Finite-frequency tomography and waveform modeling of the South Atlantic mantle

南大西洋地幔的有限频率断层扫描和波形建模

• 批准号: 172867499
• 负责人: Professorin Dr. Karin Sigloch
• 金额: --
• 依托单位: Sektion Geophysik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/172867499?language=en
• 关键词: Finite; frequency; tomography; waveform; modeling

This body-wave tomography aims to image the entire cluster of hotspots in the South and Central Atlantic, at all mantle depths. The goal is to extract a maximum of information from observed broadband seismograms. Exploiting all available regional data sets, it will be embedded in a global finite-frequency P- and PP-wave inversion. As a central component and technical novelty, we will develop the tomography of core-diffracted P-waves, by means of sensitivity kernels from full-waveform modeling. This wave type grazes the core and therefore samples the deepest part of the mantle extensively. Hence we hope for better information on the “footing” of mantle plumes and the internal structure of the vast African anomaly. The South and Central Atlantic is the prime target for diffracted P-wave tomography, since it is the only region with both decent sampling and an accumulation of presumed mantle plumes. The tomographic models will be verified with full 3D waveform modeling, which we will push to the highest observed frequencies using our considerable supercomputing resources. Their interpretation -- in terms of heat fluxes and mantle heating regime -- will be quantitatively tied to numerical mantle circulation simulations and mineralogical modeling.

这种体波断层扫描旨在对大西洋南部和中部所有地幔深度的整个热点群进行成像。目标是从观测到的宽带地震图中提取最大限度的信息。利用所有可用的区域数据集，它将嵌入到全球有限频率P波和pp波反演中。作为核心组件和技术新颖，我们将通过全波形建模的灵敏度核来开发核心衍射p波的层析成像。这种波类型掠过地核，因此对地幔最深处进行了广泛的采样。因此，我们希望对地幔柱的“立足点”和巨大的非洲异常的内部结构有更好的了解。南大西洋和中大西洋是绕射纵波断层成像的主要目标，因为它是唯一一个既有像样的采样又有假定地幔柱堆积的地区。层析模型将通过完整的3D波形建模进行验证，我们将利用我们可观的超级计算资源将其推至最高观测频率。他们的解释——根据热通量和地幔加热机制——将定量地与数值地幔循环模拟和矿物学建模联系起来。