Sikyon survey project

The 2007 season

Geophysical research

Pat Gibbs and Geary Milward surveying beekeeper style.

Geophysical survey was carried out in July and September by teams of the University of York headed by Ben Gourley, and the Institute of Mediterranean Studies under Dr. Apostolos Sarris. The aim of the geophysical prospection is to supplement and control the data of the surface survey, with the identification of buried man-made features.

The team of the University of York worked in the field from July1 to 28, and has covered with a gradiometer an area of 123,753 sq. m.

Research covered all three parts of the plateau (UP, NP, SP) and has yielded important results for the architecture and planning of the ancient city. At the North Plateau eight new parallel streets, oriented E-W and measuring 6-6.5 m in width, were detected this year.

One of them in particular we can follow to a total length of 600 m. At the north plateau, an equal number of perpendicular streets (oriented N-S) were recognized, of similar width except for one, which is almost 10 m wide. This true avenue crosses the plateau from north to south since it was also recognized to the south of the ancient agora. Research in the south plateau has produced one more perpendicular street and at least three horizontal.

Geophysical research of the University of York during the 2006-2007 seasons in the North Plateau.

Geophysical research of the University of York during the 2006-2007 seasons in the South Plateau.

In addition, survey in both the Northern and Southern plateau produced many data as to the content of the insulae with spaces developed around open courtyards. Contrary to the picture that we gained from these two areas, survey of the Upper Plateau produced no sign for the presence of a grid here and the planning of streets and building plots. Linear "anomalies" detected close to the northern and southern edge of the upper plateau probably correspond to geological fractures, and betray the process of the on-going natural erosion of the soft, marly bedrock.

The team of the Institute of Mediterranean Studies worked in the field from August 31 to September 10 and covered with various geophysical methods areas to the north, east and south of the agora, of a total surface of 56.373 sq.m.

Geophysical prospection with the use of a Ground Penetrating Radar.

Instruments for the measurement of electrical resistivity and the magnetic susceptibility of the soil were used, as well as a ground penetrating radar.

At least 13 streets of E-W and N-S orientation were identified, along with three cross-roads and parts of buildings and complexes which belonged to the residential quarters of the ancient city. Of particular importance are the results of the geophysical prospections in tracts directly to the east and the north of the ancient agora, where the identification of streets helps us to determine the extent and size of the agora, which was hitherto unknown. In addition, GPR prospection showed that the layers of the Hellenistic and Roman periods lie at an average depth of 0.7 - 1.3 m, which is verified by excavations conducted on the plateau.

Mosaic of all electrical measurements during 2004-2007.

Mosaic of all magnetic measurements during 2004-2007.

Mosaic of all GPR measurements during 2004-2007.

GPR readings at different depths in a field to the east of the ancient agora.

Ancient survey geometry based on known streets and avenues.

Thanks to the combined efforts of the University of York and the Institute of Mediterranean Studies with their geophysical prospections, as well as to the location and mapping of in-situ architectural remains visible on the surface we are now in a position to reconstruct the ancient city grid, which was made out of squares some 69 m of a side.