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A regularized inversion with a smoothing (SM) stabilizer is commonly used in 3D inversion of direct-current (DC) resistivity data. We have developed a new 3D inversion algorithm for DC resistivity data to investigate the efficiency of various stabilizing functionals. This algorithm is capable of incorporating 3D regularized inversion with [Formula: see text]-norm, [Formula: see text]-norm, SM, minimum support (MS), minimum gradient support (MGS), first-order minimum entropy, and total variation (TV) stabilizers. This is, to our knowledge, a comprehensive study of the effects of these seven different stabilizers on the inverse solution using synthetic and field data. As expected, the structure boundaries are found to be smooth when a SM stabilizer is used in the synthetic data examples. The upper bounds of the structures are recovered close to true model with [Formula: see text]-norm, [Formula: see text]-norm, first-order minimum entropy, and TV stabilizers, but the lower bounds cannot be recovered. Moreover, these stabilizers cannot completely resolve the resistivity of structures. The boundaries and resistivity of the structures are determined to be close to the true model with MS and MGS stabilizers. Similar results are obtained from inversions of field data collected in the Kültepe archaeological site (Kayseri, Turkey). A buried wall structure is correctly identified when the inversion used MS or MGS stabilizers. The archaeological structure found in the excavation studies reveals the success of the solution using MS and MGS stabilizers. These two stabilizers are recommended for an exploration of sharp boundaries structures.

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In this study, we investigated the Kuriki Mound Area using direct current resistivity and magnetometry. The investigation site is considered the first settlement area and is dated to four thousand years. The purpose of the geophysical study was to direct the excavation and to rescue the historical heritage, which will be flooded due to a dam to be constructed in the region. The resistivity data that were measured in the field along parallel lines were interpreted using 2D and 3D inversion algorithms and we investigated the deficiencies of 2D inversion compared to the 3D inversion. Moreover, we identified anomalous zones very clearly by applying a tangent hyperbolic filter to the magnetic gradiometer data. Regions with anomalies identified with both geophysical methods were excavated, and remains from 4th to 1st millennium BC were found. Furthermore, we discovered that there were no connecting structures between the two mounds, therefore preventing an unnecessary and large-scale excavation.

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