Thorsten W. Becker , Sergei Lebedev

Seismic anisotropy records continental dynamics in the crust and
convective deformation in the mantle. Deciphering this archive holds
huge promise for our understanding of the thermo-chemical evolution of
our planet, but doing so is complicated by incomplete imaging and
non-unique interpretations. Here, we focus on the upper mantle and
review seismological and laboratory constraints as well as geodynamic
models of anisotropy within a dynamic framework. Mantle circulation
models are able to explain the character and pattern of azimuthal
anisotropy within and below oceanic plates at the largest
scales. Using inferences based on such models provides key constraints
on convection, including plate-mantle force transmission, the
viscosity of the asthenosphere, absolute plate motion reference
frames, and net rotation of the lithosphere. Regionally, anisotropy
can help further resolve smaller-scale convection, e.g.\ due to slabs
and plumes in active tectonic settings. However, the story is more
complex particularly for continental lithosphere, and many systematic
relationships remain to be established more firmly. More integrated
approaches based on new laboratory experiments, consideration of a
wide range of geological and geophysical constraints, as well as
hypothesis-driven seismological inversions are required to advance to
the next level.