| Three-Dimensional P-Wave Velocity Structure of the Crust of North China |
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| 作者姓名： | 魏文博 叶高峰 李艳军 金胜 邓明 景建恩 |
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| 作者单位： | State Key Laboratory of Geological Processes and Mineral Resources Geo-detection Laboratory Ministry of Education School of Geophysics and Information Technology，China University of Geosciences，Beijing 100083，China，State Key Laboratory of Geological Processes and Mineral Resources Geo-detection Laboratory，Ministry of Education School of Geophysics and Information Technology，China University of Geosciences，Beijing 100083，China，State Key Laboratory of Geological Processes and Mineral Resources Geo-detection Laboratory，Ministry of Education School of Geophysics and Information Technology，China University of Geosciences，Beijing 100083，China，State Key Laboratory of Geological Processes and Mineral Resources Geo-detection Laboratory，Ministry of Education School of Geophysics and Information Technology，China University of Geosciences，Beijing 100083，China，State Key Laboratory of Geological Processes and Mineral Resources Geo-detection Laboratory，Ministry of Education School of Geophysics and Information Technology，China University of Geosciences，Beijing 100083，China，State Key Laboratory of Geological Processes and Mineral Resources Geo-detection Laboratory，Ministry of Education School of Geophysics and Information Technology，China University of Geosciences，Beijing 100083，China，Beijing 100083，China，Beijing 100083，China，Beijing 100083，China，Beijing 100083，China，Beijing 100083，China，Beijing 100083，China |
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| 基金项目： | 国家自然科学基金，the Focused Subject Program of Beijing |
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| 摘 要： | Since the Xingtai (邢台) earthquake in 1966,China Earthquake Administration has carried out a survey campaign along more than thirty deep seismic sounding (DSS) profiles altogether about twenty thousand kilometers long in North China to study the velocity structure of the crust and the upper mantle in this region,and has obtained a great number of research findings. However,these researches have not provided a 3D velocity structure model of the crust of North China and cannot provide seismic evidence for the study of the deep tectonic characteristics of the crust of the whole region. Hence,based on the information from the published data of the DSS profiles,we have chosen 14 profiles to obtain a 3D velocity structure model of North China using the vectorization function of the GIS software (Arc/Info) and the Kriging data gridding method. With this velocity structure model,we have drawn the following conclusions: (1) The P-wave velocity of the uppermost crust of North China changes dramatically,exhibiting a complicated velocity structure in plane view. It can be divided into three velocity zones mainly trending towards north-west. In the research area,the lowest-velocity zones lie in the Haihe (海河) plain and Bohai (渤海) Bay. Although the geological structure of the sedimentary overburden in the study area is somewhat inherited by the upper crust,there are still several differences between them. (2) Generally,the P-wave velocity of the crust increases with depth in the study area,but there still exists local velocity reversion. In the east,low-velocity anomalies of the Haihe plain gradually disappear with increasing depth,and the Shanxi (山西) graben in the west is mainly characterized by relatively low velocity anomalies. Bounded by the Taihang (太行) Mountains,the eastern and western parts differ in structural trend of stratum above the crystalline basement. The structural trend of the Huanghuaihai (黄淮海) block in the east is mainly north-east,while that of the Shanxi block and the eastern edge of the Ordos block is mainly north-west. (3) According to the morphological features of Moho,the crust of the study area can be divided into six blocks. In the Shanxi block,Moho apppears like a nearly south-north trending depression belt with a large crustal thickness. In the southern edge of the Inner Mongolia block and the south of the Yanshan (燕山) block,the Moho exhibits a feature of fold belt,trending nearly towards east-west. In the eastern edge of the Ordos block,the structure of Moho is relatively complex,presenting a pattern of fold trending nearly towards north-west with alternating convexes and concaves. Beneath the Huanghuaihai block,the middle and northern parts of the North China rift zone,the Moho is the shallowest in the entire region,with alternating uplifts and depressions in its shape. For the anteclise zone in the west of Shandong (山东) Province,the Moho is discontinuous for the fault depression extending in the north-west direction along Zaozhuang (枣庄) -Qufu (曲阜).
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| 关 键 词： | 中国北部 地壳 地震探测 地震波 |
| 收稿时间： | 20 March 2007 |
| 修稿时间： | 2007-03-20 |
Three-Dimensional P-Wave Velocity Structure of the Crust of North China |
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| Wei Wenbo,Ye Gaofeng,Li Yanjun,Jin Sheng,Deng Ming,Jing Jian'en.Three-Dimensional P-Wave Velocity Structure of the Crust of North China[J].Journal of China University of Geosciences,2007,18(3):257-268. |
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| Authors: | Wei Wenbo Ye Gaofeng Li Yanjun Jin Sheng Deng Ming Jing Jian'en |
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| Institution: | State Key Laboratory of Geological Processes and Mineral Resources; Geo-detection Laboratory, Ministry of Education, Beijing 100083, China;School of Geophysics and Information Technology, China University of Geosciences, Beijing 100083, China |
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| Abstract: | Since the Xingtai (邢台) earthquake in 1966, China Earthquake Administration has carried out a survey campaign along more than thirty deep seismic sounding (DSS) profiles altogether about twenty thousand kilometers long in North China to study the velocity structure of the crust and the upper mantle in this region, and has obtained a great number of research findings. However, these researches have not provided a 3D velocity structure model of the crust of North China and cannot provide seismic evidence for the study of the deep tectonic characteristics of the crust of the whole region. Hence, based on the information from the published data of the DSS profiles, we have chosen 14 profiles to obtain a 3D velocity structure model of North China using the vectorization function of the GIS software (Arc/Info) and the Kriging data gridding method. With this velocity structure model, we have drawn the following conclusions: (1) The P-wave velocity of the uppermost crust of North China changes dramatically, exhibiting a complicated velocity structure in plane view. It can be divided into three velocity zones mainly trending towards north-west. In the research area, the lowest-velocity zones overburden in the study area is somewhat inherited by the upper crust, there are still several differences between them. (2) Generally, the P-wave velocity of the crust increases with depth in the study area, but there still exists local velocity reversion. In the east, low-velocity anomalies of the Haihe eastern and western parts differ in structural trend of stratum above the crystalline basement. The Shanxi block and the eastern edge of the Ordos block is mainly north-west. (3) According to the morphological features of Moho, the crust of the study area can be divided into six blocks. In the Shanxi block, Moho apppears like a nearly south-north trending depression belt with a large crustal the Moho exhibits a feature of fold belt, trending nearly towards east-west. In the eastern edge of the Ordos block, the structure of Moho is relatively complex, presenting a pattern of fold trending nearly towards north-west with alternating convexes and concaves. Beneath the Huanghuaihai block, the middle and northern parts of the North China rift zone, the Moho is the shallowest in the entire region, with alternating uplifts and depressions in its shape. For the anteclise zone in the west of Shandong (山东) Province, the Moho is discontinuous for the fault depression extending in the north-west direction along Zaozhuang (枣庄) -Qufu (曲阜). |
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| Keywords: | North China crust deep seismic sounding three-dimensional P-wave velocity structure |
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