Influence of Temperature on Seismic Moment as a Diagnostic for Crustal Permeability Creation

Understanding what controls permeability is important in modulating crustal processes and the recovery of fuels and energy from the subsurface. Permeability may be created by the reactivation of fractures creating connected flow pathways that result in microearthquakes (MEQs). We explore the influence of temperature on the linkage between permeability evolution and induced MEQs through a series of concurrent flow‐through reactivation experiments conducted on laboratory faults at elevated temperatures (20°–140°C). A distinct proportional relationship is observed between changes in permeability () and seismic moment () across the tested temperature range. These observations are consistent with a mechanistic model accommodating shear dilation on the reactivated fault. We show a direct, power‐law link between permeability change and seismic moment. Two prefactors that scale this relationship reduce with increasing temperature and are proportional to shear stress drop and shear dilation angle and inversely proportional to shear modulus. The sensitivity to temperature is mainly due to a decrease in shear dilation angle when temperature‐activated deformation mechanisms increase. In addition to these laboratory data, observations from four geothermal reservoirs at temperatures in the range 20°–250°C confirm this power‐law relationship and similarly indicate that the prefactor λ in the expression decreases with increasing temperature. This temperature‐dependent relationship can provide credible constraints on the progress of permeability increase and induced seismicity in field‐scale reservoir stimulations.