Structures and parameters

Seismic section of buried valley in Northern Germany; clayey, water-retarding layers are marked in brown (LT=Lauenburg clay, OGT=Upper Glimmerton (mica clay), UGT=Lower Glimmerton, HT=Hamburg clay), OBKS, UBKS = Upper and Lower Braunkohlensande (lignite sand; water-bearing layer), Q=Quaternary, T=Tertiary

For a sustainable or clever management of groundwater resources a profound knowledge of their extent, hydraulic properties and contamination risk is necessary. The methods of applied geophysics provide a wide range of techniques whose potential is not yet sufficiently used. Especially the combined and integrated interpretation is still in the focus of research that is enhanced by the combination of results from geophysics, hydrology, geology, geochemistry etc.
Geophysical methods can image structures due to contrasts in physical parameters. E.g., changes in seismic velocity and density at a layer boundary lead to an impedance value that causes reflection and refraction of seismic waves. Reflection seismic is able to image structures down to large depths. With resistivity methods changes in resistivity or electrical conductivity point to structural changes. Or, with gravity, density differences are modelled to fit a structural picture.

A further characterisation and modelling of groundwater systems needs hydrogeologic important parameters like porosity, hydraulic conductivity or storage capacity. Porosity, water content and clay content are in turn related to seismic velocity, electric resistivity or permittivity. There is the hope that via geophysical surveys lateral changes of hydrogeologic parameters may be ascertainable. For an absolute determination we need boreholes and laboratory measurements.







New techniques in hydrogeophysics for the evaluation of sedimentary aquifers

Geophysikalische Charakterisierung des Grundwassers Quartäre Rinne
Lithologische Relevanz des oberflächennahen Geschwindigkeitsmodells