We develop a new dynamic earthquake simulator to numerically simulate both spontaneous rupture and aseismic slip over earthquake cycles on geometrically complex fault systems governed by rate‐ and state‐dependent friction. The method is based on the dynamic finite‐element method (FEM) EQdyna, which is directly used in the simulator for modeling 3D spontaneous rupture. We apply an adaptive dynamic relaxation technique and a variable time stepping scheme to EQdyna to model the quasi‐static processes of an earthquake cycle, including the postseismic, interseismic, and nucleation processes. Therefore, the dynamic and quasi‐static processes of an earthquake cycle are modeled in one FEM framework. Tests on a vertical strike‐slip fault verify the correctness of the dynamic simulator. We apply the simulator to thrust faults with various dipping angles, which can be considered as the simplest case of geometrically complex faults by breaking symmetry, compared with vertical faults, to examine effects of dipping fault geometry on earthquake cycle behaviors. We find that shallower dipping thrust faults produce larger seismic slip and longer recurrence time over earthquake cycles with the same rupture area. In addition, we find an empirically linear scaling relation between the recurrence interval (and the seismic moment) and the sinusoidal function of the dip angle. The dip‐angle dependence is likely due to the free‐surface effect, because of broken symmetry. These results suggest dynamic earthquake simulators that can handle nonvertical dipping fault geometry are needed for subduction‐zone earthquake studies.

中文翻译：

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几何复杂断层上地震破裂过程中动态破裂和地震滑移的3D有限元建模

我们开发了一种新的动态地震模拟器，以数值模拟在由速率和状态决定的摩擦控制的几何复杂断层系统上，地震周期内的自发破裂和抗震滑动。该方法基于动态有限元方法（FEM）EQdyna，该方法直接在模拟器中用于对3D自发破裂进行建模。我们对EQdyna应用了一种自适应动态松弛技术和一个可变时间步进方案，以对地震周期的准静态过程进行建模，包括后地震，间震和成核过程。因此，在一个有限元框架内对地震周期的动态和准静态过程进行了建模。在垂直走滑故障上进行的测试验证了动态模拟器的正确性。我们将模拟器应用于具有各种倾角的推力故障，与垂直断层相比，通过破坏对称性可以将其视为几何复杂断层的最简单情况，以研究浸没断层几何形状对地震循环行为的影响。我们发现，在相同破裂面积的地震周期内，较浅的俯冲冲断层会产生较大的地震滑动和较长的复发时间。此外，我们在递归间隔（和地震矩）与倾角的正弦函数之间找到了经验线性比例关系。倾斜角度的依赖性很可能是由于自由表面效应所致，因为对称性被破坏了。这些结果表明，对于俯冲带地震研究，需要能够处理非垂直倾角断层几何特征的动态地震模拟器。