Integrating electrical resistivity tomography and ground‐penetrating radar methods to map archaeological walls near northern Ishtar gate, ancient Babylon city, Iraq

Abstract

Electrical resistivity tomography (ERT) and ground‐penetrating radar (GPR) were collected on the eastern side of the northern Ishtar gate in ancient Babylon, Iraq, to locate the palace wall and other surrounding walls. Due to the presence of a low resistivity (highly conductive) top layer associated with brick rubble and other debris, the GPR reflection profiles show a high‐energy attenuation, but a series of processing and filtering steps produced coherent reflections of about 2 m depth. Profile analysis shows the geometry and layering of the walls and the surrounding matrix. With the ERT, the surface conductive zone produces various distortions in ERT inverse models, making identifying the features' lower boundaries difficult. Here, we suggest that instead of analysing these two data sets independently, the integration of both reveals not just the walls but their composition and defines material in the surrounding units. This integration shows how the interpretation of the shallow features on the 3D ERT maps is improved by comparison and interpretation in conjunction with the reflections visible on both reflection profiles and the 3D GPR amplitude slices. The orientation of these features and reflections emphasizes the existence of one series of buried walls at a depth of 90–150 cm. The thickness of these walls varies between 0.25 and 1 m. Another wall‐like feature is visible only on 3D ERT maps and not with the 3D GPR slices at 2 m depth, which indicates a thickness of 11 m. It is interpreted as the palace wall, which is consistent with earlier archaeological excavations. An analysis of the geometry and composition of both wall components, perhaps of different ages, and constructed for different reasons, indicates that some shallower walls may be the remains of rooms built as residences for soldiers, or they may belong to the other ruins of northern Ishtar gate.

Computer Vision and Image Processing Approaches for Corrosion Detection

“…The accurate edges of multiple segments areas were detected with a Sobel edge detector. Moreover, GPR was used with Fourier transform and a Gaussian filter [40] with 1 GHz frequency to monitor and predict the degree of corrosion. Reinforced steel structures, such as floors, roofs, and concrete walls, were scanned and the obtained images were pre-processed to detect noise and anomalies.…”

Electrical resistivity tomography and ground‐penetrating radar methods to detect archaeological walls of Babylonian houses near Ishtar temple, ancient Babylon city, Iraq

“…As archaeological excavations are prohibited in the ancient Babylon city, approaches of geophysical prospecting techniques have revealed an increasing interest by archaeologists thanks to the recent developments offered by new instruments, methods, processes and presentations that provide greater fieldwork productivity and high‐resolution results. These geophysical techniques are non‐invasive and non‐destructive methods that offer accurate images to help archaeologists define the exact locations and depths of the buried architecture (AL‐Hameedawi, Thabit, Al‐Menshed, Conyers, 2021). Among these geophysical methods, ERT and GPR can produce 2D and 3D high‐resolution images of the subsurface.…”