The aim of the study is find out the groundwater potential in the granite and quartzite terrain in the Thoothukudi District using Azimuthal Square Array (DC) electrical resistivity method. The case study carried out in Mangalagiri (Quartzite terrain), Kovilpatti(Quartzite, weathered gneiss), Chandragiri (Weahtered gneiss and granite rock) is occurred in the geological formation of Archaen age. The Square array electrical resistivity methods were carried out in field using CRM-500 electrical resistivity meter, wire spool, electrodes with square array configuration. The depth of penetration ‘a’ is equal to the length of electrode spacing. The collected resistivity data was processed by the formula and calculate the apparent resistivity, anisotropy and lithostratigraphy of the study area. The fault zone direction was identified in the study area by using the azimuthal polar plots and curve matching techniques. The obtained apparent resistivity is ranging from 1-50,soil and Caliche deposits, quartzite 50-100 Ohm.m and freshwater apparent resistivity 100-120 ohm.m.
