Assessing the SPLASH Empirical Formula for Run-Up Prediction of Subaerial Landslide-Generated Tsunamis

Tsunamis generated by subaerial landslides can cause severe damage along shorelines over large distances, making run-up assessment a critical component of landslide hazard and risk analysis. While site-specific numerical modelling provides detailed insight into wave generation and propagation, such approaches are often time-consuming and data-intensive. For preliminary hazard assessments, more general methods requiring limited input parameters are therefore needed. Empirical relationships offer a practical means to rapidly estimate tsunami impact and associated risk prior to undertaking detailed numerical modelling.In this study, we evaluate the performance of the SPLASH empirical formula (Oppikofer et al., 2019) by applying it to several well-documented landslide-generated tsunami events in Greenland and Alaska. Modelled run-up estimates are compared with mapped run-up observations, and for one case, with results from numerical modelling. Our results indicate that the SPLASH empirical formula is a valuable and promising tool for first-stage hazard and risk assessment of unstable rock slopes located above water bodies. Finally, we discuss potential improvements to the formula to enhance its applicability and predictive capability. Oppikofer, T., Hermanns, R.L., Roberts, N.J., Böhme, M., 2019. SPLASH: semi-empirical prediction of landslide-generated displacement wave run-up heights. Geol. Soc. Lond. Spec. Publ. 477, 353–366. https://doi.org/10.1144/SP477.1