Combining cross-hole georadar velocity and attenuation tomography for site characterization: a case study in an unconsolidated aquifer

Information extracted from crosshole georadar data has been used to characterize a gravel- and sand-dominated aquifer. Inversions of direct arrival traveltimes and amplitudes have provided electromagnetic velocity and attenuation tomograms that have allowed critical hydrological structures and parameters to be determined. An integrated interpretation of the velocity and attenuation tomograms was performed via a k-means cluster analysis. As a result of this multivariate statistical analysis, major trends in the relationship between velocity and attenuation were identified, thus enabling us to outline the major hydrostratigraphicu nits ofthe surveyedd eposit.