ZONATION OF DISASTER ENVIRONMENTS OF COLLAPSE, LANDSLIDE AND DEBRIS FLOW GEOLOGIC HAZARDS AND THEIR FORMATION MECHANISMS IN XINJIANG

Xinjiang spans a vast area, and is characterized by a high incidence and wide range of geological disasters. Given the significant differences in its natural geography and geological environment, it is crucial to rationally divide its disaster-prone environments. This paper zones these environments and consideres the factors including topography, geological structures, precipitation, and engineering geological conditions. These factors can influence the distribution of landslide and debris flow geological disasters. This paper also conducts specialized studies on the formation mechanisms of representative geological disasters within typical regions. The results are as follows: The disaster-prone environments of landslide and debris flow geological disasters in Xinjiang are divided into seven regions: the Altai Mountains and the western hills of Junggar, the Junggar Basin, the northern and southern foothills of Tianshan, the Turpan-Hami Basin, the Tarim Basin, and the Kunlun Mountains. (1)Spatially, the unique distribution pattern of landslide and debris flow geological disasters in Xinjiang is characterized by an "E" shape, with three major mountain systems surrounding two major basins. Specifically, the Altai Mountains and North Tianshan surround the Junggar Basin, while South Tianshan and the Kunlun Mountains surround the Tarim Basin, forming an eastward-opening circular distribution. The development of geological disasters weakens gradually from west to east. (2)Temporally, the occurrence of landslide and debris flow geological disasters in Xinjiang is closely related to atmospheric precipitation and melting of ice and snow. Interannual occurrence is mainly controlled by variations in water-rich years, while intra-annual variations are mainly controlled by the rainy season and the ice and snow melting season. The regions with the most developed geological disasters are the Altai Mountains and the western hills of Junggar, the southern slope of Tianshan, and the Altun Mountains and the Kunlun Mountains. The northern slope of Tianshan is the most developed area for landslide and debris flow geological disasters. Their formation mechanisms are closely related to geological environmental conditions such as topography, stratigraphic lithology, and precipitation. (3)The results of this study contribute to summarizing and generalizing the distribution, disaster-prone environment, and disaster-prone mechanisms of landslide and debris flow geological disasters in Xinjiang. This is beneficial in further addressing the key issue of "where geological disasters occur" in geological disaster prevention and control.