断层演化过程中的周期和非周期地震滑移及非地震滑移——一维断层模型分析  

The periodic and aperiodic slip during earthquake faulting and aseismic faulting slip:1D fault model analysis

作　　者：解孟雨 史保平[1] 

机构地区：[1]中国科学院大学地球科学学院,中国北京100049

出　　处：《地震学报》2016年第4期590-608,658,共19页Acta Seismologica Sinica

基　　金：国家国际科技合作专项(2015DFA21260);北京市高校共建项目;国家基金委(41574040);中国科学院创新团队项目(KZZD-EW-TZ-19)共同资助

摘　　要：本文首先根据Dieterich和Ruina提出的含速率和状态的摩擦定律(Dieterich-Ruina定律),基于一维弹簧-滑块模型推导了地震复发周期的解析表达式,然后将该近似解与数值模拟结果以及Barbot等的相关研究进行了对比分析.此外,本文还利用数值模拟与理论分析研究了断层周期和非周期演化的力学成因机制以及非地震滑移形成的另类力学机制,并讨论了一维弹簧-滑块模型的优点及其局限性.结果表明:1震后滑移和自加速/成核阶段的持续时间在整个演化过程中不能被忽略;2在修正后的复发周期模型中,复发周期的长短除了与断层特征尺度、作用于断层面上的有效正应力和远场加载速率相关外,还受Dieterich-Ruina定律中摩擦参数的取值以及临界滑移距离的影响;3当给定各个物理参数和几何参数时,目前所得到的解析近似解可以很好地估计地震的复发周期,其相对误差可小于5%;4在断层演化过程中,施加剪切应力加载会产生非周期的地震滑移,而在自加速/成核阶段后期或震后滑移阶段早期,施加较大的剪切应力加载,则会出现非地震滑移.With a simple 1D spring-slide block model governed by DieterichRuina law,this study derived an approximate analytical solution used to calculate the earthquake recurrence time and compared its approximate solution with previous results given by Barbot et al.The comparison between approximate solutions and the results by numerical simulation also demonstrated that current solution gives us a better approximation compared with previous result.Furthermore,it should be emphasized that,because only 40%to 80% of earthquake recurrence time belongs to interseismic stage,therefore,the duration of postseismic and nucleation/preseismic stage could not be ignored in the whole faulting process.Specifically,the time scale of earthquake recurrence in current earthquake recurrence model is not only related to the characteristic dimension of fault,the effective normal stress and remote loading rate,but also strongly depends on the values of the frictional parameters in the Dieterich-Ruina law and the critical distance obtained from laboratory.It is necessary to point out that,if all parameters we used represent a real situation in the earth,the approximate solution proposed in the present paper can give us an excellent estimation of earthquake recurrence time for a given tectonic region,of which relative error is less than 5%.Moreover,numerical simulation and theory are also used to study the mechanical mechanisms which cause the periodic and aperiodic evolution of the earthquake faulting and aseismic faulting slip.In addition,this paper also discussed the limitations and advantages of using 1Dspring-slide block model to describe the elasticity in modeling evolution of fault.And it is found that applying shear stress loading during evolution of earthquake faulting can cause aperiodic evolution.Specially,applying shear stress loading at late nucleation/preseismic stage or early postseismic stage will lead to aseismic faulting slip.

关 键 词：含速率和状态的摩擦定律 地震循环 地震复发周期 非地震滑移 

分 类 号：P315.3[天文地球—地震学]