川藏公路迫隆藏布流域段泥石流活动特征

迫隆藏布流域是川藏公路 (西藏境内 )泥石流最活跃、类型最齐全、危害最严重的地区。根据以往资料、遥感普查以及现场考察 ,确定流域内公路两侧分布有灾害性泥石流沟 10 4条 ,其中沟谷型泥石流沟 87条。泥石流沟沟口高程在 2 5 0 0～ 3 5 0 0 m之间 ,流域面积介于 0 .8～ 185 km2之间 ,其中 83 .7%的流域面积在 1.0～ 4 0 .0 km2之间。按成因 ,泥石流可分为冰川型、溃决型、降雨型泥石流 ,其变化特性与泥石流流域的高程、降雨变化和地震活动密切相关。最后讨论了泥石流活动对地方经济发展的危害以及对当地山地环境的影响。

Characteristics of Debris Flow in Polongzangbu Basin of Sichuan- Tibet Highway

Polongzangbu Basin, located in southeastern Tibet, is known by the world for its debris flow hazards, especially the debris flow, taking place in Zamulongba gully on 9th April, 2000, which blocked Yigong Lake 62 days and the following breaking flood cursed severely losses. Presently, the debris flow activities occur frequently. Based on the historical data, remote sensing conveying and field investigation, authors have determined that there are 104 debris flow gullies in Polongzangbu Basin, 87 of which have clear channel. The debris flow gullies locate the altitude between 2 500 m and 4 000 m, and their basin areas are between 0.8 km 2 and 185 km 2, especially 80 percent of which are between 1.0 km 2 and 30 km 2. According to the cause of formation, debris flow gullies in this area could be divided into 3 types: glacial, glacial lake burst and rainfall debris flow. At last, this paper discusses the impact of debris flow on the local economic development and environment.