## 6 Conclusions  
The effects of the four types of the seismic waves on the dynamic response and failure behavior of landslides were numerically investigated. The following conclusions were drawn:  
(1) The velocity contour shows that the velocity increases with the growing altitude, and the surface velocity is more significant than the internal velocity at the same altitude. In other words, the dynamic response of the slope is affected by vertical and surface amplification. By contrast to the velocity field of East-West, Up-Down, and three-directional seismic waves, it can be investigated that each seismic wave actually affects the landslide independently and will not interfere with each other.  
(2) By comparing the failure behavior of four cases, the East-West and three-directional seismic wave have more vital damages to slope stability than North-South and Up-Down seismic wave. The East-West wave plays a dominant role in the failure behavior of landslides in the three-directional seismic wave. Still, the existence of North-South and Up-Down seismic wave will accelerate the failure process of landslides.  
(3) The displacement/velocity of the slope's edge is more significant than that of its inside, and the height of the landslide is positively correlated with the displacement/velocity. As for the distinctive effects of different waves, the effects of seismic waves on the displacement of landslides are different at low altitude, while the effects of seismic waves are equivalent at high altitude.  
(4) The farthest distance (\(X\) direction) of the rock slide is in East-West seismic wave case, while in other cases, they are very close. The reason the earthquake can trigger long-distance movement of landslide is that the slope can obtain energy from the continuous shaking of the ground surface and convert this energy into kinetic energy, which is reflected in the block movement. In addition, the displacement of the landslide along the dynamic loading direction is the largest, while the vertical loading direction is the smallest.  
(5) The local damping ratio and the joints dip angle can affect the failure behavior of the rock slide. The stability of the perilous rock mass increases with the growing value of local damping ratio. The failure behavior of the rock slide changes from toppling movement to sliding movement with the increasing joint dip angle.  
Conceptualization, Z.G. and H.L.; Funding acquisition, Z.G and H.L.; Writing--original draft, Z.G. and H.L.; Writing--review & editing, Z.G and H.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Key Research and Development Plan of China (Grant No.: 2019 YFC1509701).  
Not applicable.  
The data presented in this study are available on request from the corresponding author.  
The authors would like to thank the editor and the reviewers for their helpful comments. Acknowledgement for the data support from \"China Earthquake Networks Center, National Earthquake Data Center ([[http://data.earthquake.cn](http://data.earthquake.cn)]([http://data.earthquake.cn](http://data.earthquake.cn)) (accessed on 20 March 2020))\".  
The authors declare no conflict of interest.