Modelling fluid induced seismicity on a nearby active fault

Abstract

We present a numerical investigation of the effect that static stress perturbations due to fluid injection have ona nearby active fault where the fluid does not come in physical contact with the fault. Our modelling employs a latticeBoltzmann pore diffusion model coupled with a quasi-dynamic earthquake rupture model. As diffusivities and frictionalparameters can be defined independently at individual nodes/cells this allows us to replicate complex 3-D geological media in our simulations. We demonstrate the effect an injection can have on an active nearby fault. Compared with our control catalogue (identical to the original simulation but without the injection), the injection not only altered the timing of the next earthquake sequence, it also changed its size, producing a Mw 6.7 event, the largest observed earthquakeon the fault. This large event pushes the fault into a subcritical state from which it took roughly 200 yr of continuous tectonic loading for the fault to return to a critical state. © The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society.