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引用本文:刘传正,吕杰堂,童立强,陈红旗,刘秋强,肖锐铧,涂杰楠. 雅鲁藏布江色东普沟崩滑-碎屑流堵江灾害初步研究[J]. 中国地质, 2019, 46(2): 219-234.
LIU Chuanzheng,LÜ Jietang,TONG Liqiang,CHEN Hongqi,LIU Qiuqiang,XIAO Ruihua,TU Jienan. Research on glacial/rock fall-landslide-debris flows in Sedongpu basin along Yarlung Zangbo River in Tibet[J]. Geology in China, 2019, 46(2): 219-234(in Chinese with English abstract).
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雅鲁藏布江色东普沟崩滑-碎屑流堵江灾害初步研究
刘传正1, 吕杰堂1, 童立强2, 陈红旗1, 刘秋强1, 肖锐铧1, 涂杰楠2
1.自然资源部地质灾害技术指导中心, 北京 100081;2.中国自然资源航空物探遥感中心, 北京 100083
摘要:
2018年10月17日5时许,西藏林芝市雅鲁藏布江左岸色东普沟上游发生冰崩岩崩,冲击下部的早期崩坡积物和冰碛物,形成滑坡-碎屑流进入雅鲁藏布江,堵江堰塞约56 h后自然漫顶泄流,整个过程形成崩滑-碎屑流-堰塞湖-溃决洪水灾害链。采用多年气温降水数据分析、多时相卫星遥感解译冰川退缩、直升机抵近观察堰塞坝、Scheidegger公式计算崩滑-碎屑流运动速度、Gutenberg-Richter公式计算地震活动序列b值和多因素赋值统计研判未来冰崩地点规模,得到堰塞坝体积约为3100×104 m3(含以往多次崩滑堵江残留堆积),滑坡-碎屑流运动距离超过8 km,平均运动速度约20 m/s,整个运动过程历时6.7 min,具有高速远程性质。色东普沟域崩滑-碎屑流是在地貌高陡、岩体破碎、气候变暖、局地降水、冰川退缩、断裂活动和地震效应(b值在0.7左右)等多种因素综合作用下形成的,今后相当长的时期内仍会多次发生。初步预测,当局地平均气温超过13℃、1 h降雨量超过5 mm或24 h降雨量超过10 mm,或地震PGA大于0.18 g,可能引发新的崩滑-碎屑流事件,造成雅鲁藏布江再次壅堵。针对该区域山高谷深,人烟稀少,交通困难的实际,提出了适应自然、全面避让和适当疏导的防灾减灾对策。
关键词:  滑坡-碎屑流  堰塞湖  气候变化  冰川作用  地震活动  累积效应
DOI:10.12029/gc20190201
分类号:P642.2
基金项目:国家财政事业专项(1211221481001)资助。
Research on glacial/rock fall-landslide-debris flows in Sedongpu basin along Yarlung Zangbo River in Tibet
LIU Chuanzheng1, LÜ Jietang1, TONG Liqiang2, CHEN Hongqi1, LIU Qiuqiang1, XIAO Ruihua1, TU Jienan2
1.Consultative Center of Geo-Hazard Mitigation, MNR, Beijing 100081, China;2.Aero Geophysical Survey and Remote Sensing Center for Natural Resources of China. Beijing 100083, China
Abstract:
A large-scale glacial/rock fall occurred in the upstream of Sedongpu basin on the left bank of the Yarlung Zangbo River in Linzhi of Tibet on October 17, 2018. The runout materials were composed of glaciers and rocks, which impacted the accumulation and moraine of the lower part, then formed a debris flow and dammed the Yarlung Zangbo River impounding a barrier lake. This study aims to identify the triggering mechanisms and propose a theoretical basis for the development of landslide hazard prevention and reduction. In this paper, the authors adopted short distance observation by helicopter, statistical analysis of climate change data, interpretation of multi-temporal satellite remote images, calculation of landslide-debris flow velocity using the Scheidegger formula and the b value of seismic activity sequence calculated by Gutenberg-Richter formula as well as multi-factor assignment statistics to evaluate the site and scale of the future glacial falls. It was found that the debris flow was triggered under the condition of high and steep terrain, broken rock mass, climate warming, regional rainfall, glacier ablation, fracture activity and earthquake damage (b value being about 0.7). The volume of the deposition materials was estimated at 31×106 m3 (including previous residual accumulation), which were mainly composed of gravel soil, a small amount of ice and big boulder. The whole event lasted 6.7 minutes with an average movement speed of about 20 m/s. The runout distance of the landslide was more than 8 km. Two-thirds of the Yarlung Zangbo River had been blocked before the glacial/rock fall-landslide-debris flow event that occurred on October 17, 2018. The countermeasures of disaster prevention and reduction which include adaption to the nature, comprehensive avoidance and reasonable dredging are put forward in consideration of the reality of high and steep hillslope, sparse population and traffic inconvenience in this area. The Sedongpu event that occurred on October 17, 2018 was a typical cascading landslide hazard, with a process of landslide-debris flow-dammed lake-outburst flood disaster. Such events will continue to occur frequently for a long time in the future. Based on a comprehensive analysis, the authors have reached the conclusion that a new landslide-debris flow-dammed lake event will be triggered again when the average temperature exceeds 13℃, or precipitation exceeds 5 mm/h or 10mm/d, or the earthquake PGA is greater than 0.18g.
Key words:  landslide-debris flows  dammed lake  climate change  glacial action  seismic activity  accumulating effects