西秦岭北缘断裂宝鸡—武山段活动触发滑坡分布规律与成因机制

发布时间：2018-06-26 17:32

本文选题：断裂 + 滑坡　；参考：《地质力学学报》2017年05期

【摘要】：西秦岭北缘断裂沿"一带一路"交通廊道展布,是南北活动构造带强震丛集发育的节点之一,地震地质灾害风险极高。基于地质调查、测绘与数值分析,查明了断裂在天水地区触发的地震滑坡分布特征,探讨了断裂触发滑坡的形成机制。研究表明:(1)西秦岭北缘活动触发的巨、大型滑坡为断裂地貌过程的一部分,易在断裂的阶区聚集发育,其枢纽部位也有零星的分布;(2)巨大型滑坡集中于历史极震区内,断裂破裂过程中的近场惯性滑移、远场地震动是主要触发因素,二者耦合作用导致巨大型滑坡在断裂带两侧具有对称分布特征,活动强度由近及远而逐渐变弱;(3)断裂水平滑移、破裂引起的斜坡滑动变形以结构面贯通为主要表现形式,具有强烈的方向效应、近直立断层的区域地震动效应及地震波的山体地形放大效应,这些力学效应在滑坡破坏过程产生断裂结构面、次级羽裂结构面与滑动面,它们协同控制了滑坡的运动;(4)极端降雨触发的泥流是巨大型滑坡堆积体复活运动的主要形式,是现今防灾减灾重点。
[Abstract]:Along the "Belt and Road" traffic corridor, the fault in the northern margin of the West Qinling Mountains is one of the nodes of strong earthquake clusters in the North and South active tectonic belts, and the risk of seismic and geological disasters is extremely high. Based on geological survey, mapping and numerical analysis, the distribution characteristics of seismic landslide triggered by fault in Tianshui area are found out, and the formation mechanism of fault-triggered landslide is discussed. The results show that: (1) the large landslide is a part of the process of fault geomorphology, it is easy to gather and develop in the stage of the fault, and the junction of the landslide is distributed sporadically, (2) the giant landslide is concentrated in the historical extreme earthquake area, which is triggered by the activity in the northern margin of the western Qinling Mountains, and is a part of the process of fault geomorphology. The near field inertial slip in the fracture process and the far field ground motion are the main triggering factors. The coupling between the two factors leads to the symmetrical distribution of the giant landslide on both sides of the fault zone, and the intensity of the activity gradually weakens from near to far. (3) horizontal slip of the fault. The slope sliding deformation caused by rupture is mainly manifested by structural plane transfixion, which has strong directional effect, regional ground motion effect near vertical fault and mountain terrain magnification effect of seismic wave. These mechanical effects produce fracture structure plane in the process of landslide failure, secondary plume structure plane and sliding surface, which control the landslide movement in cooperation. (4) the mudflow triggered by extreme rainfall is the main form of the reactivation movement of the huge landslide accumulation. Is the current disaster prevention and mitigation focus.
【作者单位】：中国地质科学院地质力学研究所;国土资源部新构造运动与地质灾害重点实验室;中国地质调查局;
【基金】：国家自然基金项目(41402281,41372374) 中国地质调查局项目(1212011220088,DD20160271)
【分类号】：P642.22

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