THE GEOPHYSICAL SURVEY OF AN IRON AGE CITY IN CENTRAL ANATOLIA: 
KERKENES DAG 
Nahide Aydin (1), Vedat Toprak (2), Niliifer Baturayoglu (3) 
(1) Proj. Asst., Kerkenes Project, Department of Architecture, Middle East Technical University, Turkey: nahide@metu.edu.tr 
(2) Assoc. Prof. Dr., Department of Geological Engineering, Middle East Technical University, Turkey: toprak@metu.edu.tr 
(3) Res. Asst., Department of Restoration, Faculty of Architecture, Istanbul Technical University, Turkey: niluferb@superonline.com 
KEY WORDS: Geophysical Survey, Central Anatolia, Iron Age, Non-destructive Methods, Survey and Documentation, 
Archaeology 
ABSTRACT 
The Iron Age settlement on Kerkenes Dag located in central Anatolia is a large ancient city. The size of the site has necessitated the 
use of alternative remote-sensing techniques for its documentation and evaluation. This paper focuses on one of these techniques, the 
geophysical survey of the city and the evaluation of the geophysical data and its integration with the other methods of survey. 
1. INTRODUCTION 
Kerkenes Dag, the site of the largest known pre-Hellenistic settlement on the Anatolian Plateau, is a low granitic mountain with an 
altitude of c. 1400 m above sea level located on the northern edge of the Cappadocian plain in central Turkey (Figs, la and lb in 
Baturayoglu et al. also in this volume). This city was most probably Herodotus’ Pteria, founded by the Medes around 600 B.C., 
totally burnt by Croesus, the Lydian king of Sardis in 547 B.C. and thereafter abandoned (Summers 1997; Summers 2000). 
The size of the city and the visibility of so many features and especially the impressive defensive wall above ground has drawn the 
attention of earlier generations of archaeologists. In 1928 E. F. Schmidt established the Iron Age date of the settlement by test 
excavation (Schmidt 1929). However, expeditions of this period preferred multi-period sites as they were limited to excavation as the 
main technique and Kerkenes Dag was not studied any further until the initiation of Kerkenes Project in 1993 by Geoffrey and 
Françoise Summers under the auspices of the British Institute of Archaeology at Ankara (Summers and Summers 1998). A 
combination of traditional and modem survey techniques are being used in order to plan the remains. Research design and 
methodology are being developed together with advances in new technologies and their application, among which geophysical 
survey plays an important role in the survey and documentation of the sub-surface features, making it possible to plan the entire 
settlement area without large scale excavation. 1 
2. THE GEOPHYSICAL SURVEY 
The geophysical survey was started experimentally in 1993 during the first season of the project. Until the 1998 season it was 
restricted to specific areas. However in 1998, it was extended to cover the whole site and became the main survey method of the 
project with the aim of producing the complete site plan (Fig. 6a in Baturayoglu et al.). The other geophysical prospecting methods 
such as GPR and electromagnetics were also experimented with (Fig. 6b in Baturayoglu et al.) but geomagnetics remained to be the 
main survey method due to the site's unique features in terms of both geology (granite bedrock) and archaeology (the existence of 
only a single occupation level). (See Sections 4.5. and 4.6. and Fig. 6c in Baturayoglu et al.) 
The instrument that was chosen for geomagnetic survey is an FM36 fluxgate gradiometer, and the selected grid size is 20x20m. The 
data-sampling rate is four readings per meter and the traverse interval is lm. Experimentation with different sampling rates and 
traverse intervals has shown that increasing either the sampling rate or the traverse interval does not reveal any further information. 
The average daily data collection may reach up to 30 (20x20m) grids under optimum conditions. 
In order to produce a plan of the whole site, some additional remote sensing techniques, which allow the interpretation of the 
geomagnetic maps with greater confidence, were used. Of these, GPS is the most important one as it provides detailed information 
about the surface topography so that the relationship between the landscape and the cultural remains may be analysed (Figs. 3a, 7a 
and 8b in Baturayoglu et al.). Another remote sensing methodology applied is balloon photography, which was the major survey tool 
at the beginning of the project (Figs. 2a and 2b in Baturayoglu et al.). 
3. INTEGRATION AND EVALUATION OF THE GEOPHYSICAL DATA 
An image of the geophysical map showing the study area located at the northern section of the site, is aligned and scaled to its origin 
and the visible architectural features are digitised on CAD software. A total of 1512 units of sub-surface features have been 
identified. Digitised features are drawn on the basis of visual interpretation. (Fig. 6c in Baturayoglu et al.) 
The next process is to convert the digitised data from the local grid system to UTM projection. This new file is composed of 
coordinates of the start and end points of vertices (lines). Thus, the digitised features can be integrated with the GPS data, which is 
originally in the UTM projection system. This task was performed by using the “align” tool in AutoCAD software, utilizing the 
“ground control points” as reference points in both local and UTM coordinate systems. 
Proceedings 18 th International Symposium CIPA 2001Potsdam (Germany), September 18 - 21, 2001