## 5 Conclusions  
In this paper, the generation and propagation of a landslide-induced tsunami with different initial submergence condition were investigated, which consider three aspects. In the first aspect, because the essence of landslide-induced tsunami is that the gravitational potential energy of landslide is converted into wave energy, the effect of falling height with a different initial submergence condition is considered. In the second aspect, due to the different slope angles of landslides in reality, the investigations on the effect of the falling angle of the slider with different initial submergence conditions are conducted. In the third aspect, under different geotechnical characteristics of coasts, the geometry of a landslide is various, therefore, the effect of the ratio of the long axis to the short axis of the slider is also studied. The conclusions of this paper are as follows. As the slider moves in the water, it squeezes and pushes the water in the horizontal direction, while creating a pressure gradient in the vertical direction causing the water to rush downward and bounce upward. The effects of squeezing and pushing produce a naturally attenuated wave at the front of the wave train. The effects of the vertical moving of the slider cause the increase in the amplitude at the back of the wave train. * For a subaerial landslide-induced tsunami, the maximum wave height decreases with the increase in the initial falling height, and there is an optimal falling height range within which landslides cause the maximum surge height. For submarine landslides and partial subaerial landslide-induced tsunamis, the maximum wave height increases with the increase in initial falling height, except for the accidental elevation of submarine landslide-induced tsunamis at smaller falling heights. When the slider is initially partially submerged, the attenuation of landslide-induced waves appears in the propagation process, and the attenuation becomes more serious with the increase in the initial submersion range. Figure 19: The change of the maximum wave height with R.  
* Since there is a greater total horizontal acceleration at a smaller falling angle and a greater total vertical acceleration at a larger falling angle, the hazard of the subaerial landslide-induced tsunami is greater under a small or large falling angle. However, when it comes to a submarine and partial subaerial landslide, the horizontal acceleration is the main factor affecting the wave height, so the hazard of the partial subaerial and submarine landslide-induced tsunami is greater under a small falling angle. * The total wave energy decreases and the shape of the wave train proportionally reduces as the ratio of the long axis to the short axis of the semi-elliptical slider increases, while the wave propagation mode does not change. However, the sliders of soil landslides have rheological properties and the sliders of rock landslides have irregular properties, which leads to the landslide process is no longer simply that the sliders slide steadily along the slope. Compared with the semi-elliptic rigid body slider in this paper, these slider characteristics will lead to the different generation and propagation characteristics of the landslide-induced tsunami [34; 35]. These situations are not considered in this paper but are worth further studying in the future. It is anticipated that the findings in this paper can provide the reference for the disaster prevention and mitigation of landslide-induced tsunamis. Reducing tsunami damage to offshore structures such as submarine pipelines, risers, cross-sea bridges, and offshore platforms will be further discussed in future studies. Conceptualization, E.Z. ; methodology, E.Z. ; software, J.S. ; validation, J.S. ; formal analysis, J.S. ; investigation, J.S. ; resources, E.Z. ; data curation, Y.W. ; writing--original draft preparation, J.S. ; writing--review and editing, E.Z., Y.W., C.H., W.W., H.W. ; visualization, Y.W. ; supervision, C.H. ; project administration, Y.W. ; funding acquisition, Y.W., C.H.