## 5 InSAR's Role in Landslide Susceptibility Mapping  
### Factors and Their Utilization Frequency  
Data-driven models for LSM typically rely on historical landslide events (landslide inventory dataset) and evaluation factors, referring to the input data layers such as lithology and precipitation. According to [125; 126], these factors mainly comprise preparatory factors or predisposing factors which render the movement susceptibility of a slope and were widely used in LSM, and triggering factors like earthquake events and precipitation that directly trigger the movement. To ascertain whether variables derived from InSAR, such as deformation velocity, can serve as evaluation factors in constructing data-driven LSM models, we first categorized and analyzed all evaluation factors used in the selected articles. This enabled us to determine the frequency of InSAR-derived factors and to extract the exact studies that incorporated these factors. While previous LSM studies have typically proposed diverse classification methods for evaluation factors and the factors they encompass, there is no standard or protocol for classifying and utilizing these factors in LSM due to the data accessibility and inter-relationships within the evaluation factors. Despite the uncertainty arising from the articles' inclusion criteria, this review summarized the extensive use of 84 evaluation factors from the selected articles and categorized all factors into seven classifications (Table 1, Figure 9). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Classification** & **Factors/Subcategory** & **Factors/ Count** \\ \hline \multirow{4}{*}{Topographic Factors} & Slope, slope shape, slope length, slope aspect, relative slope position, slope height, elevation (or altitude), elevation coefficient of variation (EVC), surface cutting depth (SCD), topographic \\  & roughness index (TRI), landorn, curvature, plane curvature, profile curvature, cross-sectional \\ \cline{1-1}  & curvature, longitudinal curvature, land relief (LR), convergence index, topographic position \\ \cline{1-1}  & index (TPI), channel network base, valley depth, distance to ridge, and distance to nearest hill. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: 84 evaluation factors in seven classifications. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Classification** & **Factors/Subcategory** & **Factors/Count** \\ \hline Geological and Geomorphological & Geomorphology map, lithology (geology), rock mass strength, geological folds, dip slopes, bed rock-slope relationship, gravity anomaly (Ga) factor, peak ground acceleration (PGA) *, seismic intensity *, epicentral distance *, distance to lineament, lineament density, fault density, and distance to fault. & 14 \\ \hline Hydrological Factors & Specific catchment area (SCA), topographic wetness index (TWI), guilty density, drainage density, distance to drainage, river/stream density, distance to river/stream, distance to catchment, catchment slope, normalized difference water index (NDWI), rainfall (precipitation) *, total surface radiation, soil moisture, hydrologic soil group, flow path length (FPL), stream transport index (STI), stream power index (SPI), and compound topographic index (CTI) & 18 \\ \hline Human Factors & Road density, distance to road, distance to settlement/built-up, settlement density, population density, distance to mine, land use and land cover (LULC), land use change (LUC), and normalized difference built-up index (NDBI). & 9 \\ \hline Vegetation Factors & Normalized difference vegetation index (NDWI), tree cover, vegetation index, and fraction vegetation cover (FVC). & 4 \\ \hline Soil Factors & Soil type, soil depth, texture, erosion, percent sand, percent silt, percent clay, saturated hydraulic conductivity, available water capacity, one third bar water content, plasticity index, and liquid limit. & 12 \\ \hline Others & Deformation velocity, band factor, physically based stability coefficient, and temperature. & 4 \\ \hline \hline \end{tabular}
\end{table}