Comparison Between ATEM, RMT, ERT and CPTR Data at a Quick Clay Site in Sweden
M. Bastani, L. Persson, H. Löfroth and C.A. Smith
Event name: Second European Airborne Electromagnetics Conference
Session: Data Visualization, Integration and Interpretation
Publication date: 03 September 2017
Info: Extended abstract, PDF ( 2.08Mb )
Price: € 20
In 2015, airborne transient electromagnetic (ATEM) surveys at four areas were conducted to study feasibility of using the method for identification of areas with possible presence of quick clay in Sweden. Here we present the results from survey in area 3. Using resistivity models from 1D inversion of ATEM data ground investigations were planned. These include radio magnetotelluric (RMT), electrical resistivity tomography (ERT), and cone penetration tests with resistivity (CPTR) measurements together with core samplings. The RMT models show the best correlation with the CPTR measurements in the upper 10 meters of the boreholes however they lack sensitivity to resolve underlying resistive bedrock. The ATEM models show the same resistivity variations seen in the CPTR data and RMT models at shallower depths with less resolution. They also demonstrate reasonable sensitivity to detect bedrock. At locations where 1D assumption is not valid the ATEM models are biased and the depths to the bedrock are underestimated and do not coincide with the observations in the boreholes. Our analyses reveal that the ATEM data contain valuable information to use for identifying areas with quick clay provided that geotechnical data are available for calibration of models and interpretations in the survey areas.