Numerical Simulations of Induced Seismicity at a Geothermal Power Plant near Munich, Germany

In the North Alpine Foreland Basin, especially in the greater Munich area, several geothermal plants exploit a deep hydrothermal reservoir. Only at three sites events with ML > 2.0 were detected, in an otherwise seismically inactive region. In this study we investigate a site to the east of Munich, where moderate seismicity started to appear around five years after the beginning of geothermal circulation. Two larger events (ML = 2.1/ 1.8) occurred on 07/12/2016 and 20/12/2016, followed by an additional event (ML = 2.1) about 10 months later on 09/09/2017. As this is a densely inhabited area, the estimation of the maximum ground motion and its distribution is of great importance for the authorities and the public. We perform 3D seismic simulations of the main events using the spectral element code SALVUS to estimate the possible seismic impact in the area. The results of the numerical simulations are validated against the ground motion recordings. In addition, we evaluate the influence of different parameters on the peak ground velocity (PGV), such as hypocentre location, focal mechanism, and Vs30. Such a numerical approach can help to improve the seismic monitoring network, identify affected zones, and mitigate the seismic risk.