Slip tendency analysis for 60 3D faults in Germany and adjacent areas

Tectonic faults are of great importance for many underground applications such as hydrocarbon extraction, geothermal operations or nuclear waste repositories. In particular, the fault reactivation potential is crucial in regards of safety and efficiency of these applications. Major influences on the reactivation potential are the contemporary tectonic stress field and changes to it due to anthropogenic activities. One measure of the reactivation potential of faults is the ratio of resolved shear stresses to normal stresses on the fault surface, the slip tendency. The components of the stress tensor required for slip tendency analysis have been provided by the 3D geomechanical numerical model of Germany and its adjacent regions of the SpannEnD project. The derived stresses are mapped onto selected faults in order to calculate their slip tendency. As only a finite number of 3D fault geometries could be generated, criteria for the selection of faults relevant to the scope of the SpannEnD project were identified. Their application led to the selection of 60 faults in the model area. For the selected faults simplified geometries were created (fault set 1). For a subset of the selected faults, vertical profiles and seismic sections could be used to generate semi-realistic 3D fault geometries (fault set 2). Slip tendency calculations using the stress tensor from the SpannEnD model were performed for both 3D fault sets and allow for an assessment of the fault reactivation potential which can be compared with the distribution of seismicity.