Enhancement of the Germany stress model

Updated stress database Germany 2025

Assuming that the vertical stress (Sv) is a principal stress, the 3D stress tensor is defined by the orientation of the maximum horizontal stress (SHmax) and the magnitudes of SV, SHmax and the minimum horizontal stress Shmin. In the stress map of Germany the SHmax orientation is indicated by lines where the line length is a measure for data quality. The orange triangles in the stress map denote the location of stress magnitude data and their size is proportional to the data quality from A (most reliable) to E (poor).

The stress database of Germany and adjacent regions contains 1780 data records for the SHmax orientation (883 with A-C quality) and 1330 stress magnitude data records (827 with A‑C quality) The SHmax orientation data are integrated in the new World Stress Map (WSM) database release 2025 (Heidbach et al., 2025). Further information is provided on the WSM webpage: www.world-stress-map.org and in the technical report TR 25-01 by Rajabi et al. (2025).

Germany Stress Map 2025. Displayed are A-E quality data records for the SHmax orientation as lines and stress magnitudes as orange triangles. (download high resolution map).

Structural diversification of the geomechanical model for Germany

The new geomechanical numerical model of Germany has the same dimensions as the two previous versions of Ahlers et al. (2021, 2022) and the same workflow is used. The main improvements are the implementation of a new geological model (Ahlers & Henk, 2025; Ahlers 2025), an increased vertical resolution and the extended stress database used for calibration. The new model contains 49 geological units parametrized with individual elastic rock properties (Young’s modulus and Poisson’s ratio) and rock densities. Overall, the model contains ~10 million hexahedral elements providing a lateral resolution of 4 km and a vertical resolution of up to 45 m in the uppermost 5 km.

Final geomechanical-numerical model of Germany.

Preliminary results show an overall good fit with stress magnitudes used for calibration, indicated by a mean of the absolute stress differences of ~3 MPa for Shmin and of ~5 MPa for SHmax. Furthermore, the results agree well with additional data sets (not used for calibration) ,e.g., an absolute mean deviation of the orientation of SHmax with regard to the WSM data of ~10°. The higher vertical numerical resolution, the increased stratigraphic resolution and the extended calibration dataset enable a significantly improved and more robust prediction of the recent crustal stress state. Both, the geological model and results of the geomechanical-numerical model will be published soon.

Slip Tendency analysis

The stress data provided by the updated model is used to calculate the potential of faults to be reactivated. A compilation of geological models provides 3D geometries of faults for large parts of Germany. By mapping the stress data of the updated model onto these fault geometries, a first order estimate of the fault reactivation potential is facilitated. One widely used measure for the fault reactivation potential is the slip tendency. The slip tendency is the ratio of the maximum resolved shear stress to the normal stress acting on the fault plane (Morris et al. 1996). Small slip tendency values close to 0 indicate that a fault is unlikely to be reactivated whereas higher values indicate that faults are more likely to be reactivated.

The compiled 3D fault geometries are color-coded by the slip tendency. A hydrostatic pore pressure was used for the slip tendency calculation.

References:

Ahlers, S. and Henk, A.: 3D Geological Model for Germany and Adjacent Areas [preprint], Earth Syst. Sci. Data Discuss, https://doi.org/10.5194/essd-2025-320, 2025.

Ahlers, S.: 3D geological model for Germany and adjacent areas, TUdatalib, https://doi.org/10.48328/tudatalib-1791, available at: https://tudatalib.ulb.tu-darmstadt.de/handle/tudatalib/4615, 2025

Ahlers, S., Röckel, L., Hergert, T., Reiter, K., Heidbach, O., Henk, A., Müller, B., Morawietz, S., Scheck-Wenderoth, M., and Anikiev, D.: The crustal stress field of Germany: a refined prediction, Geotherm Energy, 10, https://doi.org/10.1186/s40517-022-00222-6, 2022.

Ahlers, S., Henk, A., Hergert, T., Reiter, K., Müller, B., Röckel, L., Heidbach, O., Morawietz, S., Scheck-Wenderoth, M., and Anikiev, D.: 3D crustal stress state of Germany according to a data-calibrated geomechanical model, Solid Earth, 12, 1777–1799, https://doi.org/10.5194/se-12-1777-2021, 2021.

Heidbach, O., Rajabi, M., Di Giacomo, D., Harris, J., Lammers, S., Morawietz, S., Pierdominici, S., Reiter, K., Specht, S. von, Storchak, D., and Ziegler, M. O.: World Stress Map 2025, https://doi.org/10.5880/WSM.2025.002, 2025.

Rajabi, M., Lammers, S., and Heidbach, O.: WSM database description and guidelines for analysis of horizontal stress orientation from borehole logging, GFZ German Research Centre For Geosciences, Potsdam, WSM Technical Report, 25-01, https://doi.org/10.48440/wsm.2025.001, 2025.

Shapefiles Countries: © EuroGeographics for the administrative boundaries

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