GeoTief is a research project for surveying the geological conditions in the eastern part of Vienna. The focus here is scientifically investigating the potential for environmentally-friendly heat from subterranean reservoirs of hot water. For this purpose, seismic readings were taken on the earth’s surface using 16,000 sensors, a process which was completed in 2018. The complete set of data collected from the readings is now being scientifically evaluated, with a view to producing a 3D model of Vienna’s geology by 2021. The tests cost around EUR 5 million.