Reconstructing the Greenʹs function through iteration of correlations

Correlations of ambient seismic noise are now widely used to retrieve the Earth response between two points. In this study, we reconstruct the surface-wave Greenʹs function by iterating the correlation process over the tail of the noise-based correlation function. It has been demonstrated that the so-called C3 function shows the surface-wave part of the Greenʹs function. Using data from 150 continuously recording stations in Europe, the C3 results help in the extraction of the travel-times from noise-based measurements, especially through the suppression of effects caused by non-isotropic source distributions. We present the results of the next iterative step (i.e. C5), which show that some coherent signal is still present in the coda of the C3 function, and we investigate the evolution of the reconstruction of the Greenʹs function throughout the iteration process. Finally, we discuss the interest of combining information from the different correlation functions to improve noise-based tomography analysis.