ISSN 1003-8035 CN 11-2852/P

    西藏林芝地区崩滑流灾害影响因子定量评价

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

    • 摘要: 林芝地区地形复杂,断层活动强烈,水系分布广泛,气候条件多变,地质灾害频发,对整个林芝地区经济发展和工程建设的影响日趋显著。其中,滑坡、崩塌、泥石流是林芝地区最常见的几种地质灾害,为了定量分析林芝地区内灾害对影响因子敏感性,文章基于GIS与确定性系数分析法,选取了高程、坡向、地形起伏度、地形湿度指数等10个因子开展对崩滑流灾害敏感性分析。分析结果表明:(1)林芝地区崩滑流灾害影响因子敏感性区间为:高程在0.82~3.79 km,坡向为东向、东北向、南向、西向,地形起伏度在0~24 m/km2,距水系距离0~3 km,归一化植被指数0.47~0.81,距道路距离0~1.5 km,距活动断裂带距离0~3 km,多年平均降雨量51.15~146.14 mm,多年平均气温4.02~17.22 °C,灾害与影响因子之间表现出良好的相关性。(2)影响因子间敏感性大小:多年平均气温>距水系距离>高程>地形起伏度>距道路距离>归一化植被指数>多年平均降雨量>地形湿度指数>距活动断裂带距离>坡向。研究结果对林芝地区工程建设与防灾减灾工作提供参考。

       

      Abstract: 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 elevation between 0.82 and 3.79 km; slope aspects facing eastward, northeastward, southward, and westward; topographic relief ranging from 0 to 24 m/km2; distances from the water system within 0 to 3 km; normalized vegetation index ranging from 0.47 to 0.81; distances from the road wihtin 0 to 1.5 km; distances from the active fault zone within 0 to 3 km; annual average rainfall ranging from 51.15 to 146.14 mm; annual average temperatures between 4.02 and 17.22 °C. 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 > topographic relief > distance from road > normalized vegetation index > average annual rainfall > topographic humidity index > distance from the active fault > aspect. The research results provide references for engineering construction and hazards prevention and mitigation work in the Nyingchi area.

       

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