Global seismic noise correlations-Manuscript without peer review 1 Noise-derived broadband full Green functions for a radially layered Earth

Abstract

The emerging noise correlation technique provides a way to approximate the Green function of medium with the correlation function between ambient noise wavefields. It has been recognized that not only the regularly observable seismic phase, but also spurious phases that have no correspondence in real seismograms, are constructed from noise correlations. In this study, we synthesize global noise correlations by stacking the source-wise correlation functions of numerically simulated 10 Green functions for a spherically layered reference Earth model. The inelasticity and discontinuities of the Earth model are well honored. The synthetic data are broadband (3 to 300 s periods; from microseisms to seismic hum) and comprise the full components of the complete empirical Green functions that include all wave types. Comparisons between the results at periods of microseisms and seismic hum reveal that the noise-derived spurious phases should be primarily observable in the microseism period band, so do the core-related reflections and transmissions. Compared to real observations, S-type waves are 15 supposed to be overestimated in the secondary microseism frequency band. The data are publicly accessible from online repository (https://doi.org/10.6084/m9.figshare.8982506) and are promised to serve as reference to real-data noise correlations. The authors expect that the database of reference noise correlations can benefit the research of colleagues from the seismological or the whole solid-Earth community. 20