Scattering in Earth's Lower Mantle and Implications for Mantle Flow Models

地球下地幔中的散射及其对地幔流模型的影响

• 批准号: 9814614
• 负责人: Robert van der Hilst
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-06-01 至 2001-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9814614&HistoricalAwards=false
• 关键词: Scattering; Earth; Lower; Mantle; Implications

9814614van der HilstThis research involves the systematic mapping of scatterers in the deep mantle, in particular in the bottom 1000 km of the mantle where recent high-resolution tomography revealed unexpected changes in the planform of mantle heterogeneity. The objectives of this research are threefold. First, imaging techniques will be integrated to develop a powerful migration method for studies of lower mantle heterogeneity. Second, additional evidence will be sought for constraints on the postulated change in bulk chemistry in the lower mantle. Preliminary inversions to 1300-km depth suggest limited structures in the upper lower-mantle. This work will continue this work into the bottom third of the mantle. Third, by means of a combination of scattering and transmission tomography, improved understanding will be sought of the structure and dynamics of the base of the mantle. The integration of the techniques of body-wave scattering with those of transmission tomography will better determine that gradients and amplitudes of wave speed variations and thus produce a new class of Earth models that place tighter constraints on the chemical and thermal history of our planet.

9814614 van der Hilst这项研究涉及系统地绘制深地幔中的散射体，特别是在地幔底部1000公里处，最近的高分辨率层析成像显示了地幔异质性平面形状的意外变化。 这项研究的目标有三个方面。 首先，将成像技术结合起来，发展一种强有力的偏移方法，用于研究下地幔的非均匀性。 第二，将寻求更多的证据来限制下地幔中的体化学的假设变化。 初步反演到1300公里的深度表明有限的结构在上下地幔。 这项工作将继续这项工作到地幔底部的三分之一。 第三，通过散射和透射层析成像相结合的手段，将寻求更好地了解地幔底部的结构和动力学。 体波散射技术与透射层析成像技术的结合将更好地确定波速变化的梯度和幅度，从而产生一类新的地球模型，对我们星球的化学和热历史施加更严格的限制。