Rei Yokoyama

Study on Analytical Methods for Topographic Changes Induced by Tsunami Run-up

Tokuzo Hosoyamada

This study investigates a numerical method to improve the reproduction of topographic changes caused by tsunami run-up. A one-dimensional model was developed by coupling nonlinear shallow-water equations with a bedload transport formula, an advection–diffusion equation for suspended sediment, and the Exner equation. Numerical experiments were conducted with five different tsunami amplitudes while keeping other parameters constant. Results show that bedload controls local erosion and deposition near the run-up front, whereas suspended sediment contributes to wider spatial changes through advection and diffusion. Sensitivity analysis indicates that sediment transport and morphological change increase nonlinearly with tsunami magnitude. The integrated model successfully reproduces complex erosion–deposition patterns and provides a foundation for future multidimensional simulations and applications to real coastal environments.