メルト輸送過程を考慮した地球内核成長モデルによる地震波異方性の成因解明

使用考虑熔体传输过程的岩心生长模型阐明地震波各向异性的起源

• 批准号: 18K13632
• 负责人: ラスブレイス マリン
• 金额: $ 1.66万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Early-Career Scientists
• 财政年份: 2018
• 资助国家: 日本
• 起止时间: 2018-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-18K13632/
• 关键词: geodynamics, Earth; deep Earth; inner core; two-phase dynamics; crystallisation

The goal of the project was to determine the range of parameters for which melt is trapped in depth and the system is unstable and instabilities should develop, and to describe and quantify the deformation induced by such flows.I developed a semi-analytical model, based on two-phase flow dynamics to study the compaction of the inner core as it is growing. Following previous study of Sumita et al. (1986), I modeled the compaction of a self-gravitating sphere, while the sphere is growing from crystallization at the top. The system allow for variations of two main parameters: growth rate and compaction length.To explore the possible dynamics for the Earth’s inner core, I studied three different set-up for the growth: constant growth rate, realistic growth from Labrosse et al. 2014 and supercooled core from Huguet et al 2018. As the compaction length for the inner core of the Earth is thought to be smaller than 100km, the most promising scenario to trap melt in the system is the supercooled core, trapping up to 30% of melt in the depth of the core. This amount of melt is too large for the observations of shear waves in today’s inner core, which help us constraining reasonnable upper bound for supercooling.

该项目的目标是确定的参数范围内，熔体被困在深度和系统是不稳定的，不稳定性应该发展，并描述和量化的变形引起的这种flow.I开发了一个半分析模型，基于两相流动力学研究压实的内核，因为它是不断增长的。根据Sumita等人（1986）的先前研究，我模拟了自引力球体的压实，而球体从顶部的结晶生长。该系统允许两个主要参数的变化：增长率和压实长度。为了探索地球内核的可能动力学，我研究了三种不同的增长设置：恒定增长率，Labrosse等人的现实增长。2014和Huguet等人的过冷核心2018。由于地球内核的压缩长度被认为小于100公里，最有希望在系统中捕获熔体的情况是过冷核心，在核心深处捕获高达30%的熔体。对于今天内核的剪切波观测来说，这个熔化量太大了，这有助于我们限制合理的过冷上限。

项目成果

Combining seismic observations and geodynamical models for exploring the Earth’s inner core

结合地震观测和地球动力学模型探索地球内核

• 发表时间: 2018
• 作者: Morishige;M.;Marine Lasbleis
• 通讯作者: Marine Lasbleis

Compaction of a mushy inner core : the fate of liquid trapped by fast growth

糊状内核的压实：快速生长所困液体的命运

• 发表时间: 2018
• 作者: M. Kervazo;M. Lasbleis (presenting author)
• 通讯作者: M. Lasbleis (presenting author)