A Semi-Empirical Approach for Tsunami Inundation:Application to the Italian Tyrrhenian coasts

Research interest on tsunami propagation and coastal impact in the Mediterranean Sea has recently grown due to recent catastrophic events, like the ones in Indian and Pacific Oceans.
A novel operational approach for evaluating tsunami-induced inundation, based on a generalization of Green's law and a chain of intermediate and small-scale simulations, has been recently proposed (Lalli et al. 2019; Melito et al., 2022).
The original Green’s law provides the amplitude of a long wave at a given water depth, accounting only for the wave shoaling, while neglecting both diffraction and refraction effects. The new formulation of Green’s law allows one to overcome such limitations, by introducing a semi-analytically computed coefficient α, encompassing the effects due to refraction and diffraction phenomena, and other interactions with natural obstacles and artificial structures, which play a crucial role in the case of natural, complex bathymetry. Therefore, α represents a proxy for coastal susceptibility to tsunami impact. Melito et al. (2022) performed intermediate-scale simulations to identify the distribution of α along the south-eastern Italian coasts. To validate the employed procedure, small-scale modeling of coastal flooding has been also performed by Melito et al. (2022), for two case studies: the Esaro river estuary (Calabria) and the nearshore of Bari (Apulia). A good agreement was found between the inundation levels obtained by small and intermediate-scale modeling, the latter allowing for a significant reduction of the computational costs. The present work aims at extending the research by applying the described procedure to all the Italian Tyrrhenian coasts.

References
Lalli, F., Postacchini, M. & Brocchini, M. (2019) Long waves approaching the coast: Green’s law generalization. Journal of Ocean Engineering and Marine Energy, 5, 385–402. https://doi.org/10.1007/s40722-019-00152-9.
Melito, L., Lalli, F., Postacchini, M., & Brocchini, M. (2022). A semi-empirical approach for tsunami inundation: An application to the coasts of South Italy. Geophysical Research Letters, 49, e2022GL098422. https://doi.org/10.1029/2022GL098422.