Spatial and Temporal Evolution of Landslide-Generated Waves

Abstract

The waves generated by an underwater landslide exhibit strong dependence on the landslide motion. In this experimental study, the landslide is modelled as a solid semi-elliptical block moving along a horizontal boundary in a flume. The landslide initially accelerated at a constant rate to its terminal velocity, and after travelling for 2 seconds at this velocity it decelerated to rest (at the same rate as its acceleration). An application of laser-induced fluorescence provided free surface elevation measurements along the flume length, generating a robust dataset to investigate the spatial and temporal evolution of the generated waves. The landslide acceleration and Froude number (Fr) were varied during the experiments. The wave field is dominated by the acceleration-generated waves at low Fr, but at higher Fr energy is transferred from the landslide to the trailing waves during its constant-velocity motion. The landslide Froude number is the primary parameter affecting the evolution of the wave field, the magnitude of the landslide acceleration modifies the nonlinearity of the generated waves.