Recent advances in the integrated geophysical exploration of buried archaeological targets

We propose the integration of magnetic, electromagnetic (ground- penetrating radar, GPR) and seismic methods to study the inner structure of pre- historic funerary mounds. The combination of techniques allows high-resolution imaging and detection of buried targets and characterization of subsurface materi- als based on magnetic susceptibility, dielectric permittivity, conductivity and seismic velocity/attenuation. The 2012 archaeo-geophysical expedition to Scythian necrop- oleis in Kazakhstan allowed advancement of the integrated procedure through opti- mization of the individual techniques. We improve the results of seismic tomography inversion through an ART algorithm with a relaxation parameter which is progres- sively reduced during the iterative reconstruction process. We use instantaneous at- tributes and spectral decomposition to improve the interpretation of GPR reflection data. The results obtained from the 2012 dataset allow detailed reconstruction of the inner structure of three kurgans (i.e. funerary mounds) with maximum 7 m cen- tral elevation. In particular, localized anomalies related to metallic targets smaller than the GPR and seismic resolution limits are identified from magnetic data after high pass filtering; GPR data allow imaging of inner stratigraphy up to a maxi- mum depth of about 250 cm; seismic tomography maps large traveltime anomalies probably related to funerary chambers at the base of the mound.