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    西准噶尔地区多源遥感信息的线性构造提取与定量分析

    Linear structure extraction and quantitative analysis of multi-source remote sensing information in West Junggar Basin

    • 摘要: 夹持在近东西向额尔齐斯断裂和天山走滑断裂系统之间的西准噶尔地区,经历了自晚古生代晚期以来长期复杂的陆内构造变形历史。线性构造的长度、方向以及空间分布能够反映构造变形的强度和样式,指示应力作用的方式。本文选取新疆西准噶尔地区为研究区,利用ASTER、Landsat等多源遥感数据通过彩色合成、主成分分析、波段比值和Sobel滤波等增强显示断裂构造在遥感影像上的空间分布和光谱信息,并利用Canny边缘检测与人工解译相结合的方法提取研究区内线性构造;运用地质统计学的原理和方法对提取出的线性构造进行定量分析。结果表明,研究区内依长度优选方位确定的主断裂走向为N50°~60°E,代表了区域一级构造即达拉布特断裂展布的方位;依线性构造数量优选方位确定的次级断裂走向为80°~90°(近东西向),代表了区域三级构造的方位;介于以上两者之间的线性构造,即数量与长度均适中的线性构造,代表了区域二级构造的方位。线性构造的区域分布,揭示了在南北向主压应力作用下,西准噶尔地区构造体系的组成与构造变形特征。由此说明,多源遥感信息提取的线性构造定量分析,对于区域断裂构造体系的厘定具有重要意义。

       

      Abstract: The western Junggar region, which is sandwiched between the nearly EW-trending Irtys fault and the Tianshan strikeslip fault system, has experienced long and complicated history of intracontinental tectonic deformation since the Late Paleozoic. The length, direction and spatial distribution of tectonic lineaments can not only reflect the strength and style of structural deformation but also indicate the mode of stress action. In this paper, the western Junggar region in northwest Xinjiang was selected as the research area. The spatial distribution and spectral information of fault structures in multi-source data such as ASTER and Landsat were displayed by color composite, principal component analysis(PCA), band ratio and Sobel filtering. The linear structures in the study area were extracted by combining Canny edge detection and visual interpretation. The principle and method of geostatistics were used to quantitatively analyze the extracted linear structures. The results show that the strike of the main faults determined by the optimum orientation of length in the study area is N50°-60°E, which represents the orientation of the distribution of the regional first-order structure, namely the Dalabut fault. The strike of the secondary faults determined by the optimum orientation of the number of linear structures is 80°-90° (in nearly EW direction), which represents the orientation of the regional third-order structures. The linear structures between the above two structures, namely moderate structures in number and length, represent the orientation of the regional secondary structure. The regional distribution of linear structures reveals the structural system composition and deformation characteristics of the western Junggar region under the action of the principal compressive stress in the NS direction. Therefore, the quantitative analysis of linear structures extracted from multi-source remote sensing image is of great significance for the determination of regional fault tectonic system.

       

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