Applications of global optimization in geophysics

Inversion of self potential (SP) and vertical electrical sounding (VES) data was carried out by using three global optimization algorithms including simulated annealing (SA), genetic algorithm (GA) and particle swarm optimization (PSO). Data sets including both synthetic and field data were used for model parameter estimation studies based on SP and VES applications. The model parameters of SP including electrical dipole moment, shape factor, polarization angle and depth were estimated by SA, GA and PSO. Also the parameters of DES anomaly including resistivities and thicknesses of a layered earth model were obtained by GA. The estimated parameters were compared with those from the previous studies based on various optimization algorithms using the same data sets. The test studies based on the global optimization algorithms used in the present study were characterized as being consistent with each other; and they yielded results which are compatible with those from local optimization algorithms.