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

全球地震层析成像及其对地球构成和演化的影响

• 批准号: 9909492
• 负责人: Robert van der Hilst
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-15 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9909492&HistoricalAwards=false
• 关键词: Global; Seismic; Tomography; Implications; Composition

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.

该项目将继续调查地球深处的结构和演化。 这项研究将建立在之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岩石圈板片已经沉入下地幔中。 该研究将通过以下方式改进地震波速模型：1）使用新数据（例如基于波形的 PP、PKP、PcP 和 Pdiff 数据）增强数据覆盖范围，并使用真实的 3D 灵敏度内核来解释有限频率效应，2）使模型兼容通过观测到的地球自由振荡的频移，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)优化数据覆盖范围后，使用灵活的参数化来解决采样良好区域中的小尺度结构。 拟议的工作还将获得不确定性的定量估计。 对于选定的区域，PI 将与同事合作，通过集成高分辨率成像、波形建模、详细板块重建和数值流计算，详细研究跨越上地幔和下地幔过渡区的地幔流。