Near-surface S-wave Estimation base on Inversion of Rayleigh Wave Dispersion Curve Using Genetic Algorithm

Multi-channel analysis of surface wave (MASW) is a suitable technique to infer shallow structure of vertical shear-wave velocity profile from seismic record data. The processing stage is focused on obtaining the reliable dispersion curves, and the final stage of the method is that to obtain the shear velocity model that can explain the observation. The genetic algorithm (GA) method, one of the global optimization approaches, has been implemented to obtain shear wave model from Rayleigh wave dispersion curve. The GA method mimic biological evolution in order to obtain the optimum solution. Application of GA method to two synthetic models for normal velocity profile and low velocity anomaly give good results indicated with small misfit. Finally, we demonstrate the GA to Rayleigh dispersion curve for real data which calculated by using phase-shift method. (paper)