Geodynamic modelling and tomographic visibility of a mantle plume under La Réunion

留尼汪岛地幔柱的地球动力学建模和层析可见性

基本信息

批准号：
247034637
负责人：
Professor Dr. Heiner Igel
金额：
--
依托单位：
Sektion 2.5: Geodynamische Modellierung
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/247034637?language=en
关键词：
Geodynamic modelling tomographic visibility mantle

项目摘要

The goal of the German-French experiment RHUM-RUM is to seismologically image a mantle plume - or its absence - under the hotspot of La Réunion, and to understand the results in terms of convective flow at all depth levels of the Earth mantle. Most of the ocean-bottom and island data will become available in late 2013.The work we propose here consists of two kinds of interrelated, a priori modeling studies, meant to accompany the data analysis components of RHUM-RUM. In Work Package 1 (one Ph.D. student) we propose to develop a new geodynamic model of the Réunion mantle plume interacting with large-scale flow, which is commonly considered to be largely driven by subducted slabs, but possibly also by active upwellings under Africa and the Indian Ocean. In Work Package 2 (one Ph.D. student), we will investigate the tomographic observability of such a priori reasonable plume structures.We propose a full-fledged parameter and uncertainty study a priori (Down to which threshold of each rheological / physical parameter should a plume still be detectable, at each depth?), rather than the very topical resolution tests that are typically shown a posteriori in order to justify a preferred model obtained from the real data. Our geodynamic models, and their expected tomographic signatures, can therefore be regarded as a true predictions. As observations become available from the RHUM-RUM data analyses by colleagues, the models will be compared to them, geodynamical parameters will be narrowed down, and modified models will be run. Both work packages contain strong components of computational method development, in terms of mantle convection simulations and broadband waveform inversion.Our overarching objectives are:1. Better geodynamical models in general, of the process of a hypothesized classical plume rising from a Large Low Shear wave Velocity Province (LLSVP) - a generation mechanism currently thought to apply to most oceanic hotspots. 2. A clear and comprehensive understanding of which structures, if present, could or could not be resolved by the actual RHUM-RUM data.3. An immediate geodynamical context for actually observed structures, once they become available, i.e., at a moment when the project experiences its maximum momentum and greatest interest from the scientific community.

德国和法国联合进行的 RHUM-RUM 实验的目标是对留尼汪岛热点下的地幔柱（或不存在的地幔柱）进行地震成像，并了解地幔所有深度水平的对流流动结果。海底和岛屿数据的数据将于 2013 年末提供。我们在此提出的工作包括两种相互关联的先验建模研究，旨在伴随数据分析组件RHUM-RUM。在工作包 1（一名博士生）中，我们建议开发一种新的留尼旺地幔柱与大规模流动相互作用的地球动力学模型，通常认为该模型主要是由俯冲板片驱动的，但也可能是这样的。同样通过非洲和印度洋下的活跃上升流，在工作包 2（一名博士生）中，我们将研究这种先验合理羽流结构的层析成像可观测性。全面的参数和不确定性先验研究（在每个流变/物理参数的哪个阈值下，在每个深度仍可检测到羽流？），而不是通常在后验中显示的非常热门的分辨率测试，以证明其合理性因此，我们的地球动力学模型及其预期的断层扫描特征可以被视为真实的预测，随着同事从 RHUM-RUM 数据分析中获得观察结果，这些模型将与它们进行比较，地球动力学参数将被缩小，并且修改后的模型将被运行，这两个工作包都包含计算方法开发的强大组成部分，在地幔对流模拟和宽带波形反演方面。我们的总体目标是：1。开创性的经典羽流从大低剪切波速省 (LLSVP) 升起的过程 - 目前认为适用于大多数海洋热点的生成机制 2. 对哪些结构有清晰、全面的了解。如果存在，可以或不能通过实际的 RHUM-RUM 数据来解决。3. 实际观测到的结构的直接地球动力学背景，一旦它们可用，即在项目经历其最大动力和最大兴趣的时刻。科学界。