Wavemaker Curves for Tsunamis Generated by Underwater Landslides

Abstract

A nondimensional wavemaker curve of a characteristic water wave amplitude is constructed from the landslide length, the initial landslide submergence, the incline angle measured from the horizontal, the characteristic distance of landslide motion, and the characteristic duration of landslide motion. This wavemaker curve applies broadly to water waves generated by unsteady motion of a submerged object, provided the motion is governed by only one characteristic distance scale and one characteristic time scale. An analytical solution of solid block motion provides the characteristic distance scale and time scale. Two-dimensional experimental results on a 45° incline confirm that a wavemaker curve for solid block landslides exists as a function of the nondimensional initial submergence and what is called the Hammack number. Water wave amplitudes generated by solid block landslides can be predicted from the wavemaker curve if the solid block motion is known. Criteria for the generation of linear water waves are given.