Electrical resistivity tomography modelling studies using gradient configurations in archaeological site investigation

Electrical Resistivity Tomography (ERT) is a widely used geophysical method for investigating near-surface structures. In this study, some archeological structures were modeled theoretically using the gradient array in ERT method. Synthetic subsurface models are designed with RES2DMOD program. The thesis includes synthetic and archaeological models. In this study applied to synthetic models, four models are considered in order to determine the responses of the depth, structure size, structure and environment in the case of resistive or conductive. In the first part of our modeling studies applied to archaeological structures, there are structures with different resistivity values in a semi-infinite environment. In the second model, there are structures with different resistivity values in a layer above the half-space layer. Synthetic data sets with noise-free and 5 percent noise were created for each model. The data obtained by the modeling process were inverted. The RES2DINV program was used for the inversion process. The results were evaluated by calculating the data and model misfit values for each iteration and observing the variations of these values according to the iteration step. The results obtained with gradient array are compared with other commonly used arrays. The difference in resistivity between the archaeological structure and the covering soil suggests that the ERT method provides successful subsurface models. Gradient array gave good results in high resistivity structures, while this array did not produce satisfactory subsurface images for low resistivity structures. As a result, although the gradient array is not a widely used array type in ERT studies, it is a type of array that yields good results especially when high resistivity structures are determined.