Abstract:
Liangshan Prefecture is located in the northeastern margin of the Hengduan Mountain system and in the southern section of the Sichuan-Yunnan tectonic belt. Due to active structure, landforms, river cutting, etc., there are
4016 occurrences of geological disasters in Liangshan Prefecture, mainly small and medium-sized soil landslides, and small and medium-sized gully debris flows. Liangshan Prefecture is a high-risk area of geological disaster in Sichuan Province. This paper uses data collection, mathematical statistics, ArcGIS software analysis, and other methods to analyze and find that, according to the analysis of administrative region, Dechang County has the highest number of geological disaster developments, with a total of 387 occurrences. Ningnan County has the highest density of disasters development, with 17.7 sites per 100 km
2. According to the analysis of river basins, the number of geological disasters in the Anning River Basin is the largest, reaching 779. The Meigu River Basin has the highest density of hazard development, with 11.18 places per 100 km
2. In this paper, the spatial distribution of geological hazards of different disaster types is analyzed with disaster development density as the index. For landslides, 4 extremely high-density areas and 15 high-density areas are classified. The development of landslide is mainly controlled by active structures and slippery strata (such as red beds, Xigeda formation, etc.). For collapses, 2 extremely high-density areas and 5 high density areas are classified. The collapses are distributed along valleys and tributary channels in a zonal pattern, greatly influenced by slope cutting activities related to hydropower reservoir development and highway construction. For debris flows, 2 extremely high-density areas and 10 high-density areas are classified. The development of debris flows is greatly impacted by structural fractures, landforms and human engineering activities. The research results can provide data support and scientific references for disaster prevention and mitigation in Liangshan Prefecture.