3D geological modeling of graben structures in northern Hesse – concept, methods and first results

For some years now, the Hessian Agency for Nature Conservation, Environment and Geology (HLNUG) is focusing its 3D-modeling activities on urban areas, aiming to contribute to both integrated modeling and urban planning (e.g., Lehné et al. 2017, Lehné et al. 2013, Budde et al. 2017). Experiences gained in the frame of the project “Darmstadt_3D”, which is delivering the urban subsurface including the technical infrastructure (sewage system, foundations, etc.), now are adopted for a working area in northern Hesse, southeast of Kassel. Geologically it is located in the Hessian depression and mainly characterized by WNW-ESE trending graben system of Kassel, and major features perpendicular to the main direction of the graben structure. The just emerging 3D geological model is addressing the stratigraphic horizons Quaternary, Tertiary as well as the lower triassic formations Röt, Solling and Hardegsen and based on 449 quality checked drillings, of which several also have been used for the construction of 8 cross sections that help to better elaborate the fault network. In addition, geological maps and already existing cross sections are considered. First results show a complex tectonic situation with displacement rates that often exceed 100m. They also confirm the conceptual approach to be expedient and suitable for the intended extension of the working area to the area of Kassel. On the way the geological 3D-content will be parameterized for downstream applications such as modeling groundwater, and radon potentials as well as enriched by urban subsurface infrastructure in order to get a fully integrated urban 3D-information system.