| 华夏地块东南部地壳地震各向异性特征初步研究 |
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| 引用本文： | 吴晶,高原,蔡晋安,石玉涛,林树,鲍挺,李祖宁.华夏地块东南部地壳地震各向异性特征初步研究[J].地球物理学报,2007,50(6):1748-1756. |
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| 作者姓名： | 吴晶 高原 蔡晋安 石玉涛 林树 鲍挺 李祖宁 |
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| 作者单位： | 1.中国地震局地震预测研究所，北京 100036;2.福建省地震局，福州 350003 |
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| 基金项目： | 中国地震局地震预测研究所基本科研专项(2007-24),，闽科计[2002y004]和地震科学联合基金(青年基金)606045共同资助 |
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| 摘 要： | 本研究采用SAM剪切波分裂分析方法，使用福建区域数字地震台网记录到的（1999年01月～2003年12月）的波形资料，挑选符合剪切波窗口条件的记录，得到华夏地块东南部地区23°N～29°N，116°E～120°E）10个台站的剪切波分裂参数. 研究结果表明，该区域快剪切波平均偏振方向为NW109.4°±42.6°，慢剪切波平均时间延迟为2.5±1.5(ms/km)，快剪切波平均偏振方向对应该区的水平主压应力方向. 闽东台站NW方向的快剪切波偏振优势方向揭示了NW向的水平主压应力和NW走向断裂的构造意义. 两个闽西台站NE方向的快剪切波偏振优势方向与区域水平主压应力方向不一致，与NE走向的断裂一致，体现了局部构造和局部应力场的复杂性. 本研究证实，位于活动断裂上的台站的快剪切波偏振方向的优势方向与断裂走向一致，位于海边或岛上的台站的快剪切波偏振方向较为离散，主要是受到不规则表面地形和断裂交汇的影响. 慢剪切波延迟时间的空间分布特征，显示沿海地区慢剪切波延迟时间变化较大，而内陆地区则较为平缓.
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| 关 键 词： | 华夏地块东南部 地震各向异性 剪切波分裂 地壳 活动断裂 应力 |
| 文章编号： | 0001-5733（2007）06-1748-09 |
| 收稿时间： | 2007-2-7 |
| 修稿时间： | 2007-02-07 |
Preliminary study on seismic anisotropy in the crust in southeast of Cathaysia Block |
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| WU Jing,GAO Yuan,CAI Jin-An,SHI Yu-Tao,LIN Shu,BAO Ting,LI Zu-Ning.Preliminary study on seismic anisotropy in the crust in southeast of Cathaysia Block[J].Chinese Journal of Geophysics,2007,50(6):1748-1756. |
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| Authors: | WU Jing GAO Yuan CAI Jin-An SHI Yu-Tao LIN Shu BAO Ting LI Zu-Ning |
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| Institution: | 1.Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China;2.Earthquake Administration of Fujian Province, Fuzhou 350003, China |
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| Abstract: | With SAM shear-wave splitting analysis and seismic wave data of Fujian Seismic Network (FJSN) from Jan. 1999 to Dec. 2003, seismic anisotropic parameters of 10 stations are obtained in southeast of Cathaysia block (23°N～29°N，116°E～120°E). The results show that the average polarization of fast shear-waves is NW109.4°±42.6°, and the average time delay of slow shear-waves is 2.5±1.5 (ms/km). It is shown that the average polarization of fast shear-waves corresponds to the horizontal principal compressive stress of Fujian area. The predominant polarizations of stations in eastern Fujian are in NW direction, which suggests that the predominant polarizations are related to the horizontal principal compressive stress in Fujian, as well as to the strikes of faults in eastern Fujian. However, the predominant polarizations of two stations in western Fujian are in NE direction. It is shown that the predominant olarizations in western Fujian are different from the direction of horizontal principal compressive stress of Fujian area, but same with the strikes of faults in western Fujian area, which means that local tectonics and local stress field are very complicated. The results prove that the predominant polarizations are parallel to the strikes of faults if the stations are on active faults. It is also proved that the polarizations are scattered if the stations are on seashore or on isles, which may be caused by irregular topography and crossing faults. From the spatial distribution of time delay of slow shear-waves, it is shown that the change of time delays is more obvious in seashore area than inland. |
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| Keywords: | Southeast of Cathaysia block Seismic anisotropy Shear-wave splitting Crust Active fault Stress |
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