Numerical investigation of the effect of landslide relative density on the impulse wave amplitude

Abstract

Landslide-induced waves, generated by mass movements such as ice and rock avalanches impacting water bodies, represent significant hazards. These phenomena have garnered considerable attention from the scientific and engineering communities. Previous studies have explored the influence of landslide density on the characteristics of impulse waves, but the specific conditions of deep water, where the landslide thickness is less than several times the water depth, remain less extensively examined. This gap in knowledge hinders the accurate assessment of the risks associated with landslide-induced waves. In this study, we systematically examine the parameters of landslide density ρs, velocity vs, thickness hs, and water depth hw to elucidate the effects of ρs. Additionally, we analyze wave amplitudes along the propagation path using the smoothed particle hydrodynamics (SPH) method, which incorporates a density diffusion term. Our findings reveal that the landslide density significantly influences the maximum wave amplitude in water conditions where the relative landslide thickness S=hs/hw≥0.5, whereas it has a negligible impact in water conditions where the relative landslide thickness S=hs/hw<0.5. We observe three distinct patterns in wave amplitude evolution along the propagation path: linear decrease, exponential decrease, and an initial increase followed by an exponential decrease. Finally, we propose a model for predicting the amplitudes of landslide-induced waves at varying distances from the starting point of a landslide into a water body. This study is beneficial for the prediction and prevention of landslide-induced wave disasters.