Assessment of shallow subsurface characterisation with non-invasive geophysical methods at the intermediate hill-slope scale

S. Popp, D. Altdorff, P. Dietrich
2013 Hydrology and Earth System Sciences  
<p><strong>Abstract.</strong> Hill-slopes of several hectares in size represent a difficult scale for subsurface characterisation, as these landscape units are well beyond the scope of traditional point-scale techniques. By means of electromagnetic induction (EMI) and gamma-ray spectroscopy, spatially distributed soil proxy data were collected from a heterogeneous hill-slope site. Results of EMI mapping using the EM38DD showed that soil electrical conductivity (ECa) is highly variable at both
more » ... variable at both temporal and spatial scales. Calibration of the integral ECa signal to a specific target like soil moisture is hampered by the ambiguous response of EMI to the clay-rich hill-slope underground. Gamma-ray results were obtained during a single survey, along with EMI measurements and selected soil sampling. In contrast to ECa, a noticeable correlation between Total Count and K emission data and soil-water content seemed to be present. Relevant proxy variables from both methods were used for <i>k</i> means clustering in order to distinguish between hill-slope areas with different soil conditions. As a result, we obtained a suitable partition of hill-slope that was comparable with a previously obtained zonation model based on ecological factors.</p>
doi:10.5194/hess-17-1297-2013 fatcat:yd5xgx6igvc5xmvn6dzi5cdqei