中国及邻区地震的天文潮汐触发特征研究—附加潮汐应力对发震断层的作用模式及其应用

本文在潮汐应力、构造应力、地震断层和岩石破裂滑动理论的基础上，建立了潮汐应力对地震断层作用的力学模式，该模式将潮汐应力与地震应力作用相结合，描述了沿地震主压应力和地震主张应务方向的附加潮汐应力对发震断层的力学作用方式，从而切入潮汐应力触发地震的物理机制，认为潮汐对地震的触发作用在实质上归结为潮汐应力对地震断层的促滑作用，这种促滑作用分增压型和减压型。在此模式基础上，对中国大陆及邻区的不同类型地震的潮汐触发性进行了研究，内容包括：计算了中国及邻区一千多个地震震源处沿主压应力P轴和主张应力T轴方向的附加潮汐应力分量，分析了这些量对发震断层的作用方式，按纬度区域统计了受到潮汐应力促滑作用的发震断层类型以及它们与潮汐应力作用方式的关系，得到了如下结论：受到潮汐应力促滑作用的发震断层的比例随区域纬度增加有减小趋势，其中，走滑型断层的比例在低纬区较大，而倾滑斜型断层的比例在中高纬度区较大；对整个统计区域而言，受增压型潮汐应力促滑作用的发震断层数比例大于受减压型潮汐应力促滑作用的发震断层；对不同的纬度区域，不同的潮汐应力作用方式与之促滑的发震断层类型也有不同的分布特征。最后，本文将中国及邻区受到潮汐触发作用的地震按构造应力区域划分，计算了这些地震发震时刻的日月位置参数，得到了各构造区域上具有潮汐触发物理机制的地震发震时的日、月位置参数分布图象。     

中国及邻区地震的天文潮汐触发特征研究——附加潮汐应力对发震断层的作用模式及其应用

本文在潮汐应力、构造应力、地震断层和岩石破裂滑动理论的基础上 ,建立了潮汐应力对地震断层作用的力学模式 ,该模式将潮汐应力与地震应力作用相结合 ,描述了沿地震主压应力和地震主张应力方向的附加潮汐应力对发震断层的力学作用方式 ,从而切入潮汐应力触发地震的物理机制 ,认为潮汐对地震的触发作用在实质上归结为潮汐应力对地震断层的促滑作用 ,这种促滑作用分增压型和减压型。在此模式基础上 ,对中国大陆及邻区的不同类型地震的潮汐触发性进行了研究 ,内容包括 :计算了中国及邻区一千多个地震震源处沿主压应力P轴和主张应力T轴方向的附加潮汐应力分量 ,分析了这些量对发震断层的作用方式 ,按纬度区域统计了受到潮汐应力促滑作用的发震断层类型以及它们与潮汐应力作用方式的关系 ,得到了如下结论 :受到潮汐应力促滑作用的发震断层的比例随区域纬度增加有减小趋势 ,其中 ,走滑型断层的比例在低纬区较大 ,而倾滑斜型断层的比例在中高纬度区较大 ;对整个统计区域而言 ,受增压型潮汐应力促滑作用的发震断层数比例大于受减压型潮汐应力促滑作用的发震断层 ;对不同的纬度区域 ,不同的潮汐应力作用方式与之促滑的发震断层类型也有不同的分布特征。最后 ,本文将中国及邻区受到潮汐触发作用的地震按构造应力     

国内天文地球动力学中的潮汐研究

简要说明了天文地球动力学范畴内所研究的潮汐现象，包括由日月引潮力引起的固体潮、海洋潮、大气潮和由于地球自转轴的极移引起的极潮，以及这些潮汐对地球自转和地球自转的测量产生的效应。重点阐述中国天文学界在这一领域里的研究成果。这些研究涉及潮汐影响地球自转的机制，也就是各种潮汐效应与极移、自转速率变化和章动的关系，包括构建这类关系的理论模型，分析潮汐对它们的影响，利用中国古代丰富的天象记录计算地球自转的长期减慢，计算弹性或滞弹地球的洛夫数，依据某一地球模型计算潮汐效应或章动序列等等。研究也涉及在测量地球自转参数的不同技术中各种潮汐效应对测量结果产生的影响及其改正，并涉及与潮汐有关的观测方法的优化和数据处理过程的改进。最后介绍了中国学者所发现的脉冲星的周期和周期变率测量中的潮汐效应，尽管它们的量级甚微，但不容忽视。     

全球巨震的天文背景

分析了全球8．5M以上巨震的天文背景，分析结果表明，这些巨震大都发生在处于月亮轨道运动所对应的地震活跃期的地震带区，太阳活动的下降段与地球自转的加速期。这是就天文因素的长周期变化而言。对于天文因素的短周期变化，无论是对于地方时，地方恒星时与月相，都有集中发生在某一段时间的现象；对于地球自转的短周期变化更是比较明显，要么发生在其变化最快时期，要么发生在其变化的最慢时期。这一切都表明，这些地震的发生是受天文因素的影响的。天文因素是外界发震动力之一，长周期变化的天文因素可能是对地震的孕育、发展与发生起着调制作用，而短期变化的天文因素则是当其作用于远离平衡态的发震构造上时，引起系统的巨涨落，从而诱发地震。     

对月日潮汐摩擦耗散的估计

月日潮汐摩擦和地球惯量矩变化是日长长期变化的主要原因．在本文中，利用最新的地球物理和古生物钟数据，对过去15亿年以来的月日潮汐摩擦、地球惯量矩变化和日长长期变化等作了数值对比研究．由此得到二个重要结论：一是仅利用地球的自转形变不能解释J2的变化，这说明地球的重力分异现象至今仍存在着；其二是在几亿年前的潮汐摩擦比现在大得多，若取潮汐耗散与距离的立方成反比时，理论结果与由古生物钟得到的回归年日数和朔望月日数数据较为符合。     

地月系潮汐演化长期趋势的估计

根据角动量守恒原理,计算了地月系经潮汐演化到达平衡状态时的旋转周期和地月距离.并根据当前与平衡状态时地月系的总能量差,计算了到达平衡状态的时间.进而估计了地月距离变化和地球自转速率变化的长期趋势.     

日震

日震良辰地球上每年大约发生５００多万次大大小小的地震，但是象２０年前的唐山大地震毕竟少见，地震主要发生在地壳中，地震工作者通过记录研究来自地壳中的震波，可适时作出预报。登上月球的宇航员，用月震仪发现厂“月震”，月震波表明月球内部是热的和易塑的物质。很...     

滞弹地球自转速率的潮汐变化

本文根据勒夫数和负荷载夫数的数值扰动原理，利用ｈａｎｄｌｅｒ摆动的理论周期作为滞弹吸收带模型参数估计的约束条件，讨论了地幔滞弹性对有效勒夫数ｋ的直接影响，以及滞弹地球对平均海潮的响应所产生的间接扰动，分析了它们对带谐潮尺度因子ｋ／Ｃ的影响，由此定义了一个具有动力学海潮、滞弹地幔和液核地球的世界时ＵＴ１潮汐变化序列，与天文新技术观测结果相比较表明，高频带谐潮变化的理论值与实测值是一致的。频散效应对低     

汶川地震的天文背景

比较系统地分析了汶川地震发生时的天体位置、月亮白赤交角、太阳活动与地球自转等天文因素的影响,结果表明,无论从地震的孕育还是从发生来看这些天文因素的影响都是不可忽视的,是值得进一步深入研究的.     

月震、LTP和地震

月震、ＬＴＰ和地震喻传赞人类赖以生存的地球，经常会发生地震，给人们生命财产造成很大的损失。观测表明：太阳有日震，星球有星震。那么月球有震吗？回答是肯定的，称为月震。自１９６９年７月２０日阿波罗１１号飞船登月以来，人类共６次登上月球，在上面安置了４个月...     

从云南最近三次强震看天体位置对地震的影响

本文详细分析了近期云南连续发生的三次强震与天体位置的关系。这三次大震都在期望期，又出现很多天文奇点，表明天体的引潮力影响也是这三次大震发震的重要因素。     

The precession and nutation of deformable bodies

The aim of the present paper will be to derive from the fundamental equations of hydrodynamics the explicit form of the Eulerian equations which govern the motion about the centre of gravity of self-gravitating bodies, consisting of compressible fluid of arbitrary viscosity, in an arbitrary external field of force. If the problem is particularized so that the external field of force represents the attaction of the sun and the moon, this motion would represent the luni-solar precession and nutation of a fluid viscous earth; if, on the other hand, the external field of force were governed by the earth (and the sun), the motion would define the physical librations of the moon regarded as a deformable body. The same equations are, moreover, equally applicable to the phenomena of precession and nutation of rotating fluid components in close binary systems, distorted by mutual tidal action; and the present paper contains the first formulation of the effects of viscosity on such phenomena.Investigation supported in part by the U.S. National Aeronautics and Space Administration under Contract No. NASW-1470.     

Tidal pattern instabilities on multi-moon planets

The equilibrium tide-generating forces in the lunar orbital plane of a planet of radius R are calculated for the case of N moons of mass Mi orbiting the planet at instantaneous polar coordinates (Di, αi). For the case of a single moon, there are only two high tides. For the case of two moons, it is found that there can exist a critical lunar orbital distance at which two high tides become unstable with respect to formation of three high tides. Bifurcation diagrams are presented which depict how the angular positions of the high and low tides on the planet vary with the lunar distances and lunar separation angle. Tidal stability diagrams, which illustrate the stability regions for various tidal patterns as a function of lunar distances and lunar separation angle, are presented for various values of D₂/D₁ and M₂/M₁. Generally speaking, the aforementioned tidal instability, and hence the propensity for formation of three high tides on a two-moon planet, exists over a significant range of lunar distances and separation angles provided that M₂/M₁∼³(D₂/D₁). For the case of N>2 moons, the tidal stability diagram becomes more complex, revealing a diversity of potential tidal patterns.     

Study of the Correlations Between Long-Periodic Terrestrial Tides and Occurrence of Earthquakes in the Vrancea Site

Following studies already performed by various authors concerning specific tectonic faults we analyse statistically the possibility that earthquakes in the very active seismological zone of Vrancea (Roumania) may be triggered by the vertical luni-solar tidal oscillations when retaining only the components other than diurnal and semi-diurnal. Our conclusion is that for three of the four leading tides, with periods 18.6 y, 182.62 d, and 13.66 d, the earthquakes occur preferentially during the ascending part of each of the sine oscillation. This property is especially visible for the leading 13.66 d fortnightly wave, and for the 18.6 y wave, for which results are very similar to that of Kilston and Knopoff (1983), who analyzed data related to the San Andreas fault in Southern California. As a complement, we carried out an analysis of earthquake periodicities w.r.t. the variation rate of each of the tides above, given by the half-period sine oscillation, which also leads to interesting possible correlations. This revised version was published online in July 2006 with corrections to the Cover Date.     

用太阳系主要天体的位置建立特大地震的时间预测模型

根据某类事件发生时太阳系主要运动天体的位置，通过对其历史资料的归算，尝试并设计出一种具有普适性的事件时间预测模型．以1900-1980年间全球所有8级及以上的99次地震为例，定义与天体特征位置(视黄经)相关的发震率，初步建立预测发震时刻的概率曲线．指出这可能成为研究地震预报问题的新途径．     

Researches in China on the Effects of Tides on the Earth Rotation

In this paper the tidal phenomena on the Earth are concisely specified, including solid tides, ocean tides and atmospheric tides due to the luni-solar tide-generating force, and the Earth pole tide due to the motion of the Earth's rotation axis (polar motion); as well as their effects on the Earth rotation. The outcomes of scientific researches of Chinese astronomers on these topics are described in some detail. These researches deal with the mechanisms responsible for tidal effects on the earth rotation, and on the measurements of the Earth rotation parameters. Finally, the effects discovered by Chinese researchers on the measurements of the period and change in period of pulsars are discussed. These effects are very small in magnitude but not negligible.     

Are Planetary Tides on the Sun and the Birthplace of Sunspots Related?

We study whether the birthplaces of sunspots (defined as the location of first appearance in the photosphere) are related to the planetary tides on the Sun. The heliocentric longitudes of newly emerging sunspots are statistically compared to the longitudes of tidal peaks caused by the tidal planets Mercury, Venus, Earth, and Jupiter. The longitude differences between new sunspots and tidal planets (and their conjugate locations) as well as the magnitudes of the vertical and horizontal tidal forces at the birthplace of new sunspots are calculated. The statistical distributions are compared with simulation results calculated using a random sunspot distribution. The results suggest that the birthplaces of sunspots (in the photosphere) are independent of the positions of tidal planets and the strength of tidal forces caused by them. However, since the sunspots actually originate near the tachocline (well below the photosphere) and it takes considerable time for the disturbances to reach photosphere, we hesitate to conclude that the formation of sunspots are not related to planetary positions.     

The motion of a lunar satellite

Presented in this theory is a semianalytical solution for the problem of the motion of a satellite in orbit around the moon. The principal perturbations on such a body are due to the nonspherical gravity field of the moon, the attraction of the earth, and, to a lesser degree, the attraction of the sun. The major part of the problem is solved by means of the celebrated von Zeipel Method, first successfully applied to the motion of an artificial earth satellite by Brouwer in 1959. After eliminating from the Hamiltonian all terms with the period of the satellite and those with the period of the moon, it is suggested to solve the remaining problem with the aid of numerical integration of the modified equations of motion.This theory was written in 1964 and presented as a dissertation to Yale University in 1965. Since then a great deal has been learned about the gravity field of the moon. It seems that quite a number of recently determined gravity coefficients would qualify as small quantities of order two. Hence, according to the truncation criteria employed, they should be considered in the present theory. However, the author has not endeavored to update the work accordingly. The final results, therefore, are incomplete in the lunar gravitational perturbations. Nevertheless, the theory does give the largest such variations and it does present the methods by which perturbations may be derived for any gravity terms not actually developed.