Imaging subsurface fracture characteristics using Electrical Resistivity Tomography: A case study in Dougherty County, southwest Georgia

This study employed Electrical Resistivity Tomography (ERT) to investigate the correlation between lineaments and subsurface bedrock fractures within the Ocala Limestone in Dougherty County, southwest Georgia. Borehole geophysical logs were analyzed to guide survey site selection and served as reference data for simulating ERT field responses. Synthetic data generated from these forward models helped determine the dipole-dipole as the suitable array for the ERT survey. Seven surveys were carried out using this array, of which six were across mapped lineaments. Of these six surveys, only one showed evidence of a potential fracture within the Ocala limestone. While remote sensing techniques such as aerial photographs are useful for identifying potential fractures through lineament mapping, they provide limited field evidence regarding the precise location of these fractures. Interpretations from the inverted sections also revealed lentiform features within the upper unit of the Ocala limestone, suggesting the presence of water filled or clay-filled cavities.