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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.

德国和法国的实验项目rum - rum的目标是在La r<s:1>热点下对地幔柱（或地幔柱不存在）进行地震学成像，并根据地幔所有深度的对流流动来理解结果。大部分海底和岛屿的数据将在2013年底提供。我们在这里提出的工作包括两种相互关联的，先验的建模研究，意味着伴随着rham - rum的数据分析组件。在Work Package 1（一名博士生）中，我们提出了一种新的r<s:1>地幔柱与大规模流动相互作用的地球动力学模型，这种流动通常被认为主要是由俯冲板块驱动的，但也可能是由非洲和印度洋下的活跃上升流驱动的。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可观测性。我们建议进行全面的先验参数和不确定性研究（在每个深度，每个流变/物理参数的阈值下，羽流仍然可以检测到？），而不是通常显示的非常局部的分辨率测试，以便证明从实际数据中获得的首选模型是合理的。因此，我们的地球动力学模型及其预期的层析特征可以被视为真实的预测。当同事们从rham - rum数据分析中获得观测结果时，将对模型进行比较，缩小地球动力学参数范围，并运行修改后的模型。这两个工作包都包含了计算方法开发的强大组件，包括地幔对流模拟和宽带波形反演。我们的总体目标是：1。更好的地球动力学模型，一般来说，一个假设的经典羽流从一个大低横波速度省（LLSVP）上升的过程-一种目前被认为适用于大多数海洋热点的产生机制。2. 对于哪些结构（如果存在的话）可以或不可以通过实际的rham - rum数据来解决的清晰和全面的理解。实际观察到的结构，一旦它们可用，即，在项目经历最大动力和科学界最大兴趣的时刻，立即提供地球动力学背景。