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

A survey was conducted to investigate buried archaeological walls near the Ishtar temple in the ancient Babylon city using electrical resistivity tomography and ground-penetrating radar methods. The survey includes applying 12 electrical resistivity tomography profiles using dipole-dipole array and a ground-penetrating radar grid of 55 m x 50 m using 250 MHz antenna. Although the buried walls are consisting of mudbrick masonry and are embedded in a clayey environment, the electrical resistivity tomography method is still able to differentiate the tiny differences between the host materials and the buried walls, which show distinctive wall-like features with resistivity values ranging between 9 and 15 omega m. These features may reflect underground-buried walls with a general width reaching about 2.5 m. The comparison of ground-penetrating radar profiles and their corresponding electrical resistivity tomography profiles presents that the main architectures are coinciding well. The analysis of the geometry and composition of the walls around the Ishtar temple suggested that the wall-like reflections on the ground-penetrating radar slice at a depth between 140 and 150 cm (may be shallower) are underground-buried walls. These wall-like reflections show a special trend and orientation that indicate that they may be the remains of rooms belonging to two small houses or the remains of one big private house.