CLARIFICATION OF DAMAGE MECHANISM ON THE SEAWALLS AT YAMADA FISHING PORT IN IWATE PREFECTURE, AFFECTED BY THE 2011 OFF THE PACIFIC COAST OF TOHOKU EARTHQUAKE TSUNAMI

Abstract

 Damage points, damage lengths and damage modes of seawalls with or without steel-type piles at Yamada fishing port in Iwate Prefecture, affected by the 2011 off the Pacific coast of Tohoku earthquake tsunami were clarified by analyzing associated Google Earth data and structure drawings of subject 187 seawall units. Dependency of the damage ratios defined as the number of damaged seawall units divided by total number of exposed seawall units by the associated inundation depths and overflow depths was revealed, with considering the failure and non-failure mechanism on sliding and turning failure modes of the 42 seawall units without steel-type piles based on computation of safety factors.