Evaluation of Effectiveness of Lifejackets and Injury risk against tsunami running on land

Abstract

A human body stricken by the run-up tsunami on land were simulated with a coupled human fluid numerical model. In addition to the efficacy of lifejacket to keep the victim floating, injury risk of collision both against tsunami front and obstacles were assessed with different wave height ranging from 0.5 m to 20 m. Regardless of the wave height and wearing lifejacket, a body of victim stricken by the tsunami was swept by the edge of propagating tsunami and not swallowed into the water, clear function of lifejacket to keep a body floating was not found. Injury risk was assessed with the criterion of automobile accident that are evaluated from acceleration working on a head and chest. In the case of simple striking of tsunami against the body, risk of serious damage and death significantly increases when the wave height exceeds 10m. The simulations considering the collision to a floating steel-drum or a fixed wall showed that the risk of serious injury or death can arise even if a tsunami height is less than 1 m.