Modelling of coastal dynamics generated by landslide

N. E. Voltzinger, A. A. Androsov

Landslide dynamics is considered in the framework of a two-layer system involving water and landslide material. The problem is formulated both in the Cartesian coordinates and in a generalized form relying on curvilinear boundaryfitted coordinates. An essential element of landslide dynamics is the account for nonhydrostatic pressure component defined by the solution of the nonlinear dispersive Boussinesq equation. A numerical implementation for curvilinear coordinates uses the second-order difference splitting scheme with restriction on the grid size only imposed by advection, and includes a module for computing draining in the shallow zone. The results of extensive series of numerical experiments simulating changing physical and energetic characteristics of landslide in function of slope angle are presented together with modeling results for coastal wave dynamics generated by a landslide as well as estimation of the impact of nonhydrostatic effects. The model is verified by comparing its simulation results with the results of laboratory experiments for three events: a tsunami wave at the Japan coast, wave passage over a submarine barrier and a gravity wave generated by a landslide. As a practical model application simulations of the flow generated by the Alaska mega-landslide (1958) are presented.

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