SGER: Channel incisions produced by tsunami waves along the coasts of Indonesia and Thailand

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ABSTRACTThe overarching hypothesis addressed by the project is whether tsunami waves concentrate fluxes of water and sediments in few selected locations, producing incisions resembling to tidal channels. Despite the fact that tsunami waves cause an almost uniformrunup that floods large areas of the coastal landscape, the corresponding currents are most likely concentrated in few selected areas producing local enhanced erosion. This hypothesis is corroborated by recent studies by the applicant investigator on the morphological development of channels in tidal environments. Tidal fluxes in shallow areas clearly concentrate the discharge within few incisions thus producing scour and channel formation. The proposed research is based on the analysis of high-resolution remote sensing images of the coastline of Indonesia and Thailand impacted by the recent tsunami of December 26, 2004. The analysis will shed light on the different mechanisms by which currents scour tidal channels or, more generally, incisions, during the flood and ebb phase of a tsunami. We will finally analyze the geometric features of the new channels with a set of morphological tools developed for geomorphic studies in intertidal environments.Broader impact and motivation for exploratory research supportThe proposed research has a high societal impact, since we can gain insight into how the water is carried in and out coastal lowlands during a tsunami. We can thus assess what areas are more fragile from a morphological viewpoint (i.e. what areas are mostly affected by such a disastrous event) with a clear impact on local population and economy.After the powerful tsunami in Indonesia and Thailand of December 26 2004, the reconstruction of the waterfront is underway. It is then of crucial importance a timely dissemination of the project results. Our results will provide key information for both tsunami relief and rebuilding process, indicating what areas are more prone to erosion and giving insights on the mechanisms in which the tsunami wave concentrated its deadly energy along the coast. Furthermore this project can be seen as a first component of a broader investigation on the effects of tsunami waves on coastal areas, which will be developed in the near future in collaboration with researchers from universities inThailand and Indonesia. Both a graduate and a high school student through the FloridaState University Young Scholar Program Summer Camp will be involved in the project.