Numerical simulation of effect of inundation flow caused by the 2011 Tohoku earthquake tsunami on the Pinus thunbergii coastal forest

- A case study of Misawa City of the Aomori Prefecture -

Abstract

The Pinus thunbergii coastal forest in Misawa City of the Aomori Prefecture was partially damaged by the 2011 earthquake tsunami, which occurred off the Pacific coast of Tohoku. Using the numerical simulation of the inundation flow caused by the tsunami, we investigated the cause of the partial damage and the mitigation of the inundation flow by the coastal forest. The results of the numerical simulation showed that the maximum inundation depth and maximum discharge flux at the inland edge of the coastal forest were reduced by the coastal forest and the tree damage index, which was calculated as the ratio of the turning moment to the section modulus at the stem base, accounted for the approximate distribution of the damage to the coastal forest.