SPH simulation of the 2007 Chehalis Lake landslide and tsunami

Abstract

A multi-phase smoothed particle hydrodynamics (SPH) formulation in combination with a granular rheological model is applied to simulate the 2007 Chehalis Lake landslide and the subsequent tsunami. The model is implemented within the open-source 3D code GPUSPH. The lake geometry is built using the British Colombia Hydro (BCH) topography and bathymetry surveys, and the landslide initial geometry is reconstructed from pre- and post-failure geological profiles under the assumption of constant thickness across the entire width. The water and the landslide are treated as immiscible continua, discretized in two distinct sets of SPH particles with different mass and behaviour laws. The landslide material is modelled as a continuum whose shear stresses obey a friction law that takes its granular nature into consideration. A sensitive analysis for various physical parameters is carried out, and numerical results are checked by comparing run-up heights to BCH's surveys.