- 1Tianjin University, School of Civil Engineering, China (wangchonglang@tju.edu.cn)
- 2China University of Geosciences (Beijing)
Injection-induced earthquakes (IIEs) are commonly attributed to pore-pressure elevation and associated Coulomb stress changes, leading to widespread adoption of Traffic Light Systems (TLS) that primarily focus on injection rate modulation for hazard mitigation. However, recent field observations have identified aseismic slip as an alternative mechanism for fault reactivation during direct fault-zone fluid injection, with evidence showing that slip propagation can outpace fluid migration fronts. Despite these insights, the critical conditions that determine when aseismic slip becomes the dominant mechanism—particularly the role of injection parameters—remain poorly understood. Here, we present direct fault-injection experiments equipped with high-resolution monitoring of fault slips and fluid difussions. Our findings reveal two fundamental insights into IIE mechanisms: (1) When faults are subjected to specific combinations of injection rates and pre-stress conditions, aseismic slip can initiate and propagate beyond the fluid-pressurized zone, becoming the primary mechanism for IIEs. (2) In near-critically stressed faults, the maximum seismic moment release may remain elevated even after injection rate reduction, undermining a core assumption of TLS protocols. Overall, these observations highlight that fault stress conditions, rather than injection parameters alone, dictate the upper bound of seismic hazard.
How to cite: Wang, C., Wang, P., and Xia, K.: How Does Injection Rate Control Injection-Induced Earthquakes?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19763, https://doi.org/10.5194/egusphere-egu25-19763, 2025.