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| Titel |
Evidence for a change in the global shear velocity pattern ∼ 1,000 km depth |
| VerfasserIn |
Stephanie Durand, Eric Debayle, Yanick Ricard, Christophe Zaroli, Sophie Lambotte |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250137461
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| Publikation (Nr.) |
 EGU/EGU2017-181.pdf |
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| Zusammenfassung |
| In this study, we show evidence for a change in the shear velocity spectrum around 1,000 km
depth based on a new shear velocity tomographic model of the Earth’s mantle, SEISGLOB2.
SEISGLOB2 is based on Rayleigh surface wave phase velocities, self- and cross-coupling
structure coefficients of spheroidal normal modes and body wave travel times which are, for
the first time, combined in a tomographic inversion. SEISGLOB2 is developed up to
spherical harmonic degree 40 and in 21 spline functions. The spectrum of SEISGLOB2
shows it is the flattest around 1,000 km depth and this flattening occurs between 800 and
1,500 km depth. The presence of such a transition in the spectrum suggests an accumulation
of shorter scale heterogeneities at around 1,000 km depth. This change in the spectrum
is also observed when looking at the model, where some behaviour changes of
slabs, hotspots and LLSVPs occur around 1,000 km depth. The existence of such a
velocity change in the mid-mantle can have great impacts on our understanding of
the mantle dynamics and should thus be taken into account in future modeling. |
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