Landslide Tsunami Amplitude Prediction in a Numerical Wave Tank

Tsunami generation by underwater landslides is simulated in a three-dimensional (3D) Numerical Wave Tank (NWT) solving fully nonlinear potential flow equations. The solution is based on a higher-order Boundary Element Method (BEM). New features are added to the NWT to model underwater landslide geometry and motion and specify corresponding boundary conditions in the BEM model. A snake absorbing piston boundary condition is implemented on the onshore and offshore boundaries. Results compare well with recent laboratory experiments. Sensitivity analyses of numerical results to the width and length of the discretized domain are conducted, to determine optimal numerical parameters. The (3D) effect of landslide width on tsunami generated is then estimated. Results show that the 2D approximation is applicable when the ratio of landslide width over length is greater than three.