1. 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

2. 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 …

3. Contour line spacing is every 20 deg in epicentral distance

4. Estimated slope is -2.56 for L-curve result in the shaded region

5. Estimated slope is -1.28 for L-curve result in the shaded region

6. 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)