Geomorphic formation and artificial transformation of the piedmont gentle slopes along the tsunami-hazardous mid-Sanriku coast, northeastern Japan

Abstract

Along the middle part of the Sanriku coast, particularly in the zone composed of granitic rocks, piedmont gentle slopes are developed contrary to the northern part where high marine terraces dominate. The piedmont gentle slopes in the area are partially used as traditional settlement and provide sites both temporal evacuation and permanent settlement relocation from tsunami hazard which repeats frequently on the coast. We first investigate the geomorphic development processes and history of the piedmont gentle slopes. The investigation is flowed by hypothetical presentation of the morphological and geological characteristics of the piedmont gentle slopes, which have been locally and tacitly evaluated as the transformation capabilities of the geomorphic resources for the use as settlement and evacuation site. The hypotheses will be verified by the following papers.