Investigation of Global Scale Seismic Mantle and Core Structure Using Forward and Inverse Approaches

这笔赠款将支持一项利用地震学方法在全球范围内调查地幔和地核的横向非均质性的计划。这项研究计划有两个主要组成部分。首先是全球地震波层析成像和相关的正演模拟。全球地震层析成像可以对一些关键的地幔动力学问题提供约束，如：俯冲板块的命运、D“作为热力边界层的作用、地幔羽流的起源深度和在全球环流中的作用、或上下地幔之间的耦合性质和地球化学库的分布。第二部分是对核敏感相的研究，并从核和深部地幔的结构/各向异性角度对其进行解释。虽然内核只占地球的一小部分，但它被认为在外核的动力学和磁场产生中发挥着重要作用。关于其各向异性结构的复杂性的证据一直在积累，核心和地幔结构之间的权衡需要进一步探索。在分量(1)下，研究人员将扩展他们的波形层析方法，在合成波形和偏导数的计算中结合使用近似解析和精确数值方法。在组成部分(2)下，他们将继续收集和分析岩心敏感的旅行时数据，以测试最近提出的内核复杂模型，并进一步评估内核、外核和地幔结构之间的权衡。广泛的影响：拟议的地球深部结构调查方案将使更多地球物理学(地球动力学家、矿物物理学家)和地球化学家的非地震学家社区受益，因为它旨在为全球地幔地球动力学模型(本提案的第一部分)以及核心(本提案的第二部分)提供地震学约束。

RomanowiczThis grant will support a program of investigation of lateral heterogeneity in the earth's mantle and core at the global scale, using seismological methods. There are two main components in this research program. The first is global seismic waveform tomography and related forward modeling. Global seismic tomography can provide constraints on key mantle dynamics questions such as: the fate of subducted slabs, the role of D" as a thermo-mechanical boundary layer, the depth of origin and role of mantle plumes in the global circulation, or the nature of coupling between upper and lower mantle and the distribution of geochemical reservoirs. The second component is the investigation of core-sensitive phases and their interpretation in terms of structure/anisotropy of the core and of the deep mantle. While a very small part of the earth, the inner core is thought to play an important role in the dynamics of the outer core and the magnetic field generation. Evidence for complexity in its anisotropic structure has been accumulating, and trade-offs between core and mantle structure need to be further explored.Under component (1), the investigators will extend their waveform tomography approach to include a combination of approximate analytical and exact numerical methods in the computation of synthetic waveforms and partial derivatives. Under component (2), they will continue to collect and analyze core sensitive travel time data to test recently proposed complex models of the inner core and further evaluate trade-offs between inner core, outer core and mantle structure.Broader Impacts: The proposed program of investigation of deep earth structure will benefit a broader community of non-seismologists in geophysics (geodynamicists, mineral physicists) and geochemists, in that it aims at providing seismological constraints on global geodynamical models of the earth's mantle (part 1 of this proposal) as well as the core (part 2 of this proposal).