喜马拉雅山地区泥石流发育特征研究

DEVELOPMENT CHARACTERISTICS OF DEBRIS FLOWS IN HIMALAYAS USING REMOTE SENSING TECHNOLOGY

喜马拉雅山地区是世界上最高大的也是最年轻的山脉,这里地处两大板块的碰撞带,地质构造复杂,新构造运动强烈,山地灾害发育,泥石流异常活跃,经常给生命线工程和当地人民生命财产造成威胁。但是由于高寒缺氧,加之技术手段所限,研究程度一直很低。本文在对该区大型、巨型泥石流进行了遥感研究和实地调查资料基础上,发现该区泥石流存在16个泥石流较集中分布区,并且北坡比南坡更为发育。在此基础上,对其发育规律进行细致分析,发现：（1）喜马拉雅山地区泥石流的活动目前正处于活跃期;（2）研究区泥石流沟口主要分布在两个高程段,一个是2800-3400m范围,另一个是4200-4900m范围;（3）研究区衰败期泥石流沟道比降大都小于100‰,而发育期的泥石流沟道比降一般比较大,大都大于300‰,旺盛期的泥石流沟道比降则介于100‰-300‰之间。另一方面,我们发现本区冰雪融水与雨水型泥石流的沟道比降几乎相同,其动力条件相差不大。这对于该区泥石流灾害的防治、判断泥石流的活动性具有重要意义。

The Himalayan region locates in the western border area of China. It is the highest and youngest mountain chain in the world. This region situates in the collision zone of two plates. It has complicated geological tectonics,powerful neotectonic movements,serious mountain disasters and extremely active debris flows. These disasters frequently endanger the lifeline engineering and life and possession of the local people. However,fewer exploratory efforts are made due to the high-cold,oxygen deficit and the limit of the technology. This article isbased on remote sensing research and field survey data of the large-scale and giant debris flows. It reveals that 16 relative concentrated distribution areas are prensent in this region. The debris flows in the northern slope are more developed than those in the southern slope. On this basis,the development regularity is carefully analyzed. The results show that:( 1) The activities of debris flows in the Himalayan region are in the active period.( 2) The debris flow gully mouths in the research area are mainly distributed in two elevation sections. One is in the range of 2800 ~3400m and the another is in the range of 4200 ~ 4900 m.( 3) The gully slope of debris flows in old stage is usually little than 100‰,while that of debris flow in young stage is relatively larger and is usually larger than 300‰.Gully slope of debris flows in mature stage is between 100‰and 300‰. On the other hand,the ice-snow melting water mudflow and rain mudflow almost have the same gully slope and dynamic conditions. The findings can have significance to prevention and treatment of debris flow disasters and the judgement of debris flow activities in this area.