Analytical and numerical investigation on the effects of landslide acceleration in landslide-generated tsunamis

Abstract Submarine landslides are capable of causing locally catastrophic tsunamis. A landslide necessarily begins its motion by accelerating from a halt. However, the role of landslide acceleration on the tsunami generated by a landslide remains understudied. Assuming an idealized configuration, in this study we cast the landslide acceleration problem as an extension to the existing knowledge on landslide-generated tsunamis above a flat sea bottom. By using the Green’s function approach, we derived new analytical solutions for the tsunami generated by an accelerating submarine landslide. Consistent with the observations in existing studies, we found that a slower landslide acceleration results in a longer but smaller leading submarine landslide tsunami wave. Based on a large number of numerical simulations, empirical formulas were established to quantify the wave modification factors due to landslide acceleration. Combining existing analytical solutions and the newly determined empirical formulas, we assembled semi-analytical solutions that can be easily used to predict the characteristics of the tsunami generated by an accelerating submarine landslide.