On Earth tides
On Earth tides
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地球上的潮汐
DOI：
10.1029/tr031i003p00357
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发表时间：
1950
期刊：
影响因子：
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通讯作者：
E. Nishimura
中科院分区：
文献类型：
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作者：
E. Nishimura
本文共分六个主要部分，内容提要如下：
(1)这涉及到地球上地幔的刚性。通过利用两个适当选择的站的倾斜观测之间的矢量差，获得了地球上地幔的有效刚性模数值。利用这种方法，几乎完全消除了固体潮的直接影响，并准确地估计了海洋影响。(2)这涉及活动断层附近地球表面的特殊运动。文中还讨论了近海六个近距离测站的异常倾斜图与地表地质结构的关系。(3)分析了地球整体的刚度。在远离海洋的稳定站进行倾斜观测，得到了1+k−h的值，并确定了整个地幔和整个地球的有效刚度值。
(4)这是一项关于纬度潮汐变化的研究。根据6个国际纬度观测站的长期资料，分析了潮汐纬度的变化，并利用潮汐纬度变化确定了1+k−L的值，指出了观测站和分析所采用的时代所特有的不可解释的影响。根据30万对恒星观测的数据，L的平均值估计为1.2。(5)分析了地壳弹性随时间的变化规律。讨论了在Makimine观测到的地球潮汐振幅随时间的异常大变化，认为这与附近Hyuganada的海水负荷引起的地壳弯曲密切相关，Hyuganada是大规模海洋地震的活动中心。(6)这是对地球上地幔弹性各向异性的研究。通过对日本几个台站倾角资料的分析，认为地球上地幔在N-S方向上的弹性比在E-W方向上的弹性小20-30%。建议对这一问题进行更长系列的观察和独立攻击的研究。
This paper is divided into six main sections, the abstracts for which are as follows:
(1) This deals with the rigidity of the upper mantle of the Earth. A value is obtained for the effective modulus of rigidity of the Earth's upper mantle by using vector differences between tiltmetric observations at two suitably selected stations. By this method, the direct effects of Earth tides are almost entirely eliminated and the oceanic effects are accurately evaluated. (2) This deals with the particular motion of the Earth's surface near an active fault. Anomalous tilting diagrams obtained at six closely spaced stations near the sea are discussed in relation to the geologic structure of the surface ground. (3) Rigidity of the Earth as a whole is analyzed. A value of 1 + k − h is obtained from tiltmetric observations at a stable station far remote from the oceans, and values of the effective rigidity for the whole mantle and for the whole Earth are determined.
(4) This is a study of tidal variation of latitude. From data over long periods at six International Latitude Observatories, tidal latitude variations are analyzed and used to determine values of 1 + k − l. Unexplainable effects peculiar to the observing stations and to the epoch adopted in analysis are noted. From data resulting from 300,000 pairs of star observations, the mean value of L was estimated as 1.20. (5) This analyzed the time variation of the elasticity of the Earth's crust. An unusually large variation with time in the Earth tidal amplitude observed at Makimine is discussed and is considered to be intimately related to the bending of the Earth's crust caused by the load of sea water in the nearby Hyuganada, an active center of large-scale sea earthquakes. (6) This is a study of the elastic anisotropy of the Earth's upper mantle. From an analysis of tiltmetric data obtained at several stations in Japan, it is suggested that the elasticity of the Earth's upper mantle in the N-S direction is 20 to 30 per cent smaller than that in the E-W direction. The study of longer series of observations and independent attacks on the problem are recommended.