Probing the Earth's Core and Lowermost Mantle

探测地球的核心和最底层的地幔

• 批准号: 0409251
• 负责人: Xiaodong Song
• 金额: $ 19.54万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0409251&HistoricalAwards=false
• 关键词: Probing; Earth; Core; Lowermost; Mantle

The Earth's core plays an important role in the formation andchemical differentiation of our planet, in global earth dynamicsand earth rotation, and in the generation of the magnetic field.This project focuses on three related objectives, concerning theseismic imaging of the structure and rotation of the inner core andthe heterogeneity of the the lowermost mantle. (1) To constrain theinner core rotation using fixed earthquake-station paths, which reducesbiases from unmodeled mantle heterogeneities and source mislocation.The project will search for time-dependence of PKP(BC)-PKP(DF) differentialtimes and PKP(CD)-PKP(DF) differential times. Considerable effortwill also be made to address uncertainties in determining innercore rotation, in particular errors from potential systematicevent mislocation. (2) To model and invert for 3D anisotropicinner core structure using PKP waveforms and differential times.The project will test the recent proposal of a distinct innermostinner core and examine the sharpness and lateral variation of the innercore transition zone from the relatively isotropic upper inner coreto strong anisotropy in the lower inner core. (3) To map theheterogeneity of the lowermost mantle from the PKP data collected,in particular, the Central Pacific core-mantle boundary anomalyusing abundant PKP samples from the earthquakes andstations in South America and east Asia.

地球的核心在地球的形成和化学分化，全球地球动力学和磁场的产生中都起着重要作用。该项目侧重于三个相关目标，涉及对最低层的内核结构和内核的结构和旋转的旋转。 （1）使用固定的地震站路径来限制Theinner核心旋转，从而从未建模的地幔异质性和源误差中降低了次数。该项目将搜索PKP（BC）-PKP（df）差异（df）差异（df）差异（df）差异（df）差异（df）差异（CD）-pkp（cd）-pkp（df）-pkp（df）差异。还要努力解决确定内核旋转时的不确定性，特别是潜在的SystematIceVent错误分配中的错误。 （2）使用PKP波形和差异时间对3D各向异性核心结构进行建模和倒置。该项目将测试独特的Innermostinner核心的最新建议，并检查Intercore过渡区的清晰度和侧向变化，从相对等同于同位素上层内部内部核心中相对较低的内部核心强。 （3）从收集的PKP数据中绘制最低地幔的近似值，尤其是中太平洋核心掩体边界，从而从南美和东亚的地震和站点绘制了大量的PKP样品。