Predominance of long-wavelength heterogeneity in the mantle

Analysis of travel-time anomalies of long-period shear waves recorded by the Global Digital Seismographic Network indicates that mantle heterogeneities, which probably reflect patterns of mantle convection, occur most prominently on length scales greater than about 6,000 km, when projected onto a two-dimensional map at the Earth's surface. Models of mantle convection will need to be able to produce a similar power spectrum.

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