Implications of friction factor adopting in the conventional tsunami run-up analyses

Implications of friction factor adopting in the conventional tsunami run-up analyses including numerical ones are discussed through examinations of applicability of previously reported tsunami run-up theory (Theory I) depending on an incident bore height h1 at shoreline (initial condition), a constant bottom slope i and a constant sediment median particle diameter d50, that (Theory II) depending on h1, i and a constant density ρ of inundation water with sediment, and that (Theory III) depending on h1, i, ρ and a constant friction factor K under a movable bed, comparing the theories with experimental results on the run-up distance of inundation flow with sediment and the theories mutually. It is confirmed that (1) the theory I considered to have the highest universality among the three theories can properly estimate the experimental run-up distance, (2) adoption of constant values of K and ρ evaluated at shoreline cannot properly estimate the run-up process except for a case that experimental values of incident inundation water depth and incident inundation flow velocity at shoreline are explicitly and independently used to evaluate the initial condition h1 in the theory II and (3) adoption of average values of K and ρ in the run-up process is highly recommended in the present state of the art, if we would like to appropriately estimate the run-up process with constant values of K and ρ which are the conventional approach in the tsunami run-up analyses.
The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)