Integrated GPR and ERT Surveys for the Investigation of the External Sectors of the Castle of Melfi (Potenza, Italy)

The Castle of Melfi is placed on a hilltop overlooking the modern town and it includes many buildings that have been modified and expanded over time. Its Norman-era core was probably built between the end of the 11th and the start of the 12th century on top of an earlier Byzantine castrum; it was enlarged during the reign of Frederick II and additional alterations were undertaken during the reigns of the Angevin and Aragonese. Integrated ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) surveys were carried out inside two courtyards of the westernmost part of the castle, the Cortile degli Armigeri and the Cortile del Mortorio, and in an external eastern wall area in order to identify ancient buried structures through two different methods of investigation and to compare the results.