Improving local and regional earthquake locations using an advance inversion Technique: Particle swarm optimization∗

The estimation of the hypocentral parameters in seismology has remained as one of the beststudied and challenging problem. In this paper a simple procedure has been presented to obtain the improved locations of local and regional earthquakes with advance inversion technique with minimum seismograph recording geometry. The problem is formulated as a nonlinear optimization problem in which the decision variables are the hypocentral parameters and the objective function to be minimized is the sum of squares of the differences between the observed and calculated times at specified locations. The objective of this paper is demonstrating the use of the latest heuristic technique for optimization namely “Particle Swarm Optimization” for solving the stated inversion problem. The earthquakes have triggered and recorded in NW Himalayan region are taken for experiments. The results obtained are discussed in this paper.