Evaluating Tsunami Hazards From Debris Flows

Characteristics of water waves caused by subaerially generated debris flows vary with distance from the debris-flow entry point. Three hydrodynamically distinct regions (splash zone, near field, and far field) may be identified. Experiments demonstrate that characteristics of the near-field water wave-the only coherent wave to emerge from the splash zone-depend primarily on submerged volume and submerged travel time of the debris flow and on water depth where debris-flow motion stops. Near-field wave characteristics commonly may be used as a proxy source for computational tsunami propagation. An example application explores hazards associated with potential debris flows entering a reservoir.