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Low seismic resolution cannot explain S/P decorrelation in the lower mantle
Author(s) -
Della Mora S.,
Boschi L.,
Tackley P. J.,
Nakagawa T.,
Giardini D.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl047559
Subject(s) - decorrelation , geology , mantle (geology) , seismology , tomography , seismic tomography , homogeneous , geodesy , geophysics , physics , algorithm , statistical physics , mathematics , optics
Inverted models of the deep mantle show a decorrelation between maps of shear V S and compressional V P wave velocities, an anti‐correlation between the bulk sound velocity V ϕ and V S and a much larger variability of V S with respect to V P , expressed by large values of the ratio of their relative lateral variations. We carried out synthetic tests to verify if these features could be artifacts, explained by limits in tomographic resolution: synthetic data are calculated for an “input” model, and linearly inverted, as in tomography, to find an “output” model. Comparing the values of the aforementioned parameters for two different chemically homogeneous input models with the associated reconstructed output ones, we found that artifacts caused by realistic data noise and the nonuniform distribution of seismic sources and stations over the globe are not sufficient to introduce the features previously described. We confirm that compositional effects are required to explain them.