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

基本信息

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

项目摘要

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.

该项目的目的是确定熔体被困在深度且系统不稳定的参数范围内，不稳定性应该发展，并描述和量化由这种流量引起的变形。我开发了一种基于两阶段流动动力学的半分析模型，以研究内核的增长。在先前对Sumita等人的研究之后。（1986年），我对自我磨碎球的压实建模，而球体是从顶部结晶而生长的。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态，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年和Huguet等人的超冷核心。由于地球内核的压实长度被认为小于100公里，因此在系统中捕获融化的最有前途的场景是超冷的核心，在核心深度中捕获了高达30％的熔体。对于当今内部核心中剪切波的观察，这种融化的量太大，这有助于我们限制理性上的上限进行过冷的限制。