Geophysical Prospecting, Topography, Thermal Camera and DEM
Laura Cerri, Emanuele Mariotti · Brepols Publishers eBooks · 2023
During the month of January 2009 and the following June 2010 two geophysical surveys took place covering a total of 5100 m2 of the hilltop of Tricosto. Quadrants were set both inside and outside the fortified area. The anomalies that emerged from the geophysical survey revealed a whole other chapter in the medieval life of Capalbiaccio. Before the medieval phase, a pre-existing larger settlement covered most of the hilltop. The surface collection of material and the aerial photography do not reveal much of the nature of the site as it is mostly covered by olive trees and local flora with the addition of thick blocks of collapsed medieval layers. The pottery that predated the medieval settlement, found during Dyson’s excavations and recently re-analysed by Valeria Acconcia (infra) is what prompted the questions that are herein analysed in the magnetometry. The small quantity of Etruscan and little Roman pottery identified and dated confirmed that some form of earlier occupation of the hilltop indeed existed. The reason for adding three campaigns was to better understand the nature of the settlement underneath the ruins of the Tricosto Castle and its immediate suburbia and compare it within the other regional sites that have been studied since the 1970s. The geophysical survey indeed confirmed a much wider pre-exiting settlement below and beyond the castle with a different orientation from the medieval village. The dwellings face northeast to southwest and northwest to southwest are at variance of about 45 degrees clockwise from the medieval layer. Now, with a more precise dating of the pottery and the evidence shown from the magnetometry, we can suggest there was an Etruscan community between the sixth and the fifth century bce. It’s still not clear if the oval structure facing the sea and about 50 m from the city walls is an Etruscan burial or something else. The tumulus has never been excavated nor noticed before (see Chapter 15, Fig. 15.5). While drafting a new map of the site, it became increasingly clear that the erosion of the hilltop during the last thirty-five years brought to the surface what seems to be a much denser medieval community within the castle than had been identified during Dyson’s seasons. Further, new alignments of houses were plotted on the map together with the discovery of a second church. Outside of the fortified area and around the hilltop there are traces of the ancient road that led to the top to the castle’s gate and touched five springs that provide good drinking water still today. These wide roads, which have both been integrated in the DEM (digital elevation model), followed the natural inclination of the hill and were carved out of the limestone, which is visible from the magnetometry outside the main gate of the castle. They were likely reused in pre-medieval times. Two nearby quarries of travertine - one to the northeast of the fortified village and one, of cavernous limestone, to the southwest at the bottom of the hill, near the later Torre del Tricosto - have been used through time. A final confirmation of our findings was obtained in 2021 with the use of a Thermal camera to compare and contrast the anomalies identified, showing the different information each approach provides staged on both aerial and drone views of the 1970s and 2021. [MH]