Determining sampling spacing according to volume of investigation in geophysical surveys, application of air dose rate mapping

Abstract

SUMMARY Geophysical measurements are a sort of averaging a physical property over a volume of investigation (VOI). Within the VOI, the spatial elements closer to the detector contribute more to the measured value compared to farther elements. In this study, a VOI-oriented algorithm is proposed which establishes a relation between the localization probability, the sampling spacing and the size of the exploration target. Hence, the probability of localizing a target could be calculated as a function of sampling spacing when the target dimension is known. The novelty of this work is the use of VOI in the sampling optimization, which is important for geophysical survey design in environmental sampling and mineral exploration. Although the published sampling optimization methods are often variogram-oriented, the one presented here is based on the spatial variability of the measured property. Finally, coupling the VOI-oriented algorithm with a variogram model could be recommended in order to consider both the measurement mechanism and the spatial variability in the sampling design.