则木河断裂带活动特征和地质灾害对地貌演化的影响——以鹅掌河流域为例

发布时间：2018-11-09 13:49

【摘要】：则木河断裂带具有构造活动强烈、地震活跃、次生地质灾害严重的特点。本文以鹅掌河流域为例,通过对断裂的活动特征,地质灾害的分布规律、长期活动性与成因机制和地貌演化进行分析,研究得出:(1)则木河断裂带活动特征影响地质环境的演化。新构造运动引起断裂带局部应变失衡,断裂活动诱发频繁地震;隆起和断陷断块的差异性活动,加剧地貌演化与地表过程;沉积建造环境的不同,影响岩土体的剥蚀与沉积;断裂的掀斜运动,改变地表水系格局与地热运移。(2)活动断裂对地质灾害的控制作用,表现为灾害具有时空效应。空间上,灾害沿断裂带呈带状分布,沿水系呈线状分布,具有地层倾向性,集中于断裂破碎带的软岩,微地貌效应显著;时间上,现有地质灾害在多次地震扰动和强降雨触发下形成,鹅掌河形成高频泥石流。(3)断裂活动影响灾害成因机制和灾害类型及破坏模式,脆弱的地质环境在地震持续扰动和极端降雨的耦合作用是灾害频发的根本原因;依据灾害成灾机制,将灾害分为3大类,7小类,具有震裂斜坡的典型破坏模式。(4)活动断裂与地质灾害相互作用决定地貌演化。鹅掌河泥石流影响邛海的地貌变迁,通过计算构造隆起量与灾害剥蚀量,表明鹅掌河处于隆起区,邛海处于淤积区。由此可见,则木河断裂活动特征通过影响区域地质环境演化,诱发大量的地震地质灾害,最终由地震构造作用驱动的隆起和断陷,地表灾害过程驱动的剥蚀和淤积,两者相互作用决定现有地貌的演化。
[Abstract]:The Zamuhe fault zone is characterized by strong tectonic activity, active seismicity and serious secondary geological hazards. In this paper, the characteristics of fault activity, the distribution of geological hazards, the long-term activity, the genetic mechanism and the geomorphological evolution of the Yanchang River Basin are analyzed. The results are as follows: (1) the active characteristics of the Zemuhe fault zone affect the evolution of the geological environment. Neotectonic movement causes local strain imbalance in fault zone, frequent earthquakes induced by fault activity, differential activities between uplift and fault depression fault blocks, aggravated geomorphologic evolution and surface process, different sedimentary environment, which affects erosion and deposition of rock and soil mass. The tilting movement of the fault changes the pattern of surface water system and the geothermal migration. (2) the active fault controls the geological hazard, which is manifested by the space-time effect of the disaster. In space, the disaster distributes along the fault zone as a zonal pattern, along the water system as a linear distribution, with stratigraphic tendency, concentrated in the soft rock in the fracture zone, and the effect of microgeomorphology is obvious. In time, the existing geological hazards are formed under the trigger of many earthquake disturbances and heavy rainfall, and the high frequency debris flow is formed in the Goezhang River. (3) the fault activities affect the mechanism, types and failure modes of the disasters. The coupling effect of the fragile geological environment in the earthquake continuous disturbance and extreme rainfall is the fundamental cause of frequent disasters. According to the mechanism of disaster formation, the disasters are divided into three types and seven types, which have typical failure mode of seismic crack slope. (4) the interaction between active faults and geological hazards determines the geomorphologic evolution. The geomorphologic changes of Qionghai are affected by the debris flow of the Goezhang River. By calculating the amount of tectonic uplift and the amount of disaster denudation, it is shown that the Yanzhahe River is in the uplift area and the Qionghai Sea is in the silt area. Thus, it can be seen that the active characteristics of Muhe fault induce a large number of seismic geological disasters by influencing the evolution of the regional geological environment, and eventually the uplift and fault depression driven by seismic tectonism, and the erosion and siltation driven by the surface disaster process. The interaction between them determines the evolution of the existing landforms.
【作者单位】：地质灾害防治与地质环境保护国家重点实验室(成都理工大学);四川省地质调查院;
【基金】：国家自然科学基金项目(41172278,41572291) 中国地质调查局项目(12120113010600)资助
【分类号】：P315;P694;P931

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