西藏嘉黎断裂带沿线高位链式地质灾害发育特征分析

Characteristics,types,main causes and development of high-position geohazard chains along the Jiali fault zone,Tibet,China

西藏嘉黎断裂带沿线高位链式地质灾害十分发育,多次在易贡藏布、帕隆藏布及雅鲁藏布江下游造成流域性灾害链破坏,如易贡高位滑坡灾害链、古乡高位泥石流灾害链、尖母普曲高位崩塌灾害链、米堆冰湖溃决灾害链等。本文基于实地调研,并结合前人资料,总结了嘉黎断裂带沿线高位链式地质灾害的成灾模式,认为其可划分为“高位崩滑-碎屑流-堵江-洪水灾害链”、“高位崩滑-堵江-洪水灾害链”、“高位泥石流-堵江-洪水灾害链”、“冰湖溃决灾害链”等4种类型。本文还从地质构造与地震、地貌与水系、冰川、气象等4个方面分析了高位链式地质灾害的孕灾条件,并对其成因及发展趋势进行了探讨,认为在当前条件下,随着全球变暖加剧和人类工程活动增强,嘉黎断裂带沿线高位链式地质灾害的发生将更加频繁。

High-position geohazard chains are widely distributed along the Jiali fault zone,Tibet,China.They often induced severe flood disasters in the river basins of the Yigong Zangbu,Palong Zangbu,and the downstream of Yalu Zangbu,such as the famous Yigong,Guxiang,Jianmupuqu,and Midui high-position geohazard chains.Based on the field investigations and previously published data,these high-position geohazard chains are classified into 4 types:1)high-position landslide-debris flow-dammed lake-flood,2)high-position landslide-dammed lake-flood,3)high-position debris flow-dammed lake-flood,4)glacial lake outburst flood.The formation conditions of the high-position geohazard chains are analyzed from 4 aspects,that is 1)geological structures and earthquakes,2)landscape and river system,3)glacier,4)meteorology.In the end,the main causes and development trends of these geohazard chains are discussed.We believe that the high-position geohazard chains would be more frequent along the Jiali fault zone,with the global warming and the enhancement of the human engineering activities.