Global Seismic Tomography and Implications for the Composition and Evolution of Earth

该项目将继续调查地球深部的结构和演化。这项研究将建立在以前的高分辨率全球地震模型的基础上，这些模型已经证明，许多俯冲的岩石圈板块已经沉入下地幔。这项研究将通过以下方式改进地震波速模型：1)通过新数据(例如基于波形的PP、PKP、PCP和PDIFF数据)增强数据覆盖范围，并通过使用真实的3D灵敏度核来考虑有限的频率影响；2)使模型与地球自由振荡的观测频率漂移兼容；3)使用数据来约束整体声速和波速比(例如泊松比)的变化；以及4)在优化数据覆盖范围后，使用灵活的参数化来解析采样良好的区域中的小尺度结构。拟议的工作还将获得对不确定性的定量估计。对于选定的区域，PI将与同事合作，通过整合高分辨率成像、波形建模、详细的板块重建和数值流动计算，详细研究跨越上、下地幔过渡带的地幔流动。

This project will continue investigation into the structure and evolution of the Earth's deep interior. The research will build on previous high-resolution global seismic models that have demonstrated the many slabs of subducted lithosphere have sunk into the lower mantle. The research will improve seismic wavespeed models by 1) enhancing data coverage with new data (e.g., waveform based PP, PKP, PcP, and Pdiff data) and by using realistic 3D sensitivity kernels to account for finite frequency effects, 2) make models compatible with observed frequency shifts of the Earth's free oscillations, 3) use data to constrain variations in bulk sound speed and wavespeed ratios (e.g., Poisson's ratio), and 4) after having optimized data coverage, use a flexible parameterization to resolve small scale structure in well sampled region. The proposed work would also obtain quantitative estimates of uncertainties. For selected regions, the PI will collaborate with colleagues to study mantle flow across the upper and lower mantle transition zones in detail by integrating high-resolution imaging, waveform modeling, detailed plate reconstructions, and numerical flow calculations.