An efficient two-dimensional non-hydrostatic model for simulating submarine landslide-generated tsunamis

In this study, a depth-integrated two-dimensional horizontal (2DH) non-hydrostatic model with a reduced two-layer system is developed to simulate tsunamis generated by submarine landslides. The present numerical algorithm, which extends the previous one-dimensional reduced two-layer non-hydrostatic scheme (NH-2LR), solves 3D incompressible Euler equations with hydrodynamic pressure distribution parameterization. This approach allows us to reduce the computational cost of the NH-2LR model, being relatively comparable to that of a one-layer model, while maintaining the accuracy of the full two-layer model. Comparison with analytical solutions demonstrates that the NH-2LR model can simulate landslide-generated waves up to a dispersion level of mu = 0.4, indicating its validity in shallow to intermediate water depth areas. Validation of the NH-2LR model with experimental data provides numerical results with an error of less than 10.29%. The final simulation employs the actual topography of Palu Bay. To mimic the 2018 Palu tsunami, we apply landslide scenarios as proposed in the literature. The NH-2LR model simulates landslide-generated tsunamis in Palu Bay, and the computed wave signals at the Pantoloan tide gauge station yield an error below 20.19% compared to available field data. All assessments showed the merits of our NH-2LR model in simulating tsunami waves generated by submarine landslides.