Detecting small‐scale targets by the 2D inversion of two‐sided three‐electrode data: application to an archaeological survey

The detecting capabilities of some electrical arrays for the estimation of position, size and depth of small‐scale targets were examined in view of the results obtained from 2D inversions of apparent‐resistivity data. The two‐sided three‐electrode apparent‐resistivity data are obtained by the application of left‐ and right‐hand pole–dipole arrays that also permit the computation of four‐electrode and dipole–dipole apparent‐resistivity values without actually measuring them. Synthetic apparent‐resistivity data sets of the dipole–dipole, four‐electrode and two‐sided three‐electrode arrays are calculated for models that simulate buried tombs. The results of two‐dimensional inversions are compared with regard to the resolution in detecting the exact location, size and depth of the target, showing some advantage for the two‐sided three‐electrode array. A field application was carried out in the archaeological site known as Alaca Hoyuk, a religious temple area of the Hittite period. The two‐dimensional inversion of the two‐sided three‐electrode apparent‐resistivity data has led to locating a part of the city wall and a buried small room. The validity of the interpretation has been checked against the results of subsequent archaeological excavations.