Analysis of the specific features of propagation of tsunamis in the shelf zone of the basin

Abstract

A 3D model of nonlinear long waves is applied to the numerical analysis of the propagation of tsunami waves from a rectangular zone of generation in a basin with continental slope and shelf zone. The waves are generated by unidirectional displacements of a bounded area of the bottom of the basin for a finite period of time. It is shown that the efficiency of wave generation depends on the location, horizontal sizes, and duration of deformations of the bottom. The run-up of waves onto the vertical coastal boundary is maximum for short-term shifts of the bottom, for large zones of generation, and seismic sources located on the continental slope. The reflection of waves from the coast leads to the formation of two waves entrapped by the shelf and propagating along the coast in the opposite directions from the zone of the initial wave impact. A partial entrapping of waves by the shelf is observed. This phenomenon manifests itself in the form of multiple reflections of the waves from the coast and the shallow edge of the continental slope and is absent in the case of generation of waves in the deep-water part of the basin.