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

合作研究：地球内部结构研究

• 批准号: 0838093
• 负责人: Goran Ekstrom
• 金额: $ 7万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838093&HistoricalAwards=false
• 关键词: Collaborative; Research; Studies; Structure; Earth

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.

该奖项是根据2009年美国恢复和再投资法案（公法111 - 5）资助的。摘要在世纪的最后四分之一，许多地幔或其部分的三维模型已经被推导出来。然而，它们中的大多数只描述一个参数（例如，S速度），并且基于限于窄频率范围的数据集。这限制了从这些模型中可以得出的结论的范围。在此，我们请求提供两年的支持，利用各种地震数据调查地球内部的弹性和密度结构，分辨率跨越从地表到地球中心的深度范围，频率从1赫兹到0.3兆赫。特别是，我们建议：从Kustowski等人（2008年）的数据集、程序和模型开始，收集一个附加的简正波中心频率数据集，收集一个附加的简正波分裂函数数据集，收集一个附加的ISC走时数据集和其他走时数据集，包括一个在斯克里普斯海洋研究所测量的大量波形导出走时。将这三个新的数据集与Kustowski等人使用的数据集相结合。（2008）反演三维地幔模型，该模型包括径向各向异性弹性体声速和剪切速度以及410 km、650 km和核幔边界的地形。新的数据库，涵盖了广泛的频率，将使我们能够执行联合反演弹性参数和密度，并调查大规模的各向同性和各向异性变化的地幔内的重要性。同时反演将确保自洽性。与仅模式反演相比，通过限制从弹性变化到密度的能量泄漏，它将对密度结构施加更强的约束。密度异质性的鲁棒性将建立与此数据集，并将有助于解决围绕难以捉摸的，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、地幔热化学状态和部分熔融分布等问题中发挥重要作用。智力优势。拟议的研究将导致一套模型，描述弹性参数（各向同性和各向异性地震波速度扰动）和密度在地球地幔内的变化。它将解决围绕三维密度模型的争议。新的模型将为测试热变化和化学变化的相对重要性以及部分熔融和地幔对流的不同情景提供基础。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。新模型的组合为理解地幔状态提供了必要的约束（即，热和成分异常的不均匀性以及部分熔融）。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。该项目还将成为计划于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。