Simulation of induced seismic ground motions using coupled geomechanical and seismic wave propagation models

Abstract

Numerical simulations of seismic wave propagation usually rely on a simple source model consisting of an idealized point location and a moment tensor. In general, this is a valid approximation when the source dimensions are small relative to the distance of points at which the seismic wave motions are to be evaluated. Otherwise, a more realistic spatio-temporal source representation is required to accurately calculate ground motions at the position of monitoring stations. Here, we present a generic approach to couple geomechanical simulations to seismic wave propagation models using the concept of the equivalent force field. This approach allows the simulation of seismic wave propagation resulting from the spatio-temporal dependent earthquake nucleation and rupture processes. Within the geomechanical package two separate geomechanics codes are used to simulate both the slow loading stage leading to earthquake nucleation as well as the successive dynamic rupture stage. We demonstrate the approach to a case of induced seismicity, where fault reactivation occurs due to production from a natural gas reservoir.