Assessing Fault Reactivation Using Slip and Dilation Tendency

Understanding the reactivation potential of geological fault zones in the deep subsurface is crucial for evaluating the feasibility of subsurface uses, such as CO₂ and hydrogen storage, geothermal energy, and radioactive waste disposal. This study investigates the reactivation potential of faults across Germany, using fault-specific datasets (e.g., fault traces, 3D models, or focal mechanism solutions) to demonstrate different application procedures. We considered the parameters of slip tendency (ST) and dilation tendency (DT), where ST quantifies the tendency of fault reactivation by shear under a given stress field, and DT indicates the tendency of a fault to open, thus acting as a fluid migration pathway.

For a first approximation of present-day stress conditions, we used data from a 3D geomechanical numerical model by Ahlers et al. (2022), which covers the onshore and parts of the offshore regions of Germany. From our perspective, ST and DT are robust and computationally efficient parameters that can be reliably derived from fault data in various formats. This study presents the methodology for calculating these parameters and discusses the strengths and limitations of the input data.

The results contribute to a better understanding of fault behaviour under current stress conditions and may support a first approximation of geological suitability for subsurface applications. However, further refinement of the stress model would be essential to achieve more reliable and site-specific results.