Induced seismicity in enhanced geothermal systems: a numerical investigation on the influence of the friction model

Abstract

Hydraulic stimulation in Enhanced Geothermal Systems (EGS) produces low-magnitude induced seismicity that sometimes can result in damage at the Earth's surface. Numerical simulations taking into account the hydrothermo- mechanic behaviour of geological reservoirs are an essential tool in order to evaluate and forecast induced seismicity in such systems. In this study, the numerical code CFRAC is used to evaluate the seismicity of an isolated fault during fluid injection using two different frictional models: (i) rate-and-state and (ii) velocity weakening. The results show that both models predict similar microseismicity, although there are differences in the number of events and their magnitudes between both models.