| 鄂尔多斯块体及其周缘上地幔各向异性分析研究 |
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| 引用本文： | 胡亚轩,崔笃信,季灵运,郝明.鄂尔多斯块体及其周缘上地幔各向异性分析研究[J].地球物理学报,2011,54(6):1549-1558. |
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| 作者姓名： | 胡亚轩 崔笃信 季灵运 郝明 |
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| 作者单位： | 中国地震局第二监测中心, 西安 710054 |
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| 基金项目： | 国家自然科学基金项目，中国地震局地震行业科研专项 |
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| 摘 要： | 对布设在鄂尔多斯块体及其周缘的固定宽频带地震台网90个台站记录作远震SKS波形资料偏振分析,采用最小切向能量法求得每个台站的SKS快波偏振方向和快慢波时差,获得块体及其周缘上地幔各向异性图像,并结合1999～2007年相对鄂尔多斯块体的GPS水平地壳运动速度场,分析块体及其周缘的各向异性特征和壳幔耦合特征并重新认识块体...
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| 关 键 词： | 地震波横波分裂 水平运动场 动力学成因 鄂尔多斯块体及其周缘 |
| 收稿时间： | 2010-05-06 |
Seismic anisotropy of upper mantle in Ordos block and adjacent regions |
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| HU Ya-Xuan,CUI Du-Xin,JI Ling-Yun,HAO Ming.Seismic anisotropy of upper mantle in Ordos block and adjacent regions[J].Chinese Journal of Geophysics,2011,54(6):1549-1558. |
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| Authors: | HU Ya-Xuan CUI Du-Xin JI Ling-Yun HAO Ming |
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| Institution: | Second Crust Monitoring and Application Center, China Earthquake Administration, Xi'an 710054, China |
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| Abstract: | Based on the polarization analysis of teleseismic SKS waveform data recorded at 90 broadband stations in Ordos block and adjacent regions, the splitting parameters of fast polarization direction and delay time between the fast and slow shear waves are determined at each station using the minimum transverse energy method, and the image of upper mantle anisotropy was acquired. Combined with the GPS horizontal velocity field relative to the Ordos block during 1999 ~2007, we analyze the seismic anisotropy as well as the crust-mantle coupling in Ordos block and its adjacent regions. At last, a new understanding of the block movement and the dynamic causes of the adjacent fault zone is achieved. The results reveal that there are nulls in the block which show an obvious isotropic characteristic. The delay time of the adjacent stations is obviously greater than those in the central block, which indicates an obvious anisotropy; the fast polarization directions are compatible with the tectonic strike direction and the horizontal velocity direction, which shows the crust-mantle coupling, however, the differences between the directions at some stations may possibly be explained by early block activities. According to the SKS shear wave splitting results and the current GPS velocity field, we know that the Ordos block does not rotate. Meanwhile, the horizontal and ascending intrusion and the transverse extension of the plastic material in the upper mantle lead to the bifurcated flow along the southwestern margin of Liupanshan. One flow forms the Fenwei graben. |
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| Keywords: | Shear wave splitting Horizontal velocity field Dynamic causes Ordos block and adjacent regions |
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