Evaluation of Dispersion Diagrams Distances Based on Usual Histogram Analysis for the Surface Wave Difference Inversion

Summary In some recent geophysical monitoring studies, researchers have proposed a method of difference inversion, which means taking the difference between data into inversion process. It overcomes the crucial problem of the initial model for local optimization and reduce the environmental or system error in the results. Until now, there has not been an application of this method in the global inversion of Seismic Surface Waves. However using directly the difference between the dispersion curves as the data to be inverted can be not robust. Here, we propose to calculate differences between dispersion diagrams, which contains a part of the measurement uncertainty. Based on histograms distances definitions, several diagram distance calculations are used and tested numerically and experimentally in order to study the impact of the distance definition on the misfit assessment in case of a small variation about 10% in a deep part of a 2-layer medium. Results show the feasibility of this method. even if the accuracy of the the inversion result of the preliminary part remains a key issue on the assessment of medium’s variation.