雅鲁藏布江加拉白垒峰色东普流域频繁发生碎屑流事件初步探讨

摘要

以Landsat等中高分辨率多源遥感影像为基础,对色东普流域近40 a来冰川的分布和变化情况进行研究,梳理分析了2014年以来色东普流域内发生的8次碎屑流堵塞雅鲁藏布江事件,并结合雷达数据以及气象资料探讨该流域内频繁发生碎屑流事件的原因.分析结果表明:色东普流域内"陡-缓-较陡"的阶梯状地形为碎屑流频繁发生提供了地形基础,沟口河道的半堵塞状态、冰川后缘的大量裂隙、林芝地震和充沛的降雨量等多种因素共同作用导致色东普流域内碎屑流事件频发.依据研究结果预计未来较长时间内色东普流域仍会发生多次冰崩碎屑流事件,建议在雅鲁藏布江大峡谷区域内建立长期灾害监测预警体系,为色东普沟冰崩碎屑流灾害的应急工作提供有效支撑.%We used Landsat and other high-moderate space resolution images to analysis the glacial retreat in the recent 40 years of Sedongpu Basin, and combed the eight times debris flow blocking Yarlung Zangbo river incidents of Sedongpu Basin after 2014. Combined with the radar and meteorological data, we analyzed the reasons of frequent collapse disasters occurred in the basin. Then we found the following factors. First, the"steep-gentle-relative steep"ladder terrain is the foundation of the frequent occurrence of the debris flows in Sedongpu Basin.Second, the debris flow always block the channel at a large extent. Third, there are lots of crevasses in the glaciertrailing edge. Fourth, earthquake and abundant rainfalls also lead to the frequent debris flow of Sedongpu Basin.Combined the above factors, we speculate the glacier avalanche induced debris flow (GAIDF) of Sedongpu Basin will happen frequently for a long time with typical periodicity. So, we suggested to establish a long-time monitoring and warning system for the Yarlung Zangbo Grand Canyon in order to provide effective support to the emergency work of Sedongpu Basin glacier debrisflow.