## 1 Introduction
At the same time, a depression appears where the shoreline retreats and will result in a significant stress gradient. Affected by these pressure gradient forces, a massive amount of water poured into the depression and rebounded to form two traveling waves propagating along the coastline [15]. [PERSON] and [PERSON] systematically studied the generation and propagation characteristics of landslide-induced tsunamis from 2008 to 2012. The study in 2008 found that the large amplitude waves did not appear in the front of the wave list, but in the middle, which was different from the earthquake-induced tsunami and caused great disaster in the early stage, when people did not know much about the landslide-induced tsunami [16]. The 2010 study of [PERSON] and [PERSON] found that traveling waves around the conical islands do not travel completely along the coastline and are partly free from the constraints of the circular coastline, but still have run-up [17]. They found in 2012 that irregular landslide geometry could lead to sharp twin peaks of waves and that the continental shelf could reduce the severity of the tsunami [18]. However, most studies in the past have focused on traveling waves, and few have studied the generation and propagation of offshore waves. An in-depth study of this part is necessary. Because, on the one hand, the amplitude of an offshore wave as it travels from the near field to the far field does not decay as quickly as earlier studies suggested [19,20]. This suggests that, in the limited near field and the part of far field, offshore waves actually have non-negligible energy and destruction, especially in enclosed basins (to as fjords, reservoirs, and lakes), which were seriously underestimated in the past study [13]. On the other hand, in the path of offshore wave propagation to the far-field, there are usually some important offshore structures, such as submarine pipelines, risers, cross-sea Bridges, and offshore platforms, which will lead to huge economic losses and environmental pollution if they are damaged. In order to protect these important structures, it is necessary to study the characteristics of the generation and propagation of near-sea waves and their interactions with these structures. In addition to ignoring the importance of studying the near-sea waves, most past research has focused on a single initial inundation condition [21,22]. Few studies have investigated and compared the effects of the three different initial submersion conditions (submarine, subaerial, and partial subaerial) on tsunamis, and few studies have explained the differences in the characteristics of the generation and propagation of the three landslide tsunamis. In this paper, considering the importance of the vertical physics acceleration in the initial stage of the landslide-induced tsunami [23,24,25] and the importance of the whole development process of the landslide [26], the general moving-object module and hydrodynamic and turbulence module are coupled to numerically simulate the production and propagation of landslide-induced tsunamis, which compares the physical experiment to verify the model. Through a large number of simulation cases with different settings, this paper analyzes the characteristics of the generation and propagation of offshore waves and studies the influence of different initial submergence conditions of sliders (submarine, subaerial, and partial subaerial). In addition, the effects of sliding height, sliding angle and slider geometry on landslide-induced tsunami are also studied. The rest of the paper is organized as follows. The second Section introduces the numerical simulation methods and equations. The verification of this model is conducted in the third Section. The systematic simulationsare carried out in the fourth Section where the effects of the different initial submergence conditions, sliding heights, sliding angles and slider geometry are analyzed. The conclusions of this work and prospects for the future are given in the fifth Section.