Investigating behind the lining of the Tunnel of Eupalinus in Samos (Greece) using ERT and GPR

• Published in: Near surface geophysics (Online) 2015-12, Vol.13 (6), p.571-583
• Main Authors: Tsokas, Gregory N., Jung‐Ho, Kim, Tsourlos, Panagiotis I., Angistalis, Georgios, Vargemezis, Georgios, Stampolidis, Alexandros, Diamanti, Nectaria
• Format: Article
• Language: English
• ISSN: 1569-4445; 1873-0604
• DOI: 10.3997/1873-0604.2015012

The 2.5‐km‐long Eupalinian Aqueduct in the island of Samos, Greece, comprises the most impressive sample of ancient Greek engineering surviving almost intact. The main construction is a tunnel 1036 m long and almost 1.8 m wide excavated from both ends into mainly the massif limestone. In some parts of the overall length of about 240 m, the tunnel is dressed by lining of archaic and Roman age. This is of remarkable quality, and presumably, it protected the parts of the tunnel that were affected by subsidence and cave‐ins. At some particular locations, it suffers deformations and other failures. Thus, prior to its restoration and protection measures design, an integrated geophysical survey was carried out on the faces of the supporting walls, consisting in ground‐penetrating radar and electrical resistivity tomography works. The survey aimed to investigate the structure at the unseen area behind the lining. The thickness of the lining walls was accurately assessed by the ground‐penetrating radar method and proved to be about 0.3 m–0.5 m on average. On the other hand, the width of the excavation behind the walls was predicted and checked at some particular locations with the electrical resistivity tomography works.