Abstract
A linearized tsunami model of Kelvin wave type is introduced, and possible propagation speeds of fracture at tsunamigenic earthquakes are considered. This theoretical model shows that direction of the fracture line at the epicenter significantly affects the dynamical properties of the tsunami observed at a coast facing an ocean. Interest is focused on the amplitude of the tsunami at the coast in relation to the direction of the fault line formed at a tsunamigenic earthquake. A qualitative application of the model could be helpful for understanding past hazardous tsunami events in the northwestern Pacific.