Delineate subsurface lithology and groundwater investigation of Ongur Sub Basin, South India

Abstract

The electrical resistivity method is extremely useful to investigate the nature of subsurface formations by studying the variations in their electrical properties. This method assumed considerable importance in subsurface exploration because of very good resistivity contrasts among the lithological units, controlled depth of investigation, ease of field operations and low cost of instrumentation and operation. The Vertical Electrical Sounding (VES) method by Schlumberger electrode array applied in 77 Locations at Ongur River Sub Basin in Tamil Nadu, India. The Signal stacking Resistivity Meter Model SSR-MP-ATS was used to collect the VES data by employed a Schlumberger electrode configuration, with one side current electrode spacing (AB/2) ranging from 1 to 100 m and the potential electrode (MN) from 0.5 to 10 m. The concept of the VES data interpreting is the foundation of IPI2Win. It means for a VES data are treated as a unity representing the geological structure of the Ongur River watershed. The output Geo-electrical layers with iso- resistivities and thickness in spatial maps by using ARCGIS software were created. Accordingly, the following zones with different resistivity values were detected, corresponding to different formations: (1) identification of lithologyOngur River Sub Basin, (2) strata’s saturated with fresh groundwater, (3) determine saltwater horizon.