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| Titel |
A multiscale model of Earth's inner-core anisotropy |
| VerfasserIn |
Sébastien Merkel, Ainhoa Lincot, Renaud Deguen, Philippe Cardin |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250125541
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| Publikation (Nr.) |
 EGU/EGU2016-5130.pdf |
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| Zusammenfassung |
| The Earth’s solid inner-core exhibits a global seismic anisotropy of several percents. It results
from a coherent alignment of anisotropic Fe-alloy crystals through the inner-core history that
can be sampled by present-day seismic observations. By combining self-consistent
polycrystal plasticity, inner-core formation models, Monte-Carlo search for elastic moduli,
and simulations of seismic measurements, we introduce a multiscale model that can
reproduce a global seismic anisotropy of several percents aligned with the Earth’s rotation
axis. Cubic-structured Fe-alloy fail at producing significant global scale anisotropy.
Conditions for a successful model are an hexagonal-close-packed structure for the inner-core
Fe-alloy, plastic deformation by pyramidal ⟨c + a⟩ slip, and large-scale flow induced by a
low-degree inner-core formation model. For global anisotropies ranging between 1 and 3%,
the elastic anisotropy in the single crystal ranges from 5 to 20% with larger velocities along
the c-axis. |
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