Effects of the soil properties on the sea pressure profile due to seismic motions

Large number of earthquakes have epicenters in offshore areas and their effects are a matter of great concern. This paper applies, for two dimensional problems, the Indirect Boundary Element Method to calculate the seismic pressure profile with the water depth due to the incidence of P- and SV-waves on the seabed, which can be characterized using the soil properties. Moreover, seismic amplifications of the seabed are highlighted. Our formulation can be considered as a numerical implementation of the Huygens' Principle in which the diffracted waves are constructed at the boundary from which they are radiated. Thus mathematically, it is fully equivalent to the classical Somigliana's representation theorem. Numerical results show the importance of knowing the properties of the marine soil because the pressure profile has an enormous dependence with respect to them. In some cases, pressure amplifications of six times between extreme values of soil materials can be expected. In addition, results from a layered numerical model evince that large seismic amplifications may be found, they can reach values up to 15.57 and 18.36 times the incident P- and SV-waves, respectively.