Global imaging of the Earth's deep interior: seismic constraints on (an)isotropy, density and attenuation

Abstract

Seismic tomography is the principal tool to probe the deep interior of the Earth. Models of seismic anisotropy induced by crystal alignment provide insight into the underlying convective motion, and variations of density allow us to discriminate between thermal and compositional heterogeneities. This chapter reviews on which class of models there is agreement and where further investigation is required. The main emphasis is on the imaging itself and not so much its thermo-chemical interpretation, although the chapter provides some indications. It also discusses the case of isotropic velocity tomography, anisotropy, density and attenuation imaging in decreasing order of consensus. Finally, it provides some suggestions for future work.