We investigate how temperature, and mineral composition jointly control frictional behavior and induced seismicity in granite fault gouges under simulated geothermal reservoir conditions. Laboratory shear experiments on seven Gonghe granitic gouges (2.45–3.6 km depth) in hydrothermal conditions reveal two temperature-dependent slip regimes: velocity-weakening between ≈ 100–250°C, and velocity-strengthening above ≈ 250°C. Gouges richer in tectosilicates show enhanced frictional strength and unstable slip tendencies, while phyllosilicate-rich samples favor stable aseismic slip. Simulations quantify Coulomb failure stress change (ΔCFS) perturbations up to ~0.013 MPa at distances of 1000 m, demonstrating the potential for fault reactivation across the reservoir. These findings clarify the conditions under which granitic pre‑existing faults transition to unstable slip during geothermal operations, offering critical insights into induced seismicity risk.
Southwest Jiaotong University, China (SWJTU) International Consortium on Geo-disaster Reduction (ICGdR) UNESCO Chair on Geoenvironmental Disaster Reduction
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Southwest Jiaotong University, China (SWJTU) International Consortium on Geo-disaster Reduction (ICGdR) UNESCO Chair on Geoenvironmental Disaster Reduction