2D Electrical Resistivity Imaging for Lineament Mapping

Lineament mapping plays a major role in analysing structural deformation, and geologic boundaries, and inferring ground strength. Lineament analysis also provides crucial information about subsurface fractures that may be in direct link with hydrogeological interests. As lineaments are a reflection of subsurface occurrences brought about by various deformation processes, regions in the vicinity of lineaments and active faults are potentially weak zones for installing infrastructure thus necessitating its identification. ERI is based on the principle that different geological materials have distinct electrical resistivity values. By measuring the resistivity distribution of the subsurface, ERI allows for the visualization and characterization of lineaments. However, it’s important to take some precautions while taking readings and interpreting the data. The interpretation of resistivity data can be complex, as several factors can influence electrical conductivity, including porosity, moisture content, and mineral composition. Additionally, the resolution of ERI is influenced by factors such as electrode spacing, subsurface heterogeneity, and noise in the data. Careful data acquisition and processing are necessary to mitigate these challenges. To maximize the effectiveness of ERI for lineament mapping, it is often combined with other geophysical techniques or geological data sources. Integration with methods such as ground-penetrating radar (GPR), seismic surveys, or borehole data can provide complementary information, improving the accuracy and interpretation of lineament mapping results. As a result, Electrical Resistivity Imaging (ERI), a well-established, non-invasive geophysical method has been used at two different locations in the current study to locate potential lineaments. Eighteen profiles of 2D Electrical Resistivity Imaging were performed at the first location ‘M1’, along with fifteen profiles at the second location ‘M2’. Data acquisition has been done in two different types of electrode configurations namely Wenner and Wenner-Schlumberger array on natural ground with a constant electrode spacing of 5m. Data processing has been carried out using RES2DINV software. Resistivity results show anomalous zones at various locations in the profiles with very low resistivity values relative to the nearby value range. Electric Resistivity Imaging is used to get a picture of the internal resistivity distribution of the subsurface, understand the internal structure, etc. In the present work, the application of ERI for identifying lineament is discussed as it is essential, particularly during the design and construction stages, to ensure potential hazard mitigation