TSUNAMI SCIENCE IN THE NORTHWEST

Researchers Are Working To Understand, Predict, And Mitigate One Of Nature's Deadliest Hazards

By Sara J. Bender

Imagine that you are standing on a remote beach on the Washington coast. As you explore the tidal pools and dig your toes into the sand, the waves lap gently along the shore. Then, unexpectedly, the sound of the ocean ceases. The water begins to recede out to sea, farther than the eye can see. Suddenly, in the distance, a giant wave roars landward. You begin to run.

The threat of a tsunami hitting the Pacific Northwest became all too real on Feb. 27, 2010, when waves generated from a massive Chilean earthquake propagated across the Pacific Ocean. Seaside towns along the West Coast were put on alert as scientists and citizens waited to see what paths the tsunamis might take. Live television cameras positioned on beaches around Hawaii allowed the world to watch and wait to see what this force of Nature would do.

The notion of a tsunami reaching the coast is terrifying. Both the 2004 Indian Ocean tsunami and the more recent 2009 Samoan Islands tsunami demonstrated the horror and destruction associated with large tsunamis, from death tolls in 2004 exceeding 230,000 people to decimated landscapes and collapsed structures.

Although awareness is increasing of the immediate effects of tsunamis on local communities, there is still a need for a better understanding of the science behind this natural phenomenon. How does the force of a tsunami affect the surface of a region? What infrastructure is needed to implement more effective warning systems? Why are social science and public outreach essential aspects of tsunami awareness and safety?

In the Pacific Northwest, these questions are being answered by researchers at Oregon State University (OSU), at NOAA's Pacific Marine Environmental Lab (PMEL), and at the University of Washington (UW). Researchers' efforts include teasing apart the science behind tsunami generation, propagation, and inundation. At Western Washington University (WWU), Oregon Health Sciences University (OHSU), and the Washington State Emergency Management Division (EMD), educators are taking a social science-based approach to better educate local communities on the imminent dangers associated with tsunamis.

At the O.H. Hinsdale Wave Research Laboratory, part of OSU, Solomon Yim serves as acting director and oversees the Network for Earthquake Engineering (NEES), a state-of-the-art facility completed in 2004 with funding from the National Science Foundation.

What makes the NEES facility unique is that "it serves the entire tsunami research community," says Yim. NEES was created so that researchers could benefit from one large tsunami facility, rather than from ten small ones. As Daniel Cox, the former director of the O.H. Hinsdale Wave Research Laboratory, explains, "We're good at waves."

Each year, more than 4,000 visitors get an up-close and personal look at small-scale tsunami waves, which are generated by the long, narrow flume and wave basin tanks at NEES. Scientists take optical measurements using high-resolution cameras and quantify the energy generated by the man-made tsunamis in order to measure the impact of these waves on different structures.

One of the goals of the NEES facility is to develop more quantitative means for predicting the impact of tsunamis on structures made of various materials. Yim works with an interdisciplinary team of researchers to build a numerical model using computer simulations from wave experiments. The goal is not to replace the wave basin, but to complement it, allowing for both real-time and simulated experiments.

Down the hall from Yim is Cox, who takes an engineering-based approach to understanding tsunami inundation effects on the constructed environment. Cox has helped lead projects entitled "NEES House Smash" and "Tsunamis Kinematics" that utilize the wave facilities. His research questions focus on how robust structures are in tsunami-prone areas, as well as how buildings change the flow field of a tsunami.

A few hours north, tsunami research is also underway at PMEL and UW. Eddie Bernard, director of PMEL, highlights the modeling work being conducted in conjunction with the National Center for Tsunami Research (NCTR). This includes the Method of Splitting Tsunami model (MOST).

Following a seismic event, tsunami data are transmitted from deepwater ocean detection buoys to NOAA's tsunami warning centers, where these data are assimilated into the MOST model. Within ten minutes of receipt, the MOST model can generate a tsunami forecast for a specific harbor in the Pacific Northwest. In the deep ocean, MOST has a resolution of two kilometers, and in a harbor, it has a resolution of ten meters.

Bernard is quick to point out that making these complicated models work in real-time is no trivial task; they pose a great computational challenge. However, on Feb. 27, MOST proved that it could provide accurate, quantitative tsunami information for state agencies very rapidly. Following the Chilean earthquake, PMEL researchers compared the MOST model output to tide gauge data, and they demonstrated that the model was more than 80 percent accurate in predicting tsunami propagation: an impressive feat.

Along with the research underway at PMEL, other improvements continue to be made in the Pacific Northwest, emphasizes Jenifer Rhoades, Tsunami Program Manager at NOAA's National Weather Service. This progress includes more rapid access to seismic data in collaboration with the U.S. Geological Survey (USGS), enhanced tidal gauges, an expanded network of tsunami-detection stations (called Deep-ocean Assessment and Reporting of Tsunamis, or DART, stations), among other accomplishments.

"Our focus has been on making all of this research and development work in an operational setting, cross-checking everything," explains Bernard.

At UW, Breanyn MacInnes and Beth Martin, doctoral students in the lab of Joanne Bourgeois in the Department of Earth and Space Sciences, are focusing their studies on understanding the impacts of tsunamis on topographical features and the history of tsunamis in the Pacific Northwest.

MacInnes began her research on the Kuril Islands, a remote set of Russian islands in the eastern Pacific. A collaborative team of scientists from Russia, Japan, and the U.S. initially set out to do a "rapid-fire survey" aimed at understanding the recurrence of the frequency, magnitude, and location of past tsunamis on the islands. Camping along coastlines and in open fields over the course of three field seasons, MacInnes and a team of researchers documented the effects of a series of tsunamis on these topographically distinct islands.

"The part that makes it really exciting and interesting is that this is the first time that a group of tsunami-scientists were in a location before the tsunami happened," MacInnes explains. "We could exactly reoccupy places we had been and see what tsunami-related changes had occurred." MacInnes is using her findings to create more accurate models to understand earthquake formation around the Kuril Islands.

Her officemate, Martin, focuses her research locally, and she spends her time wading through low-lying areas of Puget Sound in search of past evidence of earthquakes. By studying the structure of earth layers using core samples, Martin is able to provide evidence for uplift, earthquakes, and tsunamis over the past 1,000 years.

Martin's interests stem from a desire to combine scientific discovery with public policy. In addition to her scientific pursuits, Martin spent nine months helping to develop a course to teach hazard professionals from the Indian Ocean region about tsunamis and the science behind them. "I was always interested in the zone where science interacts with policy or what people care about," she says, in order to "either save lives or better people's lives."

The intersection among physical and social sciences and policy appears to be an increasingly important area of focus when it comes to tsunami awareness in the region. Citing the recent improvements by NOAA, Rhoades says, "I think sometimes we focus a lot on our physical capabilities (such as detection systems), but outreach and education are key."

And that is exactly what David Sattler, professor of psychology at WWU, has set out to do. Sattler established the International Tsunami Museum in Khao Lak, Thailand to educate local communities on the causes of tsunamis. "My initial research projects were looking at psychological distress and recovery following the tsunami and as a result of those projects and interviews with those people, I came up with the idea to build a museum. I saw a great need for education."

Since it opened in 2006, the museum has attracted tens of thousands of visitors and continues to expand its outreach programs. Sattler worked with a student and WWU video services manager Robert Clark to produce a tsunami awareness video in Thai. Sattler is now distributing tsunami-awareness videos to area schools and helping to improve educational resources. Locally in the Northwest, Sattler talks to civic groups and focuses on the impending danger of earthquakes and tsunamis off of the Olympic Peninsula.

In Beaverton, OR, Karen Wegner, the director for the Coastal Margin Observation and Prediction's (CMOP) K12 Education program at OHSU, has also worked to promote tsunami awareness locally through the Tsunamis! Coast Challenge day camp. As part of this week-long camp, students in grades 7-10 engaged with area researchers to learn about aspects of tsunamis, including causation, formation, and effects.

The camp utilized various outlets for teaching, including the O.H. Hinsdale Wave Research Laboratory at OSU and multimedia tools such as YouTube. The camp concluded with a capstone project where the students developed a Tsunami Public Service announcement. Last year's camp was so successful that CMOP is planning on running the same camp again this year.

John Schelling, earthquake/tsunami/volcano program manager for the Washington State EMD, is taking a "bottom-up-approach" to improving tsunami education by designing evacuation procedures at the ground level based on citizen feedback. This work is being conducted with David Johnston, a visiting social scientist from the Institute of Geological and Nuclear Sciences (GNS) in New Zealand. Their collaboration has lead to improvements in the all hazard alert broadcast system (AHAB) along the coast and to changes in how the service industry educates their guests on tsunami threats.

Like others, Schelling notes, "If you're not incorporating social science in your program, then you're missing the boat. We think social science is the key to implementing a successful program because it helps us to understand, as emergency managers, what messages are going to resonate best with the public and where there might be some gaps in our program, [and] if there are populations that aren't being served. We are able to take that information and fill those gaps."

During last month's Chilean earthquake, Johnston was on the Washington coast, and witnessed how local jurisdictions responded to the tsunami advisory. Some beaches were closed; others had a police officer posted at entrances to alert the public. Schelling notes that although the Washington and Oregon coasts demonstrated preparedness during last month's tsunami alert, there were still a lot of people on the beaches, unaware of the tsunami advisory. As Rhoades explains, "With every system, there's always room for improvement, and we are continually doing that."

Back at NEES, Cox reflects upon his findings throughout his career: "We're getting there, and just from going from research to outreach, I'm starting to hear more people discuss the combined earthquake and tsunami, like, ‘Hey, we've got to be ready for both. We've got to think of the whole scenario.' That's improving. I think overall, very positive."

Sara Bender is a graduate student studying oceanography at the University of Washington.

Images

Cover Thumbnail: Computer-generated model (MOST model) of expected tsunami wave propagation following the Feb. 27 Chilean earthquake. In this image, warm colors denote greater wave intensity. Image: NOAA Center for Tsunami Research, Pacific Marine Environmental Laboratory

Top:

A tsunami will result from a large earthquake on the Cascadia subduction zone. The waves will travel outward, striking the Washington and Oregon coast within 15 minutes. Waves will hit Japan and areas across the Pacific much later.

Courtesy of the city of Richmond, BC; online at http://www.richmond.ca/shared/assets/Tsunami_-_Fig12408.jpg

Middle: The tsunami wave basin (342 ft wide by 12 ft long) at OSU allows scientists to study and model the impact of large propagating waves on coastal structures and habitat. The facility also houses a wave flume tank, measuring 160 ft x 87 ft. Photo: Solomon Yim

Bottom: MacInnes (left) and Martin (right) conduct extensive field campaigns for their research projects examining the impacts of tsunamis on past and present topography. Photos: Mike Etnier and Brian Atwater