Deformation of the lowermost mantle from seismic anisotropy
نویسندگان
چکیده
منابع مشابه
Seismic anisotropy in the lowermost mantle near the Perm Anomaly
The lower mantle is dominated by two large structures with anomalously low shear wave velocities, known as Large Low-Shear Velocity Provinces (LLSVPs). Several studies have documented evidence for strong seismic anisotropy at the base of the mantle near the edges of the African LLSVP. Recent work has identified a smaller structure with similar low-shear wave velocities beneath Eurasia, dubbed t...
متن کاملVariable azimuthal anisotropy in Earth's lowermost mantle.
A persistent reversal in the expected polarity of the initiation of vertically polarized shear waves that graze the D'' layer (the layer at the boundary between the outer core and the lower mantle of Earth) in some regions starts at the arrival time of horizontally polarized shear waves. Full waveform modeling of the split shear waves for paths beneath the Caribbean requires azimuthal anisotrop...
متن کاملLowermost mantle anisotropy and deformation along the boundary of the African LLSVP
Shear wave splitting of SK(K)S phases is often used to examine upper mantle anisotropy. In specific cases, however, splitting of these phases may reflect anisotropy in the lowermost mantle. Here we present SKS and SKKS splitting measurements for 233 event-station pairs at 34 seismic stations that sample D′′ beneath Africa. Of these, 36 pairs show significantly different splitting between the tw...
متن کاملPost - Perovskite in the Lowermost Mantle Anticorrelated Seismic Velocity
www.sciencemag.org (this information is current as of July 7, 2008 ): The following resources related to this article are available online at http://www.sciencemag.org/cgi/content/full/320/5879/1070 version of this article at: including high-resolution figures, can be found in the online Updated information and services, http://www.sciencemag.org/cgi/content/full/320/5879/1070/DC1 can be found ...
متن کاملMantle dynamics and seismic anisotropy
a r t i c l e i n f o Keywords: seismic anisotropy mantle flow geodynamic modeling shear wave splitting surface wave analysis mantle convection Observations of seismic anisotropy yield some of the most direct constraints available on both past and present-day deformation in the Earth's mantle. Insight into the character of mantle flow can also be gained from the geodynamical modeling of mantle ...
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ژورنال
عنوان ژورنال: Nature
سال: 2010
ISSN: 0028-0836,1476-4687
DOI: 10.1038/nature09507