基于变维分形理论的日喀则市滑坡空间分布及其敏感性分析
Spatial Distribution and Sensitivity Analysis of Landslides in Shigatse City Based on Variable Dimension Fractal Theory

“4？25”尼泊尔Ms8.1级地震导致我国西藏自治区日喀则市受灾严重，根据西藏国土部门汇总灾害排查数据分析研究发现：日喀则市境内17个县(区)滑坡灾害共计206处，其分布极不均匀，其中亚东县、吉隆县、仁布县和定结县数量较多，占比达到73.3%。研究发现坡度、坡向和高程对于滑坡灾害分布影响明显，滑坡灾害密度在15°~30°范围内密度最大，且其敏感性系数值在该坡度上最大，坡度与滑坡数量呈一阶累计和变维分形关系；滑坡在各坡向上分布明显不同，其中在东南方向上数量最多，而在北坡和西南坡滑坡数量最少，滑坡坡向与滑坡灾害数量呈一阶累计和变维分形关系；滑坡在在高程3000~5000 m范围内滑坡数量分布最多，占总量的79.6%。高程越低，其滑坡灾害密度越大。滑坡的坡向与其在该坡向上分布的滑坡灾害数量呈二阶累计和变维分形关系。高程越低，滑坡在该高程上敏感性系数值越大，说明滑坡灾害在该高程上越敏感，研究成果可以为日喀则市灾后重建和灾后次生地质灾害监测预警提供参考。
The “4.25” Nepal Ms8.1 earthquake caused serious disasters in Shigatse City, Tibet Autonomous Region of China. According to the data analysis of disaster investigation collected by Tibetan ter-ritorial departments, it is found that: There were 206 landslide hazards in 17 counties (districts) in Shigatse City. The distribution of landslide hazards was extremely uneven. Among them, East Asia, Jilong, Renbu and Dingjie counties account for 73.3%. It was found that the gradient, direc-tion and elevation have obvious effects on the distribution of landslide hazards. Landslide hazard density was the highest in the range of 15~30 degrees, and its sensitivity coefficient value was the largest on the gradient. The gradient and the number of landslides show a first-order cumulative and variable-dimensional fractal relationship. The distribution of landslides was obviously different in each slope direction, in which the number of landslides was the largest in the southeast, while the number of landslides was the smallest in the north and southwest slopes. The relationship between slope direction and the number of landslide disasters was first-order cumulative and variable fractal. The number of landslides was the largest in the range of 3000~5000 m, accounting for 79.6% of the total. The lower the elevation, the greater the density of landslide hazards, the direction of landslides had a second-order cumulative and variable-dimensional fractal relationship with the number of landslide hazards distributed on the slope. The lower the elevation is, the greater the sensitivity coefficient of landslide is. This indicates that landslide hazards are more sensitive at this elevation. The research results can provide reference for post-disaster reconstruction and monitoring and early warning of secondary geological hazards in Shigatse City.