'Granular is the Mantle, Really?' - Multiple Scattering Analysis of PKP Precursors

Princeton University, Princeton NJ

Investigators

Abstract

EAR-0003348 Nolet, Guust Recent observations of waves preceding the arrival of seismic PKP waves (that traverse the Earth's core) suggest that scattering not only occurs in the D" layer at the core-mantle transition, but may occur over a wide depth range in the lower mantle. Determining the location and length scales of inhomogeneities in the mantle has important implications for both geodynamics and geochemistry. The goal of this project is to study the origin of scattering in the Earth's mantle by applying multiple scattering (radiative transfer) theory to PKP precursive waves, rather than with the single scattering (Born) approximation. In this project we aim to: - Develop radiative transfer modeling for realistic variations of the background velocity, such as those in PREM. - Use this realistic formulation to explore the consequences of multiple scattering for the interpretation of scattered waves. - Invert a global collection of PKP precursors for the length scales and depth extent of scattering using the new theoretical tools.