Determination of optimum residual gravity anomalies for mineral exploration: a least squares collocation approach

Abstract

Analysis of gravity anomalies, measured on the earth's surface, can reveal information on sub-surface structures of the earth. The first step in this analysis is to extract residual gravity anomalies (needed for mineral exploration) from the observed gravity anomalies. Currently, a classical least squares technique is used to achieve this aim. However, this technique does not produce optimum results because it assumes that the observed gravity anomalies used for the computation of residual gravity anomalies are error free, whereas, all observed quantities are affected by random errors. In this study, an attempt was made to extract the residual gravity anomalies from the observed gravity anomalies using a least squares collocation technique. The least squares collocation technique was considered to be a better alternative because its formulation takes the presence of random errors of observations in the observed quantities into consideration and makes provision for filtering out the errors from the observed quantities while predicting the needed signals at the required number of points.