Characteristics of wave amplitude and currents in South China Sea induced by a virtual extreme tsunami

Abstract

This paper investigates the potential extreme tsunami hazards of the worst case scenario of the magnitude Mw = 9.30 in South China Sea (SCS) as the Manila Trench is becoming one of the most hazardous tsunami source regions. Using nonlinear shallow water equations model, the time series of surface elevation, arrival time, spatial distributions of maximum wave amplitude and velocity distribution are presented. The characteristics of wave and currents are analyzed. The numerical results indicate that most of the energy of tsunami wave distributes in central and north part of SCS. The offshore regions around SCS will be influenced significantly by the tsunami currents generated by an earthquake in the Manila subduction zone. The maximum wave amplitude near Guangdong Province, Hainan Island, and Taiwan Island exceeds 4 m and velocities at the majority of measured locations near coast exceeds 2 m/s. Nested grid with high resolution is used to study the impacts of the tsunami on Hainan Island, Taiwan Island, and Lingding Bay. The regions with high hazard risk due to strong currents are identified. Finally, a fast tsunami warning method in SCS is developed and discussed, which can provide tsunami warning information in 5 min.