Numerical Analysis Of Landslide Tsunami

As a suddenly and extremely destructive marine disaster,tsunami has been widely concerned in recent years.At present,the domestic and abroad research on tsunami mainly focuses on the tsunami disaster caused by earthquakes.There are few studies on landslide tsunami characteristics and physical mechanisms caused by submarine landslides,mainly based on laboratory observations and simulations.In the northern continental shelf area of the South China Sea,various unstable landforms such as submarine landslides,flowing sand slopes,large erosion gullies and submarine steeps are well developed,which are potential factors that can cause landslide tsunami,and enough attention should be paid on this situation.Firstly,this paper takes the 2017 Mexico earthquake tsunami as the research object,uses DART(Deep-ocean Assessment and Reporting of Tsunamis)and offshore tide gauges sea level data to get the tsunami wave data,generalize and summarize the energy distribution characteristics of tsunami waves in the deep ocean and coastal areas,and the wavelet analysis was used to further analyze the frequency and energy characteristics of tsunami waves.Through the above research,it is found that the interaction between the gulf topography and tsunami waves causes the amplitude to increase and the fluctuation duration to become longer.The sea level data of the Palu Bay tsunami in Indonesia was analyzed.Referring to the field investigation report,this paper uses the elastic half-space dislocation theory,the finite fault model and the submarine landslide model to calculate the initial water elevation of the tsunami,and simulate the propagation of the tsunami.According to the simulation results and the tsunami propagation time of the pantoloan station,it is believed that the tsunami was mainly caused by earthquake,and it is likely to be affected by submarine landslide Palu Bay,which aggravated the tsunami disaster.According to the wavelet analysis of tsunami waves in the pantoloan station,the Palu Bay terrain produced the effect of “zooming in” the tsunami amplitude.The area of Baiyun depression in the northern part of the South China Sea is selected as a potential source of landslide tsunami.According to the previous research,the landslide tsunami source parameters are given and numerical simulation is carried out.By analyzing the simulation results,it is believed that the landslide tsunami in the Baiyun depression area will cause a maximum tsunami amplitude of more than 6m in the deep ocean of the South China Sea and a maximum amplitude of 0.3-3m in the nearshore area,which will cause a serious damage to the vessels,engineering,near-shore personnel and property safety,which need to be given sufficient attention.Through the sensitivity experiment,the tsunami scenarios caused by submarine landslides in the Baiyun depression are compared,and the risk of landslide tsunami in this area is comprehensively evaluated.It is believed that the maximum amplitude of deep water and nearshore area in the South China Sea region is different under different scenarios.But under each scenario,the amplitude all reaches the level of tsunami disasters,which will have a catastrophic impact of varying degrees.