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 Texas A&M University (lead institution). This project will utilize the NEES equipment site at Oregon State University.
The destructive power of a tsunami on the world's coastlines is unquestioned; ample evidence can be seen in photos of the aftermath of the 2004 Indian Ocean tsunami. The scale of destruction, however, has perhaps inadvertently justified the study of tsunamis in isolation from the other components of the ocean wave climate. The intellectual merit of the proposed work is the investigation of the tsunami phenomenon not as an isolated event, but as an inherent part of the world's ocean climate. For all their differences in destructive power, size, and generation, tsunamis and swell waves (which are always present on the ocean surface) are both gravity waves, and follow many of the same physical laws. Additionally, gravity waves of different frequencies exchange energy, which affects the shape of the front face of the wave and, in turn, the destructive power, travel time, and damage potential (structural damage and erosion) of the tsunami.
Experiments will be conducted in the NEES Tsunami Wave Basin during summer 2010 to investigate this interaction. Both tsunamis and swell-band waves will be generated, in isolation and in combination, and their interaction determined by analysis of the measured velocities and free surface heights. Both standard (Fourier-based) and advanced (Hilbert-Huang transforms) methods will be used to determine the degree of the tsunami-swell interaction and the resulting changes on the evolution of the front face of the tsunami wave. These data will be used to determine the change in the tsunami front face characteristics due to the interaction with swell waves and further deduce the effect to its destructiveness.
The broader impacts of the proposed activities concern the effect of the investigation on the profession's present understanding of the destructive power of the tsunami. This may in turn alter present policies for evacuation, construction, and public safety in coastal areas potentially subject to tsunami inundation. In addition, the research team will work with the NEES Tsunami Basin Facility's education and outreach personnel to enhance their programs for public education and engaging students into science and engineering. This will include live demonstrations of the added effect of swell wave-tsunami interaction on the destructiveness of an onrushing tsunami.
Data from this project will be archived and made available to the public through the NEES data repository.
