Comparing methods for computation of run-up heights of landslide-generated tsunami in the Northern Sicily continental margin

Abstract

The North Sicily continental margin is a very active region located in the Central Mediterranean. Strong seismicity, active tectonics and volcanism, fluid escape, high sediment supply, and widespread mass movements historically have exposed this region to marine geohazards, with a potential for tsunami generation. Morpho-bathymetric analysis revealed that one of the most common mechanisms associated with marine geohazards is due to submarine mass failure processes, genetically linked to the other processes active in this margin. With the aim to assess the risks associated with landslide-generated anomalous waves, we selected two sectors of this margin, Gulf of Palermo to the west and Patti offshore to the east. The workflow included analysis of the morpho-bathymetric data, morphometric characterization, calculation of parameters of landslide-generated waves, and com- putation of run-ups by using different algorithms. Assuming that each of the identified landslides could be a potential tsunamigenic source, we calculated the associated theoretical run-ups, referring to the main computation methodologies proposed in the scientific literature. In order to identify the methodology that better suits run-up values for landslide-generated tsunami, we compared the known run-up values of actual, historical cases with those calculated through the different methodologies. The values obtained with the most suitable equation, both for theoretical and historical events, fit a curve that we used to formulate an empirical law describing the relationships between amplitude and depth, at the source point, and relative run-up. It can be used to calculate easily and promptly the run-up associated with a generic landslide-generated tsunami.