scholarly journals The Messapic Site of Muro Leccese: New Results from Integrated Geophysical and Archaeological Surveys

2019 ◽  
Vol 11 (12) ◽  
pp. 1478 ◽  
Author(s):  
Bianco ◽  
De Giorgi ◽  
Giannotta ◽  
Leucci ◽  
Meo ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Ground Penetrating Radar ◽  
Electrical Resistivity Tomography ◽  
Soil Depth ◽  
Survey Methods ◽  
Geophysical Survey ◽  
Archaeological Sites ◽  
Good Correspondence ◽  
Resistivity Tomography ◽  
Ground Penetrating

The regular application of geophysical survey techniques to evaluate archaeological sites is well established as a method for locating, defining, and mapping buried archaeological materials. However, it is not always feasible to apply a range of different methods over a particular site or landscape due to constraints in time or funding. This paper addresses the integrated application of three geophysical survey methods over an important archaeological site located in south Italy. In particular, it is focused on the results achieved from a past geophysical survey and the ongoing excavations performed by archaeologists in the site of Muro Leccese. Muro Leccese (Lecce) is one of the most important Messapian archaeological sites in southern Italy. The archaeological interest of the site was generated since the discovery of the remains of Messapian walls (late 4th–3rd centuries BC). With the aim of widening the archaeological knowledge of the Messapian settlement, several integrated methods, including magnetometry, ground-penetrating radar, and electrical resistivity tomography were used on site to fulfill a number of different research objectives. Since the most important targets were expected to be located at shallow soil depth, a three-dimensional (3D) ground-penetrating radar (GPR) survey was carried out in two zones, which were labeled respectively as zone 1 and zone 2, and were both quite close to the archaeological excavations. The GPR investigations were integrated with a 3D electrical resistivity tomography (ERT) survey in zone 1 and with a magnetometric, in gradiometry configuration survey in zone 2. The integration of several techniques allowed mapping the structural remains of this area and leading the excavation project. The geophysical results show a good correspondence with the archaeological features that were found after the excavation. Current work on the geophysical survey data using different codes for the processing of the data and merging different datasets using a Geographic Information System allowed achieving a user-friendly visualization that was presented to the archaeologists.

Ground-penetrating radar and electrical resistivity tomography studies in the biblical Pisidian Antioch city, southwest Anatolia

2018 ◽  
Vol 25 (4) ◽  
pp. 285-300 ◽  
Author(s):  
Çağlayan Balkaya ◽  
Ümit Yalçın Kalyoncuoğlu ◽  
Mehmet Özhanlı ◽  
Gözde Merter ◽  
Olcay Çakmak ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Ground Penetrating Radar ◽  
Electrical Resistivity Tomography ◽  
Resistivity Tomography ◽  
Ground Penetrating

Application of Electrical Resistivity Tomography and Ground Penetrating Radar to assess salinity in a coastal aquifer with tidally-driven saline recirculation cell

2020 ◽  
Author(s):  
Jesús Fernández Águila ◽  
Mark McDonnell ◽  
Raymond Flynn ◽  
Alastair Ruffell ◽  
Eric Benner ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Seawater Intrusion ◽  
Ground Penetrating Radar ◽  
Water Samples ◽  
Electrical Resistivity Tomography ◽  
High Water ◽  
Fresh Groundwater ◽  
Resistivity Tomography ◽  
Tidally Driven ◽  
Ground Penetrating

<p>Seawater intrusion is a major issue worldwide, as coastal aquifers often act as the primary source of drinking water for more than one billion people. With climate change and projected population increases in coastal areas, this problem is anticipated to become more pressing over the next decades. Effective site characterisation strategies provide a crucial component in understanding subsurface saltwater migration. Density differences cause freshwater to float on seawater creating the classical saltwater intrusion saline wedge. However, tides often control coastal groundwater dynamics causing the emergence of an upper saline recirculation cell beneath the intertidal zone (Intertidal Recirculation Cell, IRC). Here we present the application of Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) techniques to characterize the coastal sand aquifer underlying Benone Strand (Magilligan, Northern Ireland) where tides induce an IRC. The aquifer is approximately 20 m thick and rests directly on Lr. Jurassic mudstones.</p><p>2D ERT profiles were generated at Benone beach using the SYSCAL Pro 72 ERI system (Iris Instruments). Two different array configurations (Wenner-Schlumberger and dipole-dipole) were used to provide both improved horizontal and vertical resolution. Because of the homogeneity of the sand, the ERT profiles made it possible to clearly define the configuration of the IRC and the fresh groundwater discharging “tube”. The presence of the tidally-driven recirculation cell causes fresh groundwater to flow below the IRC (“discharge tube”) and discharge in the vicinity of the low water mark. ERT data suggest that the IRC has a resistivity of approximately 1 Ωm and a thickness of 8 m. Resistivity increases below the IRC, but declines moving towards the low water mark. These findings suggest a possible mixing zone between saline water and the freshwater discharge. To verify the accuracy of the resistivity values measured in the ERT profiles, water samples were collected at various distances along a perpendicular transect from the high water mark to the low water mark. The electrical conductivities of the water samples were measured and compared with the resistivities obtained in the ERT profiles using Archie's law. Similar values were obtained in both cases.</p><p>A MALÅ ground penetrating radar system, operating at 50 MHz, 100 MHz and 500 MHz, was used to collect 2D GPR profiles at Benone beach from the low tide mark to beyond the high water mark. Findings suggested that the IRC attenuated the radar signal in all cases. However, GPR profiles were crucially important to demarcate the interfaces between freshwater and saltwater near the ground surface. GPR profiles obtained using higher frequencies (500 MHz) were the most informative.</p><p>The research work carried out at Magilligan allows us to conclude that the application of ERT and GPR techniques is effective in delineating seawater intrusion in aquifers where tides create an IRC. In addition, ERT profiles very clearly identified the IRC through field measurements (which in most cases is studied through numerical models and laboratory tests).</p>

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