The structure of the core-mantle boundary from diffracted waves

M. E. Wysession, E. A. Okal, C. R. Bina

Research output: Contribution to journalArticle

80 Scopus citations


Diffracted P and S waves (Pd, Sd) traveling around the core-mantle boundary (CMB) of the Earth give us information about the velocity structure and therefore the thermochemistry of D″, the base of the Earth's mantle. By examining Pd and Sd arrivals, the apparent ray parameter for different regions at the base of the mantle were determined. By comparing the data slownesses to those found from reflectivity synthetic seismograms it was possible to quantify D″ average velocities. Using these averaged velocities with a thermochemical modeling of lower mantle minerals using a Birch-Murnaghan equation of state, it has been possible to make chemical and physical inferences as to the causes of lateral variations at the CMB. Thermochemical modeling suggests that the D″ Poisson ratio is very sensitive to variations in the silicate/oxide ratio and that a decrease in the amount of perovskite relative to magnesiowustite may play an important role in this region. -from Authors

Original languageEnglish (US)
Pages (from-to)8749-8764
Number of pages16
JournalJournal of Geophysical Research
Issue numberB6
StatePublished - Jan 1 1992

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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