Probabilistic Seismic Hazard Analysis of Induced Seismicity Associated with Deep Geothermal Energy Production

In the course of planning and licensing, but likewise for the development and operation of deep geothermal systems, estimates of the frequency of exceedances of limits of ground motion are of interest. The limiting values used for evaluation of ground motion (PGV, Peak Ground Velocity) were taken from engineering regulations (standard value for perceptibility of vibrations, German DIN 4150 ). We developed a PSHA (probabilistic seismic hazard analysis) model for ground motion of induced seismicity. Thus, it is possible to specify the probability of exceedance of limiting values of PGV and to decide (e.g. by the regulator responsible for commissioning) whether the number of exceedances at these given limits are acceptable at a site or not. Additionally, hazard curves of induced and natural seismicity are compared to study the different impacts. Preliminary results which were derived using data from the operation phase of a plant, - for stiff soil, ignoring site effects - indicate higher frequencies of exceedance for induced seismicity than for natural seismicity only for low PGV values. The current work aims at refining our PSHA model by incorporating effects of local site conditions. They will be quantified using a concept of ambient seismic noise array measurements.