Joint application of surface electrical resistivity- and GPR-measurements for groundwater exploration on the island of Spiekeroog—northern Germany

Groundwater ages, recharge conditions and hydrochemical evolution of a barrier island freshwater lens (Spiekeroog, Northern Germany)

“…It is assumed to be continuous below the main dune area (OOWV, 2009). Tronicke et al (1999) suggested the absence of this clay layer southeast of the main dune arc from geophysical measurements.…”

“…2). Groundwater level rises up to a maximum height of 2 masl (Tronicke et al, 1999). The appropriate resulting maximum depth of the freshwater-saltwater interface of 80 m according to Herzberg (1901) is prohibited by the clay layer.…”

Discharge of nitrate-containing groundwater into a coastal marine environment

“…However, a bulk resistivity above 30 X m must be considered as a reliable indicator for the presence of freshwater saturated sediments for all three methods. Tronicke et al (1999) adopted the same value for delineating freshwater saturated sediments in a geophysical survey on the island of Spiekeroog, northern Germany. Using the 30 X m boundary, a comparison of the MEP and UMEP results of Fig.…”

Investigation of a slope endangered by rainfall-induced landslides using 3D resistivity tomography and geotechnical testing

“…It is well known that multiparameter analyses (e.g., GPR and ERT) can significantly reduce the uncertainty in geophysical interpretation (e.g., Dannowski and Yaramanci, 1999). Recently, such combined information has been used to infer structural boundaries from smooth data using stochastical cluster and fuzzy approaches (e.g., Tronicke et al, 1999;Paasche et al, submitted for publication). In our case, no GPR data could be obtained because of high attenuation in conductive soil layers.…”