Research Unit 5 "Georessources" (RU5)

3D prediction of the in situ stress field and its anthropogenic changes

The stress information data compiled in the World Stress Map project that we coordinate is sparse and incomplete. In particular, data on the magnitudes of the three principal stresses, that are necessary to quantify the criticality of the initial natural stress state, are usually missing in the area of interest. Thus, we develop geomechanical-numerical model concepts and workflows to obtain from point data a 3D description of the stress field (Hergert et al. 2015; Ziegler et al. 2016; Reiter & Heidbach 2014; Heidbach et al. 2014). In particular, the multi-scale approach and the automated calibration method FAST of Ziegler et al. (2016) allows efficient modelling across model scales from the borehole to regional models. Furthermore, we investigate the anthropogenic induced stress changes on the regional stress field to derive recommendations to mitigate induced seismicity and to contribute to the safe and sustainable use of the underground (Gritto et al. 2014; Hakimhashemi et al. 2014a, Hakimhashemi et al. 2014b; Zang et al. 2014; Yoon et al. 2015a, Yoon et al. 2015b, Yoon et al. 2016; Ziegler et al. 2017).

The role of crustal stress and seismic hazard assessment for nuclear waste repositories

The site selection process for geological nuclear waste repositories is an unsolved problem and a major social challenge in many countries. The state of stress in potential repository sites is of key importance for the construction of the underground facility and for the prediction of the development of unwanted fluid pathways due to the excavation as well as due the heat generation of the radioactive waste. The focus of our research is the estimation of the spatial variability of the in situ stress field (Hergert et al. 2015; Heidbach et al. 2014). The aim of the ongoing work is the development of tools based on the Bayesian statistics, which allow a quantification of the uncertainties of geomechanical-thermal numerical models. Another research topic is the long-term stability of the repositories. We investigate e.g. the impact of glacial loads and strong earthquakes on the stability of the host rock and the geological barrier (Heidbach et al. 2014; Hergert et al. 2015; Bracket et al. 2016; Yoon et al. 2016, Yoon et al. 2017a, Yoon et al. 2017b).