摘要
天摩沟是西藏东南部典型的泥石流沟,分别于2007年、2010年和2018年暴发泥石流灾害,对当地居民和川藏公路造成多次危害。通过多期次遥感解译、现场调查、现场观测等手段确定历次泥石流事件前后物源分布和类型,运用GIS统计和剖面测绘,对比不同时期该泥石流沟物源面积平面和剖面上的变化,研究该沟物源的动态演变。天摩沟泥石流物源类型主要为冰碛型物源、崩滑型物源和侵蚀型物源。平面上,冰碛型物源面积最大,崩滑型物源最集中,侵蚀型物源延伸距离最远。剖面上,主沟道13°~23°物源变化最活跃,其中17°~23°为泥石流侵蚀型物源启动部位,13°~17°为泥石流侵蚀最剧烈部位。天摩沟物源动态演变特征为逐年雪崩堆积物的"汇聚快融"效应,以及该效应引发的沟道底部和两侧松散物质的失稳。具体表现为海洋性冰川前缘雪崩活跃,每年10月至次年6月雪崩堆积物在主沟内堆积并向下游延伸,最远可达1800 m;7—9月雪崩堆积物快速消融,释放出裹挟在雪崩堆积物中的松散物质,加速泥石流物源汇聚,并使沟道内径流量急剧增大,径流激增侵蚀主沟两侧老冰碛物,使其转化为泥石流物源。研究天摩沟泥石流的物源演变特征,可揭示帕隆藏布流域泥石流近期频发原因,为该区域泥石流预警和防灾减灾工作提供参考。
The Tianmo Gully debris flow in southeastern Tibet is a typical one,which broke out frequently in 2007,2010 and 2018,causing harm to local residents and the Sichuan-Tibet highway for many times.The source materials distribution and types before and after debris flow events were drawn by means of multi-stage remote sensing interpretation,field investigation and field observation.GIS statistics and profile mapping were used to compare the changes of debris flow source materials area in plane and profile in different periods in the gully for the study of the dynamic evolution of the source materials.The source materials types of debris flow in Tianmo Gully are mainly moraine type,collapse type and erosion type.On the plane,moraine type source materials has the largest area,collapse type source materials is the most concentrated,and erosion type source materials extend the longest distance.On the profile,the source materials of the main channel varies most actively from 13° to 23°,among which,17° to 23° is the starting site of debris flow erosion type,and 13° to 17° is the most intense site of debris flow erosion.The dynamic evolution of the source materials in Tianmo Gully is characterized by the "convergence and rapid melting" effect of avalanche accumulations year by year,and the instability of loose materials at the bottom and both sides of the channel.The avalanche accumulates in the main gully and extends downstream 1800 m from October to June of the next year.From July to September,the avalanche deposits are rapidly melted,releasing a large number of loose materials bound in the avalanche deposits and making the runoff in the gully increase sharply.The surge of runoff erodes the old moraines on both sides of the main ditch and converts them into debris flow sources.Research on the provenance evolution characteristics of debris flow in Tianmo Gully can reveal the reasons for the frequent occurrence of debris flow in Palongzangpo Basin,and provide reference for the early warning and disaster prevention and
作者
陈龙
余斌
黄海
刘建康
李元灵
高波
CHEN Long;YU Bin;HUANG Hai;LIU Jiankang;LI Yuanling;GAO Bo(Institute of Exploration Technology,Chinese Academy of Geological Sciences,Chengdu 611734,Sichuan,China;Technical Center for Geological Hazard Prevention and Control,CGS,Chengdu 611734,Sichuan,China;School of Environmental and Civil Engineering,Chengdu University of Technology,Chengdu 610059,Sichuan,China;School of Emergency Science,XiHua University,Chengdu 610039,Sichuan,China)
出处
《地质通报》
CAS
CSCD
北大核心
2021年第12期2089-2097,共9页
Geological Bulletin of China
基金
中国地质调查局项目《藏东昌都地区城镇灾害地质调查》(编号:DD20190644)
第二次青藏高原综合科学考察研究(编号:2019QZKK0902)
国家自然科学基金青年项目《泥石流对全衬砌排导槽的冲刷磨蚀机理研究》(批准号:41807300)。
关键词
泥石流
雪崩
物源
演变特征
debris flow
avalanche
source materials
evolution characteristic
