3D seismic at the Asse nuclear waste repository site
At the moment the former salt mine "Asse" in Lower Saxony is used as nuclear waste repository for low- and medium-level radioactive waste. However, due to water influx and resulting instabilities the repository needs to be abandoned. In order to allow for a safe retrieval of the nuclear waste, it is mandatory to have precise information on the complex geological structures in the area and the properties of the subsurface. We give an overview of the Asse and demonstrate from a geophysical perspective why seismic imaging in this area poses real challenges and what efforts the "Bundesanstalt für Endlagerung" (BGE) undertakes to tackle them, including a recent high-density 3D seismic data acquisition. Using snapshots of simulated wavefields and seismograms as well as comparisons with field data, we show that considering anisotropy and possibly also attenuation combined with the latest technology in seismic processing and migration is required to properly image the complex subsurface in this area.