| 张家口-宣化盆地断裂特征与活动性研究 |
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| 引用本文： | 周江林,尤惠川,唐方头.张家口-宣化盆地断裂特征与活动性研究[J].西北地震学报,2015,37(3):702-709. |
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| 作者姓名： | 周江林 尤惠川 唐方头 |
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| 作者单位： | 中国地震局地球物理研究所, 北京 100081;中国地震局地球物理研究所, 北京 100081;中国地震局地球物理研究所, 北京 100081 |
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| 基金项目： | 河北省城市活断层探测与地震危险性评价项目(冀发改投资[2007]1684号);地震行业科研专项(200908001) |
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| 摘 要： | 运用地质地貌调查、地球物理勘探和年代测定等方法,对张家口—宣化盆地的四条主要断裂(张家口断裂、万全断裂、洗马林—水泉断裂和洋河断裂)的空间展布特征和活动性进行分析和研究,获得其活动时代、活动速率等参数。研究表明:上述断裂第四纪期间持续活动,以脆性变形为特征;总体上NW向断裂以高角度的正(或逆)倾滑断层为主,NE或NEE向的断裂以高角度的正断层为主;盆地内活动断裂总体来说活动强烈,多处可见断裂正断运动及左旋走滑运动的地质剖面,早更新世以来单条断层的平均垂直活动速率大于0.07~0.30mm/a,总垂直活动速率可能达到1.33mm/a。
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| 关 键 词： | 张家口-宣化盆地 活动断裂 构造变形 活动性 |
| 收稿时间： | 2014/12/5 0:00:00 |
Characteristics and Tectonic Activities of Faults in Zhangjiakou-Xuanhua Basin |
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| ZHOU Jiang-lin,YOU Hui-chuan and TANG Fang-tou.Characteristics and Tectonic Activities of Faults in Zhangjiakou-Xuanhua Basin[J].Northwestern Seismological Journal,2015,37(3):702-709. |
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| Authors: | ZHOU Jiang-lin YOU Hui-chuan and TANG Fang-tou |
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| Institution: | Institute of Geophysics, China Earthquake Administration, Beijing 100081, China;Institute of Geophysics, China Earthquake Administration, Beijing 100081, China;Institute of Geophysics, China Earthquake Administration, Beijing 100081, China |
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| Abstract: | An active fault leads to disaster in the world, and within the general development of disasters, an active fault''s frequency and the damage it causes is based on the degree of the fault layer, and gradually intensifies. In recent years, earthquake prediction research and engineering construction developments have vigorously promoted the study of active faults. The Zhangjiakou-Xuanhua Basin, situated in the intersection of the Zhangjiakou-Bohai fault zone and the Shanxi seismic tectonic zone, is a typical Cenozoic extensional fault-depression basin. There are many active faults in this basin, which control the basin''s development and evolution. However, there is scant research on the active faults in the Zhangjiakou-Xuanhua Basin, and existing research is confined to a few areas. As such, a systematic analysis of this area''s active faults, the identification of quantitative information regarding active faults, and a better understanding of the characteristics of this basin''s long-term activity is important in theory and practice. Based on an analysis and reorganization of relevant information from detailed field investigations and shallow seismic exploration, this study describes the geometric characteristics and tectonic activities of the active faults in the Zhangjiakou-Xuanhua Basin. The faults for which there are research data include the Zhangjiakou, Wanquan, Ximalin-Shuiquan, and Yanghe faults. The results showed that:The Zhangjiakou fault strikes mainly to the northwest and east-west, dipping to the north, and extending over 70 km. As a major geological and geomorphologic boundary, the Zhangjiakou fault controls the geotectonic movement in this region, in which its southern side is characterized by Late Quaternary unconsolidated basin deposits, and its northern side by Mesozoic volcano debris and Pre-Mesozoic metamorphic rocks in the form of lower mountains and hills. The Zhangjiakou faults are mainly high-angle inverse strike-slip faults with some normal strike-slip faults. The activity of the central segment of the Zhangjiakou fault is stronger than that in other segments. Since the late Pleistocene, the average vertical slip rate along a single fault is over 0.07~0.30 mm/a, while the total vertical slip rate over the entire fault is as high as 1.33 mm/a. The Wanquan fault lies in the northwest of the Zhangjiakou-Xuanhua Basin, striking mainly northeast or north-northeast, dipping southeast, and extending over 15 km. It is a major geological and geomorphic margin, controlling the neotectonic movement in this region. On the southeast side of the Wanquan fault there are Late Quaternary unconsolidated deposits, forming a basin or deposition; but on the other side there is Mesozoic volcano debris, forming lower mountains and hills. The Wanquan fault is a normal fault with southeast-dipping at a medium-high-angle. This fault was active in the Quaternary. Since the middle-late time of the late Pleistocene, the average rate with vertical slip of a single fault has been about 0.03~0.3 mm/a, but the fault has multiple slipping surfaces, and a total large-rate with vertical slip is yet to be estimated. The Ximalin-Shuiquan fault is located in the southwest of the Zhangjiakou-Xuanhua Basin, and can be divided into four sections. The fault strikes mainly northwest, with high-angle inverse strike-slip fault or normal strike-slip fault characteristics. The latest active time of the Ximalin-Shuiquan fault is in the late Middle Pleistocene. The Yanghe fault is a subsurface fault, and its active time was in the Middle Pleistocene. The fault strikes mainly northwest, and controlled the Yanghe River''s flow direction and terrace development. The fault strikes mainly northwest, with high-angle slip fault characteristics. |
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| Keywords: | Zhangjiakou-Xuanhua Basin active fault structural deformation activity |
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