  $\bullet$ Multiscale model of inner-core anisotropy produced by hcp alloy
deformation$\bullet$ 5 to 20% single-crystal elastic anisotropy and plastic
deformation by pyramidal slip $\bullet$ Low-degree inner-core formation model
with faster crystallization at the equatorThe 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. Conditions for a
successful model are an hexagonal-close-packed structure for the inner-core
Fe-alloy, plastic deformation by pyramidal \textless{}c+a\textgreater{} 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.
