雅鲁藏布江大峡谷地区特大地质灾害链发育现状及对策

The Chain of the Major Geological Disasters and Related Strategies in the Yalu-Zangbu River Canyon Region

雅鲁藏布江大峡谷地区位于我国西藏的南部,其构造运动活跃、强震多发、地表侵蚀作用强烈,由崩滑(冰崩)—碎屑流—泥石流—堰塞湖等灾害要素组成的特大地质灾害链频繁发生。这类超高位超远程的链式地质灾害影响范围广、流域性成灾风险很高,近70年以来已发生15次特大地质灾害链堵江事件,造成很大破坏。研究发现,其发生与活跃的新构造运动和地震活动、丰富的降水以及较强的冰川活动紧密相关,而沿河谷分布的高陡斜坡处的松散堆积体则为地质灾害链的发生提供了物源。本文就此依次分析了其形成所需的地形地貌、地质构造、地震活动和气象水文等条件。针对当前存在的问题,本文在最后提出了3条对策建议:①加强特大地质灾害链调查与识别能力;②加强特大地质灾害链监测预报预警与风险防范能力建设;③加强特大地质灾害链工程防灾减灾与应急处置能力建设。

The chain of the major geological disasters consisting of landslide,avalanche,debris flow,mud-rock flow,dammed lake,occurs frequently in the Yalu-Zangbu River Canyon region,which is located in the southern area of Tibet,China,because of the active tectonic movement,frequent earthquakes,and strong ground surface erosion.This geological disaster chain with ultra high-elevation and long-runout is powerful and destructive in an extensive area along the river valleys.Especially during the past 70 years,the occurrence of the dammed lake associated to the chain of the major geological disasters in the Yalu-Zangbu River Canyon region have repeated 15 times.This paper argues that the formation of this disaster chain has tight correlation with the active neo-tectonic movements,strong seismic activities,abundant precipitation and strong glacier activities and the material sources were provided by the loose deposits and accumulations on the steep slope with a high elevation along the river valleys.To demonstrate it,the topography,geomorphology,geological structures,seismic activities,meteorology and hydrology in this region were analyzed.This paper also raised 3 advises for disaster reduction and control:1.to strengthen the ability to investigate and early identify this chain of the major geological disasters;2.to strengthen the capacity of disaster monitoring,forecasting,early warning and risk preventing;3.to strengthen the capacity of disaster prevention,mitigation and emergency response.