地质通报2016，Vol.35Issue(8)：1332-1345,14.
青藏高原东缘理塘乱石包高速远程滑坡发育特征与形成机理
Huge long-runout landslide characteristics and for- mation mechanism:A case study of the Luanshibao landslide, Litang County, Tibetan Plateau
摘要
Abstract
In the Tibetan Plateau, the complex geological tectonic background causes frequent earthquakes, together with the abnor⁃mal climate change, there are many large or even huge geological hazards, causing serious consequences. In this paper, based on the interpretation of remote sensing and the analysis of field geological survey, geophysical prospecting, trenching, and geological dating data, the authors studied the development characteristics of the Luanshibao landslide and investigated its formation mechanism. The Luanshibao long-runout landslide has the following features: ① The Luanshibao landslide is located on the northeastern margin of the Maoyaba Basin in Litang County, western Sichuan. The sliding direction of the landslide is perpendicular to the northwestern segment of the Litang-Dewu fault, with the top part of the Luanshibao landslide approaching the current snow line. ②The maxi⁃mum sliding distance of the Luanshibao landslide is 3.83km; the elevation difference between the back wall of the landslide and the accumulation zone at the leading edge is approximately 820m, with a sliding body volume of approximately 0.64×108~0.94×108m3 and an average sliding velocity of approximately 53.25m/s. ③ The dating data indicate that the Luanshibao landslide occurred at about 1980±30a BP.④The compositional lithology of the landslide rocks is mainly granite, and the joint fractures are developed as cracked rocks under the impact of long-term tectonic dynamics and freezing weathering. The analysis indicates that the Luanshibao landslide has been substantially affected by the fault structure, terrain topography, and ancient climate change, and its formation mechanism is complicated:①Since the Holocene, the Litang-Dewu fault has experienced frequent, strong earthquake activity. The strong earthquakes resulting from the fault activity might have been one of the main factors for the formation of the Luanshibao landslide. Under the impact of earthquakes, the seismic wave at the top of the slope would be"amplified", producing a vertical accel⁃eration greater than the horizontal acceleration. The rock bodies experienced shock expansion and were thrown, forming the long-runout landslide. ② Dating back to approximately 2000a BP, the temperature change in the Tibetan Plateau area was relatively large, and the large-scale glacial activity occurring in this period was most likely one of the main factors behind the formation of the Luanshibao landslide. ③ The combination of earthquakes and climate change seems to have been one of the conditions causing the occurrence of the Luanshibao landslide, forming a complete chain of geological disasters, i.e., earthquake→avalanche→rockfall→high speed debris flow.关键词
高速远程滑坡/理塘地区/古滑坡/活动断裂/形成机理Key words
granite rock/Luanshibao/ancient landslide/Tibetan Plateau/active fault分类
天文与地球科学引用本文复制引用
郭长宝,杜宇本,佟元清,张永双,张广泽,张敏,任三绍..青藏高原东缘理塘乱石包高速远程滑坡发育特征与形成机理[J].地质通报,2016,35(8):1332-1345,14.基金项目
中国地质调查局项目（编号12120113038000）、国家自然科学基金项目（批准号41402321）、科技基础性工作专项（编号2011FY110100-2）和中铁二院科研计划项目 （）
