A geophysical pilot study of Black Sea Fortresses
The Akkerman Fortress Project (AFP) is an international and interdisciplinary project that brings together archaeological investigation and documentary study to ascertain the evolution and characteristics of the ancient site of Akkerman Fortress in Bilhorod-Dnistrovsky, Ukraine.
The attention of archaeologists has previously primarily been focused on antiquity while later strata have been ignored or destroyed. This is particularly true of the remains of the Ottoman period at the Akkerman fortress, and it is on these that the project concentrates.
The fortress of Akkerman (long. 30.35; lat. 46.20) is located on a promontory inside the estuary (Liman) of the Dniester River, some 15 km from the point where the river enters the Black Sea. With a circumference of over 2 km, an area of 9 hectares, double walls, a ditch 13 m. deep, and 30 towers still standing.
A geophysical pilot study was undertaken, during August 2007, of the Akkerman fortress, in the Ukraine, by Alex Turner and Richard Haddlesey, from the University of Winchester (UK). The primary aim of this initial survey was to ascertain the effectiveness of a geophysical survey, to aid and advance the understanding of the Ottoman phase of the site.
As the geography of the area was unknown, the geophysical instrument chosen for this initial survey was the resistivity meter, as the nature of this instrument offers the highest probability of results under these conditions. A vital requirement of such a survey is a small degree of ground moisture, as this provides a path for the electrical current to flow, from one probe on the meter, to the other. Although the aridity of the southern coast of the Ukraine would normally have an adverse effect upon the instrument readings, a thunderstorm during the initial stages provided the required ground conditions. Toward the end of the survey, this had virtually dried out, making viable results more difficult to achieve.
Due to the dry terrain and compressed earth, from many years of tourist access, it was decided to carry out a brief survey, employing 1m spacing over a 20m grid. This was purely to determine whether it was possible to collect any meaningful data (fig. 1 illustrates the result). This particular grid was chosen after walking the site, as it seemed to offer the best possibility of achieving good results. This was due to a visible inserted roof line and remains of a wall; the only contemporary structural evidence not yet under archaeological investigation. The resulting grid data was downloaded onto a laptop and processed in Geoplot 3. A jpeg image was then exported for geo-referencing in the Geographical Information System (GIS) program, ESRI ArcView 9.2 (fig 2). The image was also downloaded onto a Nokia N80 mobile phone to facilitate the comparison of data analysis, with on-site evidence, in real time. The results were very encouraging and a further ten grids were surveyed at a higher resolution of 0.5m intervals in 20m grids, rendering higher quality results.