2-D GEOELECTRICAL SURVEY FOR THE PRELIMINARY ROUTE OF THE NATURAL GAS PIPELINE INSTALLATION AT ALISTRATI CAVES, N. GREECE

An extensive 2-D geoelectrical survey was carried out at the Alistrati caves, prefecture of Serres, Ν. Greece, as part of a preliminary route survey for the planned natural gas pipeline that was about to cross these regions of Northern Greece. Geophysics can play a significant role in this procedure. Synthetic modeling and inversion examples presented in this work support the above claim. The dipole-dipole array was used with inter-electrode spacing of 5m and maximum dipole separation of n equal to 8 dipole spacing. Two groups of personnel, including geophysicists and technicians, worked for one month to realize this survey. The number of measurements is really enormous for such type of research. A total of 7616 measurements (952 electrode points) were obtained. The area of investigation was chosen on the basis of the local geological conditions, which appeared to favor the existence of void structures. The survey line had a length of approximately 5 km. The 2-D geoelectrical survey proved to be an effective tool for delineating the subsurface lithology and structure of the surveyed area. Most importantly, the technique proved successful in locating highly karstified areas and can be used to aid void mapping as well as to provide useful information about their general setting

Near Surface Geophysical Archaeological Prospection at the Prehistoric Site of Akrotiri on Santorini/Thera

In February 2014 high-resolution ground penetrating radar and earth resistance tomography measurements have for the first time been used successfully for the distinct mapping of buried archaeological structures in the vicinity of the Bronze Age archaeological site of Akrotiri on Santorini/Thera in Greece

Characterization of a Pre-Trajan wall by integrated geophysical methods

The purpose of this study was to characterize a pre-Trajan mosaic-decorated wall structure located beneath the Cryptoporticus of the 'Baths of Trajan' complex in Rome. The surveyed wall is 15m long, 0.9m wide and 3 to 5m high. Ground penetrating radar (GPR) and P-wave seismic refraction tomography profiles were used to reconstruct the wall's inner structure, generate a map of the fractures and to evaluate the seismic velocities of the building materials. The wall was surveyed with horizontally and vertically dense GPR profiles and two seismic lines. The seismic lines and GPR profiles were capable of detecting a discontinuity between brick and travertine materials that compose the wall. The combined interpretation of the two non-invasive techniques allowed us to locate weak zones and fractures. This rapid, non-destructive and multi-parametric approach has proved to be effective for characterizing the current status of the wall and the results will be used by archaeologists to evaluate the wall's integrity and to preserve the structure in the future archaeological excavations

A geophysical survey in the archaeological site of Archontiko, Yannitsa

The ancient settlement of Archontiko is 4.5 km NW of ancient Pella in North Greece (Figure 1). The findings showed that the area was first occupied by the end of the Iron Age, i.e. 650-550 B.C. Also, showed that the topographic table of Archontiko was a major settlement of the Yannitsa province due to its concessive position by the main roads of Macedonia (Chrysostomou A. and Chrysostomou P., 1993). At the upper layers of the ruins, findings of the Roman and Byzantine times were also unearthed. The geophysical methods have been used in order to detect and map antiquities in various sites in Greece (e.g., Tsokas et al., 1994; 1995; Sawaidis et al., 1999). The resistivity mapping employing the twin probe array, the total magnetic field variations, the airborne photos and the Ground Probing Radar are the most popular methods in this respect. However, almost all geophysical methods can be used to tackle specific problems. From 1992 till 1994, many geophysical surveys were carried out in the area of Archontiko to collect mainly magnetic data. Resistivity measurements were also conducted in a small part of the area. The data presented in this study cover the northern side of the topographic table of Archontiko and they were collected during two campaigns during the summer of the years 1992 and 1993 (Figure 2)