## 3 Materials and Methods
### Physical and Mechanical Parameter System  
The data of large-scale rock groups that were defined via field investigations were divided into three levels. The first level was data from investigated landslide inventories, collected with sufficient accuracy to quantitatively analyze the spatial densities and seismic parameters of landslides [25]. The second level was made up of interpreted remote sensing data of the loose accumulation layer, and the third was data on geological units originating from regional geological maps.  
The research region was divided into 45 areas on the basis of physical and mechanical parameters on the basis of the three levels (Figure 5), in which the number of landslide inventory units was 17 and the regional point density was 0.7 points/km\({}^{2}\). The loose accumulation layer differed greatly from the geological units; therefore, it was not based on the classification of geological units but rather divided into different categories, with 22 groups numbered SS01-SS22, including the alluvial proluvial accumulation layer, ice water accumulation layer, eluvial accumulation layer, and collapse accumulation slope. The geological units were divided into six groups on the basis of regional geological maps numbered DZ01-DZ06; rivers were excluded from the division.  
Figure 5: Distribution of the physical and mechanical parameters of the 45 groups in the study area.  
In this work, the parameters and details for each group are adopted from geotechnical bibliography: Code for Geotechnical Engineering Investigation (GB 50021-2001) [26], Standard for Engineering Classification of Rock Masses (GB/T 50218-2014) [27], and Code for seismic design of building (GB 50011-2010) [28] and previous studies [18,19]. The physical and mechanical parameter values (Table 1) of the 45 groups were assigned, and a map (Figure 6) was produced via ArcGIS 10.8 software.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Groups** & **Number** & **Z/m** & \(\boldsymbol{\gamma}\)**/(t**-m\({}^{-3}\))** & \(\boldsymbol{c^{\prime}}\)**/kPa** & \(\boldsymbol{\varphi^{\prime}}\)**/(\({}^{\circ}\))** \\ \hline \multirow{9}{*}{Landslide inventory (first level)} & SM448 & 2.5 & 19.0 & 27 & 30 \\  & SM506 & 2.5 & 19.0 & 25 & 30 \\  & SM505 & 2.5 & 20.0 & 25 & 31 \\  & SM107 & 2.5 & 22.0 & 26 & 31 \\  & SM311 & 2.5 & 21.5 & 25 & 31 \\  & SM125 & 2.5 & 21.5 & 26 & 30 \\  & SM121 & 2.5 & 21.5 & 25 & 30 \\  & SM309 & 2.5 & 21.5 & 24 & 30 \\  & SM310 & 2.5 & 21.5 & 25 & 30 \\  & SM312 & 2.5 & 21.5 & 24 & 32 \\  & SM313 & 2.5 & 21.5 & 25 & 30 \\  & SM452 & 2.5 & 22.0 & 24 & 32 \\  & SM205 & 2.5 & 21.5 & 25 & 31 \\  & SM206 & 2.5 & 21.5 & 26 & 30 \\  & SM203 & 2.5 & 22.0 & 24 & 30 \\  & SM204 & 2.5 & 21.5 & 25 & 30 \\  & SM209 & 2.5 & 21.5 & 26 & 30 \\ \hline \multirow{9}{*}{Loose accumulation (second level)} & SS01 & 3.0 & 21.5 & 28 & 35 \\  & SS02 & 3.0 & 21.5 & 31 & 34 \\  & SS03 & 3.0 & 21.5 & 31 & 34 \\  & SS04 & 3.0 & 21.5 & 31 & 34 \\  & SS06 & 3.0 & 20.0 & 31 & 34 \\  & SS09 & 3.0 & 22.0 & 31 & 34 \\  & SS10 & 3.0 & 22.0 & 30 & 34 \\  & SS11 & 3.0 & 21.5 & 31 & 34 \\  & SS12 & 3.0 & 21.0 & 30 & 35 \\  & SS22 & 3.0 & 21.0 & 30 & 35 \\ \hline \multirow{9}{*}{Geological units (third level)} & DZ01 & 4.0 & 22.0 & 32 & 38 \\  & DZ02 & 4.0 & 22.0 & 36 & 42 \\ \cline{1-1}  & DZ03 & 4.0 & 22.0 & 36 & 42 \\ \cline{1-1}  & DZ04 & 4.0 & 22.0 & 34 & 39 \\ \cline{1-1}  & DZ05 & 4.0 & 22.0 & 36 & 38 \\ \cline{1-1}  & DZ06 & 4.0 & 22.0 & 36 & 42 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Values of the physical and mechanical parameters.