UAV images and historical aerial-photos for geomorphological analysis and hillslope evolution of the Uggiano medieval archaeological site (Basilicata, southern Italy)

摘要

ABSTRACT In this work, we introduce the results of a multi-temporal analysis of UAV (unmanned aerial vehicle) images of the Uggiano castle, a highly degraded medieval archaeological site located about 5????km to the north-west of the Ferrandina town (Basilicata, southern Italy). The geomorphological analysis carried out by multi-temporal images has been integrated with a geological field survey in order to retrace the hillslope evolution of the site as well as the adjacent slopes. This kind of analysis allows to investigate the main stratigraphical and topographic factors responsible for the slope processes, acting along the outer edges of the archaeological site, which is today reduced to a few ruins located at the top of a circular ridge with steep slopes shaped on sandy-conglomerate Pleistocene regressive deposits. The instability phenomena are mainly due to localized erosional processes and falls in conglomerates, which affected the edges of the top surface, where the castle was built. High-resolution images also highlight several collapses of artificial cavities (cisterns) in the central sector of the archaeological site. In addition, a comparison between oblique and vertical UAV images, historical maps, aerial-photo images and the relationships with rainfalls permitted to acquire key data about evolution of slope and erosional processes. Such integrated approach allowed us to individuate in safety conditions the more exposed sectors of archaeological site, where the slope failure processes and collapse cavities occurred, as well as their time activation.