Using electrical resistivity tomography to evaluate the relationship between groundwater potencial and tectonism in northeast Mexico

Abstract

The relationship between groundwater potential and tectonic conditions in three sectors of clastic and carbonated sedimentary rocks of northeastern Mexico was identified using electrical resistivity tomography performed in seven transects. The electrical resistivity data were measured using Schlumberger, Wenner and dipole-dipole arrays of the electrodes. Subsequently, the data obtained were combined to carry out a 2D inversion. From interpretation of the electrical resistivity tomography data, several aquifers are located and characterized within varying thicknesses of conglomerates, sandstones and limestones. Additionally, fractures, faults and boundaries between rock types are identified in the obtained 2D models. These structural elements indicate that the aquifers have a strong relationship with the tectonism of the region. Depressed and uplifted blocks are generated through normal faults. The orientations of the inferred fractures and faults fit the structural characteristics of the study region. The aquifers are classified as semi-confined and confined. In clastic materials, these aquifers are classified as granular, while in limestone, they are mainly fractured. Fracture zones that connect most of the aquifers and connect the aquifers with the ground surface are also identified using electrical resistivity tomography. These zones can constitute the main recharge (including contamination) paths to the aquifers. This pollution can be related to livestock and industrial activities, as well as agriculture and mining in the region. Using these results, water wells were drilled to corroborate the identified aquifers.