3D NUMERICAL MODELLING OF FIVE SUBMARINE LANDSLIDE SCENARIOS IN PERTH CANYON, AUSTRALIA TO ASSESS TSUNAMIGENIC HAZARD

Abstract

Submarine canyons have been identified on nearly all margins around the world (Urlaub et al., 2013). Their configuration and morphology has been attributed to several factors including geology, tectonism, sea-level variations, and sediment supply to the region (Laursen and Normark, 2002) with processes occurring over varying temporal and spatial scales driving complex morphologies (Drexler, et al., 2006). A common process in submarine canyons is the mass wasting of sediment in the form of submarine landslides (SMLS) (Brothers, et al., 2013). A SMLS is a displacement of sediment or debris driven by gravity where the downslope forces are greater than the forces that are acting to resist the mass-failures (Mountjoy and Micallef, 2018). The potential tsunami hazard posed by these SMLS was assessed by Buller et al. (2021) using empirical calculations which showed that these SMLSs posed a tsunami threat to the adjacent coastline with calculated wave amplitudes ranging from 2.13 – 15.90 m. However, the tsunami risk assessed in their study was a conservative initial assessment and did not consider how local bathymetry influenced tsunami propagation.