Apparent Splitting of S Waves Propagating Through an Isotropic Lowermost Mantle.

ABSTRACT: Observations of shear wave anisotropy are key for understanding the mineralogical structure and flow in the mantle. Several researchers have reported the presence of seismic anisotropy in the lowermost 150-250 km of the mantle (i.e., D '' layer), based on differences in the arrival times of vertically (SV) and horizontally (SH) polarized shear waves. By computing waveforms at a period > 6 s for a wide range of 1-D and 3-D Earth structures, we illustrate that a time shift (i.e., apparent splitting) between SV and SH may appear in purely isotropic simulations. This may be misinterpreted as shear wave anisotropy. For near-surface earthquakes, apparent shear wave splitting can result from the interference of S with the surface refl

SUBMITTER: Parisi L 

PROVIDER: S-EPMC6049884 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature