Formation of surface depressions is a significant geological hazard. Prediction of future sinkholes in buried karstic areas needs knowledge about the subsurface. In order to determine the varying topography of the karstifiable bedrock we carried out multielectrode measurements. Due to the hard field conditions, the bedrock depth could not be detected. The resistivity anomalies in some places had a seasonal variation (low-resistivity in springtime, high-resistivity in the end of summer); therefore we interpreted the springtime resistivity lows as indicators of locations with high water content, that is as high porosity, saturated with water. At the same time, when pushing the current- and potential electrodes into the ground, we discovered a regularity in the areal distribution of the soil's rock debris content. Therefore we carried out a systematic electrode-pricking experiment, and categorized the soil's "toughness" corresponding to soft penetration, scratching or blockage within the upper 30 cm. We have found a close relationship between the locations of resistivity- and the soil's toughness extremes. From some epikarstic features we think that high "pricking probe" values indicate smaller depths of the bedrock. The corresponding (springtime) resistivity minima may indirectly indicate more or less collapsed horsts of the carbonate rock.
|Publication status||Published - Jan 1 2008|
|Event||14th European Meeting of Environmental and Engineering Geophysics of the Near Surface Geoscience Division of EAGE, Near Surface 2008 - Krakow, Poland|
Duration: Sep 15 2008 → Sep 17 2008
|Other||14th European Meeting of Environmental and Engineering Geophysics of the Near Surface Geoscience Division of EAGE, Near Surface 2008|
|Period||9/15/08 → 9/17/08|
ASJC Scopus subject areas
- Geotechnical Engineering and Engineering Geology