Simulation of tsunami induced by a submarine landslide in a glaciomarine margin: the case of Storfjorden SL1 landslide (Southwestern of the Svalbard Islands)

Abstract

Abstract. A modelling approach to understand the tsunamigenic potentiality of submarine landslides will provide new perspectives on tsunami hazard threat, mostly in polar margins where global climatic change and its related ocean warming may induce future landslides. Here, we use the Landslide L-ML-HySEA numerical model, including wave dispersion, to provide new insights in factors controlling the tsunami characteristics triggered by the Storfjorden SL1 landslide (Southwestern Svalbard). Tsunami waves, determined mainly by the sliding mechanism and the bathymetry, consist of two initial wave dipoles, with troughs to the northeast (Spitsbergen and towards the continent) and crests to the south (seawards) and southwest (Bear Island), reaching more than 3 m of amplitude above the landslide, and finally merging into a single wave dipole. The tsunami wave propagation and its coastal impact are governed by the Kveithola and Storfjorden glacial troughs, and by the bordering Spitsbergen Bank, which shape the continental shelf. This local bathymetry controls the direction of propagation with a crescent shape front, in plan view, and is responsible for shoaling effects amplitude values (-4.2 to 4.3 m), amplification (-3.7 to 4 m), diffraction of the tsunami waves, as well as influencing their coastal impact times.