Resistivity and Radar surveys at the Archaeological site of Ercolano

In this paper we describe the application of GPR and resistivity (dipole-dipole) methods to an archeological investigation. The aim of this study was to obtain information about buried pre-Roman structures below the Roman residence “Casa dell’Atrio a Mosaico”, in the ancient town of Ercolano (Naples). A number of resistivity (dipole-dipole) and GPR profiles were carried out on the mosaic floor of the house. To perform resistivity profiles in a nondestructive way on the mosaic floor, special flat-base copper electrodes were used. The electrode spacing used was 1 m and 0.5 m. GPR data were collected using 100 MHz and 500 MHz antennas. The radar profiles were carried out primarily along the electrical profiles in order to obtain a direct comparison between the two methods. Both resistivity and GPR methods evidenced a number of structures buried at shallow depths. Both methods located a structure identified as a conductive body with electric parameters strong contrasting those of the surrounding material. The archaeological interpretation of such structures is in terms of remnants of walls of pre-Roman houses and of a cistern used for collecting rain, connected to a pipe.