Indirect preservation of Egyptian historical sites using 3D GPR survey

Non-invasive geophysical techniques are used to collect information about the environmental risks that threaten the historical sites in Egypt and indirectly preserve them. In this study the modern 3D-GPR imaging at two important Egyptian sites was applied for preservation purposes. The first site is the internal Piazza of Al-Azhar Mosque, while the second site is the proposed route through which the Ramesses-II statue will be transported to the main entrance of the Grand Egyptian Museum. The 3D-GPR surveys were performed using the 100 MHz GSSI antenna at Al-Azhar Piazza and the Hi-Mode IDS GPR system with 200 and 600 MHz dual antenna at the Grand Egyptian Museum. The analysis and interpretation of the 3D-GPR data at the first site led to image large voids and walls objects, which are very likely to represent shallow water tanks that were frequently used in the past. One main water tank was recently discovered at the southern part of the piazza, which causes water leakage to the walls of Al-Azhar Mosque. Moreover, the GPR results at the second site have showed that the proposed route is totally covered by sand and has neither cracks nor cavities or any other archeological features. There is only a PVC water pipe, which is buried at a relatively shallow depth of 0.25 m. Such PVC pipe might collapse during the transportation of Ramesses-II Statue and should be taken into consideration.