Magnetic, GPR and geoelectrical measurements for studying the archaeological site of 'Masseria Nigro' (Viggiano, southern Italy)

The results of a geophysical survey carried out at the archaeological site of Masseria Nigro, located on a fluvial terrace on the north-eastern flank of the Agri valley (Viggiano, Basilicata Region), are presented and discussed. The site includes an important ancient structure, developed in successive phases between the 4th and 3rd centuries BC and destroyed after the Roman conquest. Magnetic mapping, GPR profiling and electrical resistivity tomography were applied in the course of geophysical exploration in the archaeological area. The application of these methods revealed information about buried ancient walls, helping to define the boundaries of the whole building. During the first phase of the excavation, archaeologists targeted only the western part of the ancient structure (about 1000 m(2)), but the geophysical survey performed in a second phase was able to cover the entire ancient structure (1400 m(2)), enabling the archaeologists to define the extent of the buried structures. Our findings confirmed the hypothesis of the larger extent of the archaeological area in the eastern part and revealed the complete plan of the ancient building.