The Ancient Roman Aqueduct of Karales (Cagliari, Sardinia, Italy): Applicability of Geophysics Methods to Finding the Underground Remains

Abstract

Detection of the buried antique Roman aqueduct, which supplied fresh water to the ancient town of Karales (Cagliari, Italy), is not a trivial problem because of the small size of its cross section, its depth (about 10 m), and of the presence of shallow conductive layers. In order to determine the best geophysical method to use in the research of the conduit, a test was carried out over a well-known section of the underground aqueduct in its extra-urban part. Taking into account the geological features of the site, time-domain electromagnetic (TEM), very low-frequency (VLF) and electrical tomography methods were chosen. The test was conducted over several profiles. The results showed that among the electrical resistivity arrays, the Wenner-Schlumberger is the most suitable for the detection of the conduit some metres in depth, whereas the other electrical methods did not have enough resolution to distinguish between the aqueduct and other non-related anomalies at the requested depth. The TEM method also showed good capability to detect the presence of the aqueduct in spite of very conductive superficial layers. With the exception of one profile, all VLF profiles showed anomalies that could be correlated to the aqueduct.

The Use of Geophysical Prospections to Map Ancient Hydraulic Works: The Triglio Underground Aqueduct (Apulia, Southern Italy)

“…Identification of the underground stretches of these hydraulic works can be extremely difficult if direct access is not possible (due to closure or destruction of the shafts, and to falls within the structure). In the last years several authors have used different geophysical techniques to explore for and map these features, with particular regard to ground‐penetrating radar (GPR) (Bavusi et al ., ; Chaminé et al ., ; Galli et al ., ; Leucci, ; Leucci et al ., ; Leucci and De Giorgi, ; Nuzzo et al ., ; Sammarco et al ., ; Trogu et al ., ). However, the GPR literature is for the most part lacking models for what complex void spaces of various geometries look like in reflection profiles and other images, so these studies are still in their infancy (cf.…”

Portable gamma ray spectrometry for archaeological prospection: A preliminary investigation at Silchester Roman Town

“…Comparing the two data sets may highlight less distinctive anomalies that could have otherwise been overlooked. The value of using multiple surveying techniques has been exemplified in multiple studies including those by Creighton and Fry (2016), Halgedahl et al (2009), Putiška et al (2014), Trogu et al (2014) and Zheng et al (2013).…”

Automated Resistivity Profiling (ARP) to Explore Wide Archaeological Areas: The Prehistoric Site of Mont’e Prama, Sardinia, Italy

“…Electrical resistivity prospection specifically proved to be an effective method to characterize the subsoil and materials in various fields of study, such as applied geology [2][3][4], hydrogeology [5,6], engineering [7][8][9], environmental sciences [10,11], and agriculture [12][13][14]. This method is widely used for archaeological surveys: many past research has shown that the variations of electrical resistivity are often related to walls, floorings, paving and burials [15][16][17][18][19][20][21][22]. These structures are generally characterized by different electrical properties compared to the geological layers that, over time, have buried them.…”