Analysis of surface displacements caused by mine flooding for the project FloodRisk with SAR Interferometry

During the last decades, one hard coal mine in Germany after the other stopped production and entered the post-mining phase. The last pits that terminated active mining were Ibbenbüren and Prosper-Haniel in 2018. For reasons of cost efficiency, the pumping of mine water is reorganized in this phase and levels are allowed to rise up to a certain depth below the surface. This process goes along with pressure changes in the rock that may e.g. cause surface displacements, seismicity or increased leakage of soil gases. In order to gain a better understanding of its effects and their dependency on the geological situation, the interdisciplinary project FloodRisk funded by the German Federal Ministry of Education and Research (BMBF) started investigating the post-mining process from the perspectives of geology, geophysics and geodesy. The present paper takes the perspective of geodesy and uses Interferometric Synthetic Aperture Radar (InSAR) to investigate surface displacements at Ibbenbüren and in the eastern Ruhr area for the period January 2018 to March 2021.