Comparison between multiple gradient and pole dipole array protocols for groundwater exploration in quaternary formation

Abstract

The demand for groundwater supply has been increasing in recent year. In the past, Electrical Resistivity Method has been one of the well-known non-destructive methods for groundwater surveying using various protocols to obtain the tomography of the soil subsurface. This study interpreted the difference of imaging results between two different protocols, the Pole-dipole array and the Multiple Gradient array using ABEM TERRAMETER LS 2 due to the complexity of geological setting. The geophysical survey shows the imaging result of the resistivity and induced polarization for the Pole-dipole array that differs from the imaging results from Multiple Gradient array because of the different path the electric current C2 passing through different soil types before reaching to the other side of the current electrode C1. The positioning of the remote cable was practically perpendicular to the alignment of the electrode spacing for Pole-dipole and parallel for Multiple Gradient array and this causes the data collected at both protocols to have different values because of the difference in composition of soil that the current has to go through. This study has verified the differences of resistivity and induced polarization imaging results by using a drilled tube well to identify the soil types.