Hydrodynamic Modeling of Tsunamis Generated by Submarine Landslides: Generation, Propagation, and Shoreline Impact

On July 17, 1998, an earthquake occurred near the Pacific coast of western Papua New Guinea (PNG), and a large tsunami followed. The death toll had been the worst from a tsunami in the previous 50 years, with over 1,000 persons killed by the 10-m waves. The exact causative mechanism of the tsunami had been the subject of considerable debate; detailed offshore investigations coupled with analysis of runup patterns eventually and convincingly indicated a slump source (e.g., Tappin et al. 2001; Synolakis et al. 2002). Since PNG, the tsunami community has expended significant energy into examining the state of knowledge regarding landslide tsunamis, with a particular hope to determine the risk associated with these events. This paper will detail some of these recent advances, as well as provide a fundamental background into the physics of wave generation by submarine mass movements. Topics to be discussed include coupling seafloor motion to the hydrodynamics, characteristics of landslide tsunami waves as compared to "traditional" subduction earthquake tsunamis, and the behavior of landslide tsunamis in shallow water.