Seismo Lab Seminar

Fluid-driven frictional ruptures play an important role in both geo-energy applications and natural earthquake-related phenomena. Industrial operations involving subsurface injections such as deep geothermal energy, CO₂ geological storage, and wastewater disposal can induce fault slip, while natural processes like earthquake swarms and slow slip events are often linked to fluid motion and frictional slip within the Earth's crust. In this talk, I will present recent advances in our theoretical understanding of injection-induced fault slip. I will discuss how fault stress conditions, injection history, and frictional and hydraulic fault properties collectively control the dynamics of fluid-driven slip in three dimensions. Building upon this theoretical understanding, I will examine two important issues in injection-induced seismicity using laboratory data and a global catalog of injection-induced events. First, I will address the extent of aseismic slip propagation, which can transmit stress changes well beyond pore pressure diffusion, potentially triggering seismicity at large distances from injection wells. Constraining the maximum extent of aseismic ruptures is thus important for better delineating the influence zone of injections concerning their seismic hazard. I will present a theoretical upper bound for the run-out distance of aseismic ruptures from injection points, demonstrating its consistency with data across a wide range of scales, from lab experiments to field observations. Similarly, I will introduce an upper-bound scaling relation for the moment magnitude of these events. Next, I will discuss how the spatiotemporal evolution of seismicity during injection operations can reveal key properties of the medium, including stress state, frictional parameters, and hydraulic characteristics. I will introduce a physical model with only two fitting parameters that successfully describes seismicity migration in deep geothermal reservoirs due to the combined effect of pore pressure diffusion and aseismic-slip stress changes. Furthermore, I will explore the model's applicability to complex fracture networks where injection affects thousands of randomly oriented fractures. I will conclude with perspectives for future research, including areas that need further theoretical work, opportunities for experimental validation, and model applications to wastewater injection, CO₂ storage, natural seismic swarms, and slow slip events in subduction zones.