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Wavelet-based multifractal analysis of earthquakes temporal distribution in Mammoth Mountain volcano,Mono County,Eastern California 总被引：1，自引：1，他引：0
This paper presents a wavelet-based multifractal approach to characterize the statistical properties of temporal distribution of the 1982–2012 seismic activity in Mammoth Mountain volcano. The fractal analysis of time-occurrence series of seismicity has been carried out in relation to seismic swarm in association with magmatic intrusion happening beneath the volcano on 4 May 1989. We used the wavelet transform modulus maxima based multifractal formalism to get the multifractal characteristics of seismicity before, during, and after the unrest. The results revealed that the earthquake sequences across the study area show time-scaling features. It is clearly perceived that the multifractal characteristics are not constant in different periods and there are differences among the seismicity sequences. The attributes of singularity spectrum have been utilized to determine the complexity of seismicity for each period. Findings show that the temporal distribution of earthquakes for swarm period was simpler with respect to pre- and post-swarm periods. 相似文献
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利用多重分形维数谱估计的Hill方法，讨论了新西兰地震活动区地震活动的震源分布、震中分布以及时间间隔分布的多重分形特征．结果表明，该地区浅源地震的震中分布和震源分布在给定不同的起始震级的条件下均具有明显的丛集特征；对于中、深源地震这种特征不甚明显．而地震活动时间间隔分布则无论对于浅源和中、深源地震均呈单重分形的性质，但具有分形性质的尺度范围有较大的差别．这些结果表明，浅源地震与中、深源地震的活动特征显著不同． 相似文献
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Andrea Cortis Carlos E. Puente Bellie Sivakumar 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(7):897-906
We present the extension of a deterministic fractal geometric procedure aimed at representing the complexity of patterns encountered
in environmental applications. The procedure, which is based on transformations of multifractal distributions via fractal
functions, is extended through the introduction of nonlinear perturbations in the generating iterated linear maps. We demonstrate,
by means of various simulations based on changes in parameters, that the nonlinear perturbations generate yet a richer collection
of interesting patterns, as reflected by their overall shapes and their statistical and multifractal properties. It is shown
that the nonlinear extensions yield structures that closely resemble complex hydrologic spatio-temporal datasets, such as
rainfall and runoff time series, and width-functions of river networks. The implications of this nonlinear approach for environmental
modeling and prediction are discussed. 相似文献
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强震前后广义地震应变释放过程的丛集特征 总被引：1，自引：0，他引：1
利用基于小波变换的多重分形奇异谱估计方法,研究了部分强震前后地震活动广义应变.释放过程的多重分形特征。结果表明,晨中区附近- -定范围内地展活动广义应变释放过程具有多重分形特征,但多重分形维数谱随7变化复杂,在强震发生前多重分形维数谱没有明显的变化。广义地震应变释放过程的多重分形奇异谱形态和Hausdorff奇异指数范围能提供更多关于地屣活动过程的信息,特别当η取较大值时Hausdorff奇异指数范围在强晨前明显变窄。研究还表明深源地展和浅源地晨发生前广义应变释放过程多重分形特征存在明显不同。 相似文献
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Using the Hill estimator,general multifractal characteristics of events in the New Zealand area have been dis-cussed.Results show that the spatial distribution of shallow events has apparent clustering characteristics,inde-pendent of the threshold magnitude;but for deep events these characteristics are not clear.While the time interval distribution has obvious clustering characteristics both for deep and shallow events,although with a different scal-ing range,the Hill estimates tend to indicate that the time interval distribution has a unifractal rather than a multi-fractal nature.All above reveal that the seismicity nature for shallow and deepevents is apparently different. 相似文献
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Multifractal versus monofractal analysis of wetland topography 总被引：2，自引：1，他引：1
I. Tchiguirinskaia S. Lu F. J. Molz T. M. Williams D. Lavallée 《Stochastic Environmental Research and Risk Assessment (SERRA)》2000,14(1):8-32
The land surface elevation distribution will serve as fundamental input data to any wetland flow model. As an alternative
to the traditional smooth function approach to represent or interpolate elevation data, we explore the use of Levy monofractals
and universal multifractals as a means for defining a statistically equivalent topography. The motivation behind this effort
is that fractals, like natural topography, are irregular, they offer a way to relate elevation variations measured at different
scales, and the relationships are of a statistical nature. The study site was a riparian wetland near Savannah, GA, that contained
beavers, and a total of four elevation transects were examined. The elevation increments showed definite non-Gaussian behavior,
with parameter values, such as the Hurst coefficient and Lévy index (α), depending on the question of presence of beaver activity.
It was obvious that the data were highly irregular, especially the transects influenced by beavers. Significantly different
α values were obtained depending on whether the entire data set or just the tails were examined, which demonstrated inability
of the monofractal model to reflect fully the irregularity of wetland data. Further analysis confirmed definite multifractal
scaling, and it is concluded that the multifractal model is superior for this data set. Universal multifractal parameters
are calculated and compared to those obtained previously for more typical terrain. Although it is difficult to consider a
unique universal multifractal parameter α for the entire wetland, multifractal-like scaling was evident in each transect as
reflected by the nonlinear behaviors of the scaling functions. We demonstrate a good agreement between theory and measurements
up to a critical order of statistical moments, q
D
, close to 3.5 and obtain realistic unconditioned simulations of multifractal wetland topography based on our parameter estimates.
Future work should be devoted to conditioning multifractal realizations to data and to obtaining larger data sets so that
the question of anisotropy may be studied. 相似文献
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Jian-Ping Yan Xu He Bin Geng Qin-Hong Hu Chun-Zhen Feng Xiao-Pan Kou Xing-Wen Li 《应用地球物理》2017,14(2):205-215
Pore structure characteristics are important to oil and gas exploration in complex low-permeability reservoirs. Using multifractal theory and nuclear magnetic resonance (NMR), we studied the pore structure of low-permeability sandstone rocks from the 4th Member (ES4) of the Shahejie Formation in the south slope of the Dongying Sag. We used the existing pore structure data from petrophysics, core slices, and mercury injection tests to classify the pore structure into three categories and five subcategories. Then, the T2 spectra of samples with different pore structures were interpolated, and the one- and three-dimensional fractal dimensions and the multifractal spectrum were obtained. Parameters α (intensity of singularity) and f (α) (density of distribution) were extracted from the multifractal spectra. The differences in the three fractal dimensions suggest that the pore structure types correlate with α and f (α). The results calculated based on the multifractal spectrum is consistent with that of the core slices and mercury injection. Finally, the proposed method was applied to an actual logging profile to evaluate the pore structure of low-permeability sandstone reservoirs. 相似文献
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本文提出形成地震序列的多分形断层模型并利用分形分维理论讨论该模型及其序列。给出本模型的震级—频度关系、余震序列中强余震预报公式和多分维D_q—q关系式,探讨了利用多分维预报地震的有效性。 相似文献
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Using multifractal spectrum estimating method based on the wavelet,the multifractal characteristics of GSR of earthquakes in China,Japan and New Zealand regions have been studied.It is shown that the multifractal spectra of GSR are obviously different in inter-and intra-plate regions.Moreover,though Japan and New ZeaIand are all located at the boundary of plates,West and East China are all characterized of continental tectonic structure,the multifractal spectra of GSR for both the two regions are also different.Further analysis shows that the natures of multifractal spectra of GSR are somehow related to the complexity of tectonics. 相似文献
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Introduction For a long time, the seismologists have paid great attentions to the research on the spatio- temporal distribution of earthquake intensity, which provide us with significant information for the researches on crustal stress variation, tectonic activity and earthquake risk prediction in a certain spatio-temporal region. The existing results have shown consistently that the intensity of earth- quakes is characterized by non-stability, non-linearity in temporal domain and non-uniformi… 相似文献
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We review recent studies of the statistics of return intervals (i) in long-term correlated monofractal records and (ii) in
multifractal records in the absence (or presence) of linear long-term correlations. We show that for the monofractal records
which are long-term power-law correlated with exponent γ, the distribution density of the return intervals follows a stretched
exponential with the same exponent γ and the return intervals are long-term correlated, again with the same exponent γ. For
the multifractal record, significant differences in scaling behavior both in the distribuiton and correlation behavior of
return intervals between large events of different magnitudes are demonstrated. In the absence of linear long-term correlations,
the nonlinear correlations contribute strongly to the statistics of the return intervals such that the return intervals become
long-term correlated even though the original data are linearly uncorrelated (i.e., the autocorrelation function vanishes).
The distribution density of the return intervals is mainly described by a power law. 相似文献
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Multifractal characteristics of the jet turbulent intensity depending on the outfall nozzle geometry
Yongwon Seo Siwan Lyu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2016,30(2):653-664
The multifractal measure enables an examination of the characteristics of a quantity distributed over a domain. This study examined the multifractal properties of turbulent intensities obtained from jet discharge experiments, where three types of nozzle geometries were examined in terms of the velocity fields and turbulent characteristics using particle image velocimetry. Depending on the nozzle geometry, the experimental results showed that the distribution of turbulent intensities and resulting dilution exhibited different behaviors. The experiment also showed that the transversal velocity profiles are similar to each other regardless of the outfall nozzle shapes and demonstrates the traditional similarity assumption at the same time. The multifractal exponents of the turbulent intensities were obtained with Box Count Method in a two-dimensional space. The results showed that the turbulent intensities obtained in two-dimensional space have a common multifractal spectrum, which was not the case for the velocity or shear stress observed in the same space. Although the transversal velocity profiles are similar, the multifractal exponent clearly shows a difference depending on the outfall geometries. In particular, the minimum value of the Lipschitz–Hölder exponent (α min) and the entropy dimension (α 1) tends to increase as turbulent intensity and dilution increase. These results suggest that the multifractal properties can be utilized potentially to categorize and evaluate the discharge outfall capabilities in terms of the resulting dilution. 相似文献
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The nonlinear effects on the characteristics of gravity wave packets: dispersion and polarization relations 总被引：6，自引：0，他引：6
By analyzing the results of the numerical simulations of nonlinear propagation of three Gaussian gravity-wave packets in isothermal atmosphere individually, the nonlinear effects on the characteristics of gravity waves are studied quantitatively. The analyses show that during the nonlinear propagation of gravity wave packets the mean flows are accelerated and the vertical wavelengths show clear reduction due to nonlinearity. On the other hand, though nonlinear effects exist, the time variations of the frequencies of gravity wave packets are close to those derived from the dispersion relation and the amplitude and phase relations of wave-associated disturbance components are consistent with the predictions of the polarization relation of gravity waves. This indicates that the dispersion and polarization relations based on the linear gravity wave theory can be applied extensively in the nonlinear region. 相似文献
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赵灿晖 《地震工程与工程振动》2006,26(6):127-132
根据三类钢管混凝土构件的荷载位移曲线论述了Prager硬化规则应用于钢管混凝土材料非线性分析的合理性,由随动硬化材料屈服面方程的全微分出发,采用塑性势理论推导了钢管混凝土梁单元的非线性刚度矩阵。建立了钢管混凝土梁单元的初始屈服面方程,由Prager硬化规则建立了后继屈服面方程,并推导了屈服面移动量的计算公式。根据钢管混凝土的特点,探讨了确定硬化参数的方法。算例的结果有良好的精度。 相似文献
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This study aims to reveal the multi-scaling behavior and quantify the irregularity of near-fault earthquake ground motions from a new perspective of multifractal theory. Based on multifractal detrended fluctuation analysis, the multifractal characteristic parameters of acceleration time series for typical near-fault ground motions are calculated, and their correlations with two period parameters (i.e., mean period Tm and characteristic period Tc) and box-counting fractal dimensions are analyzed. Numerical results of strong nonlinear dependence of generalized Hurst exponents h(q) upon the fluctuation orders q indicate that near-fault ground motions present the multifractal properties and long-range correlation obviously. Furthermore, the scaling exponent h(2) of near-fault records has a strong correlation with their periods Tm and Tc, and strongly negative correlation with their box dimension. Moreover, h(2) can be regarded as a measure of frequency content and irregularity degree of strong earthquake ground motions. Finally, it is pointed out that the long-range correlation of small and large fluctuation is the major source of multifractality of near-fault ground motions. 相似文献
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地震活动性的多重分维特征 总被引：2，自引：0，他引：2
本文根据多重分维的定义,研究了华北和西北地区地震的空间和时间分布的多重分维特征。结果表明,地震时空分布的多重分维特征能较好地描述地震时空分布的有序性。一般在地震活动性较强的阶段,多重分维D_q,尤其是高阶的D_q有明显的异常变化,其D_q—q曲线较陡;而D_q—q曲线变化较平缓的阶段,统计区内一般无大震发生。 相似文献