A Fast High Order Accurate Method For Tsunami Propagation

This paper presented an explicit and time-space decoupled numerical algorithm based on the exact solution of wave equation for tsunami propagation. The recursion formulas derived from this algorithm can reach 2M-order accuracy (M is the positive integer) both in time and space domain by coefficients choosing. The recursion formulas with second order accuracy by setting M=1 are used in this paper. In order to consider the frequency dispersion during the propagation of tsunami, the numerical dispersion is manipulated to mimic it and the corresponding dispersive recursion formulas are derived. The generally accepted model COMCOT is used to validate the new algorithm by simulating 2011 Tohoku tsunami. The simulation results demonstrate that the new algorithm can save much more computational time than COMCOT without reducing computational accuracy.