Inside the polygonal walls of Amelia (Central Italy): A multidisciplinary data integration, encompassing geodetic monitoring and geophysical prospections

• Published in: Journal of applied geophysics 2016-04, Vol.127, p.31-44
• Main Authors: Ercoli, M., Brigante, R., Radicioni, F., Pauselli, C., Mazzocca, M., Centi, G., Stoppini, A.
• Format: Article
• Language: English
• Subjects: 3D imaging; Amelia; Cultural heritage; Electrical resistivity; ERT; Geomatic techniques; Geophysics; GPR; Ground penetrating radar; Historical buildings; Imaging; Multidisciplinary; Quantitative analysis; Walls
• ISSN: 0926-9851; 1879-1859
• DOI: 10.1016/j.jappgeo.2016.02.003

We investigate a portion of the ancient (VI and IV centuries BC) polygonal walls of Amelia, in Central Italy. After the collapse of a portion of the walls which occurred in January 2006, a wide project started in order to monitor their external facade and inspect the characteristics of the internal structure, currently not clearly known. In this specific case, the preservation of such an important cultural heritage was mandatory, therefore invasive methods like drilling or archaeological essays cannot be used. For this purpose, a multidisciplinary approach represents an innovative way to shed light on their inner structure. We combine several non-invasive techniques such as Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT), specifically adapted for this study, Laser Scanning and Digital Terrestrial Photogrammetry, integrated with other geomatic measures provided by a Total Station and Global Navigation Satellite Systems (GNSS). After collecting some historical information, we gather the whole datasets exploring for their integration an interpretation approach borrowed from the reflection seismic (attribute analysis and three dimensional visualization). The results give rise for the first time to the internal imaging of this ancient walls, highlighting features associable to different building styles related to different historical periods. Among the result, we define a max wall thickness of about 3.5m for the cyclopic sector, we show details of the internal block organization and we detect low resistivity values interpretable with high water content behind the basal part of the walls. Then, quantitative analyses to assess their reliable geotechnical stability are done, integrating new geometrical constrains provided by the geophysics and geo-technical ground parameters available in literature. From this analysis, we highlight how the Amelia walls are interested, in the investigated sector, by a critical pseudo-static equilibrium. [Display omitted] •We use a multidisciplinary approach using geophysical and geomatic techniques.•We study and define the inner structure of the ancient Amelia walls (Central Italy).•We highlight a critical pseudo-static equilibrium of the investigated sector.•We have obtained a 3D rendering encompassing the inner imaging of the walls.•We provide significant information useful for their preservation.