Evaluation of tsunami inundation reduction effects due to the reconstruction projects from the Great East Japan Earthquake based on elevation change using DEM

In the regions affected by the Great East Japan Earthquake, the topography has undergone significant changes as a result of extensive reconstruction projects. The aim of this study is to evaluate the effect of post-disaster topographic changes on reducing the risk of tsunami inundation. In order to determine inundation, elevation change using DEM of after the earthquake and the present was compared to tsunami inundation depth. It was found that the reduction effect was estimated to be 3.6% in Iwate Prefecture and 5.1% in Miyagi Prefecture and the effects were higher in the inner bay and inland municipalities. Furthermore, it is crucial to prioritize tsunami evacuation plans for residents in areas that are deemed non-inundated as a result of land readjustment projects and highway embankments.