# Study on Temporal and Spatial Distribution of Landslides in the Upper Reaches of the Yellow River
## 3 Temporal and Spatial Distribution of Landslides in the Upper Reaches of the Yellow River
### Spatial Geometric Distribution Characteristics of Landslide  
Using high-resolution satellite remote sensing images (Table 2), it is found that there are 508 landslides of various types in the Sigovakia-Laganxia section of the upper reaches of the Yellow River. The remote sensing image and the 1:50,000 digital elevation model are superimposed to obtain the spatial distribution pattern of each landslide, the length and width of the landslide accumulation body, the elevation value of the front and rear edges, the slope value of the landslide accumulation body, and the slope direction. Based on the field investigation, the author obtained the thickness information for 116 landslides. On the basis of remote sensing interpretation, we selected some typical landslides for detailed field investigation and field verification. The landslide distribution map of the study area is shown in Figure 4.  
Figure 4: Landslide distribution map of the study area. The morphological characteristics of landslides in the study area are very obvious; the plane shape of the trailing edge of the landslide presents a typical ring chair shape, and the back wall is generally steep, with a slope of 15-25\({}^{\circ}\). The front edge of the landslide is tongue-shaped or long tongue-shaped. The front edge of the ancient landslide and the old landslide have been eroded many times, and even most or all of the sliding body has been eroded clean. Only the chair-shaped shape of the trailing edge and a small amount of steep slope remaining due to erosion are preserved. A high floodplain or terrace can be seen at the foot of the old landslide slope. According to the characteristics of its spatial distribution (Google Earth), this study divides it into six types: dumb-bell shape, rectangle, saddle type, long arc shape, triangle, and side-by-side shape. The spatial form and detailed information of the representative landslide remote sensing images of each type of landslide are shown in Figure 5 and Table 3. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Data Type** & \begin{tabular}{c} **Spectral** \\ **Characteristics** \\ \end{tabular} & **Spatial Resolution** & **Receiving Time** & **Main Uses** \\ \hline QuickBird & \begin{tabular}{c} 4 bands from visible to \\ near-infrared, 1 band of \\ full color \\ \end{tabular} & \begin{tabular}{c} Panchromatic image \\ 0.61 m, multispectral \\ image 2.4 m \\ \end{tabular} & August 2006 & \begin{tabular}{c} Landslide information \\ extraction in \\ disaster area \\ \end{tabular} \\ \hline GeoEye & \begin{tabular}{c} Multi-spectral blue, \\ green, red and near \\ infrared four bands, \\ panchromatic one band \\ \end{tabular} & \begin{tabular}{c} Panchromatic image \\ 0.41 m, multispectral \\ image 1.65 m \\ \end{tabular} & May 2007, September \begin{tabular}{c} Macro information \\ extraction of landslide \\ development \\ \end{tabular} \\ \hline ZY-3 & \begin{tabular}{c} Multispectral 4 bands, \\ panchromatic 1 band \\ \end{tabular} & \begin{tabular}{c} Panchromatic image 2.1 \\ m, multispectral image \\ 6 m \\ \end{tabular} & May 2012 & \begin{tabular}{c} Natural disaster \\ prevention, \\ environmental \\ monitoring and \\ protection \\ \end{tabular} \\ \hline ZY-1 02C & \begin{tabular}{c} Multispectral 3 bands, \\ panchromatic 1 band \\ \end{tabular} & \
\begin{tabular}{c} Panchromatic image \\ 2.36 m, multispectral \\ image 10 m \\ \end{tabular} & April 2012 &
\begin{tabular}{c} Geological disaster \\ investigation, \\ monitoring, etc. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Satellite data characteristics used in landslide remote sensing image interpretation. Figure 5: _Cont._  
According to the interpretation of remote sensing images, the author counted the length, width, slope, area, and volume of 508 landslides. Based on the statistical division of the above data, the main distribution areas and the most concentrated distribution areas of the length, width, thickness, area, and volume of each landslide were obtained.