ИСТИНА

In order to describe dispersive gravitational and hydroacoustic waves in a basin of arbitrary bathymetry generated by dynamic bottom deformation we developed a combined 2D/3D numerical tsunami simulation model. It consists of two modules solved simultaneously in shared calculation domain: depth-integrated (2D) in shallow water area and depth-resolving (3D) in deep ocean area. Both modules are based on the linear potential theory of ideal homogeneous fluid, but 2D module assumes water layer as incompressible and 3D module assumes water layer as compressible. Dynamic bottom displacement of small amplitude (tsunami source) is specified as time-dependent vector velocity field. Equations are written in spherical coordinates (2D) and in sigma-spherical coordinates (3D). The explicit finite-difference scheme is used to solve these equations. The numerical model was tested on exact analytical solutions in case of flat bottom. Recent tsunamis (Kuril Islands 2006, 2007) was simulated. Manifestations of water compressibility and phase dispersion of tsunami waves are discussed.