| 帕米尔东北缘地壳结构的P波接收函数研究 |
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| 引用本文： | 唐明帅,郑勇,葛粲,王海涛,冀战波,孔祥艳,魏斌,李志海.帕米尔东北缘地壳结构的P波接收函数研究[J].地球物理学报,2014,57(10):3176-3188. |
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| 作者姓名： | 唐明帅 郑勇 葛粲 王海涛 冀战波 孔祥艳 魏斌 李志海 |
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| 作者单位： | 1. 新疆维吾尔自治区地震局, 乌鲁木齐 830011;
2. 大地测量与地球动力学国家重点实验室, 中国科学院测量与地球物理研究所, 武汉 430077;
3. 合肥工业大学, 合肥 230009 |
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| 基金项目： | 中国地震局"测震台网青年骨干培养"专项(20130216),地震公益性行业科研专项项目(201308013),国家自然科学基金(41174086、41104037)资助. |
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| 摘 要： | 利用位于新疆帕米尔东北缘地带12个固定数字地震台和天山动力学Ⅱ期10个流动宽频带数字地震台记录的高质量远震波形数据,应用接收函数H-κ叠加方法研究了帕米尔东北缘的地壳厚度-泊松比特征和部分台站下方的壳内界面深度.研究发现:(1) 帕米尔东北缘的Moho面起伏变化剧烈,其总体分布呈现东薄西厚、南厚北薄的特征,由塔里木盆地向天山延伸,地壳厚度约从45 km加深到55 km,从塔里木盆地向西昆仑山延伸,地壳厚度约从45 km加深到69 km;(2)沿着天山动力学Ⅱ期剖面,位于塔里木盆地北缘台站的壳内间断面的深度约为13~16 km,向北进入天山南麓加深到20 km左右,继续向北进入南天山山区壳内间断面不明显,可能暗示塔里木盆地基底向北俯冲,俯冲距离可能到达南天山的山前;(3)研究区地壳泊松比变化复杂(约从0.20到0.31),显示地壳物质组成的复杂性和显著的不均匀构造;(4)整个研究区的地壳厚度和泊松比之间没有明显的相关性,但天山动力学Ⅱ期剖面的结果表明,从塔里木盆地北缘到西南天山,地壳厚度和泊松比之间存在反相关关系,意味着天山地壳的增厚可能主要是通过以长英质岩石为主要组成成分的上地壳叠置而成;(5) 研究区全部地震台地壳厚度与海拔高程的线性回归方程表明地壳厚度与海拔的相关性相对较弱(相关系数为0.66),天山动力学Ⅱ期10个台站的地壳厚度与海拔具有很好的相关性(相关系数为0.85),可能表明沿该剖面地壳整体上处于相对均衡的状态.
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| 关 键 词： | 地壳厚度 泊松比 壳内间断面埋深 接收函数 帕米尔东北缘 |
| 收稿时间： | 2014-01-11 |
Study on crustal structure in the northeastern Pamir region by P receiver functions |
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| TANG Ming-Shuai,ZHENG Yong,GE Can,WANG Hai-Tao,JI Zhan-Bo,KONG Xiang-Yan,WEI Bin,LI Zhi-Hai.Study on crustal structure in the northeastern Pamir region by P receiver functions[J].Chinese Journal of Geophysics,2014,57(10):3176-3188. |
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| Authors: | TANG Ming-Shuai ZHENG Yong GE Can WANG Hai-Tao JI Zhan-Bo KONG Xiang-Yan WEI Bin LI Zhi-Hai |
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| Institution: | 1. Earthquake Administration of Xinjiang Uygur Autonomous Region.Urumqi 830011, China;
2. State Key Laboratory of Geodesy and Earth's Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China;
3. HeFei University of Technology, HeFei 230009, China |
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| Abstract: | Using the teleseismic waveform data recorded by 12 permanent digital seismic stations from Xinjiang seismograph network and 10 campaign broadband digital seismic stations from Tienshan dynamics Ⅱ term project located in the northeastern Pamir region in Xinjiang, we investigate the crustal thickness, Poisson's ratio and the depth of inter-crustal discontinuity beneath each station by grid search and stacking method of receiver function. The result shows five characteristics in the crustal structure. (1) Strong lateral crustal thickness variations exists in this area. The crust is thicker in the western and the southern parts of the Pamir region, but thinner in the eastern and the northern parts. The crustal thickness gradually deepens from 45 km to 55 km from the Tarim basin to the south Tienshan,and gradually deepens from 45 km in the Tarim basin to 69 km in the West Kunlun Mountain. (2) Along the profile of the Tienshan dynamics Ⅱ project, the depth of inter-crustal discontinuity about is 13~16 km beneath the northern Tarim basin, and deepens to about 20 km to the north into the south Tienshan Orogen, but the inter-crustal discontinuity in further north under the south Tienshan mountains is weak. The depth changes of inter-crustal discontinuity may indicate that the Tarim basin basement subducts northward, and the front of the subduction slab may reach to the south Tienshan Mountain piedmont; (3) The crustal Poisson's ratio in the studied region changes significantly (about from 0.20 to 0.31), which suggests that the crust composition is complex. (4) There are no obvious relationship between the crust thickness and Poisson's ratio in this study area. But the Tienshan dynamics Ⅱ project profile results show that the anti-correlation pattern exists between the crust thickness and Poisson's ratio from the north rim of the Tarim basin to the southwest Tienshan, suggesting that the Tienshan crustal thickening mainly due to the upper crust superimposed, and the upper crust main composition are felsic rocks. (5) The crustal thickness of this study area is relatively weak correlated to the elevation height (the correlation coefficients is 0.66). But the crustal thickness under 10 stations in the Tienshan dynamics Ⅱ project are well correlated to the elevation height (correlation coefficient is 0.85), which may imply that the crust in a relatively well isostatic status along the profile. |
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| Keywords: | Crustal thickness Poisson's ratio Depth of inter-crustal discontinuity Receiver function Northeastern Pamir region |
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