Fluid pressure changes affect fault stability and can promote the initiation of earthquakes and aseismic slip. However, the relationship between seismic and aseismic fault slip during fluid injection remains poorly understood. Here, we investigate, through 3‐D hydromechanical modeling, the spatiotemporal evolution of seismicity and aseismic slip on a permeable, slip‐weakening fault subjected to a local injection of fluid, under different prestress conditions. The model results in an expanding aseismic slip region, which concentrates shear stress at its edge and triggers seismicity. The aseismic slip dominates the slip budget, whatever the initial fault stress. We find that the seismicity is collocated with the aseismic rupture front rather than with the fluid pressure diffusion front. On faults initially far from failure, the aseismic rupture front is located behind or at the pressure front. On faults initially closer to failure, the model predicts that both the rupture front and the seismicity outpace the pressurized zone, resulting in a sharp increase of the migration velocity and released moment of the seismicity. Insights gained from this modeling study exhibit various features that are observed in sequences of induced earthquakes in both field experiments and natural reservoir systems and can help guide the interpretation of past and future observations of induced seismicity.

中文翻译：

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在渗透性断层中注入流体时，来自地震滑动的应力扰动驱动地震前沿。

流体压力的变化会影响断层的稳定性，并会促进地震和地震滑动的发生。然而，在流体注入过程中地震和地震断层滑动之间的关系仍然知之甚少。在这里，我们通过3D流体力学模型研究了在不同的预应力条件下，在局部注入流体的情况下，渗透性减弱的断层上地震活动和抗震滑动的时空演化。该模型导致一个扩展的抗震滑动区域，该区域将剪切应力集中在其边缘并触发了地震活动。无论初始断层应力如何，抗震滑移均占滑移预算的主导。我们发现，地震活动性与抗震破裂前沿并列，而不是与流体压力扩散前沿并列。在最初远没有失败的故障上，抗震破裂前沿位于压力前沿之后或压力前沿。在最初接近故障的断层上，该模型预测断裂锋面和地震活动性都超过受压带，从而导致迁移速度急剧增加，地震活动性释放。从该建模研究中获得的见解显示出在野外实验和天然油藏系统中按诱发地震序列观察到的各种特征，可以帮助指导对过去和将来的诱发地震活动性观测结果的解释。