A Numerical Model for Tsunami-Induced Morphology Change

We describe the development of a time-resolved model for tsunami-induced morphology change, based on an existing Boussinesq model for weakly-dispersive free-surface waves coupled to a depth-integrated model for sediment concentration and an equation for bed level change. The model allows for spatial variability in bottom friction coefficients and accounts for the presence of non-erodible beds or finite depths of available sediment. The model is verified using one laboratory data set and against field observations of morphology change in the Crescent City, CA harbor during the 2011 Tohoku tsunami event. The model is then applied to a hypothetical example illustrating the impact of tsunami inundation on an undeveloped barrier island.

Automated summary

The model developed in this study uses Boussinesq and sediment concentration models to describe tsunami-induced morphology change, considering spatial variability in bottom friction coefficients and the presence of non-erodible beds or limited sediment depths. The model's accuracy is verified using laboratory data and field observations, and is then applied to assess the impact of tsunami inundation on an undeveloped barrier island.