Collaborative Research: Studies of the Structure of the Earth's Interior

摘要在过去的四分之一世纪中，许多地幔或其部分的三维模型被推导出来。然而，它们中的大多数只描述了一个参数（例如，S-velocity），并且基于一个仅限于狭窄频率范围的数据集。这限制了从这些模型中得出结论的范围。在此，我们要求对地球内部弹性和密度结构的调查提供两年的支持，使用各种地震数据，分辨率从地表到地球中心的深度范围，频率从1Hz到0.3 MHz。特别是，我们建议：从Kustowski等人（2008）的数据集、程序和模型开始，组装一个额外的正常模态中心频率数据集，组装一个额外的正常模态分裂函数数据集，组装一个额外的ISC旅行时间数据集和其他旅行时间数据集，包括在斯克里普斯海洋学研究所测量的大量波形衍生旅行时间数据集。将这三个新数据集与Kustowski等人（2008）使用的数据集相结合，反演出一个三维地幔模型，该模型包括完全各向异性的弹性体声和剪切速度，以及410公里、650公里和核幔边界的地形。新的数据库覆盖了广泛的频率范围，将使我们能够对弹性参数和密度进行联合反演，并研究地幔内大尺度各向同性和各向异性变化的重要性。同时反演将保证自洽性。通过限制从弹性变化到密度的功率泄漏，与纯模式反演相比，它将对密度结构施加更强的约束。该数据集将建立密度异质性的鲁棒性，并将有助于解决围绕难以捉摸但重要的密度模型的争议。这些新的弹性和密度模型将在解决地幔动力学、热化学状态和部分熔融分布等问题方面发挥重要作用。知识价值。提出的研究将导致一套描述弹性参数（各向同性和各向异性地震波速度扰动）和地幔内密度变化的模型。它将解决围绕三维密度模型的争议。新模型将为地幔对流的热、化学变化、部分熔融和不同情景的相对重要性测试提供依据。更广泛的影响。新模型将为地球动力学家、地球化学家、矿物物理学家，当然还有地震学家提供重要信息。这些新模型的结合为理解地幔的状态（即热异常和成分异常的非均质性以及部分熔融）提供了必要的约束。它们也与动力学密切相关，可用于地幔对流和大尺度重力模拟等研究。这个项目也将成为计划于2007-2009年在哈佛自然历史博物馆举办的固体地球博物馆展览的一部分。

This award is funded under the American Recovery and Reinvestiment Act of 2009(Public Law 111-5)Abstract During the last quarter of a century many 3-D models of the mantle, or its part, have been derived. However, most of them describe only one parameter (for example, S-velocity) and are based on a data set that is limited to a narrow range of frequencies. This has limited the range of conclusions that could have been drawn from these models. Here we request two-year support for investigation of elastic and density structure of the Earth's interior using a wide variety of seismic data, with resolution spanning depth range from the surface to the Earth's center and frequencies from 1Hz to 0.3 MHz. In particular, we propose to: start with Kustowski et al. (2008) data sets, programs, and models assemble an additional data set of normal mode center frequencies assemble an additional data set of normal mode splitting functions assemble an additional data set of ISC travel times and other sets of travel time data, including a large set of waveform derives travel times measured at Scripps Institution of Oceanography. integrate the three new data sets with those used by Kustowski et al.(2008) to invert for a 3-D mantle model that includes radically anisotropic elastic bulk sound and shear velocities and the topographies of the 410 km, 650km and core-mantle boundary. The new database, covering a wide range of frequencies, will allow us to perform joint inversion for elastic parameters and density, and investigate the importance of large-scale isotropic and anisotropic variations within the mantle. The simultaneous inversion will assure self-consistency. It will put stronger constraint on density structure compared to mode-only inversion by limiting leakage of power from elastic variations to density. The robustness of the density heterogeneity will be established with this data set, and will contribute to resolution of the controversy surrounding the elusive, and yet important, density model. These new elastic and density models will play a major role in addressing such questions as the dynamics of the mantle, its thermal and chemical state, and distribution of partial melt. Intellectual Merit. The proposed research will lead to a suite of models describing the variations in elastic parameters (isotropic and anisotropic seismic wave speed perturbations) and density within Earth's mantle. It will address the controversy surrounding three-dimensional density model. The new models will provide basis for testing relative importance of thermal and chemical variations as well as partial melting and different scenarios for mantle convection. Broader Impacts. The new model will provide important information for geodynamicists, geo-chemists, mineral physicists and, of course, seismologists. Combination of the new models Provides essential constraint on the understanding of the state of the mantle (i.e., heterogeneity in thermal and compositional anomalies, and partial melt). They are also closely related to dynamics, and can be used in studies such as those on mantle convection and large-scale gravity modeling. This project will also be a part of a museum display on solid Earth that is being planned for 2007-2009 at the Harvard Museum of Natural History.