Effects of bathymetry on the propagation of tsunamis towards the east coast of Korea

Abstract

In this study the effect of underwater topography of the East Sea on the propagation of tsunamis towards the Korean Peninsula is investigated using the dispersion-correction finite difference numerical model. A series of numerical simulations are conducted for three tsunami events including the 1964 Niigata Tsunami, the 1983 Central East Sea Tsunami and the 1993 Hokkaido South-West Sea Tsunami for the cases of examining the individual or combined influence of underwater topographic features. These include the Yamato Rise, a submerged ridge connecting Yamato Rise and the Shimane Peninsula of Japan, and K-shaped submerged ridges emerging from the east coast of Korea towards the East Sea. In particular, in order to evaluate quantitatively the effects of underwater topography On the propagation of tsunamis, a new concept of energy discharge per unit width is introduced. Using this concept, the quantitative analyses of energy propagation during tsunami events are performed. The analyses show that the underwater topographies including the submerged rises and ridges capture the tsunami energy and transport it to coastal areas connected to those topographies.