Magnetometer array studies

A review of experiments in which arrays of recording magnetometers deployed over an area of land to study induction problems is presented. Intensive array activities take place on a continual basis in North America, Australia, Scotland and Africa and array studies have been conducted in India, Scandinavia, and Russia. The main results are summarised. Analysis, presentation and interpretation of array data have also enjoyed significant developments which are discussed with illustrations. The use of multi-techniques in the analysis of array data has improved the reliability of the interpretational inferences. One-dimensional conductivity profiles can now be deduced by the simple inversion of the inductive response functionC(w, t) estimated from the vertical field Z and spatial gradient of the horizontal field components (ΔX/Δx+ΔY/Δy) of magnetometer array data with large gradient. Bounds can be placed on accepted profiles using the Monte Carlo process just as it is done in magnetotelluric data inversion. The results from array studies continue to improve our understanding of the synthesis of realistic tectonic models of the continents. The structure under some geothermal zones are now known through a number of recent studies.