Quantitative evaluation of influencing factors for landslide, rockfall and debris flow hazards in the Nyingchi area of the Tibet Autonomous Region

The Nyingchi area exhibits complex topography, high fault activity, an extensive water systems distribution, variable climatic conditions, and frequent geological hazards. These factors have a significantly growing impact on the economic development and engineering construction in the entire Nyingchi area. Among these hazards, landslides, collapses, and debris flows are the most common geological hazards in Nyingchi area. In order to quantitatively analyze the sensitivity of hazards in the Nyingchi area to the impact factors, this study, based on GIS and the certainty coefficient analysis method, selected ten factors, including elevation, slope aspect, topographic relief, and topographic humidity index, to conduct sensitivity analysis on landslide, rockfall and debris flow hazards. The analysis results show that: (1) The sensitive range of factors influencing landslide, rockfall and debris flow hazards in the Nyingchi area include slope aspects facing eastward, northeastward, southward, and westward; topographic relief ranging from 0 to 27 m/km²; elevation between 0.82 and 4.20 km; distances from the water system within 0 to 3 km, distances from the road wihtin 0 to 0.3km; distances from the active fault zone within 0 to 3 km; normalized vegetation index ranging from 0.47 to 0.81; annual average temperatures between 4.02 and 17.22 °C; annual average rainfall ranging from 51.15 to 146.14 mm. There exists a strong correlation between hazards and these impact factors. (2) Sensitivity among influencing factors follows this order: annual average temperature>distance from water system>elevation>distance from road>normalized vegetation index>average annual rainfall>topographic humidity index> distance from the active fault >topographic relief >aspect. The research results provide references for engineering construction and hazards prevention and mitigation work in the Nyingchi area.