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Anisotropic seismic structure of the lithosphere beneath the Adriatic coast of Italy constrained with mode‐converted body waves
Author(s) -
Levin Vadim,
Margheriti Lucia,
Park Jeffrey,
Amato Alessandro
Publication year - 2002
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 - 10.1029/2002gl015438
Subject(s) - geology , lithosphere , seismology , lineation , seismic anisotropy , anisotropy , crust , mantle (geology) , geophysics , shear wave splitting , receiver function , shear (geology) , slab , seismic array , petrology , tectonics , physics , quantum mechanics
P S converted waves observed near Ancona on the Adriatic coast of central Italy, as revealed by teleseismic receiver functions (RFs), vary with earthquake back‐azimuth and epicentral distance in a manner consistent with a 1‐D anisotropic seismic structure. Using reflectivity calculations, we develop a profile of anisotropic seismic velocity through the Adriatic lithosphere at this locality. We infer crustal thickness of ∼45 km. Anisotropy within the crust appears at ∼15‐km depth, suggesting a decollement between the subducting Adriatic lithosphere and the overriding crustal wedge. Lineation of inferred rock fabric is compatible with simple shear in ENE‐WSW direction. In the upper mantle, we infer an anisotropic layer at 80–90 km depth. If caused by olivine crystals alignment, the nearly north‐south lineation of the inferred rock fabric would be consistent with some nearby shear‐wave splitting observations. This anisotropic layer may be related to mantle deformation induced by the rollback of Adriatic lithosphere.