Lagrangian hydrocode simulations of the 1958 Lituya Bay tsunamigenic rockslide

Abstract

[1] The interaction of debris flows, whether subaqueous or subaerial, with bodies of water can produce tsunamis with a locally devastating impact. When debris flows begin above the water surface, the impact can produce a large air cavity, corresponding to a large effective volume of water displaced and complicating efforts to model the resulting tsunami. Because grid-based, Eulerian numerical methods have an inherent difficulty tracking material boundaries, we have implemented a particle-based, Lagrangian model (Smoothed Particle Hydrodynamics). We treat the debris flow as an incompressible, viscous fluid and the body of water as inviscid. We use this model to simulate the 1958 Lituya Bay rockslide and resulting tsunami. Our simulation results compare favorably with field observations as well as a scaled laboratory experiment and numerical studies.

Landslides and tsunamis predicted by incompressible smoothed particle hydrodynamics (SPH) with application to the 1958 Lituya Bay event and idealized experiment

“…Initially, the computational problem is defined and preliminary computational results are shown which, following the method of Schwaiger & Higman [10], include a laminar approach for both phases and a gravitational acceleration for the landslide which retains its rheological characteristics without considering any saturation effects. This preliminary analysis shows that although ISPH with shifting and non-Newtonian rheology can improve upon the results of Schwaiger & Higman [10] it fails to capture both the wave run up and landslide-entry profile presented in the benchmark experimental work of Fritz et al [2]. This motivates further investigations into the physical phenomena during the landslide-tsunami process, which leads to the introduction of a RANS turbulence model for the water phase and a saturation model for the landslide.…”

“…(c) Initial comparisons with the weakly compressible smoothed particle hydrodynamics method of Schwaiger & Higman [10] Initially, a laminar approach is considered for both the landslide and the water phases (following [10]). Moreover, the landslide is accelerated only under the influence of gravity.…”

“…The idealized experiments [2] related to the 1958 Lituya Bay tsunami and landslide are reproduced. It is initially shown that, with a preliminary ISPH method which follows the physics used in the computational model of Schwaiger & Higman [10], the experimental wave run-up height can be reproduced but the landslideentry profile is not well predicted. The ISPH model is then extended to include a turbulence model for the water phase and a saturation model for the landslide phase.…”

“…A variety of different computational studies have been performed to reconstruct this event (e.g. [4][5][6][7][8][9]), with notable examples being the work of Basu et al [3], who used commercial volume-of-fluid software, the smoothed particle hydrodynamics (SPH) simulation of Schwaiger & Higman [10] and the Sanchez-Linares et al [11] Monte Carlo finite volume method for shallow water equations. All of these studies have used the experimental work of Fritz et al [2] as a reference.…”

Numerical simulation of landslide-generated waves using a soil–water coupling smoothed particle hydrodynamics model

“…A generalized viscoplastic fluid model was used to describe the landslide. Schwaiger and Higman (2007) applied a Newtonian fluid model in the SPH method for the landslide.…”