ABSTRACT

Destructive events from the recent past reminded us how it is important to understand tsunamis. Usually, they are consequences of earthquakes and motions of the seafloor. But in most studies, the dynamics of the deformation is not taken account and the final vertical deformation of the ground is instantaneously transferred to the free surface. With this method, some aspects of the generation are not included, see Nosov (2014). In this work, only the impact of the dynamics on generated waves is studied by introducing two temporal parameters. The first parameters is the rise time tr . This parameter has been studied by Hammack (1973); it corresponds to the time of the vertical deformation of the ground. The second parameter is the propagation rupture velocity vp, closer to the geological properties of the fault, it is the horizontal spreading timescale. A previous work about the influence of vp was performed by Todorovska & Trifunac (2001). For the present study, a linear solution of the free surface is built with a simplified deformation of the seafloor involving tr and vp. Then, to measure the relevance of the shallow water equations (SWE) assumption, a potential energy ratio is defined, comparing the energy lost with the SWE versus the total potential energy produced. First, this ratio is calculated at the end of the motion of the ground for a large panel of tr and vp. Then, it is studied as a function of time.