资源环境科技发展态势分析平台

Fault/fracture slip and induce seismicity caused by fluid injection is of major interest to subsurface science and engineering. However, some fundamental aspects of the temporal and spatial evolutions of induced seismicity remain unresolved. Here, laboratory injection‐induced shear test was conducted on a rough granite fracture with concurrent acoustic emission (AE) monitoring. The results demonstrate a sequence of aseismic‐seismic‐aseismic fracture motion during fluid injection. It is observed that the temporal evolution of AE/microseismic activities was accompanied by the changes of slip velocity, stress drop, and friction coefficient. The seismic slip phase consists of three sub‐phases, namely, 1^st quasi‐static slip, dynamic slip, and 2^nd quasi‐static slip. The dynamic slip corresponding with AE mainshock could be a reliable simulation of earthquake instability triggered by injection in deep crystalline rocks. In addition, slip heterogeneity controlled by fracture roughness is directly evidenced by the spatially heterogeneous distributions of AE hypocenters and fracture surface topography.