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1.
新疆塔里木盆地艾协克—桑塔木南地区油气地球化学指标的多重分形性分析 总被引：1，自引：0，他引：1
用分形与多重分形的方法研究地球化学场中地球化学指标的分布规律具有重要的意义。本文运用多重分形矩方法研究了新疆塔里木盆地艾协克一桑塔木南地区2000km^2内采集的2085个土壤样中20项油气化探指标的多重分形谱函数形态特征。结果表明，主要成油气指示指标的多重分形谱基本上呈单一“钩状”，显示较弱的多重分形或单一分形；而其他指标多显示较强的多重分形特征。这些性质在研究区广泛存在，将对区域含油性研究有重要的指示意义。 相似文献
2.
Measuring multifractality in seismic sequences 总被引：6，自引：0，他引：6
We investigated the multifractal structure of the interevent times between successive earthquakes that occurred in Umbria-Marche, which is one of the most seismically active areas of central Italy. We used the Multifractal Detrended Fluctuation Analysis (MF-DFA), which permits detection of multifractality in nonstationary series. Analyzing the time evolution of the multifractal behaviour of the seismic sequence, a loss of multifractality during the aftershocks is revealed. 相似文献
3.
Multifractal Analysis of the Arnea,Greece Seismicity with Potential Implications for Earthquake Prediction 总被引：2，自引：0，他引：2
Two-dimensional multifractal analysis is performed in a seismic area of Northern Greece responsible for recent strong earthquakes, including the Arnea sequence of May 1995, culminating in a Mw 5.3 event on 4/5/1995. It is found that multifractality gradually increases prior to the major seismic activity and that declusterization replaces clusterization not long before its initialization. The fractal dimensions D(q) (q > 0) abruptly drop for aftershocks, reflecting their very strong spatial clustering. The observed seismicity patterns seem to be compatible with a percolation process. Before the main sequence, the fractal dimension is consistently in the range 1.67–1.96 (standard deviation included). Percolation theory predicts 1.9 for 2D percolation clusters and 1.8 for the backbone of 3D percolation clusters. If the observed gradual increase in multifractality is due to multifractality reaching a maximum prior to the major slip (percolation), this may enable us to roughly estimate its time of occurrence. 相似文献
4.
To quantify the spatial distribution of geochemical elements, the multifractality indices for Zn, Cu, Pt, Pd, Cr, Ni, Co, Pb, and As in lake-sediment samples in the Shining Tree area in the Abitibi area of Ontario are determined. The characterization of multifractal distribution patterns is based on the box-counting moment method and involves three functions: a mass exponent function (q); Coarse Hölder Exponent (q); and fractal dimension spectrum f( (q)). Properties of these functions at different values of q, characterize the spatial distribution of the variable under study. It is shown that the degree of multifractality defined by (1) can be used as a measure of irregularity of geochemical spatial dispersion patterns. The variations of Zn and Cu in the study area are characterized by relatively low degree of multifractality, whereas those for Pt, Pd, Cr, Ni, and Co; and particularly for As and Pb are characterized by higher multifractality indices.In the case of Zn and Cu, singularity spectra are close to a monofractal compared to the ones for As an Pb. The determination of multifractality indices allows us, in a quantitative way, to study the pattern of metal dispersions and link them to different physical processes, such as metal adsorption by organic material or glaciogenic processes. 相似文献
5.
成矿元素品位的变化受控于长期地质作用过程,具有较强的非线性特征,定量刻画其变化特征有助于深入理解成矿过程,并为找矿预测提供理论依据。运用多重分形去趋势移动均值（MFDMA） 法,分析云南普朗斑岩型铜矿床4号勘探线钻孔Cu元素品位的多重分形特征及其对矿化强度的指示意义。结果显示：所有钻孔Cu元素品位具有多重分形特征,且不同矿化等级的元素分布存在局部奇异性差异,多重分形强度随矿化强度等级减弱而增加;这些特征指示在钾硅化带—带内侧强矿化钻孔的高品位相对聚集,而带外侧角岩化—青磐岩化带的高品位相对分散;通过数据随机重排技术推测Cu品位多重分形结构奇异性差异是由其分布概率密度和长相关性共同作用引起,后者的作用贡献大于前者。 相似文献
6.
多重分形理论能够有效地分析地球化元素局部富集和贫化规律。对取自个旧高松矿田的1 783件断裂构造地球化学样品的13种元素进行了多重分形统计以及局部奇异性方法分析。结果表明:多重分形维谱函数α-f(α)曲线呈连续上凸的特征,曲线的不对称反映了元素局部富集程度差异,并据此将13种元素划分为包含Sn、Cu、Pb、Ag、As、Mn在内的主要成矿元素组合以及包含Zn、Sb、Cd、W、Mo、Bi、Hg的次要成矿元素或伴生元素组合。多重分形的特征值τ″(1)以及Dq的变化规律表明:在主要成矿元素中,Sn在断裂空间上局部富集程度最高,其次为Ag,而Cu相对最低,各元素的τ″(1)值与对应的变异系数的大小具有较为显著的相关性;各元素在空间上的奇异性指数α增强了地球化学富集地段的指示信息,可以作为判别局部富集的重要参数。运用多重分形方法可揭示矿化元素局部富集的奇异性特征以及空间局部富集规律。 相似文献
7.
新疆阿尔泰地区断裂控矿的多重分形机理 总被引：3，自引：2，他引：1
新疆阿尔泰地区断裂构造非常发育并对热液成矿有重要控制作用。分形分析表明该区断裂和矿床的空间分布均为多重分形分布,断裂的奇异指数为1.597～2.403,多重分维谱值为0.551～1.706;矿床的奇异指数为0.925～2.287,分维谱值为0.138～1.363。断裂的高的奇异指数和分维谱值表明该区断裂构造具有较高的成熟度和连通性,有利于提高岩石渗透性、促进流体流动和热液矿床的形成。断裂构造的多重分形分布导致该区热液成矿作用的多重分形分布。断裂体系演化过程中不同断裂部位变形和渗透性存在明显差异,数值模拟表明断裂与岩性和流体之间存在强烈的耦合作用并导致不同岩性的断裂具有明显不同的断裂渗透率。断裂-脉体系演化是一个自组织过程,元胞自动机模拟表明只有在分形渗透临界以上连通性较好的脊骨断裂部位是最有利于流体流动和成矿作用的。因此只有在部分有利的断裂部位才能形成矿床,并导致了断裂构造的奇异指数和多重分维谱值明显高于矿床。 相似文献
8.
湖南省金银矿床分布的多重分形分析 总被引：1，自引：0，他引：1
矿床的空间分布具有很强的复杂性和自相似性,分形理论则是人类对具有相似性的复杂现象进行定量描述的一种新方法.目前人们主要采用单一分维模型在不同的尺度范围内求取矿床分布的容量维,本文采用多重分维模型,根据1:200万的湖南省金银矿床分布图分别对29个大中型矿床和全部75个矿床做了多重分形分析,分别获得了其多重分维谱,并对该多重维谱与理论上的多重分维谱进行了比较,分析了其差异形成的原因.研究显示湖南省仍有较好的金银找矿前景. 相似文献
9.
非线性成矿预测理论: 多重分形奇异性-广义自相似性-分形谱系模型与方法 总被引：24，自引：0，他引：24
介绍了“奇异性-广义自相似性-分形谱系”(“3S”: Singularity-generalized self-Similarity-fractal Spectrum)为核心的多重分形现代成矿预测理论与模型(Multifractal Mineralization Prediction Theory and Models)的基本内容和前沿研究方向.讨论了作为非线性、复杂性理论的重要领域之一, 多重分形理论所提供的“奇异性-广义自相似性-分形谱系”等概念和相关的模型.这些新概念和模型不仅能够合理地描述成矿系统、成矿过程、成矿富集规律、矿产资源时空分布, 还提供了定量模拟和识别成矿异常(地质、地球物理、地球化学、遥感异常)的有效模型和实用方法.将多重分形原理与成矿过程、矿产资源分布规律、矿产资源信息获取研究相结合, 可形成具有良好应用前景的现代成矿预测理论与模型.采用该多重分形矿产资源预测理论和在此基础上所开发的专用地学非线性空间信息GeoDASGIS技术, 对国内外多个金属成矿区带进行了矿产资源勘查与评价, 均取得了较理想的预测效果, 表明对开展矿产资源勘查和评价是有效和可行的. 相似文献
10.
新疆阿尔泰地区矿床分布的多重分形分析 总被引：5，自引：1，他引：4
对新疆阿尔泰地区 175个热液金、铜、铅、锌、稀有金属矿床的研究表明 ,该区矿床的空间分布为多重分形分布。在 q=- 2～ 14范围内 ,标度指数为 - 5.4 915～ 12 .80 71,奇异指数 a( q)随 q值变化较大 ,为 0 .92 4 8～ 2 .2 865,分维谱具单峰曲线特征。q=0时 ,在 1～ 150 km尺度范围内出现二个分形关系 ,在 1～ 16km尺度范围内 D0 值为 0 .2 3,在 16～ 150 km尺度范围内 D0 值为 1.51。导致该区矿床多重分形分布的主要原因是在不同尺度下矿床的形成控制机理的不同和矿床的勘探研究程度较低 ,该区还有较大的找矿前景。 相似文献
11.
Qiuming Cheng 《Mathematical Geology》2005,37(8):915-927
Two-dimensional fields (maps) generated by isotropic and anisotropic multiplicative cascade multifractal processes are common
in many fields including oceans, atmosphere, the climate and solid earth geophysics. Modeling the anisotropic scaling property
and heterogeneity of these types of fields are essential for understanding the underlying processes. The paper explicitly
derives the eigenvalues and eigenvectors from these types of fields and proves that the eigenvalues and eigenvectors are described
by non-conservative multifractal distributions. This results in a new multifractal model implemented in eigen domain to characterize
2D fields not only with respect to overall heterogeneity and singularity as characterized by the ordinary multifractal model
applied to the field itself, but also with respect to orientational heterogeneity of the field. It may also result in a new
way to characterize the distribution of extreme large eigenvalues involved in other studies such as principal component analysis.
A newly defined operator and its properties as derived in this paper may be useful for studying other types of multifractal
cascade processes. 相似文献
12.
三维岩体质量的多重分形评价及分类 总被引：7，自引：2，他引：5
岩体中结构面的存在往往会对岩体质量造成显著影响。笔者剖析了传统岩体质量指标的不足,以白云鄂博铁矿主矿边坡岩体为例,在工程地质测绘的基础上,利用蒙特卡洛（Monte Carlo）法仿真出三维岩体结构网络图,从多重分形几何的角度出发,计算和绘制出其表征岩体结构分布和复杂性的多重分形谱,对岩体质量作出定性评价和定量分析,并且进行了岩体质量的多重分形分类。 相似文献
13.
The separation of anomalies from geochemical background is an important part of data analysis because lack of such identifications might have profound influence on or even distort the final analysis results. In this article, 1 672 geochemical analytical data of 11 elements, including Cu, Mo, Ag, Sn, and others, from a region within Tibet, South China, are used as one example. Together with the traditional anomaly recognition method of using the iterative mean ±2σ, local multifractality theory has been utilized to delineate the ranges of geochemical anomalies of the elements. To different degrees, on the basis of original data mapping, C-A fractal analysis and singularity exponents, Sn differs from the other 10 elements. Moreover, geochemical mapping results based on values of the multifractal asymmetry index for all elements delineate the highly anomalous area. Similar to other 10 elements, the anomalous areas of Sn delineated by the asymmetry index distribute along the main structure orientations. According to the asymmetry indexes, the 11 elements could be classified into 3 groups: (1) Ag and Au, (2) As-Sb-Cu-Pb-Zn-Mo, and (3) Sn-Bi-W.This paragenetic association of elements can be used to interpret possible origins of mineralization, which is in agreement with petrological analysis and field survey results. 相似文献
14.
15.
Mário A. Gonçalves 《Mathematical Geology》2001,33(1):41-61
The use of multifractals in the applied sciences has proven useful in the characterization and modeling of complex phenomena. Multifractal theory has also been recently applied to the study and characterization of geochemical distributions, and its relation to spatial statistics clearly stated. The present paper proposes a two-dimensional multifractal model based on a trinomial multiplicative cascade as a proxy to some geochemical distribution. The equations for the generalized dimensions, mass exponent, coarse Lipschitz–Hölder exponent, and multifractal spectrum are derived. This model was tested with an example data set used for geochemical exploration of gold deposits in Northwest Portugal. The element used was arsenic because a large number of sample assays were below detection limit for gold. Arsenic, however, has a positive correlation with gold, and the two generations of arsenopyrite identified in the gold quartz veins are consistent with different mineralizing events, which gave rise to different gold grades. Performing the multifractal analysis has shown problems arising in the subdivision of the area with boxes of constant side length and in the uncertainty the edge effects produce in the experimental estimation of the mass exponent. However, it was possible to closely fit a multifractal spectrum to the data with enrichment factors in the range 2.4–2.6 and constant K1 = 1.3. Such parameters may give some information on the magnitude of the concentration efficiency and heterogeneity of the distribution of arsenic in the mineralized structures. In a simple test with estimated points using ordinary lognormal kriging, the fitted multifractal model showed the magnitude of smoothing in estimated data. Therefore, it is concluded that multifractal models may be useful in the stochastic simulation of geochemical distributions. 相似文献
16.
Bishwajit Chakraborty S. M. Karisiddaiah A. A. A. Menezes K. Haris G. S. Gokul W. Fernandes G. Kavitha 《Natural Hazards》2014,73(2):547-565
Here, we present the slope configuration of the submarine gullies, ridges and the adjacent slump zone off Goa, along the western continental margin of India utilizing multibeam bathymetric and single-channel seismic data. The fluid flow migration signature in the form of pockmark seepages, traces of mud volcanoes and enhanced reflectors is observed in the area. Altogether thirty-three depth profiles from the gully, ridge and slump areas depict downslope progression in gully incision and varying gradients in the gullies (1.19–4.07°) and ridges (2.13–3.70°), whereas the profiles of the slump zone are comparatively steady (2.25–2.51°). The scatter plot of the three slope characteristics, viz., gradient, mean depth and root mean square relief, characterizes the profiles of the gullies, ridges and slump zone into three distinct clusters. Principal component analysis as well corroborates the categorization. Furthermore, a stochastic multifractal technique has been employed to understand the nature of the fine-scale seafloor processes active in the slope region. The three estimated parameters of the depth profiles, i.e., the degree of multifractality (α), sparseness (C 1) and the degree of smoothness (H), substantiate a very high degree of multifractality for all the thirty-three bathymetric profiles. Except for the five adjacent profiles (four from the slump zone and one from the ridge), the remaining twenty-eight depth profiles of the gully, ridges and slump zones show negligible difference. Based on the multifractal study, we conclude that the observed discrimination might be due to the significant interaction between the bottom currents off Goa and the varied seafloor morphological aspects with seepages and faults. 相似文献
17.
新疆东准噶尔地区断裂的多重分形研究 总被引：5，自引：1，他引：4
结合东准噶尔地区强应变构造带的空间展布情况和断裂的空间分布特征 ,用多重分形模型测算了各带的多重分维值。研究结果表明 :强应变构造带在不同尺度上具有自相似性 ;断裂的空间分布为多重分形结构 ,断裂的演化有从复杂几何结构的次级断裂组合向单一连续的大断裂过渡而分维值逐渐减小的趋势 ;不同的大地构造单元有不同的分维值 ,而且有靠近板块缝合带 (或海沟 )分维值减小、远离板块缝合带 (或海沟 )分维值增大的趋势 相似文献
18.
对麻栗坡地区1∶5万水系沉积物测量数据的统计分析表明,W、Sn、Pb、Zn、Cu等主要成矿元素不完全服从正态分布和对数正态分布,而表现出多重分形结构特征。因此,采用传统的地质统计学方法提取异常显然不能客观地反映区域的成矿元素分布特征。本文引用了"C-A"多重分形模型来研究该地区成矿元素特征,并有效提取各元素异常下限值,结合区域成矿地质背景,对区内成矿潜力进行初步预测。实践表明,分形方法所提取的剩余异常与研究区的矿产分布较为相符,较好地反映了研究区成矿元素分布规律,为研究区成矿预测提供了依据。 相似文献
19.
Multifractal Analysis of Element Distribution in Skarn-type Deposits in the Shizishan Orefield, Tongling Area, Anhui Province, China 总被引：3，自引：1，他引：2
Wang Qingfei Deng Jun Wan Li Zhao Jie Gong Qingjie Yang Liqiang Zhou Lei Zhang Zhijun 《《地质学报》英文版》2008,82(4):896-905
A series of element concentrations sampled from four drill cores with a length about 1000 m into different skarn-type deposits were selected from the Shizishan orefield, central Tongling, southeastern part of Anhui Province. Using the multifractal method, the distribution and migration characteristics of the major and trace elements are analyzed. The multifractal spectrum of the major elements is left-skewed, whereas the spectrum of the trace elements is right-skewed, which shows that in the process of skarn formation, the trace elements were enriched only locally, and major elements transported within a much larger range. The correlation coefficients of the multifractal parameters Aa （width of the multifractal spectrum） of the four drill cores are relatively low, but the correlation coefficients of the multifractal parameters R （spectrum symmetry parameter） and Af are relatively higher, indicating that although the non-homogeneous intensity of the distribution of elements is inconsistent, their spatial accumulation patterns are almost the same during the ore-forming process. The statistics of the mnltifractal parameters of various elements in the different locations show that the ore-forming processes and element migration pattern in the Shizishan orefield are consistent, and that the migrations of trace elements and major elements exhibit some differences. 相似文献
20.
Narasimhan Harikrishna Ferlisi Settimio Cascini Leonardo De Chiara Giovanna Faber Michael Havbro 《Natural Hazards》2015,77(1):117-125
We analyzed the fractal and multifractal properties of the earthquake time series occurred around the Enguri dam in West Georgia by applying the methods of detrended fluctuation analysis and multifractal detrended fluctuation analysis. We examined the interevent time series in two periods: (1) 1960–1980, in which the investigated area was characterized by the natural seismicity; and (2) 1981–2012, in which the quasi-periodic change of the reservoir water level affected the earthquake generation. Our findings show that the water level variation may influence the fractal properties of earthquake temporal distribution in the local area around the Enguri dam. In particular, it is observed that the time distribution features of seismicity occurred in the second period are more persistent than the natural seismicity occurred in the first period. Furthermore, the seismic process of the second period shows a lower multifractal degree than that of the first period, indicating that the influence of quasi-periodic fluctuation of water level features the seismicity as more regular compared to the natural seismicity. 相似文献