Effects of fluvial landforms on the flow of the 2011 extreme tsunami, its geomorphic processes and damage of the cultivated area in the lower reaches of the R. Natori, northeast Japan

Abstract

This study aims to discuss the geomorphic effects on the tsunami disaster caused by the 2011 East Japan Earthquake on the dry riverbed in the lower reaches of the R. Natori, northeast Japan. The effects changed longitudinally and can be divided into four sections. Section 1 (lowest); strong flood flow and ebb flow caused strong erosion. Section 2; the flood flow was still devastating. Sedimentation process is dominant. Section 3; micro-landforms affected degree of damage of the farmland. Section 4 (6.0 kilometers from the river mouth); weakened and shallow tsunami flow went upstream through the relatively lower part.