Analysis of surface displacements caused by mine flooding for the project FloodRisk with SAR Interferometry, GNSS and Levelling

After operation of hard coal mines has been terminated in Germany, many of the mines are being flooded. In the project “FloodRisk: Earthquakes, uplift, and long-term liabilities – risk minimization during mine flooding”, the consequences of the rising mine water levels are investigated from a multidisciplinary perspective. Geodetic, geophysical, geomechanical and geological approaches are combined to develop a conceptional model for flooding induced surface displacements and seismicity. Saarland, Ruhr area and Ibbenbüren have been chosen as exemplary investigation areas. The DMT GmbH & Co. KG (DMT) and the Geodetic Institute Karlsruhe (GIK) contribute to the project by analyzing surveying and InSAR data. DMT installs ten low-cost GNSS-Sensors near Bergwerk Ost and includes them in DMT SAFEGUARD, a proprietary GNSS monitoring system, that provides an integrated evaluation and provision service. GIK is analyzing InSAR data from Sentinel 1a/b and intends to combine GNSS, levelling and InSAR data from different orbits to derive 3D displacements. Challenges that are typical for mining areas as the spatially as well as temporally diverse displacement patterns demand for new solutions in InSAR processing. The so found displacements of the earth’s surface will be integrated with geomechanical modeling in the final phase of the project. In this presentation, the goals, challenges and approaches of FloodRisk with regard to geodesy are discussed and first results are shown.