A multi-proxy geophysical study at the site of the Temple of Olympian Zeus, Athens, Greece, to address and resolve challenging archaeological and engineering issues

Greece, has many important archaeological structures and monuments, as well as a plethora of natural or anthropogenic hazards. Preservation and protection of the monuments are needed, and the deployment of geophysical surveys as part of integrated geoscience and engineering studies play important parts. The Ephorate of Antiquities of Athens had laid plans to undertake restoration works for the Temple of Olympian Zeus, located in the center of Athens, Greece. A geophysical study was completed beforehand to detect the extent of voids found by excavation as well as any other hidden anthropogenic structures around or in the area of the Temple. A 3D electrical resistivity tomography (ERT) survey detected the arched voids, which were used as tanks in the Roman sewer system and later by General Makrygiannis as a place of contemplation, and a complex of tanks to the north of the large ones have been detected by using ground penetrating radar (GPR). A detailed local mode analysis of the subsequent frequency-domain electromagnetic (FEM) survey detected the ancient stone drain lines that brought water to the tanks. A vast surveyed area analysis has detected the distribution of near-surface geological formations. The FEM survey in the area of the Temple has revealed probable rock formations exhibiting two different textures and moisture, in the more loose formation, some linear features align with the existing columns, suggesting that they are probably part of the foundation design for the Temple. These linear features have also been detected by a 3D GPR survey. This multi-proxy geophysical survey provides useful information to guide the program of work that archaeologists and engineers have to carry out in order to protect archaeological monuments and to find hidden features that may create the need for a new design for the site as a whole. •Integrated geophysical survey to detect buried ancient constructions and resolve engineering issues for restoration activities at an ancient site.•3D ERT survey•EM and GPR analysis to detect buried ancient constructions•Combined interpretation of EM-ERT-GPR data-results.