全球地震纬度分布特征和北纬35°峰值异常浅析   总被引：1，自引：0，他引：1  

唐燕娟 《华北地震科学》1997,(2)

本文取1900年─1980年全球Ms≥6．0地震7936次分析后发现，地震发生在南北回归线（23°5N—23°5S）之间占49．69％，发生在南北极因（63°5N—63°5S）之间占99．17％，发生在南北极圈外只占0．83％，即很少发生地震；其中8级地震98次，在35°N线为高峰。又分析了公元648年─1979年全球M≥8级地震257次主要亦集中在35°N线附近。尤其是历史上破坏性极大的地震在35°N线附近者多。这些现象可能和地球自转有一定关系。  相似文献   

由一次西周日食记载得到的地球自转变化     

韩延本 《地球物理学进展》1997,12(3):90-93

本文结合１９９７年３月９日全食的新疆观测及地球自转变化趋势讨论了发生在中国西周时期的一次日食的记载，以及由此得到的地球自转速度变化值。  相似文献   

A new nutation series for a more realistic model earth   总被引：1，自引：0，他引：1  

J. Schastok 《Geophysical Journal International》1997,130(1):137-150

The frequency-dependent correction coefficients with respect to the forced nutations of a rigid earth are computed using the complex scalar gravitational-motion equations for an earth model with an anelastic mantle. Oceanic loads and tidal currents enter the model via outer boundary conditions. The ellipticity of the core-mantle boundary and the dynamical ellipticity are adjusted to observations. This requires the behaviour inside the model earth to be regarded as non-hydrostatic. Some relevant equations for the evaluation of boundary conditions and some terms in the equations of motion are expanded to second order in ellipticity. The computation of the equipotential-surface ellipticity profile is carried to second order as well. These second-order expansions lead to increased accuracy of the results in general. Moreover, one achieves a better reliability for the integration at frequencies close to a resonance. This allows the integration of the equations of motion at any relevant nutation period without the need for a normal-mode expansion. A complete new nutation series for a realistic model earth is presented.  相似文献   

地幔对流中的科里奥利力     

杨学祥  陈殿友 《吉林大学学报(地球科学版)》1996,(2)

马宗晋认为，岩石圈的西向漂移和地幔东向运动的定向性显示了地球自转变化的导向作用［１］。本文证明，地球自转中的一种惯性力──科里奥利力是产生地球各圈层差异旋转的原因。  相似文献   

热幔柱的启动动力   总被引：4，自引：1，他引：4  

杨学祥  张玺云 《世界地质》1996,15(2):68-74

科氏力是地球各圈层差异旋转的原因。在重力分异过程中，随着地球质量不断向地心集中，地球自转动能也不断向地核集中，从而产生圈层分化和差异旋转。  相似文献   

地球运动的超非线性分析   总被引：2，自引：0，他引：2       下载免费PDF全文

杨文熊  马波 《地震工程学报》1997,19(4):98-100

根据超非线性速度理论，研究了地球的自转状态，得知地球自转的角速度沿半径方向有突变和减小，并由此计算了地壳相对于地核的角速度差值，算得赤道表面每年西移１．７５ｃｍ，符合已报道的观测数据。  相似文献   

地球内核快速旋转的发现与全球变化的轨道效应   总被引：3，自引：0，他引：3  

杨学祥  陈震  刘淑琴  宋秀环  陈殿友 《地学前缘》1997,(Z1)

科里奥利效应是产生内核快速旋转的主要原因。科氏力使上升物质向西漂移，下降物质向东漂移；造成地球外层自转减速，地球内层自转加速。所以，自旋体中的垂直运动可以产生大规模的水平运动——圈层差异旋转。地震波测量结果表明，内核旋转速度每年比地壳地幔快１°。对于一个内核差异旋转的地球，太阳辐射不仅形成地磁场的内外磁尾和地壳与内核的反向振动，而且影响核幔角动量交换和电磁耦合，从而控制了地球内能的释放，形成天文周期与地质旋回的一一对应关系。地球轨道和太阳轨道的全球变化响应，为太阳辐射量变化控制地球内能释放提供了证据  相似文献   

Neotectonic deformation in the transition zone between the Dead Sea Transform and the East Anatolian Fault Zone, Southern Turkey: a palaeomagnetic study of the Karasu Rift Volcanism     

O Tatar  J.D.A Piper  H Gürsoy  A Heimann  F Kobulut 《Tectonophysics》2004,385(1-4):17-43

In southern Turkey ongoing differential impingement of Arabia into the weak Anatolian collisional collage resulting from subduction of the Neotethyan Ocean has produced one of the most complex crustal interactions along the Alpine–Himalayan Orogen. Several major transforms with disputed motions, including the northward extension of the Dead Sea Fault Zone (DSFZ), meet in this region. To evaluate neotectonic motion on the Amanos and East Hatay fault zones considered to be northward extensions of the DSFZ, the palaeomagnetism of volcanic fields in the Karasu Rift between these faults has been studied. Remanence carriers are low-Ti magnetites and all except 5 of 51 basalt lavas have normal polarity. Morphological, polarity and K–Ar evidence show that rift formation occurred largely during the Brunhes chron with volcanism concentrated at 0.66–0.35 Ma and a subsidiary episode at 0.25–0.05. Forty-four units of normal polarity yield a mean of D/I=8.8°/54.7° with inclination identical to the present-day field and declination rotated clockwise by 8.8±4.0°. Within the 15-km-wide Hassa sector of the Karasu Rift, the volcanic activity is concentrated between the Amanos and East Hatay faults, both with left lateral motions, which have rotated blocks bounded by NW–SE cross faults in a clockwise sense as the Arabian Block has moved northwestwards. An average lava age of 0.5 Ma yields a minimum cumulative slip rate on the system bounding faults of 0.46 cm/year according with the rate deduced from the Africa–Arabia Euler vector and reduced rates of slip on the southern extension of the DSFZ during Plio-Quaternary times. Estimates deduced from offsets of dated lavas flows and morphological features on the Amanos Fault Zone [Tectonophysics 344 (2002) 207] are lower (0.09–0.18 cm/year) probably because they are limited to surface fault breaks and do not embrace the seismogenic crust.Results of this study suggest that most strike slip on the DSFZ is taken up by the Amanos–East Hatay–Afrin fault array in southern Turkey. Comparable estimates of Quaternary slip rate are identified on other faults meeting at an unstable FFF junction (DSFZ, East Anatolian Fault Zone, Karatas Fault Zone). A deceleration in slip rate across the DSFZ and its northward continuation during Plio-Quaternary times correlates with reorganization of the tectonic regime during the last 1–3 Ma including tectonic escape within Anatolia, establishment of the North and East Anatolian Fault Zones bounding the Anatolian collage in mid–late Pliocene times, a contemporaneous transition from transpression to transtension and concentration of all basaltic magmatism in this region within the last 1 Ma.  相似文献   

适用于大旋转角的三维基准转换的一种简便模型   总被引：33，自引：0，他引：33  

陈义  沈云中  刘大杰 《武汉大学学报(信息科学版)》2004,29(12):1101-1105

基于大角度的空间直角坐标转换，提出了以方向余弦为参数、适用于任何角度旋转的空间直角坐标转换的简明计算方法。  相似文献   

Impact of inner core rotation on outer core flow: the role of outer core viscosity     

J. Y. Guo  P. M. Mathews  Z. X. Zhang  J. S. Ning 《Geophysical Journal International》2004,159(1):372-389

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