves moving at up to 500 miles per hour flooded more than a mile inland in some regions.

"Before 2004, looking for tsunami material on the web was impossible," says Cox. "You'd get grainy photos taken in Japan in the 1960s, but there was very little knowledge of what the thing looks like as it comes onto the shore. Post-2004, there's just a ton of information on the inundation process."

Studying wave after wave

The facilities at HWRL draw researchers from around the world, from universities to the military to industry, who want to study the impact of waves, whether they are tsunamis or hurricanes or other storm waves.

"So we can run wave after wave after wave here and get lots of repeated observations of either the same wave on the same structure, or how the wave is behaving offshore and rolling into this structure. Or, we can change the conditions over and over again," explains HWRL Manager Tim Maddux. "If you tried to do that on a real coastline, you would be waiting decades for the wave to come back."

Cox says learning more about tsunamis and hurricanes is important for coastal residents everywhere. "The likelihood of having a tsunami the same size as what we saw in 2004 here on our coast is about a one-in-seven chance in the next 50 years, so that's huge," says Cox.

Real-world and computer models

There is an ongoing study of a tsunami's effects on the coastal town of Seaside, Ore., using both physical and computer models of the town of about 5,000 residents. At first, Cox says, there was discussion of just creating 'Any Coastal Town, USA.' But that led to talks about getting better information if a real town was studied.

"The city of Seaside was a very willing partner. They said, 'This is for science and for engineering, and to try to save lives.' So they were all for it," says Cox.

An important aspect of the Seaside study is the role of vertical evacuation. Tsunami warning systems can provide up to 30 minutes of lead time for a community to prepare for a destructive wave. So getting thousands of people onto the roads to escape inland may not be the best way to keep the greatest number of residents from danger.

Up, up or away?

"Going up into a building or onto an earthen mound that is within the inundation zone, you're still going to be in the flooded zone, but you are much safer just by going up," explains Cox.

While Hawaii has some vertical evacuation policies, there is no such strategy elsewhere in the United States. Cox says to better understand whether it's a policy that should be adopted, emergency managers must know how high buildings need to be, how strong, and how many would be needed for a safe evacuation plan.

"And that's where this kind of lab excels," says Cox.

Coastal and ocean engineering Professor Patrick Lynett at Texas A & M University also played an important role in the Seaside project. Lynett's research focuses on numerical modeling of coastal processes, and tsunami propagation and run-up.

"The data is useful on its own, but it's even more useful if you use it with a numerical model," explains Lynett. "After a test like that, you can recreate it in a numerical model. That gives you confidence that your numerical models are doing what they should."

Lynett combines his computer models with field studies. He has traveled to Southeast Asia and American Samoa after the devastating tsunamis there, taking measurements and getting eyewitness accounts.

"The end game of all these big projects is to try to build a better city, trying to reduce the risk of loss of life," says Lynett.

Getting out in the field

Others at HWRL also combine their work at the facility with field studies. Ocean engineering graduate student Mary Beth Oshnack has modeled a hotel in Thailand that was structurally damaged in the 2004 tsunami.

"It's great to see these models but it's all on a computer screen," says Oshnack. "We actually got to take a trip to Thailand so we got to visit the hotel. I saw the high water mark on the building, some areas that had failed, and other areas that were being rebuilt. Things like that really brought it home. My computer simulation could really help people; it can be used in communities. Understanding this [tsunami] loading can really have an effect on society," she says.

A tsunami in the Pacific Ocean in September 2009 may also help engineers learn more about how to better prepare for these disasters.

Oregon State Assistant Professor of Geomatics Michael Olsen is part of GEER, NSF's Geoengineering Extreme Events Reconnaissance Association.

Shortly after that tsunami struck the Samoan Islands, he traveled to the region to capture information before cleanup took place.

"We want to get a record into place. That's our main focus," says Olsen.

Engineering solutions

Olsen uses LIDAR, Light Detection and Ranging, a remote sensing system used to collect data about the physical features of an area.

"It's a quick, easy way to create virtual models within three to four millimeters of accuracy," says Olsen.

With powerful tools like LIDAR and the wavemakers at HWRL, Cox expects some new interest among prospective engineering students.

"The message in engineering used to be, oh, you're good at math and physics, you should think about engineering. Now, what we're trying to tell people is, oh, you're creative and you want to solve society's problems....you should think about engineering," says Cox.

Miles O'Brien, Science Nation Correspondent
Marsha Walton, Science Nation Producer


Any opinions, findings, conclusions or recommendations presented in this material are only those of the presenter grantee/researcher, author, or agency employee; and do not necessarily reflect the views of the National Science Foundation.