Investigation of the North Face Corridor in the Great Pyramid of Giza using Electrical Resistivity Tomography

Despite some impressive examples of Electrical Resistivity Tomography (ERT) characterizing the internal structure of historical monuments, ERT is rarely considered a primary method for this purpose because it is challenging to adjust measurement procedures and inversion techniques for such intricate objects. In this study, ERT was first applied in the Great Pyramid of Giza to detect the presence of the ScanPyramids North Face Corridor (SP-NFC). The ERT measurement technique and data analysis procedure were adapted for this case, which was characterized by complex surface topography and limited space for placing ERT lines. A 3D CAD model of the Chevron area was designed for inversion based on a 3D point cloud. The inversion results show the existence of the SP-NFC, with average dimensions of approximately 2.5 m by 2.5 m, starting at a depth of around 1 m and extending at least 2 m into the pyramid. The ERT study thus provided volumetric data confirming both the size and extent of the SP-NFC, complementing the ground-penetrating radar (GPR) and ultrasound tomography (UST) studies conducted simultaneously in the Chevron area.