河西地区几次强震前的垂直地形变分维特征研究   总被引：1，自引：0，他引：1  

张永志  王双绪 《内陆地震》1993,7(3):257-263

采用关联维的计算方法,对河西地区门源6.4级和天祝一景泰6.2级地震过程中的垂直地形变序列的时、空分维数分别进行了计算,得到:本文研究区内远场(远离震中区)的地形变序列分维数在0.63～0.80之间,而近场(震中地区)的序列分维数在0.17～0.44之间,近场出现明显的降维现象;地震的孕、发过程中地形变观测序列分维数在0.22～0.37之间,而无震期间则在0.57～0.77之间,地震孕、发过程中地形变观测时间序列亦存在明显的降维现象。  相似文献   

Study of the Stacking Sequences of an Irregular Mixed-Layer Illite/Smectite (I/S) Clay Mineral—with a Discussion on the Existence of Minerals with Two-Dimentional Lattice and One-Dimentional Quasi-Lattice     

Lu Qi  Lei Xinrong  Liu Huifang China University of Geosciences  Wuhan  Hubei 《《地质学报》英文版》1993,67(4)

There are two aspects in the study of irregular mixed-layer clay minerals: one is the kinds and ratios of their basic structural unit layers and the other is the junction probabilities of the unit layers. Irregular mixed-layer illite/smectite clay minerals (I/S) are widespread in nature. While studying the clay minerals from the Permian-Triassic (P/T) boundary bed, the authors found that I/S clay minerals are developed in all P/T boundary clay layers in areas from the northwest to southeast of China. Systematic mineralogical studies of the I/S clay minerals from Hunan, Hubei, Sichuan and Zhejiang were made by means of X-ray, infrared spectroscopic, electron microscopic and chemical analyses and a deepened study of the stacking sequences of their structural unit layers was conducted by the MacEwan one—dimentional direct Fourier transform. It was found that the stacking of the illite and smectite crystal layers along the c axis can be derived from Fibonacci sequences. Hence, the authors propose that such I/S clay minerals are possessed of two—dimentional crystal lattice and one—dimentional quasicrystal lattice.  相似文献   

测定岩石破损分形维的方法   总被引：6，自引：1，他引：6  

陈静曦 《岩土力学》1993,14(2):19-23

本文简述了分形的特征及其对岩石损伤断裂的影响,并着重介绍了测定岩石破损分形维的几种方法。  相似文献   

岩体结构分形及应用研究   总被引：9，自引：2，他引：9  

丁多文 《岩土力学》1993,14(3):67-72

岩体结构包括两个基本要素:结构面和结构体。通过分形理论研究岩体结构,得出结构面和结构体分布具有分形特征。根据结构网络图,可分别求出结构面和结构体的分形维数D_(PF)和D_(VF)。结构面分布分形维数D_(PF)越大,反映结构面分布越复杂,优势面(南京大学罗国煜教授提出)发育的方向范围就越大,相应地岩休质量就更差;结构体分布分形维数D_(VF)越大,反映结构体大小分布的状况是大的结构体所占分量趋于增加,结构面的密度、迹长、总面积趋于变小,则岩体质量趋于变好。最后指出结构面和结构体分布分形维数是决定岩体质量的两个指标,是对岩体质量进行评价的合适指标。  相似文献   

三维网平差的方差分量估计     

盛乐山 《武汉大学学报(信息科学版)》1990,(1)

本文将方差分量估计理论运用于三维网平差中,推导出了含定向角未知数及消去定向角未知数的方差分量估计公式,并进行了模拟和实例计算,从而建立了合理的三维网平差随机模型。  相似文献   

K≥5地磁场扰动事件的分形特征     

朱兆才 《东北地震研究》1994,(2)

根据分形观点用尺度变换法研究了北京等台测定的Ｋ≥５地磁场扰幼事件时间序列的分形特征．这是基于尺度变换的序列尺度不变过程，无标度区跨约４个数量级。随着Ｋ指数下限的提高，同一时期Ｋ指数序列的分维降低．各台测定Ｋ≥５地磁场扰动事件的分维多少有些差异。东经１２０°附近台具有高、低纬度台的分维较中部高、分维与同期测定Ｋ≥５事件数成正比的特点，中国东、西部台分维存在系统差异。部分台的分维较三个国外比较台偏高．对此作了初步分析．  相似文献   

地理现象分形研究   总被引：11，自引：2，他引：11  

赵锐  顾其钧 《地理科学》1994,14(1):9-15

  相似文献   

Fractals,fault-gouge,and friction   总被引：5，自引：0，他引：5  

Charles G. Sammis  Ronald L. Biegel 《Pure and Applied Geophysics》1989,131(1-2):255-271

The particle-size distribution of a natural fault-gouge has been determined over the range from 5 m to 40 cm. The gouge is self-similar over the range from 5 m to 1 cm having a fractal dimension of 2.60±0.11. The lower and upper fractal limits were also determined. The lower fractal limit occurs at a dimension of about 1–10 m where mineral cleavage and intergranular porosity dominate the cataclasis. The upper fractal limit occurs at particle sizes on the order of 1 cm where the scaled particle density decreases abruptly by a factor of about three. By analogy to soil-mechanics shear box tests and laboratory rock friction experiments, it is argued that the upper fractal limit of the gouge determines the characteristic displacement parameter in stick-slip friction models. A characteristic displacement on the order of 1 cm is consistent with estimates based on numerical simulations of faulting.  相似文献   

Fractal dimension of fault systems in Japan: Fractal structure in rock fracture geometry at various scales   总被引：18，自引：0，他引：18  

Takayuki Hirata 《Pure and Applied Geophysics》1989,131(1-2):157-170

Based on fault maps, whether or not the fracture geometry of rocks is self-similar, was examined by using a box-counting algorithm. The statistical self-similarity (fractal structure) of the fault fracture systems holds well at the scale of about 2 to 20 km. The fractal dimension in Japan varied from 1.05 to 1.60. The fractal dimension is about 1.5–1.6 at the central part of the Japan Arc, and decreases with distance from the center. At a smaller scale, the fractal structure also holds well in the rock fracture geometry. The fractal dimension of the North Izu Peninsula fault system (branching faults) is 1.49 at the scale of 0.625 to 10 km, the fractal dimension of rock fracture geometry at the scale order of 10^–1 to 10^–2 meters is about 1.49–1.61. The upper limit of the fractal dimension of rock fracture geometry is about 1.6, judging from the estimation of fractal dimension on actual fracture geometry of rocks. This value may impose a restraint on modeling of faulting and the fracture process of rocks.  相似文献   

基于独立分量分析的纹理特征维数减少     

黄昕  张良培  邵振锋  李平湘 《武汉大学学报(信息科学版)》2006,31(12):1055-1058

提出了基于ICA纹理特征维数减少的方法，通过QuickBird多光谱影像的实验证明，ICA对各种纹理特征降维的普适性最强，类别可分性最高。  相似文献