Tsunamis generated by earthquakes commonly propagate as long waves in the deep ocean and develop into sharp-fronted surges moving rapidly toward the coast in shallow water, which may be effectively simulated by hydrodynamic models solving the nonlinear shallow water equations (SWEs). However, most of the existing tsunami models suffer from long simulation time for large-scale real-world applications. In this work, a graphics processing unit (GPU)-accelerated finite volume shock-capturing hydrodynamic model is presented for computationally efficient tsunami simulations. The improved performance of the GPU-accelerated tsunami model is demonstrated through a laboratory benchmark test and a field-scale simulation.
Tsunamis are among the most dangerous natural disasters and are reported to potentially pose medium to high risk to most coastlines worldwide. Numerical modeling of tsunami propagation and run-up is essential for evacuation planning, risk assessment, and sometimes real-time forecasting. Numerical models based on the shallow water equations (SWEs) are commonly accepted for simulation of tsunami wave propagation from deep ocean to near shore including inundation.
To solve the SWEs for tsunami modeling, different approaches have been used, including the finite difference method, finite volume method, finite element method, and smoothed particle hydrodynamics (SPH). Most of the conventional tsunami models are based on finite difference leapfrog schemes, e.g., TUNAMI by Goto et al. (1997), MOST by Titov and Synolakis (1995), and COMCOT by Wang and Liu (2006). In recent years, finite volume Godunov-type schemes have also been implemented to solve the SWEs for tsunami modeling and have gradually gained popularity (Popinet, 2011; Leveque et al., 2011). These models boast automatic shock-capturing capability, superior conservation property, and flexibility for implementation on different types of computational grids for better boundary fitting. Because of these advantages, a second-order finite volume Godunov-type hydrodynamic model incorporated with an HLLC Riemann solver for interface flux calculation is used in this work for tsunami simulations. However, these sophisticated fully 2-D hydrodynamic models are normally computationally demanding for high-resolution simulations over large domains, restricting their wider applications.