ERT METHOD FOR THE DETECTION OF BURIED ARCHAEOLOGICAL OBJECTS IN APOLLONIA & BYLIS, ALBANIA

During the period 2010-2011 geoelectric surveys using Electrical Resistance Tomography (ERT) method, have been applied on two archeological sites of Albania, Apollonia and Bylis. The purpose of this study was the detection of the cultural layer and the underground archeological buried features from the spatial distribution of true resistivity values. The geoelectric surveys were carried out throughout very dense 2-D ERT parallel profiles 1.5m from each other, with electrodes spaced apart by 1m. The squares were surveyed using two geometric configurations: Wenner and dipole dipole arrays. The collected data were interpreted with use of the inversion resistivity method. True resistivity of the subsurface was obtained, with use of nonlinear equations defined with the least-squares inversion method, from the measured apparent resistivity values. 3-D interpretation of profiles was carried out and maps of different depths were compiled. The use of both arrays helps to better understand the spatial extent of archaeological featured from taken resistivity anomalies. The true resistivity models taken from the inversion of apparent resistivity measurements from both arrays, show little changes. The ERT method was found to delineate very well a thickness of cultural layer and buried archaeological objects inside it. The cultural layer on Bylis is depicted with lower resistivity values than the basement which is limestone, while the cultural layer in Apollonia has higher resistivity values than the basement which is clay-sand layer.