鄂西清江上游NE向活动断层束分段分形特征 |
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引用本文:吴树仁,吴淦国,胡道功,石玲,易顺华,汪华斌,徐瑞春,梅应堂.1999.鄂西清江上游NE向活动断层束分段分形特征[J].地球学报,20(2):142-149. |
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基金项目:国家自然科学基金,地质力学开放实验室项目,长江三峡勘测院委托项目 |
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中文摘要:在地质调查的基础上,初步厘定了清江上游NE向断层束7条区域性活动断层的轨迹结构,并依据断层几何轨迹的间断、连接和重叠特性,划分断层带的相对独立断裂段;进而利用分形分维分析,分别估算活动断层和相对独立断层段的轨迹结构分维值。计算结果表明:每条断层的轨迹结构具有其特征性的分维值,轨迹结构越复杂,分维值越高,咸丰断层分维值最高(D=1.268),齐岳山断层带分维值最低(D=0.980);每个相对独立的断层段也具有特征性的分维值,其中,郁江断层带的Ⅱ段的分维值最高(D=1.318),齐岳山断层带的Ⅰ段的分维值最低(D=0.962);断层轨迹结构越复杂、分段阶区分支断裂越多、分维值越高,其现今活动性越强;活动断层分段分形分析是进行断层活动性评价的有效途径之一。 |
中文关键词:断层束 分段 分形分维 |
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Segmentation and Fractal Dimension of the NE-Trending Active Fault Population in the Upper Reaches of the Qingjiang River,Western Hubei |
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Abstract:The trace patterns of seven active faults of the NE-tre nding fault population in the upper reaches of the Qingjiang River have been def ined on the lasis of geological investigations over the past five years.The trac e patterns are characterized by the segmentation due to their geometric dis continuity, fracture linkage and overlapping. Fractal analysis of the fault tra ce patterns of the area has shown the follouing:every fault has a characteristic slope value in the box-counting curve, and the more complex the fault trace pa ttern is, the larger its fractal dimension value will be ; of these faults, the Xianfe ng fault has the largest fractal dimension ( D =1.268) in the area, whereas th e Qiyueshan fault the lowest fractal dimension ( D =0.980); every segment also has its characteristic slope value, and of them, the second segment of the Yuji ang fault has the largest fractal dimension ( D =1.318) in the area, and the f irst segmant of the Qiyueshan fault has the lowest fractal dimension ( D =0.96 2). Analysis of the fault activity relating to the segmentation and fractal dime nsion of the faults trace pattern has shown that most steps and intersection poi nts of the 7 active faults in the area, in a given tectonic setting, have been i n a relatively stable state, only a few steps being in a relatively active state . For example, the first_order jog at Zhongba in the Qianjiang fault is charac terized by the relatively active structure, and earthquakes of intermediata magn itude may occur at the jogs. |
keywords:fault population segmentation fractal dimension |
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