| 河套地震带中小地震的震源机制测定及应力场特征 |
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| 引用本文： | 韩晓明,刘芳,张帆,魏建民,徐岩,侯迪,李娟,梁沙沙.河套地震带中小地震的震源机制测定及应力场特征[J].大地测量与地球动力学,2016,36(6):495. |
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| 作者姓名： | 韩晓明 刘芳 张帆 魏建民 徐岩 侯迪 李娟 梁沙沙 |
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| 摘 要： | 运用振幅比和CAP方法测定224次地震的震源机制解，进行归一频度统计和震源机制类型时空分析，以考察河套地震带的应力场在模式转换和应力作用方式两方面的变化形态。河套地震带的压应力方位在北东向存在优势分布，张应力方位在北西向存在优势分布，滑动角主要分布在近水平方向，应力场整体表现出继承性运动特征，表明水平剪切拉张运动总体控制了带内断裂的作用模式而多产出走滑型地震，并贯穿整个研究时段，属稳态应力作用模式。在太平洋板块向西俯冲和青藏块体向北运移的联合作用下，河套地震带两侧的阴山隆起和鄂尔多斯块体作相对旋性扭动，最终驱使带内众多北东-近东西向展布的断裂产生水平旋性剪切，构成相对稳定的应力场演化模式。
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| 关 键 词： | 河套地震带 震源机制解 振幅比 CAP 应力场特征 |
Focal Mechanism Determination of Medium-Small Earthquakes and Characteristic of Stress Field in Hetao Seismic Belt |
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| HAN Xiaoming,LIU Fang,ZHANG Fan,WEI Jianmin,XU Yan.Focal Mechanism Determination of Medium-Small Earthquakes and Characteristic of Stress Field in Hetao Seismic Belt[J].Journal of Geodesy and Geodynamics,2016,36(6):495. |
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| Authors: | HAN Xiaoming LIU Fang ZHANG Fan WEI Jianmin XU Yan |
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| Abstract: | In order to inspect the change form of schema transformation and the stress form of Hetao seismic stress field, we use amplitude ratio and CAP methods to calculate 224 focal mechanism solutions, based on normalized frequency statistics and analysis of fault slip type.The results show that the advantage distribution of compressive stress orientation is NE, the advantage distribution of tensile stress orientation is NW, and the rake angleis distributed nearly horizontally. Further, the whole stress field shows inheritance features, horizontal shear and tension control the stress form of faults in Hetao seismic belt, and the main outputs are strike-slip type earthquakes. Throughout the whole study period, a steady stress model is presented. Combining peripheral dynamic properties withregional tectonic movement determines that, under the joint action of the westward subduction of the Pacific plate and the Qinghai-Tibet block northward migration, Yinshan uplift and Ordos block relative to do spin twist.Finally, the NE-EW distribution faults present horizontal and rotary shear, and constitute a relatively stable evolution model of stress field. |
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| Keywords: | Hetao seismic belt focal mechanism solution amplitude ratio CAP characteristics of stress field |
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