As part of the project "WeatherSeis" 3 surveys have been carried out between July 2014 and November 2016 to explore shallow subsurface structures at the location "Waldschadensstandort Konventwald" in the Black Forest near Freiburg, Germany and at the location "Oedwies" in the Bavarian Forest near Deggendorf.
The sites are already being used for studies of the weathering zone by the GFZ Section 3.4 (Surface Geochemistry) and the Albert-Ludwigs-University of Freiburg (Hydrology). On the basis of geochemical parameters the zone of interest is analyzed for mineralogical aspects and mass transport mechanisms. Additionally core drilling has been carried out at the two locations. The core sample extends from soil continuing through autochthonous weathered rock ("saprolite") into the unweathered bedrock.
In order to develop alternative high-resolution methods to study the weathering zone (here the top 20 - 50 m) active seismic surveys consisting of 2D profiling at different altitude levels were carried out. The generation of different seismic waves (compression and shear body waves, Rayleigh and Love surface waves) was performed with different impulsive and vibrational seismic sources. The chosen recording configuration allows different evaluation methods.
Moreover, geoelectric measurements were conducted along the same profiles to get besides the knowledge about ground velocities and velocity changes also knowledge about the distribution of the electrical conductivity.
The multidisciplinary investigations at these locations open up the possibility of integrated evaluation and the combination of results of geochemical and geophysical measurements.
Special focus is put on the structure, zoning and the physico-chemical properties of the weathering zone. Knowledge of position and composition of the weathering zone makes it possible to draw representative conclusions on hydrological, rheological, petrophysical and mineralogical control factors of weathering and water balance.
Time frame (Experiment)
- 2014 - 2016
- GFZ - Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences
- Manfred Stiller (GFZ Potsdam, Sec. 2.7)
- Prof. Dr. Michael Weber (GFZ Potsdam, Sec. 2.2)
- Prof. Dr. Friedhelm von Blanckenburg (GFZ Potsdam, Sec. 3.4)
- David Uhlig (GFZ Potsdam, Sec. 3.4)
Methods & Equipment
- Accelerated weight-drop PEG-40, Shear-wave amboss, P+S micro-vibrator Elvis III
- Multichannel System "Geode" by Geometrics
- P+S Reflection/Refraction Seismics, P+S Tomography, R+L Surface Wave Inversion
- DC Geoelectrics, Multi-Electrode System GeoTom MK8E1000