Usage of the self‐potential (SP) method on archaeological sites has been very limited and the phenomena that form the SP anomalies are not very well known. We believe that the vertical capillary water flows around stone walls that can be encountered frequently in archaeological sites, the porosity of the soil surrounding the archaeological structures, the moisture and clay ratio of the soil, and the changes in pH value of the soil, may form the SP anomalies. Moreover, an SP anomaly also may be formed if there is a moisture condition cutting the sulphuric and oxidized deposits under the earth. We determined, by our research, that the SP method can be very important, especially for determining the soil distribution and for archaeological research. The study was carried out on an Assyrian Tread Colony Period artificial hill in Acemhöyük, the chemical and physical structure of which was changed significantly after a large fire in approximately 1789±50 bc. The structure boundaries were found by interpreting the anomalies obtained from analytical modelling techniques, and an analysis of the SP mechanism of the area was attempted. In addition, the noise on the anomalies was eliminated by signal analysis techniques, thus enabling us to interpret the results more precisely. © 1996 John Wiley & Sons, Ltd.