Following the end of hard coal mining in Germany, dewatering in the closed mines is undergoing a transformation. After the end of deep mine drainage, the mine water generally rises to a higher, regionally predefined level and the former extraction areas are flooded. The rise in mine water is accompanied by stress changes in the rock mass, which can also lead locally to ground movements and to the activation of mining and natural fault zones. Seismic events can also occur, which can be perceived as earth tremors at the surface.

Within the scope of the project, ground motions and seismic events will be quantified and discussed for selected localities in the Saar and Ruhr areas. In particular, the process understanding of the geomechanical coupling of surface deformations with stress changes of the geological subsurface due to a mine water rise shall be improved. For this purpose, a multidisciplinary approach consisting of geodetic, geophysical, geomechanical and geological methods will be adopted. A variety of geological and survey data collected during centuries of mining activities will be used. The goal is to gain a deeper understanding of the process in order to estimate induced seismicity in critical areas.

It is intended to use geodetic methods to determine the surface movements in the Saar and Ruhr areas. To record induced seismicity, geophysical measurement fields will be established in selected areas. With the help of drill cores and representative rock outcrops, rock parameters can be determined, geological structures characterized and three-dimensional subsurface models created. The development of low-cost sensors for the detection of gas leaks is also planned. The results from these studies will then be incorporated into an interdisciplinary, conceptual model of flooding-induced ground motions and seismicity for other areas. This will enable the derivation of recommended actions for future flooding and the creation of optimized reservoir management.