Identification of Sub-Surface Formations in Different Geological Environs Using ERI (Multi Electrodes) at Kadalangudi and Kottuchurry, Cavery Plain Area

Among all geophysical methods, resistivity methods are most widely used in ground water, mineral and oil exploration. The resistivity methods involve passage of current through two iron stakes into the ground and measuring potential by means of two other electrodes. What we measure in these methods is the resistivity of the ground, which we call as ‘apparent resistivity’. Practically a known amount of current (I) is sent into the ground using two metal stakes, called current electrodes, and the potential is measured using other two probes, called potential electrodes. The concept of apparent resistivity arises from the fact that the measured current between the two current (+I, -I) electrodes and voltage between the other two potential (P1 and P2) electrodes which are arranged in different configurations were introduced by various workers over the years in resistivity prospecting. the multi electrodes play a very significant role in the resistivity/IP prospecting, for detecting sub-surface formations and for studying sub-surface geological stratal architecture. In this type of surveys, a number of electrodes are planted on the ground surface maintaining an equal inter-electrode separation. The number of electrodes may be 12,24,48,72 or 96….depending upon type of the measuring system. For the present survey, IRIS make system called SYSCAL Pro-96 has been used for the field and lab studies. Most of the conventional electrode arrays viz., two-electrode, three-electrode, Wenner; Dipole-Dipole etc have been applied in different geological environs.