Numerous studies have reported the occurrence of aseismic slip or slow slip events along faults induced by fluid injection. However, the underlying physical mechanism and its impact on induced seismicity remain unclear. In this study, we develop a numerical model that incorporates fluid injection on a fault governed by rate-and-state friction to simulate the coupled processes of pore-pressure diffusion, aseismic slip, and dynamic rupture. We establish a field-scale model to emulate the source characteristics of induced seismicity near the Dallas-Fort Worth Airport (DFWA), Texas, where events with lower-stress drops have been observed. Our numerical calculations reveal that the diffusion of fluid pressure modifies fault criticality and induces aseismic slip with lower stress drop values (<1 MPa), which further influence the timing and source properties of subsequent seismic ruptures. We observe that the level of pore-pressure perturbation exhibits a positive correlation with aseismic-stress drops but a reversed trend with seismic-stress drops. Simulations encompassing diverse injection operations and fault frictional parameters generate a wide spectrum of slip modes, with the scaling relationship of moment (M₀) with ruptured radius (r₀) following an unusual trend, , similar to observed in the DFWA sequence. Based on the consistent scaling, we hypothesize that the lower-stress-drop events in the DFWA may imply less dynamic ruptures in the transition from aseismic to seismic slip, located in the middle of the broad slip spectrum, as illustrated in our simulations.

中文翻译：

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流体诱发的地震滑移可以解释德克萨斯州达拉斯-沃斯堡机场附近诱发地震序列的非自相似震源缩放

许多研究报道了流体注入引起的沿着断层发生的地震滑动或慢滑动事件。然而，潜在的物理机制及其对诱发地震活动的影响仍不清楚。在这项研究中，我们开发了一个数值模型，该模型结合了受速率和状态摩擦控制的断层上的流体注入，以模拟孔隙压力扩散、地震滑移和动态破裂的耦合过程。我们建立了一个现场尺度模型来模拟德克萨斯州达拉斯-沃斯堡机场 (DFWA) 附近的诱发地震活动的震源特征，那里观察到了较低应力降的事件。我们的数值计算表明，流体压力的扩散改变了断层临界性，并引发具有较低应力降值（<1 MPa）的抗震滑移，这进一步影响了后续地震破裂的时间和震源特性。我们观察到，孔隙压力扰动水平与抗震应力下降呈正相关，但与地震应力下降呈相反趋势。包含不同注入操作和断层摩擦参数的模拟生成了广泛的滑移模式，力矩 ( M ₀ ) 与破裂半径 ( r ₀ ) 的比例关系遵循不寻常的趋势，， 如同在 DFWA 序列中观察到。基于一致的尺度，我们假设 DFWA 中较低的应力降事件可能意味着从抗震滑移到地震滑移的过渡中动态破裂较少，位于宽滑移谱的中间，如我们的模拟所示。