Tsunami current inundation of ground with coastal vegetation effects; an initial step towards a natural solution for tsunami amelioration

Abstract

A densely grown coastal vegetation belt of Pandanus odoratissimus to reduce the tsunami energy was quantitatively analyzed by an enhanced one-dimensional numerical model that included variations of topography and tsunami characteristics. The drag and inertia forces were assumed as the total resistance generated by the vegetation. A relatively small period tsunami wave was more destructive than a relatively large period tsunami wave of the same height, although densely grown vegetation effectively reduced the tsunami energy in the case of the small period tsunami wave. A very mild ground slope was more vulnerable to thrashing by tsunami waves than a relatively steep ground slope. Moreover, densely growing coastal vegetation on the very mild ground slope dissipated tsunami energy more efficiently than the same vegetation on the relatively steep ground slope