CAJ | 학술논문

运用有限元法建立大尺度几何弯曲断层(长约750 km)的二维模型,并利用接触单元技术模拟断层间的作用,模拟了几千年时间尺度内走滑断层的活动,探讨了具有一定几何形态断层对断层系统活动的影响.几何弯曲的断层导致了应力的集中,而且在断层的地震事件中起到了抑制作用,但是也为孕育大震提供了条件.和平直断层的模拟结果比较得知,断层的几何弯曲不仅影响地震破裂长度、改变了地震滑移量,也很大程度影响了能量释放的空间位置,改变了地震轮回周期.此外,弯曲断层应力的不均匀也使主震前往往有前震发生.另外通过模拟可以看出,弯曲断层活动表现出明显的特征地震,使得地震-频次曲线偏离G-R公式,说明了对单个断层而言,特征地震可能更能体现断层的地震活动,这对我们进行地震预测和危险性分析有着很重要的参考意义.
운용유한원법건립대척도궤하만곡단층(장약750 km)적이유모형,병이용접촉단원기술모의단층간적작용,모의료궤천년시간척도내주활단층적활동,탐토료구유일정궤하형태단층대단층계통활동적영향.궤하만곡적단층도치료응력적집중,이차재단층적지진사건중기도료억제작용,단시야위잉육대진제공료조건.화평직단층적모의결과비교득지,단층적궤하만곡불부영향지진파렬장도、개변료지진활이량,야흔대정도영향료능량석방적공간위치,개변료지진륜회주기.차외,만곡단층응력적불균균야사주진전왕왕유전진발생.령외통과모의가이간출,만곡단층활동표현출명현적특정지진,사득지진-빈차곡선편리G-R공식,설명료대단개단층이언,특정지진가능경능체현단층적지진활동,저대아문진행지진예측화위험성분석유착흔중요적삼고의의.
Using finite element method (FEM) with contact algorithm, we established a 2D bend fault model and calculated the activities of this fault in thousands of years, and discussed how the geometry bending affects the activities. Due to the effect of geometry bending, stress concentrates on some parts of fault and the distribution of stress on fault is highly heterogeneous. Additionally, geometry bending restrains or stops some ruptures, but can produce strong earthquakes. Compared with planar fault, bend fault can not only affect earthquake ruptures and slip, but also change temporal and spacial evolution of earthquakes. Because of the heterogeneous stress distribution of bend fault, some foreshocks occurred before main shock, but not occurred on planar fault. The earthquake frequency-size distribution of simulation result deviates from the G-R relation, showing that a characteristic model is more reasonable, especially, characteristic slip can be seen from result distinctly.