Fig. 5
From: Subducted oceanic crust as the origin of seismically slow lower-mantle structures
Power spectral density plots for S40RTS and the tomographically filtered models as imaged beneath the Pacific plate. Spectral power is normalized to the maximum power at each depth and plotted as a function of wavenumber and radius. High power at low wavenumbers characterize the lower mantle in S40RTS and the filtered geodynamic models when δρ≥3.1%. This is due to the formation of large thermochemical structures at this density contrast. Below this value, power in the lower mantle is more randomly distributed across high and low wavenumbers due to a lack of broad-scale structure. The upper mantle of all geodynamic models contains more power at higher wavenumbers compared to S40RTS