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应用分数维理论与方法,对地震活动时间分布不均匀结构,建立自相似分形集。利用其相似维数D的变化特征,来研究辽宁省中强地震前后和显著地震活动的时间结构。发现中强地震前D值随时间系统减小,余震序列的D值变大,前震序列的D值明显偏低。对震群活动的研究表明,一般震群活动的D值均较高,而前兆震群活动的D值也明显偏低。 相似文献
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使用Wolf等(1985)建议的方法,计算了服从双状态变量本构律的单自由度弹性摩擦系统奇怪吸引子的Lyapunov指数谱.当该系统用无量纲形式表示,且参数值为β1=1.00β2=0.84ρ=0.048φ0=0.19885K=0.0685时,系统进入混沌态.奇怪吸引子的Lyapunov指数谱的计算结果为λ1=0.0179λ2=0λ3=-0.1578这里, ,φ和f分别为无量纲的状态变量、滑动速率的对数和摩擦应力;β1,β2,ρ,φ0和K是无量纲的系统参数.同时,还计算了该奇怪吸引子的维数,结果为DL=D0=2.11这里,DL和D0分别表示Lyapunov维数和容量维数. 相似文献
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用来描述地震活动性的基本参数有三:古登堡-里克特关系式的b值,空间分维D3和时间分Dt。主要地震序列或余震前,b值和空间分维(二维)出现显著的减小,这几种情况以前曾报道过。这里我们根据相关积分原理利用分形方法研究意大利三个重要的地震带上地震空间(二维)分布的时间变化。在三个地震带上,Ds都表现出很大的可变性,该变化与主要地震有很好的相关性,清楚地显示出一个地震回的开始与结束,最后,说明大多数主要地 相似文献
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地震分布空间分维数Ds与b值之间关系探讨谢永郑治真(中国北京100045国家地震局地震数据信息中心)主题词:b值空间分维数Ds引言地球科学中的许多现象都有自相似性质,地震的空间分布和震级分布也具有自相似性。Ds和b值正是反映地震空间分布和震级分布的自... 相似文献
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本用最大似然法对云南省几个不同地区大震发生前后时期的b值进行了扫描,并用数盒子法和相关函数法计算了相应时期内地震震中分布的容量D0,信息维D1和关联维D2的随时间变化,用最小二乘法拟合了不同地区b值与各阶段分维值的关系,发现各阶分维与b值均有正的线性相关关系,此结果与AKi从理论上推出的D=2b基本一致,本从分维与b值的物理实质对所得结果进行了分析和探讨。 相似文献
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地震活动性参数的不确定性及其对区划结果的影响 总被引:4,自引:1,他引:4
以晋中南地区和四川攀西地区为例,探讨了地震活动性参数的不确定性及其对区划结果的影响。不同的资料处理方案会造成参数的不确定性,其b值的变化范围在0.55-0.83之间,v4值的差异可达1.5-2.5倍。 相似文献
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G. S. Ivanov-Kholodny E. I. Mogilevsky V. Ye. Chertoprud 《Geomagnetism and Aeronomy》2006,46(2):139-145
Using the data of 1960–1999 on solar magnetic fields on the source surface and the Higuchi method, the fractal dimension of changes in the solar magnetic field energy at various heliolatitudes and in different time intervals is analyzed. The fractal dimension obtained on a moving 1-year interval displays substantial time variations. The 11-year cycle, which dominates at high latitudes, and quasi-biennial variations (QBVs), which dominate at low latitudes and are similar to QBVs of solar activity indices, are traced in these variations. Thus, solar QBVs that appear in all heliomagnetic activity indices are also present in the fractal structure of the solar magnetic field variations. 相似文献
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A. Mete Isikara 《Pure and Applied Geophysics》1973,104(1):544-552
Summary The sunspot cycle variation of the amplitude of the solar magnetic variation has been investigated for magnetically moderate, quiet and disturbed days at Istanbul for the period 1949–1968, and fairly good linear relationship has been found forZ andD components of the earth's magnetic field. In some cases, it is rather difficult to say that there is any linear relationship between sunspot number and the amplitude of theH component of the earth's magnetic field. Meanwhile,K indices has also been considered with sunspot number by means of multiple regression analysis to overcome some uncertainties in this investigation. 相似文献
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In the present study, the deterministic chaotic behaviour of interplanetary magnetic field (IMF) under various geomagnetic conditions of low and high solar active periods was analyzed, using the time series of IMF |B| and Bz, by employing chaotic quantifiers like, Lyapunov exponent, Tsallis entropy, correlation dimension, and non-linear prediction error. We have investigated whether the chaotic behaviour of interplanetary magnetic field would modify, when it produces major geomagnetic storms, and how it depends on the phase of solar activity. The yearly average values of Lyapunov exponent for the time series of IMF |B| and Bz, show solar flux dependence, whereas those values of entropy, correlation dimension and non-linear prediction error had no significant solar flux dependence. The yearly average values of entropy for quiet periods are higher compared to those values for major storm periods belonging to low/high solar active conditions, for both the time series |B| and Bz. 相似文献
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本文根据苏黎世天文台太阳黑子11年周期资料和太阳黑子磁场磁性变化周期特征,构建了太阳黑子磁场磁性指数MI(Magnetic Index)时间序列.分析表明:太阳活动磁性周期平均长度为222年,但是每个周期长度是不相等的;多数情况周期短时磁性指数较大,对应太阳活动水平强;周期变长时磁性指数较小,对应太阳活动水平较弱;太阳黑子磁场磁性指数序列也具有80~90年的世纪周期. 进一步研究指出,太阳黑子磁场磁性指数曲线由极小值升至极大值时期,太阳磁场南向,行星际磁场磁力线与地磁场磁力线重联,此时磁层为开磁层,太阳风将携带大量等离子体从向阳面进入地球磁层,从而使输入的动量、能量和物质大幅度增加,与北半球对流层增温时期对应;太阳黑子磁场磁性指数曲线由极大值下降至极小值时期,太阳磁场北向,与磁层顶地磁场同向,行星际磁场不会与地磁场发生重联,此时磁层为闭磁层,这种情况下,只有少数带电粒子能够穿越磁力线进入地球磁层,与北半球对流层降温时期对应. 相似文献
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D. V. Erofeev 《Geomagnetism and Aeronomy》2012,52(8):1097-1106
The behavior of correlation tensors of fluctuations in the solar wind magnetic field and velocity is studied during different phases of a solar cycle on the basis of a 45-year measurement series of solar wind parameters. It is found that the orientation of fluctuations in the magnetic field and velocity is approximately axisymmetric relative to the direction of a local magnetic field during high solar activity. This symmetry is violated significantly during periods of low solar activity, and deviations from the symmetry are regular and oppositely directed during minima of even and odd 11-year cycles, which is probably connected with variations in the orientation of the Sun??s magnetic field. The dependence of the power of fluctuations on the local magnetic field direction reveals significant deviations from local symmetry during all phases of a solar cycle, especially for velocity fluctuations. 相似文献
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Nonlinear and multifractal approaches of the geomagnetic field 总被引:2,自引:0,他引:2
L. Hongre P. Sailhac M. Alexandrescu J. Dubois 《Physics of the Earth and Planetary Interiors》1999,110(3-4):157-190
Recent nonlinear dynamics techniques have been developed to analyse chaotic time series data. We first summarize the procedure which gives an appropriate reconstruction of the unknown dynamics from scalar measurements in a pseudophase space. It permits, firstly, the representation of the trajectories of the dynamical system—they define an attractor when the system is dissipative—by preserving its topological properties. We then present the invariant measures and ergodic quantities such as the multifractal spectrum and Lyapunov exponents which can be estimated on the reconstructed attractor. The multifractal analysis provides us with a characterization of the scaling energy of the process whereas the Lyapunov exponent gives another statistical measure of the stability of the dynamics. The estimation of these quantities was tested on synthetic data. The nonlinear and multifractal analyses were finally applied to the hourly mean values of the magnetic field recorded at the Eskdalemuir (ESK) observatory over 79 years (692,520 data measurements for each component). The estimations of a 5-dimensional pseudo-phase space and a positive Lyapunov exponent confirm the possibility of low-dimensional deterministic chaos in the magnetic field observations at ESK observatory. The correlation between the solar activity (the Wolf number), the unstable nature of the magnetic field, and the singularity spectrum points out the forcing of the solar cycles on the dynamics of the magnetic field at ESK observatory. 相似文献
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Ralph Markson 《Pure and Applied Geophysics》1971,84(1):161-200
Summary The basic thesis of this paper is that the proper scope of meteorology should include, besides the earth's atmosphere, the sun's atmosphere (the solar corona), the associated interplanetary magnetic field, and lunar modulation of this environment. Recent advances in space science have enabled us to make direct measurements in this region for the first time. The shape and characteristics of the magnetosphere have been completely redefined during the last ten years from a simple magnetic dipole to the present model with an elongated tail stretched out by the solar wind. The interplanetary magnetic field has been defined with its spiral structure and sectors tied into the solar surface. This provides a magnetic link between the sun and earth. It is probable that extra-terrestrial factors do play a role in regulating weather, although the extent of this influence remains to be determined. Possibly such effects are most significant or easily detectable in the realm of atmospheric electricity. In view of the limitations in our present knowledge of all the variables responsible for regulating weather, it would seem appropriate to pursue the study of extra-terrestrial influences. Such research could lead to a better understanding of atmospheric circulation, precipitation mechanisms and thunderstorms. The field of meteorology which might particularly benefit from such research is long range weather forecasting. 相似文献
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N. Ya. Maksimov 《Geomagnetism and Aeronomy》2006,46(5):635-637
A comparison of the time variations in the geomagnetic field characteristics (the u and aa indices of geomagnetic activity) with the variation in the solar magnetic dipole inclination shows close agreement between these variations. The linear correlation coefficients between the u and aa indices, the u index and solar magnetic dipole inclination, and the aa index and solar magnetic dipole inclination are 0.93, 0.45, and 0.49, respectively. This makes it possible to extend studying the IMF evolution in the 11-year cycle of solar activity to the 170-year period beginning from 1835. It has been indicated that the time variation in the heliospheric current sheet (HCS) surface deviation from the solar magnetic equator plane, calculated based on the actual HCS configuration, is in good agreement with the time variation in the amplitude of the Fourier series second harmonics in a harmonic analysis of the series of daily data on the IMF sign in the vicinity of the Earth. The linear correlation coefficient is 0.9 in this case. 相似文献