Fig. 11

Plot of homogeneity index for stratified core based on Rivoldini et al. (2011) model. The index η _B is 1 for self-compression of a homogeneous substance. The bulk sulfur content is 11 wt%, and T _CMB = 1700 K. This causes the topmost ∼ 500 km of the core to be enriched in sulfur compared to the bulk. The index is approximately 1 in the innermost part of the outer core, but uniformly decreases in the topmost 500 km of the outer core where the sulfur concentration increase changes the wavespeed more strongly than the increase in pressure in a homogeneous material does