## 6 Conclusions  
The hazard chain caused by a landslide is usually more harmful than the landslide itself. In this study, the most common hazard chain, namely landslide-river blockage-outburst flood, was studied.  
According to 57 cases of landslide events, the formula for assessing the degree of river blockage was improved, and the accuracy rate in the studied cases reached 96.5%. According to 50 documented historical landslide dams, the discriminant formula of landslide dam stability was put forward, and the accuracy rate in the cases reached 86%. According to 34 cases of dam breaches, a formula for flood peak flow at the dam site was put forward, and the correlation coefficient \(R^{2}\) reached 0.934. A risk assessment model was proposed that combined the peak outflow rate attenuation formula and the improved vulnerability assessment index. The applicability of the proposed model was verified by the Baige landslide, and the calculated results were in good agreement with the measured results.  
In practical applications, the advantage of this model is that it can be used to improve the efficiency of the emergency evacuation once a landslide has happened, as well as for increasing the level of engineering security in advance. However, the model has some limitations. Because of the lack of the corresponding measured data, factors such as the water content of landslide material, the river's velocity, rainfall, and geological action after the landslide's occurrence cannot be taken into account. The model should be improved regarding these aspects in subsequent research.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**Assessment Stage** & **River Blockage** & **Dam Stability** & \multicolumn{3}{c}{**Peak Outflow Rate**} \\ \hline Assessment content & MOI & LBRI & BI & LDSI & \(Q_{P}\) (Equation (15)) & \(Q_{P}\) (Equation (17)) \\ \hline Calculated values & 5.27 & 5.027 & 5.91 & 4.78 & 5,680,656 m\({}^{3}\)/s & 10,786.35 m\({}^{3}\)/s \\ \hline Predicted results & \
\begin{tabular}{c} Complete \\ blockage \\ \end{tabular} &
\begin{tabular}{c} Complete \\ blockage \\ \end{tabular} & Stable & Unstable & \multicolumn{3}{c}{  
**Author Contributions:** All of the authors contributed to the study as follows. F.-Y.Y.: methodology, conceptualization, software, investigation, validation, writing--original draft, writing--review and editing. L.Z.: conceptualization; methodology; resources; writing--review and editing. M.-L.X.: conceptualization; methodology; writing--review and editing; funding acquisition. H.-Q.X.: methodology; writing--review and editing. H.-Z.L.: funding acquisition; writing--review and editing. J.-D.H.: supervision; writing--review and editing. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported by the National Key R&D Program of China (no. 2017 YFC1501100), and the National Natural Science Foundation of China (no. 52109135).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Data is contained in Appendix A.  
**Conflicts of Interest:** The authors declare no conflict of interest.