Collaborative Research: Africa Array - Imaging the Africa Super Plume

合作研究：非洲阵列 - 非洲超级羽流成像

• 批准号: 0440222
• 负责人: Stephen Grand
• 金额: $ 5.37万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0440222&HistoricalAwards=false
• 关键词: Collaborative; Research; Africa; Array; Imaging

Collaborative Research:AfricaArray - Imaging the African SuperplumeThe African Superplume is a large region of low seismic wave speeds in the lower mantle under southern Africa that has long been recognized as one of the most prominent features of the mantle. Above the African Superplume lies the African Superswell, suggesting a geodynamic link between lower mantle dynamics and geologic processes shaping the African plate. The origin and nature of the African Superplume is controversial. The initial interpretation of the low wave speed region under southern Africa attributed it to a long-lived, hot mantle upwelling. A number of seismic studies since then have suggested the presence of chemical heterogeneity within the superplume.What parts of the superplume anomaly are thermal vs. chemical (or both) remains uncertain, as does its origin. In this project, the structure, composition and origin of the African Superplume will be investigated using the first 3 years of broadband seismic data from AfricaArray, together with existing data, and concentrating on four types of analyses; 1) tomographic imaging of the upper and lower mantle using body wave travel times, 2) modeling waveforms of teleseismic body wave phases that sample the Superplume, 3) jointly inverting receiver functions and surface wave dispersion measurements for crust and uppermost mantle structure, and 4) stacking and migrating receiver functions to image topography on the 410 and 660 km discontinuities.AfricaArrayis a new 10-year-long Pan-African training and research initiative in geophysics, with an emphasis on seismology, set up by the University of the Witwatersrand, the Council for Geoscience (South African geological survey), and Penn State. AfricaArraywill provide the U.S. geophysics community with important seismic data on earth structure and processes for many years. AfricaArraywill greatly strengthen scientific ties between the U.S. geophysics community and earth scientists throughout Africa. Once established, AfricaArraywill provide opportunities for promoting geophysics to U.S. minority groups, as well as other students, through summer internships and a summer geophysics field course (both in Africa).This award is co-funded by NSF's Office of International Science and Engineering.

合作研究：AfricaArray - 非洲超地幔柱成像非洲超地幔柱是南部非洲下地幔中的一大片低地震波速度区域，长期以来一直被认为是地幔最突出的特征之一。非洲超级地幔柱上方是非洲超级涌流，表明下地幔动力学与塑造非洲板块的地质过程之间存在地球动力学联系。非洲超级羽流的起源和性质存在争议。对南部非洲低波速区域的初步解释将其归因于长期的热地幔上升流。此后的许多地震研究表明，超羽流内部存在化学异质性。超羽流异常的哪些部分是热异常，哪些部分是化学异常（或两者兼而有之），其起源仍然不确定。在该项目中，将使用 AfricaArray 前 3 年的宽带地震数据以及现有数据来研究非洲超级地幔柱的结构、组成和起源，并集中于四种类型的分析； 1) 使用体波传播时间对上地幔和下地幔进行层析成像，2) 对超羽流采样的远震体波相位波形进行建模，3) 联合反演地壳和最上地幔结构的接收函数和表面波色散测量，以及 4 ）将接收器函数叠加并迁移到 410 公里和 660 公里间断面的地形图像。AfricaArray 是一个新的为期 10 年的泛非训练和由威特沃特斯兰德大学、地球科学委员会（南非地质调查局）和宾夕法尼亚州立大学发起的地球物理学研究计划，重点是地震学。 AfricaArray 多年来将为美国地球物理学界提供有关地球结构和过程的重要地震数据。 AfricaArray 将极大地加强美国地球物理学界和整个非洲地球科学家之间的科学联系。一旦成立，AfricaArray 将通过暑期实习和暑期地球物理实地课程（均在非洲）提供向美国少数族裔以及其他学生推广地球物理学的机会。该奖项由美国国家科学基金会国际科学与工程办公室共同资助。