연안수역에서의 쓰나미 공진해석

Abstract

Recently, extreme tsunami waves generated by submarine earthquake have caused tremendous damages to the coastal cities and ports. Strong seiche oscillations and runups are observed in specific sea areas around the world. When multiple destructive tsunamis caused damage to Japan, Chile, USA, Indonesia, New Zealand, they have been recognized as a potential hazard to Korean coastal communities. Although no frequent impacts to the coast of Korean peninsula, there were some important events in the east of Korea in the past.

This study focuses on two historical events and recalculate with different fault and rupture mechanism for prediction considering the recent trend of submarine earthquake. Three-dimensional, time dependent, nonlinear, incompressible, viscous flow calculations were performed of realistic models of tsunami waves interacting with continental slopes and shelves. The present study of the 1983 Akita tsunamis demonstrates the multi-scale resonance along continental coasts. Together with the Nankai tsunami for inland sea, we have confirmed the inland sea resonance surrounded by islands in defining the impact along the coast. The damping action of submerged barriers on tsunami waves was investigated. Significant amounts of the energy of a tsunami were reflected by submerged barriers or coastal boundaries. Coherence and wavelet analyses for deducing a predominant period and time frequency are useful in reasoning the inundation.

The resonance modes, which are largely independent of the tsunami source, allow identification of at-risk communities and infrastructure for mitigation of tsunami hazards. The numerical simulation of tsunami waves can provide realistic descriptions of their propagation. Furthermore, understanding of the resonance and the predicted runups for the site of power plant and industrial complex in the east coast of Korea would allow better preparation for the future disasters.