共轭断层系统的非线性有限元模拟与震群模型讨论

NONLINEAR FINITE-ELEMENT SIMULATION OF CONJUGATE FAULTS SYSTEM AND ASSOCIATED EARTHQUAKE SWARM

采用断层摩擦接触的非线性有限元模拟方法,对单断层与交叉断层2种断层模型分别进行数值模拟计算对比,结合中国大陆双震或震群型地震孕育发生的构造条件对共轭断层系统的孕震与发震机理进行了讨论与分析。断面滑动摩擦机制较好地解释了共轭断层由闭锁状态进入发生地震的滑动状态的过程,共轭断层系统会交替地发生失稳事件,验证了2组共轭断层系统构成的地震模型的滑动习性。其数值模拟与讨论分析结果可为共轭断层发育区的地震监测预报提供科学依据。

In this paper, adopting nonlinear finite-element method for faults with frictional contact, single fault and conjugate faults are calculated and compared respectively. And conjugate faults system is analyzed about its structural significance, combined with preparation and occurrence of strong earthquakes in the capital circle region. Study shows that seismogenic process of typical conjugated fault system from lock to unlock is well explained by Coulomb friction criteria, and unstable events can take place alternately along conjugate faults. The slip behavior of seismogenic tectonic model of great earthquake composed of two conjugate faults is verified. The numerical simulation as well as the analysis and discussion on the results provide scientific basis for earthquake forecasting and monitoring in areas where conjugate faults have developed.