Graphical determination of principal stress directions for slickenside lineation populations: an attempt to modify arthaud's method     

Pawel Aleksandrowski 《Journal of Structural Geology》1985,7(1):73-82

A new method of graphic determination of principal stress directions is proposed for slickenside populations produced in anisotropic rocks. Arthaud's concept of movement planes is advanced through studying variations in their pattern relative to the changing values of the principal stresses. These variations are recognizable by means of a simple test based on the Bott equation. In contrast to Arthaud's method, the proposed procedure is applicable to fault populations resulting from stress fields geometrically reproducible by a triaxial ellipsoid. A field example is given to demonstrate the practical utility of the method.  相似文献   

Correlation of the Quaternary terrace sequence in the Lower Rhine valley and northern Alpine foothills of central Europe     

Karl Brunnacker  Manfred Löscher  Wolfgang Tillmanns  Brigitte Urban 《Quaternary Research》1982,18(2):152-173

Thirteen glacial terraces are known from the western part of the northern Alpine foothills between the Lech and Iller Rivers. In the Lower Rhine region of West Germany, a similar number of terraces are capped by interglacial floodloams and soils. Whereas the environment during individual interglaciations did not differ substantially, the glaciations were progressively more severe. The Main Terrace system of the Rhine may be an exception. The duration of the Quaternary, starting at the base of Praetiglian, is estimated at approximately 2 million yr by paleomagnetic dating. The major cold-warm climatic cycles of the earliest Pleistocene lasted approximately 100,000 yr, the same as those of the Brunhes Chron. The intervening Main Terrace system has not yet been climatically subdivided. Correlation with the Netherlands is possible because of an abundance of paleobotanic and paleomagnetic evidence. In the Alpine foothills, stratigraphically useful indicators of warm climates are missing, but analogies in terrace development permit comparison with the Lower Rhine and Danube. The terrace sequence in the Alpine foothills is incomplete, as are those along most of the other rivers in Europe. Some of the older terraces may have been eroded.  相似文献   

Assessing spatial and attribute errors in large national datasets for population distribution models: a case study of Philadelphia county schools     

Lauren Patterson  Marie Urban  Aaron Myers  Budhendra Bhaduri  Eddie Bright  Phillip Coleman 《GeoJournal》2007,69(1-2):93-102

Geospatial technologies and digital data have developed and disseminated rapidly in conjunction with increasing computing efficiency and Internet availability. The ability to store and transmit large datasets has encouraged the development of national infrastructure datasets in geospatial formats. National datasets are used by numerous agencies for analysis and modeling purposes because these datasets are standardized and considered to be of acceptable accuracy for national scale applications. At Oak Ridge National Laboratory a population model has been developed that incorporates national schools data as one of the model inputs. This paper evaluates spatial and attribute inaccuracies present within two national school datasets, Tele Atlas North America and National Center of Education Statistics (NCES). Schools are an important component of the population model, because they are spatially dense clusters of vulnerable populations. It is therefore essential to validate the quality of school input data. Schools were also chosen since a validated schools dataset was produced in geospatial format for Philadelphia County; thereby enabling a comparison between a local dataset and the national datasets. Analyses found the national datasets are not standardized and incomplete, containing 76 to 90 percent of existing schools. The temporal accuracy of updating annual enrollment values resulted in 89 percent inaccuracy for 2003. Spatial rectification was required for 87 percent of NCES points, of which 58 percent of the errors were attributed to the geocoding process. Lastly, it was found that by combining the two national datasets, the resultant dataset provided a more useful and accurate solution.  相似文献   

城市相互作用关系的一种新模式--近域城市整合研究   总被引：52，自引：7，他引：52  

王士君  高群  王丹 《地理科学》2001,6(6):558-563

市场机制下的生产要素流动以及经济发展全球化、区域集团化的走向，改变了近域城市间要么行政协调、要么纯粹竞争的传统相互关系，代之以“整合并共同繁荣”这一新的发展模式，以前期实证研究为基础，从理论上论述了城市整合的背景、理论内涵和城市不整合的状态特征；指出制度创新、生产要素互补、企业集团化、统一市场体系建设、基础设施和生态环境共享共建是近域城市整合的动力机制和“结节点”；同时还提出了“成长三角”，“雁行式”、“多极式”、“双核式”等近域城市整合发展模式。  相似文献   

油、水、干层的地球化学识别   总被引：4，自引：0，他引：4       下载免费PDF全文

张枝焕  王铁冠等 《地质论评》2001,47(5):514-520

本文介绍一种判断油、水、干层的地球化学方法，根据储层样品中有机抽提的的含量和组成特征，结合油层物性，地层测试和试油资料编制织识别油、水，干层的图版，提出判别油、水、干层的地质／地球化学指标，确定油层的地球化学参数的下限，并运用此方法对松辽盆地新站油田主要油层分布段的油、水、干层进行判别。根据试油资料验证表明，地球化学判断结果比传统的地质录井及地球物理测井资料判断结果更符合实际情况。  相似文献   

Reconstruction from three orthographic views     

Urban Herbert 《Journal of Geodesy》1996,70(5):245-249

Summary As Ullman (1979) showed, an object can be reconstructed uniquely from three orthographic views, if at least four homologous tripels of points are known. If only three homologous tripels of points are observed, the reconstruction problem has a finite number of solutions (cf. Huang and Lee (1989)). In this article the 3-point-problem is reduced to a quadratic problem: If the squares of the sides of the considered triangles are interpreted as coordinates in a three-dimensional parameter space, the reconstruction problem is equivalent to the determination of the intersection of three parallelly shifted cones subject to certain constraints.  相似文献   

Reflection from a deep interface in a strongly heterogeneous layered medium1     

Pawel Lewicki  Robert Burridge 《Geophysical Prospecting》1996,44(4):571-581

We consider the problem of acoustic pulse propagation through a layered medium with a reflector at one end. The fluctuations in the medium properties are assumed to be strong, i.e. of finite amplitude, rapid in comparison to the typical wavelength and to have statistical structure. The depth of the reflector is assumed to be large in comparison to the wavelength. In this regime, simple formulae for the reflected pulse and its arrival time at the surface are obtained. The amplitude of the pulse is broadened and attenuated as a result of multiple scattering: the fine-layered structure of the medium can be characterized by a single constant which appears in the formula for the limiting waveform and which measures the size of the fluctuations in the medium. Within the theory, the commonly observed discrepancy between the integrated sonic traveltime and the seismic traveltime can be studied and understood. The theory is a natural extension of the long-wavelength effective medium theory of Backus. The analysis is rigorous and based on the invariant embedding technique.  相似文献   

Magnetic field measurements in India during the last two centuries     

A. Janáčkova  L. Urban  M. Chmelař 《Studia Geophysica et Geodaetica》1992,36(2):151-160

Summary The direction of the geomagnetic field has changed substantially less in India than in Europe since the end of the 18th century.Whereas the European geomagnetic time series indicate a tendency of secular variation from which a remarkable westward drift of the non-axial field can be deduced, in India the field direction seems to have remained more or less fixed over the last two centuries. The drift of the non-axial field seems to be very small, or even eastward.  相似文献   

Administrative division system changes and urbanization in China     

LI Ling Centre for Urban  Regional Studies  Zhongshan University  Guangzhou CHINA 《地理学报(英文版)》1998,(4)

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Chromosome polymorphism in Salmo trutta morpha lacustris from Poland, Wdzydze Lake population: Variation in the short arm length of chromosome eleven     

Pawel Woznicki  Malgorzata Jankun  Miroslaw Luczynski 《Aquatic Sciences - Research Across Boundaries》1998,60(4):367-375

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