A novel hybrid PSO/simplex algorithm for determining earthquake source parameters using InSAR observations

Abstract

The paper presents a Paticles Swarm Optimization (PSO) and Simplex integrated approach to determine source parameters using InSAR data. In earthquake source parameter inversion, thereare differences in the sensitivity of different parameters to the objective function and a trade-off between the fault area and slip. We proposed that: (1) a local PSO algorithm is employed to perform a global search,(2) a 1-D Probability Desity Function (PDF) is utilized to describe the local minimum in the full parameters space, which is automatically recognized as the initial model in the Simplex algorithm inversion. The PSO/Simplex integrated approach has been successfully applied to three different earthquakes: the 2003 Bam (Iran) earthquake (strike-slip), the 1998 Zhangbei (China) earthquake (dip-slip), and a simulated event with a normal fault with right-lateral slips. All the case studies sugguest the robustness and reliability of the integrated approach.