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

EAR-0003348 NOLET，GuUSTER最近对地震PKP波(穿过地核)到达之前的波的观测表明，散射不仅发生在核-地幔过渡处的D“层，而且可能发生在下地幔的大深度范围内。确定地幔中非均质性的位置和长度尺度对地球动力学和地球化学都具有重要的意义。该项目的目标是通过将多次散射(辐射传输)理论应用于PKP前驱波，而不是使用单次散射(Born)近似来研究地幔散射的起源。在这个项目中，我们的目标是：-开发真实的背景速度变化的辐射传输模型，例如在PREM中的变化。-使用这一现实的公式来探索多次散射的后果，以解释散射波。-利用新的理论工具，反转PKP前体的全球集合，以确定散射的长度、尺度和深度程度。

EAR-0003348Nolet, GuustRecent 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.