【作者】 丁献文；

【导师】 杨树锋； 陈汉林；

【作者基本信息】 浙江大学 ， 构造地质学， 2007， 博士

【摘要】 青藏高原东北部现代构造变形的研究是当前活动构造研究的一个热点区域，特别是阿尔金断裂带对该区变形的控制作用。本文运用合成孔径雷达（Synthetic Aperture Radar，SAR）技术对阿尔金断裂带东段地区近期的构造变形特征进行了监测，并结合野外地质调查、地球物理以及全球定位系统（Global Positioning System，GPS）观测数据等多方面资料对阿尔金断裂带东段地区的构造变形机制进行了深入的探讨。相干斑是SAR图像的一大特色。SAR技术的应用离不开对相干斑的去除或抑制。本文引入第二代小波变换，提出了基于第二代小波变换的SAR图像斑点噪声去除方法。试验表明，该方法明显降低了原始图像的斑点噪声，改善了画面质量，同时还很好地保留了原始图像的辐射特性、纹理特征和细节信息。与传统的中值滤波、Lee滤波、小波硬阈值和小波软阈值等方法相比，噪声去除的综合性能更好。合成孔径雷达差分干涉测量技术（D-InSAR）可监测地球表面的微量形变，是近年来发展起来并得到日益重视的新方法。本文对ERS-1／2单视复数图像进行三通差分干涉处理，获取了阿尔金断裂带东段地区时间跨度为两年（从1996年1月到1998年1月）的构造变形图。通过对该图进行综合分析和解译，得到了关于阿尔金东段地区近期构造变形特征的几点认识：（1）阿尔金断裂带是青藏高原东北缘地壳变形的重要分界线，界线以北地区变形均匀，而且变形量较小，在0.8～1.8厘米之间，以南地区变形强烈且不均匀，变形强度的总体趋势为西高东低，中间受祁连山北缘冲断带西段的影响，在断裂带中出现了约为1.0厘米的变形低值。（2）南区存在N65°W和近NW两个方向的线性强变形带，前者与阿尔金左行走滑断裂带在其南部产生的次一级的压扭面方向一致；后者与祁连山北缘冲断带西段的展布方向一致。阿尔金断裂东段南北两侧构造变形存在差异，这一点认识得到了现今GPS观测结果和活动构造研究结果的证实；提出了区内强线性变形带L₁～L₆受控于阿尔金断裂的左行走滑作用，强线性变形带L₇～L₉是由祁连山北缘冲段带在新近纪的冲断过程中形成的；剖析了昌马盆地内部变形较弱的原因。更多还原

【Abstract】 Nowaday tectonic deformation in north-eastern Tibetan Plateau, especially the control of the Altyn Tagh Fault (ATF) on this region is a hot spot of current active tectonics study. In this paper, SAR (Synthetic Aperture Radar) technique is applied to study the tectonic deformation characteristics of the eastern segment of the ATF and the deformation mechanism is studied thoroughly based on the combination of field survey records, geophysical data and GPS (Global Positioning System) survey dataSpeckle noise is a typical characteristic of SAR images. The reduction of speckle is necessary for any application of SAR technique. In this paper, second-generation wavelet transformation is introduced to SAR image de-noising and a new method of SAR image de-noising based on second-generation wavelet transformation is proposed. Experimental results show that the new method has favorable performance in despeckling and preserving edge and textual details and appears preferable to conventional filters such as Median Filter, Lee Filer, hard-thresholding and soft-thresholding.In recent years, the differential Interferometric Synthetic Aperture Radar (D-InSAR) technique has been widely used in surface deformation monitoring. In this paper, D-InSAR technique is applied to study the tectonic deformation characteristics of the eastern segment of the ATF. The results demonstrate that the ATF is an important crustal deformation boundary on the northeastern margin of the Tibetan Plateau. To north of this boundary, the surface deformation is weak and uniform while to south is strong but not uniform. From the west part to the east part in this area, the deformation intensity gradually decreases. Between these two parts exists the western part of the North Qilian Shan Fault, where the minimum deformation from January 1996 to January 1998 is about 1.0 centimeter. Besides, there exist two linear intensive deformation belts in south area, one is in N65°W direction, which is in accordance with the direction of the secondary compression-shear plane of the Altyn Tagh strike-slip fault zone. The other is in a roughly NW direction, which is consistent with the trend of the western part of North Qilian Shan Fault.The curstal deformation difference between south area and north area is supported by GPS survey data and active fault data. The linear intensive deformation belts in N65°W direction is controlled by the Altyn Tagh strike-slip fault and those in roughly NW direction is controlled by the western part of the North Qilian Shan Fault. And the mechanism of weak deformation in the interior of the Changma Basin is discussed.更多还原