Fundamental mechanisms for tsunami generation by submarine mass flows in idealised geometries

Tsunami generation from submarine gravity mass flows is investigated using linear two-dimensional analytical models, a simplified slide geometry, and a prescribed sub-critical slide velocity. Slide characteristics as maximum slide velocity, initial acceleration, slide length, and thickness, are all found to determine the characteristics of the tsunami. Effects of dispersion usually turn out to be of minor practical importance. Tsunamis due to retrogressive slides are generally smaller than for a similar fixed shaped slide with the same characteristics due to an increased duration of slide mass mobilisation. However, above the rear of the slide, the surface elevation can also be increased for small time lags.