Kazuya Sakai, Takaaki Uda, Toshiro San-nami, Tatsuya Shimizu


A great earthquake with a magnitude of 9.0 occurred on March 11, 2011, with an epicenter 130 km offshore of the Oshika Peninsula in Miyagi Prefecture. After the earthquake, a giant tsunami inundated a large area along Japan’s eastern coastline. We carried out field observations to investigate the damage to Arahama Town and the formation of a trench as a result of local scouring by the jet flow over the coastal dike. Here, the results of the field observations on the inundation of the tsunami into a wide residential area on Shobuta Beach and in Arahama Town were reported. Then, the destruction of the coastal dike, as well as the formation of a large trench immediately behind the coastal dike due to the tsunami overflow on the Yamamoto coast, was investigated, where the tsunami height reached up to 19.2 m above mean sea level (MSL), estimated from the run-up height on the slope of a hill.


2011 Great Tsunami; tsunami damage; trench formation; coastal dike; coastal forest

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DOI: http://dx.doi.org/10.9753/icce.v33.currents.13