西藏林芝地区泥石流类型及形成条件分析

Classification and Initiation Conditions of Debris Flows in Linzhi Area,Tibet

西藏林芝地区是我国泥石流灾害最为严重的地区之一,特别是近年来受全球气候变化的影响,冰川融化速度加快,冰川融水型泥石流灾害频频发生,危害极其严重。自2009年7月中旬开始,对该地区林芝、米林、波密、察隅4县30条泥石流沟做了系统调查。在研究该区域20条较具代表性泥石流沟的基础上,结合该区域已有研究资料,按泥石流形成的激发条件将其分为降雨型泥石流,冰川降雨型泥石流,冰崩、雪崩型泥石流,冰湖、堰塞湖溃决型泥石流共4类。进而从地形地貌、物源、水源及气温等方面分析了其形成条件。并在此基础上提出了针对性防灾建议。

Linzhi area of Tibet is one of the most dangerous regions threatened by debris flows in China.Under the influence of global warming,the melting rate of glacier has accelerated in this area,leading to frequent initiations of glacier-melting debris flows,which is severely hazardous.Since the middle of July,2009,the authors had carried out systematic investigations regarding approximately thirty debris flow gullies in counties of Linzhi,Milin,Bomi and Chayu in Linzhi area.Based on analysis of the twenty typical debris flow gullies and related historic documents,debris flows were divided into four classes according to initial water conditions,namely,rainfall-induced debris flow,glacier-rainfall-induced debris flow,avalanche-induced debris flow,and lake-outburst-induced debris flow.The initiation conditions were analyzed regarding landform,soil source,water source and air temperature.Specific advices based on the analysis were recommended for disaster prevention.