Abstract
Statistical properties of small-scale inhomogeneities (wavelengths between 20 and 70 km) near the core-mantle boundary are inferred from scattered core waves. Observations of scattered core waves at large seismic arrays and worldwide networks indicate that the inhomogeneities have a global nature with similar characteristics. However, there may exist a few regions having markedly stronger or weaker strengths. Scattering by volumetric inhomogeneities of about 1% inP-wave velocity in the lower mantle or by about 300 m of topographic relief of the core-mantle boundary can explain the observations. At present it is not possible to rule out either of these two alternatives, or a combination of both.
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Bataille, K., Wu, R.S. & Flatté, S.M. Inhomogeneities near the core-mantle boundary evidenced from scattered waves: A review. PAGEOPH 132, 151–173 (1990). https://doi.org/10.1007/BF00874361
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DOI: https://doi.org/10.1007/BF00874361