Electromagnetic methods

The field electromagnetic methods includes a wide spectrum of geophysical methods that are based on Maxwells equations. In department 2 we focus on three of them: direct current resistivity, also known as electrical resistivity tomography (ERT), surface nuclear magnetic resonance (sNMR), and ground-penetrating radar (GPR).

Geoelectrics

Direct current and low-frequency electromagnetic resistivity measurements are frequently applied for structural geologic, geotechnical or environmental investigations, but more and more also for process monitoring. The investigation scale ranges from shallow heterogeneities (cm) to exploring deep targets (km). Measurements are done at the surface and in boreholes or combinations of them. Commonly sources are galvanic, but also capacitive or inductive coupling is used. Modern modelling and inversion algorithms are required for data analysis that are able to incorporate a-priori information and to combine different methods. Technical developments are the basis for high data quality and thus reliability of the results.

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Surface NMR

Surface-NMR is a relatively new geophysical technique based on the same principles of the well known medical MRT. Surface-NMR allows for deriving subsurface distributions on hydraulic parameter such water-content and permeability. Our Research focuses on the development of improved data analyses, measurements sequences and technical devices.

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Ground-penetrating radar (GPR)

GPR is a fast technique for investigating the near surface with a high spatial resolution. It is commonly used for a structural determination, e.g. of costal sediments, peat layers or salt deposits or to detect buried archaeological objects and landmines. Further on, physical properties can be deduced as e.g. moisture or clay content of soils which are important factors for solving hydrological or agricultural Problems.

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