共查询到17条相似文献,搜索用时 625 毫秒
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基于PREM模型,利用非自转、球型分层、各向同性、理想弹性(SNREI)地球的形变理论,讨论了地球在不同驱动力作用下的形变特征.采用地球位移场方程的4阶Runge Kutta数值积分方法,解算了在表面负荷和日月引潮力作用下地球表面和内部形变和扰动位,并给出了地球表面的负荷Love数和体潮Love数.结果表明在固体内核中的形变很小,液核中低阶(n<10)负荷位移随半径的变化非常复杂.当负荷阶数超过10时,地核中的形变和扰动位都很小,地球的响应主要表现为弹性地幔中的径向位移,且随深度增加急剧减弱,负荷阶数越高这种衰减的速度越快.SNREI地球的地表负荷Love数和体潮Love数与信号频率的依赖关系很弱.在计算体潮Love数的过程中,采用了SNREI地球的运动方程,同时考虑了由于地球自转和椭率引起的核幔边界附加压力,这一近似处理方法获得的结果能很好地符合地球表面重力潮汐实际观测结果. 相似文献
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地球内部压力变化及其构造意义 总被引:2,自引:0,他引:2
地球内部的压力远比人们预想的要高得多,地心处的压强为无穷大,在重力分异过程中,地壳地幔减压膨胀(吸热),地核增压收缩(放热),核幔边界是热交换界面,热幔 核幔边界生成。 相似文献
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本文是序列文章的第四篇,其内容包括:基于连续介质力学的基本理论,给出了固体外核(SIC)自转的动力学方程,考虑了地球的自引力、液核对内核边界的压力和二阶外部引潮力位对SIC自转的影响,并在O(mε)的量级上给出了其实用的表达式.本文的理论推导更加严密和细致,改正了文献〔1〕在推导过程中的某些错误(例如:(B39)、(B44)和(B59c)式).本文的工作是对文献〔1〕有关理论的扩展和改进,对进一步研究内核地球自转的动力学理论是非常重要的. 相似文献
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Introduction The fluid outer core separates the solid inner core from the solid elastic mantle, and as a result, makes the free and forced movement of this mechanical system more complicated and profuse. As the elastic mantle, the free oscillations may occur within the Earths fluid outer core (FOC) due to excitation of a strong and deep earthquake (Crossley, 1975b; Friedlander, Siegmann, 1982; Shen, 1983; Friedlander, 1985). However, compared with the oscillations of the elastic mantle, i… 相似文献
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The elasto-gravitational deformation response of the Earth’s solid parts to the perturbations of the pressure and gravity
on the core-mantle boundary (CMB) and the solid inner core boundary (ICB), due to the dynamical behaviors of the fluid outer
core (FOC), is discussed. The internal load Love numbers, which are formulized in a general form in this study, are employed
to describe the Earth’s deformation. The preliminary reference Earth model (PREM) is used as an example to calculate the internal
load Love numbers on the Earth’s surface, CMB and ICB, respectively. The characteristics of the Earth’s deformation variation
with the depth and the perturbation periods on the boundaries of the FOC are also investigated. The numerical results indicate
that the internal load Love numbers decrease quickly with the increasing degree of the spherical harmonics of the displacement
and depend strongly on the perturbation frequencies, especially on the high frequencies. The results, obtained in this work,
can be used to construct the boundary conditions for the core dynamics of the long-period oscillations of the Earth’s fluid
outer core.
Foundation item: State Natural Science Foundation of China (40174022 and 49925411) and the Projects from Chinese Academy of Sciences (KZCX2-106
and KZ952-J1-411). 相似文献
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本文是序列文章的第三篇,其内容包括:基于连续介质力学的基本理论,给出了液体外核(FOC)两种形式的角动量方程,对作用在FOC上外力矩进行了详细研究,同时对液核作用在固体内核(SIC)上的压力产生的压力矩进行了讨论,在O(ms)的量级上给出了它们的表达式.本文改正了文献〔1〕在推导过程中的某些错误(例如:(B18)、(B28)、(B29)、(B30)、(B35a)和(B35b)式).本文是对文献〔1〕有关理论的扩展和改进,对进一步研究内核地球自转的动力学理论是非常重要的. 相似文献
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David E. Loper 《地球物理与天体物理流体动力学》2013,107(1-2):139-155
Abstract A model of the inner-core boundary (ICB) is constructed which is consistent with current ideas of the dynamic and thermodynamic state of the core and which is capable of reflecting seismic waves with period of one second. This requires the mass fraction of solid below the ICB to grow to an appreciable fraction in roughly one kilometer. This rapid growth of solid with depth is a result of downward fluid flow from the outer core which is a part of the convective motions which sustain the geodynamo. The solid which crystallizes from this descending fluid after it crosses the ICB continually coats the dendrites which occur there. The gradual cooling of the outer core causes the ICB to advance by growth of dendrites at their tips. The balance of these two effects gives an equilibrium profile for the mass fraction of solid with depth below the ICB which is capable of yielding sharp reflection of seismic waves. 相似文献
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旋转椭球型地球的固体地幔与液态地核间相互作用而产生的逆向本征模通常称之为地球自由核章动,自由核章动的品质因子(Q值)能有效反映核幔边界层能量耗散特征,与核幔边界的黏滞度密切相关.本文首次利用全球地球动力学计划网络23个台站27组高密度采样的高精度超导重力仪器观测数据,采用迭积技术,确定了自由核章动参数Q值,进而计算了核幔边界的黏滞系数.数值结果说明获得的核幔边界动力学黏滞系数达到103 Pa·s量级,与加拿大科学家Smylie等利用VLBI观测资料获得的最新结果一致,这说明重力技术是有效应用于研究地球深内部结构的重要手段之一. 相似文献
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Experimental high-pressure results on phase stability, electrical conductivity and compression behavior up to 5 and 21 GPa respectively are used to calculate an isothermal equation of state for a monosulfid solid solution (MSS-composition) in the FeNiS system. The high-pressure relations in the range 1–8 GPa are very complex. A continuous electrical transition, from semiconducting to metallic, takes place at high pressures and temperatures and results in anomalous compression behavior at pressures in this region. No polymorphic transition from the NiAs-structure to another type could be observed; however, density increases by as much as 8.8%. Using compression values for pressure greater than 10 GPa, the bulk modulus, a zero-pressure density and a core density were calculated. Extrapolation for the conditions of the outer core yields a difference in the density of up to 20%, relative to seismological models.In a composition model with (Fe, Ni)+MSS, a MSS-content must be assumed to be in the range of 30–35 wt% at the core-mantle boundary (CMB) and 13–17 wt% at the inner-core boundary (ICB). That corresponds to a sulfur content of 10.8–13.3 wt% (CMB) and 4.9–6.5 wt% (ICB), respectively, the values increasing with increasing Ni content of the MSS-phase. 相似文献