Development and validation of a two-layer Boussinesq model for simulating free surface waves generated by bottom motion

Abstract In this work, a recently developed two-layer Boussinesq model with high accuracy regarding linear and nonlinear properties and interior kinematic properties from deep to shallow water is extended to include the time-varying bathymetry for modelling earthquake- and landslide-induced waves. The effect of bottom motion is taken into account by simply adding an additional term within the kinematic bottom condition. The moving shoreline is addressed by utilizing linear extrapolation through the wet–dry boundary and into the dry region. A wide range of numerical tests covering the generation, propagation and runup of dispersive waves induced by bottom motion are carried out with the vertical two-dimensional Boussinesq model. The computed results are compared against available theoretical solutions, experimental measurements and previous numerical simulations. Both the consistencies and the discrepancies are discussed.