An efficient two-layer landslide-tsunami numerical model: effects of momentum transfer validated with physical experiments of waves generated by granular landslides

Abstract

Abstract. The generation of a tsunami by a landslide is a complex\nphenomenon that involves landslide dynamics, wave dynamics and their\ninteraction. Numerous lives and infrastructures around the world are\nthreatened by this phenomenon. Predictive numerical models are a suitable\ntool to assess this natural hazard. However, the complexity of this\nphenomenon causes such models to be either computationally inefficient or\nunable to handle the overall process. Our model, which is based on shallow-water equations, has been developed to address these two problems. In our\nmodel, the two materials are treated as two different layers, and their\ninteraction is resolved by momentum transfer inspired by elastic collision\nprinciples. The goal of this study is to demonstrate the validity of our\nmodel through benchmark tests based on physical experiments performed by\nMiller et al.\xa0(2017). A dry case is reproduced to validate the behaviour of\nthe landslide propagation model using different rheological laws and to\ndetermine which law performs best. In addition, a wet case is reproduced to\ninvestigate the influence of different still-water levels on both the\nlandslide deposit and the generated waves. The numerical results are in good\nagreement with the physical experiments, thereby confirming the validity of\nour model, particularly concerning the novel momentum transfer approach.