Spatiotemporal Evolution and Characteristics of Colluvial Landslide Deposits in Chutou Valley Based on Vegetation Analysis after Earthquake

The normalized vegetation index (NDVI) is a kind of index that characterizes vegetation development in a region. The level of NDVI can accurately reflect the development and distribution of vegetation, so it has a good and accurate indicator function in the study of vegetation. The research area of this paper is located in the mountainous area of southwest China with dense vegetation. Strong earthquake induced a large number of coseismic landslides, which not only caused serious damage to the vegetation in the region, but also caused secondary disasters such as debris flow as loose material sources. Therefore, this paper uses NDVI index to distinguish the significant differences between vegetation and deposit bodies, and obtains the evolution trend of vegetation in the study area since the Wenchuan earthquake in 2008. The evolution trend of vegetation is analyzed and compared with the results of optical remote sensing interpretation, and finally obtains the evolution law and characteristics of slide deposit bodies. Based on the above research results, NDVI is introduced into the evolution analysis of geological hazards, which provides scientific support for the analysis of debris flow source evolution by NDVI trend.