Delineating and modelling an underground water conduit by scattered micro-gravity data and electrical resistivity sounding

Abstract

Scattered micro-gravity data and electrical resistivity sounding are used in a very rough terrain area to delineate the underground water conduit in a karst zone.A dense digital terrain model is used to compute terrain corrections and Bouguer gravity anomalies. Residual gravity anomalies are computed by the polynomial fitting method. The sun shading filter and first vertical derivatives are applied to residual anomalies to delineate the conduit.The karst zone including the conduit is modelled by the well known Marqurt-Levenberg inversion technique. An electrical resistivity survey has also been carried out. The results of electrical soundings confirm the existence of a high-resistivity layer cut by a low-resistivity channel at the depth estimated through micro-gravity data.