| 华南地壳及上地幔三维速度结构成像 |
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| 引用本文： | 谭皓原,王志.华南地壳及上地幔三维速度结构成像[J].物探化探计算技术,2014(3):318-325. |
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| 作者姓名： | 谭皓原 王志 |
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| 作者单位： | 地球探测与信息技术教育部重点实验室成都理工大学; |
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| 基金项目： | 国家自然科学基金(41372229);中科院百人计划(17314059);博士点基金(20115122110007,20125122110002);四川省科研创新团队计划(KYTD201002) |
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| 摘 要： | 利用国家地震科学数据共享中心的地震目录及临时台网资料,挑选出11 113个区域地震的77 093条P波走时和93 541条S波走时,采用1°×1°的经纬度网格划分,反演获得了深至60km的华南南部地区的地壳及上地幔三维P波和S波的速度结构。研究结果表明,纵波速度结构与横波速度结构从整体来看具有较好的一致性,说明该研究获得的深部速度结果具有较高的可信性,但是在50km的深度纵、横波速度结构的一致性较差,可能是由于该深度的纵横波走时数据存在着较大的差异所导致的。本研究显示了研究区域内的速度结构存在着明显的横向不均匀性,东南沿海地区的地壳中出现了大规模的低速异常,可能与该区地幔物质的上涌有关;而在珠江三角洲、雷州半岛、北部湾及海南岛等地区莫霍面下方出现的低速异常,则与该区的热运动有关。经分析认为,华南南部地壳及上地幔的速度不均匀性和华南板块与扬子地块的相互作用有关,因此开展进一步研究能为探索和分析华南再造以及中国南海北部的构造演化提供重要信息。
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| 关 键 词： | 华南南部 体波速度反演成像 华南再造 南海北部构造演化 |
3D seismic tomography of crust and upper mantle in South China |
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| TAN Hao-yuan,WANG Zhi.3D seismic tomography of crust and upper mantle in South China[J].Computing Techniques For Geophysical and Geochemical Exploration,2014(3):318-325. |
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| Authors: | TAN Hao-yuan WANG Zhi |
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| Institution: | (Key Laboratory of Earth Exploration and Information Techniques of Ministry of Education,Chengdu University of Technology, Chengdu 610059, China) |
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| Abstract: | We determined 3D seismic velocity structures of P-and S-waves using 77,093 P and 93,541 S travel times from 11,113 local earthquakes collected from the China Earthquake Data Center and some temporay networks.The grid space is 1＆#176;＆#215;1＆#176;in horizontal direction and 10 km in depth in this study.Our result shows that,in general,the P-wave images coincide with those of S wave,suggesting the inverted images are reliable features.However,the coherence of the Vp and Vs images is poor at 50 km depth due to the different ray paths of the P and S waves.Widely low-velocity are revealed along the south part of South China,indicating strong structural heterogeneities in the lower crust.An obvious slow velocity layer is observed in the lower crust and uppermost mantle along the coastal of south-eastern region of Huanan.This low velocity might reflect the up-welling of the asthenosphere in the upper mantle.The low-velocity anomalies in Zhujiang Delta,Leizhou Peninsula,Beibu Gulf and Hainan Island beneath Moho are associated with the thermal motion.Our study suggests that the strong structural heterogeneities could have influence on the Huanan restructure as well as the formation and evolution of South China Sea. |
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| Keywords: | South part of South China body wave seismic tomography restructure of Huanan formation and evolution of north part of South China sea |
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