利用大地测量数据反演地震位错Love数和格林函数的理论与方法   总被引：1，自引：0，他引：1       下载免费PDF全文

杨君妍  孙文科 《地球物理学报》2020,63(8):2912-2923

本文提出一种利用大地测量观测技术反演地震位错Love数及格林函数的理论和方法.首先根据地震位错理论建立理论同震变化和大地测量观测值之间的关系式;其次,以2011年Tohoku-Oki地震(M_W9.0)为例,反演体现局部构造特征的地震位错Love数和格林函数.结果表明:反演得到的位错Love数与PREM模型下的位错Love数随深度和阶数变化不同,反映出局部三维地球模型的构造差异,由此计算的同震变化跟实际大地测量观测值的吻合度提高了～60%～～80%.通过大地测量观测数据反演的地震位错Love数能体现局部地球真实的构造信息,为该地区地震研究提供更加精确的地震位错格林函数.  相似文献   

青藏高原东北缘及邻区Rayleigh和Love波背景噪声层析成像   总被引：1，自引：0，他引：1       下载免费PDF全文

付媛媛  肖卓 《地球物理学报》2020,63(3):860-870

基于青藏高原东北缘及邻区流动密集地震台阵——喜马拉雅二期2013年12月至2015年8月期间的三分量连续波形数据,采用背景噪声成像方法获得了Rayleigh波周期为6~30 s和Love波6~25 s的二维相速度.6~12 s Rayleigh和Love波相速度在鄂尔多斯盆地及银川—河套地堑呈现明显的低速异常,而在西秦岭造山带和中亚造山带则显示高速异常.16~25 s的相速度同时受中下地壳及上地幔顶部速度结构和地壳厚度影响.此周期范围内,位于青藏高原的祁连地块和松潘甘孜地块北部呈现大范围相速度低速异常,青藏高原周边的鄂尔多斯和西秦岭造山带表现为高速异常.青藏高原与周边块体相速度的横向不均匀性,可能反映了构造活动或者地壳厚度的差异.此外,中亚造山带在周期16~20 s时,Rayleigh波相速度高低相间,但Love波大范围高速异常,两者差异可能反映了径向各向异性的影响.  相似文献   

基于地球简正模理论的Love数计算     

秦明  周江存  韩保民 《大地测量与地球动力学》2018,38(9):908-912

基于地球简正模理论,深入研究球对称、非自转、弹性、各向同性地球模型下,地球受到不同外力作用(体力和面力)而发生变形引起的位移场和外部空间重力场的变化;推导计算潮汐Love数、负荷Love数、正应力和剪应力Love数的计算公式,揭示简正模与Love数之间的内在联系;利用PREM地球模型计算地表的不同Love数,并与由常规的解微分方程组的数值积分方法获得的结果进行比较。结果表明,两者具有很好的一致性,说明公式的正确性。  相似文献   

Acoustic finite-difference modeling beyond conventi-onal Courant-Friedrichs-Lewy stability limit: App-roach based on variable-length temporal and spatial operators          下载免费PDF全文

Hongyu Zhou  Yang Liu  Jing Wang 《地震科学（英文版）》2021,34(2):123-136

Conventional finite-difference (FD) methods cannot model acoustic wave propagation beyond Courant-Friedrichs-Lewy (CFL) numbers 0.707 and 0.577 for two-dimensional (2D) and three-dimensional (3D) equal spacing cases, respectively, thereby limiting time step selection. Based on the definition of temporal and spatial FD operators, we propose a variable-length temporal and spatial operator strategy to model wave propagation beyond those CFL numbers while preserving accuracy. First, to simulate wave propagation beyond the conventional CFL stability limit, the lengths of the temporal operators are modified to exceed the lengths of the spatial operators for high-velocity zones. Second, to preserve the modeling accuracy, the velocity-dependent lengths of the temporal and spatial operators are adaptively varied. The maximum CFL numbers for the proposed method can reach 1.25 and 1.0 in high velocity contrast 2D and 3D simulation examples, respec-tively. We demonstrate the effectiveness of our method by modeling wave propagation in simple and complex media.  相似文献   

A Fast Method of Computing Group-Velocity Partial Derivatives for Love Waves Propagating in a Layer on a Half-Space     

Novotný  Oldřich 《Studia Geophysica et Geodaetica》1999,43(1):78-86

The dispersion relation for Love waves in a layer on a half-space is modified by introducing the wave number and its square instead of the phase velocity. The implicit function theorem is then used to derive the analytical formulae for the group velocity and for the phase- and group-velocity partial derivatives with respect to the parameters of the medium. The formulae are compared with those obtained by Novotný (1971) where the traditional formulation of the dispersion relation was used.  相似文献   

The Characteristics of the X-ray Flares (1-8, GOES) of the Different Classes and Their Variations in Two Cycles of Solar Activity     

Sotnikova R. T 《天文研究与技术》1999,(Z1)

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Time Series Modeling of Sunspot Numbers Using Long-Range Cyclical Dependence     

Luis A. Gil-Alana 《Solar physics》2009,257(2):371-381

This paper deals with the analysis of the sunspot number time series using a new technique based on cyclical long-range dependence. The results show that sunspot numbers have a periodicity of 130 months but, more importantly, that the series is highly persistent, with an order of cyclical fractional integration slightly above 0.30. That means that the series displays long memory, with a large degree of dependence between the observations that tends to disappear very slowly in time.  相似文献   

海洋负荷潮汐对地球重力场时变特征影响的理论研究     

张捍卫  许厚泽  周旭华 《天文学报》2004,45(1):88-94

地球重力场的海潮效应可以看作是一种负荷影响，海潮负荷对重力场的影响在某些台站(例如大洋中的岛屿以及沿海岸地区)可达微伽的量级，因此在高精度的地球重力场的研究中必须加以改正．从理论和方法上研究了海洋负荷潮汐对地球重力场的影响，在推导过程中回避了将点负荷密度展开为球谐函数，而是直接以负荷引力位为基础，并将海潮潮高引入表达式中，推导出了海潮对地球重力场影响的有关公式，同时探讨了在毫微伽精度上需要注意的一些问题．  相似文献   

Dispersion of group velocities of Rayleigh and Love waves and anisotropic properties of the Asian continent     

A.I. Seredkina  V.M. Kozhevnikov  O.A. Solovei 《Russian Geology and Geophysics》2018,59(4):448-458

We have studied the structures of the Earth’s crust and upper mantle of the Asian continent using a representative sample of dispersion curves of group velocities of fundamental-mode Rayleigh and Love waves for more than 3200 seismic paths. Maps of distributions of variations in group velocities with periods of 10 to 250 s over a spherical surface were calculated by the 2D tomography method. The maps reflect the deep structure of the Earth’s crust and upper mantle of the study area and give a tentative idea of the horizontal distribution of the anisotropic properties of the mantle matter. The obtained data are confirmed by the calculations of the velocity profiles of SV- and SH-waves for the entire Asian continent and for its regions. Vertically, anisotropy is observed to the depths of ~ 250 km, with its maximum in the depth range from the bottom of the crust to 150 km.  相似文献   

On the Stochasticity of the Asteroid Belt     

Claude Froeschlé  Robert Gonczi  Elena Lega  Ugo Locatelli 《Celestial Mechanics and Dynamical Astronomy》1997,69(1-2):235-254

The study of the stochasticity of the asteroid belt requires the analysis of a large number of orbits. We detect the dynamical character of a set of 5 400 asteroids using the Fast Lyapunov Indicator, a method of analysis closely related to the computation of the Lyapunov Characteristic Exponents, but cheaper in computational time. For both regular and chaotic orbits we try to associate the motion to the underlying resonances network. For it we consider different methods of classification of rational numbers proposed by number theory, and we choose the one which seems to be strictly related to the dynamical behaviour of a system. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献