Application of the normalized full gradient (NFG) method to resistivity data

Abstract

This paper proposes the application of the normalized full gradient (NFG) method to resistivity studies and illustrates that the method can greatly reduce the time and work load needed in detecting buried bodies using resistivity measurement. The NFG method calculates resistivity values at desired electrode offsets by extrapolation of a function of resistivity measurements (i.e. the gradient) to other depth levels using resistivity measurements done at one electrode offset only. The performance and reliability of the NFG method is tested on laboratory and field resistivity data from two sites by comparing the trend of the resistivity values at six or more electrode offsets, with the trend calculated at the same electrode offsets using the NFG method. The first area is in Rize (NE Turkey) where a resistivity survey was conducted to locate a metal tailings pipeline in unconsolidated gravel deposited by a nearby stream. The second field site is in Trabzon (NE Turkey), where the purpose of the resistivity survey was to map the boundaries of a landslide in clay, marl and geologic units. © TÜBİTAK.