Tsunamis are a leading natural threat to coastal communities, and events such as the 2011 Japan, 2010 Chile, and 2004 Indian Ocean tsunamis caused widespread, crippling damages to coastal infrastructure. Yet, these events also revealed the role of mangroves and other vegetation as sustainable mitigation against tsunami hazard. The overarching goal of this research is to develop a quantitative understanding of tsunami inundation in regions with coastal forests. This project combines detailed fluid dynamics modeling with physical experiments to study tsunami inundation in the presence of discontinuous coastal forest. The transformative nature of this research lies in studying the effects of multi-scale processes on the large-scale tsunami inundation dynamics relevant for improving tsunami mitigation and preparedness. Laboratory experiments will be used to study inundation in discontinuous forest, represented by circular patches of cylinder arrays. Measurements will be used to quantify mean flow and turbulence statistics, the spatial flow field between two forest patches, runup speed, and large-scale flow structures during withdrawal. Numerical analysis will be integrated with the experimental campaign to expand the parameter set for analysis and to assess the impact of temporal changes in forest characteristics. The research team from Virginia Tech will use the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) tsunami laboratory facility at Oregon State University. Data from this project will be archived and made available to the public through the NEES Project Warehouse/data repository (www.nees.org).
Research from this award will lead to better quantification of tsunami hazard reduction, or amplification, as a function of coastal forest density and layout, topographic slope, and tsunami wave form. Additionally, this research will lead to better quantification of the impact of coastal forests in regional-scale numerical models for tsunami inundation. Both of these outcomes will enable more accurate prediction of tsunami inundation and the resulting water force on homes, commercial buildings, and other infrastructure onshore. Ultimately, these advances will lead to more effective evacuation plans, more resilient building and infrastructure design, and more effective design of protective, sustainable forest features. These measures will help to reduce tsunami mortality, community displacement, and economic losses. The broader scientific impacts are in the applicability of the research outcomes to other coastal problems like tsunami wave propagation over coral reefs and storm surge propagation through wetlands, mangroves, and upland forests. This award is part of the National Earthquake Hazards Reduction Program (NEHRP).
