Archeogeophysical application of non-traditional geoelectric arrays. A case study in a north-east Hungary site

Abstract

With the continuous development of multielectrode geoelectrical tomography (ERT) as a geophysical technique, we became able to detect small size targets. In this paper, we present ERT interpretation results obtained at an archaeological site in Szendrő village in northeastern Hungary, where a 17th century fortress once stood. Several historical notes and a collapsed entrance recall the existence of tunnels under the fortress and a water well of uncertain depth. To detect these structures, geoelectrical multielectrode measurements were carried out using conventional and quasi-null arrays. The quasi-null array applies the arrangement of the current (A and B) and potential electrodes (M and N) in a special way, i.e., the electrodes A, M, B, N follow each other in line in special distances from each other. The horizontal sensitivity of the resistivity profiling method using these types of arrays has been proven to be better than that of the Wenner or other conventional arrays. The comparative study aims not just to investigate the archeological features, but to test the sensitivity of the non-traditional quasi-null arrays to these two-dimensional inhomogeneities. As a result, the optimal array can be chosen, and the identification and delineation of shallow structures can be made more reliably. In this paper, we present the very first archeogeophysical field measurements carried out by the gamma quasi null array (γqnull).