Length scales of mantle heterogeneities from seismological perspective Yingcai Zheng w/ input from Ru-shan Wu and Thorne Lay University of California, Santa Cruz k P(k) Large scale ~100s-1000s km Small/medium scale ~10s km Fine scale, ~1km ? ? ? Seismic velocity heterogeneities: Scale issue
Observational geometry: wavefront “distortion” of a teleseismic plane wave logA(x) ϕ(x) Chernov,1950; Tatarskii 1971); Aki (1973) and others; Flatte and Wu (1988); Zheng, Wu, Lay (2007), Zheng and Wu (2008). Incomplete …
Contour line spacing is every 20 deg in epicentral distance
Estimated slope is -2.56 for L-curve result in the shaded region
Estimated slope is -1.28 for L-curve result in the shaded region
Implications to CIDER inter-disciplinary investigation Based on the seismic results: size and strength of the multiscale heterogeneities, likely to be compositional. Assuming the origin of the heterogeneity,e.g., oceanic crust long-term evolution of the Earth’s interior: vol. of the subducted oceanic crust retained in the mantle; layering of the heterogeneity and multiscale spectra of the heterogeneity (CONVECTION) mixing model of the mantle (PETRO) Compare with spectra of isotopic ratios along ocean ridges with seismic heterogeneity spectra (GEOCHEM)