Chapter 2 - Global particle swarm optimization technique in the interpretation of residual magnetic anomalies due to simple geo-bodies with idealized structure

Abstract

The Global Particle Swarm Optimization (GPSO) method using a MATLAB programme was developed for the interpretation of residual magnetic anomaly data produced by hidden subsurface bodies with simple geometrical bodies such as spheres, horizontal cylinders, and thin dyke and thin sheet-like structures. Inversion parameters such as the depth of the body, the location of the anomaly, amplitude coefficient, effective magnetization angle, and shape factor were inverted. The GPSO inversion method was tested on noise-free synthetic data, synthetic data with 10% Random noise and 20% Gaussian noise and four field examples were interpreted. The inversion results showed excellent fit with the earlier results got using different inversion and interpretation techniques. The present study also shows that the optimization technique is able to delineate all the model parameters correctly when shape factor is fixed. The computation period for GPSO optimization process is very short (less than 1seconds) for a constrained number of swarm sizes. The GPSO method is enormously fast and does not require any suppositions about the nature of the source of the residual magnetic anomaly.