则木河断裂带大箐断层枢纽运动的有限元数值模拟研究  

Finite element numerical simulation of pivotal movement of the Daqing segment of Zemuhe fault

作　　者：高翔[1,2] 邓起东[2] 陈汉林[1] 洪汉净[2] 

机构地区：[1]浙江大学地球科学系,杭州310027 [2]中国地震局地质研究所,中国地震局活动构造与火山重点实验室,北京100029

出　　处：《地球物理学报》2014年第7期2138-2149,共12页Chinese Journal of Geophysics

基　　金：我国地震重点监视防御区活动断层地震危险性评价(财1521044025)资助

摘　　要：变形局部化问题和地震成核问题,是构造变形机制与大地震研究中极其重要的问题.对走滑断裂的运动和走滑型地震而言,断裂枢纽运动是断裂带上变形局部化和地震成核孕育的条件,认识这一运动过程和机制是了解走滑断裂上地震孕育、发生机制的关键之一.本文在前人工作的基础上,以则木河左旋走滑断裂大箐断层为例,测量了大箐断层大箐梁子断头沟台地一五道箐盆地之间的构造和地貌变形,揭示了大箐走滑断层枢纽运动构造和地貌四象限分布的特点,并且在定量分析其枢纽运动的基础上,利用数值模拟方法,模拟了断裂的枢纽运动,结果表明,走滑断裂的枢纽运动表现出典型的掀斜特征,随着断层面倾角的减小,枢纽运动程度加深;随着断层面闭锁区面积的增大,枢纽运动明显受阻;发现在闭锁区及其附近存在一个应力集中区使得应力由外向内一直处于积累状态,反映了地震的成核过程.Deformation localization and earthquake nucleation are valuable issues in tectonic deformation mechanism and large earthquake research. For strike-slip movement and strike-slip type of earthquake, pivotal movement in strike-slip fault is necessary for generating deformation localization and earthquake nucleation. Realization of this process and mechanism is essential for understanding the seismogenic and occurrence mechanism of earthquake in strike-slip fault zones. This thesis is based on previous research of Zemuhe fault zone, which is controlled by pivotal movement. We tested and verified the process of pivotal movement, in which geomorphology and stress were distributed in {our quadrants, and examined the factors that can influence the pivotal movement and stress conditions of the fault plane. The result indicated that the dip angle and area of the block region can influence the pivotal movement, a stress centralization area develops to hold the accumulating stress, stress centralizes from outside to the core, the largest amount of stress always occurs in the core, and the core is significantly smaller than the block region.

关 键 词：枢纽运动 变形局部化 地震成核 数值模拟 大箐梁子 则木河断裂 

分 类 号：P541[天文地球—构造地质学]