## 2 Data and Methods  
### Study Area and Data  
Nanyu Township, which is located in the northwestern part of China, is a township under the jurisdiction of Zhouqu County in the Tibetan Autonomous Prefecture of Gannan, Gansu Province. It is positioned at the southeastern boundary of Zhouqu County and is situated between 103 deg51'30'' and 104 deg45'30'' east longitude and 33 deg13' to 34 deg1'' north latitude. The landslide occurred in Jiangdingya of Nanyu Township, which is located on the east bank of the Bailong River [17].  
According to statistics from the Zhouqu County Meteorological Station and the China Meteorological Data Network, the annual average rainfall in Zhouqu County is approximately 420.6 mm. The maximum rainfall within a 24 h period is around 63.3 mm, while the maximum hourly rainfall is recorded at 47.0 mm. Rainfall in the region commonly occurs in the form of continuous light rain and short-term heavy rain. During the rainy season, short-duration intense rainfall poses a significant risk of triggering landslides. The study area is situated within the northern and southern seismic zones of the Qinghai-Tibet Plateau, specifically in the Zhouqu-Wudu seismic subzone. It is one of the regions with the most intense neotectonic activity and is characterized by complex geological structures and severely fractured rock formations. In addition, it has undergone multiple phases of activity, which make it highly susceptible to rainfall-triggered reactivation of ancient landslides. As shown in Figure 1[18], the landslide primarily consists of fragmented accumulations composed of light yellow-gray rock, carbonaceous shale, quartzite, and a small amount of loess. Furthermore, minor occurrences of sandstone, conglomerate, gray-green slate, and shale fragments are observed. According to the survey, Jiangdingya in Nanyu Township has a length of approximately 700 m, a width of about 240 m, and an area of nearly 0.16 km\({}^{2}\). It has an estimated average thickness of around 30 m and a volume of 500,000 m\({}^{3}\); therefore, it belongs to a large landslide [19].  
Figure 1: A photograph of the Jiangdingya landslide (**left**) and the location of the study area in China (**right**).  
Landslide areas are usually complex, unstable, and potentially dangerous, which can be avoided by UAVs. At the same time, the flexibility and high-resolution characteristics of UAVs enable them to quickly fly to disaster sites for real-time aerial surveys. They can clearly observe the surface conditions of landslide areas and provide detailed information for disaster monitoring and assessment. The DEM and DOM are the core data of later information extraction, through which the spatial shape and surface texture information of the landslide can be obtained. High-precision three-dimensional point cloud data are generated by utilizing dense matching derived from aerial triangulation. These points, which feature ground characteristics, are transformed into ground control points that constitute a triangulated irregular network. A DEM is generated by employing the method of triangular interpolation. The DEM generates TIN images by image processing software based on the ground-point elevation data, as shown in Figure 1(a). The spatial resolution is 5 m. According to the high-precision DEM images, each photo undergoes digital differential correction, followed by stitching and mosaic processing to obtain the DOM image of the entire study area. The data of the DOM in the study area are obtained in GEOTIFF format, as shown in Figure 1(b). The spatial resolution is 1 m, and the coordinate system is WGS84.