Broadband Seismic Investigation of Crust and Upper Mantle Structure Beneath Kenya

肯尼亚下方地壳和上地幔结构的宽带地震调查

• 批准号: 0003424
• 负责人: Andrew Nyblade
• 金额: $ 22.34万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-15 至 2004-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0003424&HistoricalAwards=false
• 关键词: Broadband; Seismic; Investigation; Crust; Upper

Abstract for proposal EAR0003424 (PH #45x)Title: Broadband Seismic Investigation of Crust and Upper Mantle Structure Beneath KenyaPI: A. Nyblade, Penn StateIn this project, we will critically evaluate models for the origin of rifting, volcanism and uplift in East Africa by imaging the seismic structure of the upper mantle beneath the Kenya rift using broadband seismic data. Although East Africa has long been regarded as a classic area in which to study the early stages of continental breakup, the origin of the Cenozoic rifting, volcanism, and plateau uplift found there is still poorly understood. For a variety of reasons, the rifting, volcanism, and plateau uplift has been commonly attributed to one or more mantle plumes. However, whether a plume exists beneath East Africa is a contentious issue because geochemical and geophysical data from there, until recently, have provided little information on mantle composition and thermal structure beneath the lithosphere where the plume is hypothesized to lie. To further test plume models for East Africa, as well as non-plume models, we will conduct a passive source seismic experiment in Kenya to obtain broadband seismic data. The data will be analyzed using a number of proven modeling techniques for imaging crust and upper mantle structure. The resulting seismic images, combined with geochemical and other geophysical data from East Africa, will let us identify thermal and/or compositional structures in the upper mantle that can, in turn, be used to discriminate between models of the structure and development of East Africa.

EAR 0003424（PH#45x）提案摘要标题：肯尼亚地壳和上地幔结构宽带地震调查PI：A。在这个项目中，我们将通过使用宽带地震数据对肯尼亚裂谷下的上地幔的地震结构进行成像，对东非裂谷、火山活动和隆起的起源模型进行批判性评估。 虽然东非一直被认为是研究大陆分裂早期阶段的经典地区，但对那里发现的新生代裂谷、火山作用和高原隆升的起源仍然知之甚少。 由于各种原因，裂谷作用、火山作用和高原隆升通常被认为是一个或多个地幔柱造成的。 然而，在东非地下是否存在地幔柱是一个有争议的问题，因为直到最近，那里的地球化学和地球物理数据还没有提供关于地幔柱所在岩石圈下的地幔成分和热结构的信息。 为了进一步测试东非的羽流模型以及非羽流模型，我们将在肯尼亚进行被动源地震实验，以获得宽带地震数据。 将使用一些经过验证的地壳和上地幔结构成像建模技术对数据进行分析。 由此产生的地震图像，结合来自东非的地球化学和其他地球物理数据，将使我们能够确定上地幔的热结构和/或成分结构，这反过来又可以用来区分东非的结构和发展模式。