Using fault maps for the preliminary screening of areas for underground storage of radioactive waste or for geothermal energy

A qualitative approach is presented for the preliminary screening of areas for the storage of radioactive waste or for geothermal energy production based on knowledge of damage zones. Different types of fault damage zones are described in relation to the geometries and kinematics of individual faults or pairs of faults. A new type of damage zone, termed a ‘fold-related damage zone’, is also defined. Some fold-related damage zones may be indirectly related to faulting, such as folding above a thrust ramp, while others may be associated with processes such as salt movement. This knowledge is applied to a regional fault map to predict areas of relatively intense faulting and fracturing in central and southern Germany. Forty examples of potential tip, linking, interaction, bend or fold-related damage zones have been identified, and more detailed fault maps and digital elevation model data have been examined for evidence of damage. More detailed work is required, however, to ascertain the extent of damage in these zones and their influence on fluid flow. For example, some damage zones may show lower porosity and permeability than the surrounding rock mass. This approach can be applied to fault maps in other regions to identify additional potential damage zones.