NEESR-SD: Measuring Runup and Bed Shear Stress Using Long Stroke Wave-Makers

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This award is an outcome of the NSF 09-524 program solicitation "George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Research (NEESR)" competition and includes Cornell University. This project will utilize the NEES equipment site at the Oregon State University. The Intellectual Merit of the Proposed Activities: Based on the observations during the 2004 Indian Ocean tsunamis, it is evident that the leading tsunami waves could have various forms: undulating bores and long waves with a leading depression. It is certain that theses leading waves are not solitary waves. A new paradigm needs to be established for experimental tsunami research. As tsunamis inundated and flooded the land, they often left behind widespread sediment deposits. If the properties of tsunami deposits can be correlated with the flow depth, velocity, and wave characteristics of tsunamis, the dated deposits will allow estimates of times and recurrence intervals of past tsunamis. Since the sediment transport processes are primarily driven by the flow turbulence and bed shear stresses, it is essential to have an in-depth understanding on the evolution of near bed flows driven by the leading waves of tsunamis, in particular the bed shear stress. Responding to the research needs mentioned above, we will conduct the following research activities: -Developing and implementing algorithms for the new wave maker at the large wave flume at Oregon State University so that different types of leading tsunami wave forms, including bores and N- waves can be simulated in the NEES tsunami facilities; -Measuring and analyzing runup heights of various leading tsunami wave forms on a plane beach; -Design and install a new instrument package for measuring bed shear stress in the NEES facilities; -Measuring and analyzing bottom shear stress under various leading tsunami wave form. The Broader Impacts Resulting from the Proposed Activities: The proposed research is a part of a long term fundamental research program, aiming at correlating the tsunami hydrodynamics with the tsunami sediment deposits. The experimental data, obtained from the project, will provide the necessary information for parameterizing wave breaking, bottom shear stress and flow turbulence in the sediment suspension and transport models. Therefore, the proposed research will have a much broader impact on the establishment of tsunami hazard mitigation programs. The project will train one PhD student who will receive cutting edge training in experimental techniques and data analysis. The student will also have a rigorous education in numerical methods, and will be capable of performing model/data comparisons. Training in scientific writing and oral presentation will be a part of student's graduate education program. Furthermore, the student will be encouraged to attend technical conferences and meetings; Cornell graduate school will provide a partial support for presenting papers in technical conference. The PI's will also participate in the REU program organized by the NEES program so that REU students can be exposed to the large scale facilities at wave laboratory. Every effort will be made in attracting underrepresented minority students to participate in the proposed project. Data from this project will be archived and made available to the public through the NEES data repository. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).