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Shallow anisotropy in the Mediterranean mantle from surface waves
Author(s) -
Marone F.,
van der Lee S.,
Giardini D.
Publication year - 2004
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 - 10.1029/2003gl018948
Subject(s) - anisotropy , geology , rayleigh wave , seismogram , isotropy , rayleigh scattering , microseism , love wave , seismic anisotropy , geophysics , seismology , mantle (geology) , superposition principle , polarization (electrochemistry) , mediterranean climate , mediterranean sea , surface wave , physics , optics , wave propagation , longitudinal wave , mechanical wave , geography , chemistry , archaeology , quantum mechanics
We present new evidence for the existence of the Love‐Rayleigh discrepancy in the Mediterranean region and constrain the average polarization anisotropic structure of the Mediterranean mantle. We analysed regional Rayleigh and Love waveforms recorded at 3‐component broadband seismic stations. None of the 3‐component seismograms could be fit with a single 1D isotropic and smooth velocity model. However, satisfactory fits for individual Rayleigh and Love waveforms could often be obtained using realistic 1D velocity models. We used these 1D path‐average velocity structures to derive 3D S ‐velocity models for the Mediterranean region. Our results show that Love waves require higher velocities (about 200 m/s) compared to Rayleigh waves between 30 and 120 km depth. We relate the observed anisotropy to lattice‐preferred orientation of crystallographic axes of elastically anisotropic minerals such as olivine.