Study of the receiver function profile from Jiujiang, Jiangxi Province to Ninghua, Fujian Province
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摘要: 江西九江—福建宁化剖面沿NW--SE方向穿过华南大陆东部的扬子地块和华夏地块两个地质单元. 通过收集沿该剖面布设的35个流动宽频带地震台站2012—2014年记录的远震波形资料， 采用P波接收函数H-k扫描叠加和CCP叠加两种方法， 对该剖面下方的地壳厚度和泊松比分布进行了研究. 结果表明： 沿剖面地壳厚度为29—33 km， 扬子地块东南边缘与华夏地块的莫霍形态差异明显， 萍乡—广丰断裂北侧的萍乐凹陷带深部存在明显的莫霍面上隆现象， 为研究区域中地壳最薄处； 研究区大部分台站下方的泊松比值相对较低， 介于0.21—0.24之间， 萍乡—广丰断裂两侧泊松比值稍高， 可达0.26， 表明不同构造单元地壳深部岩石组成存在差异； 萍乡—广丰断裂可作为江绍拼合带的自然西延， 是扬子地块与华夏地块在赣北地区的拼合界线， 推测其深部的物质组成有相似之处.Abstract: The profile from Jiujiang, Jiangxi Province to Ninghua, Fujian Province, passes through the Yangtze block and the Cathaysia block from northwest to southeast in the east of South China continent. This paper selected teleseismic records from 35 temporary broadband stations along the profile from June 2012 to June 2014 so as to obtain the crustal thickness and Poisson's ratio by the H-k stacking method and common conversion point (CCP) stacking method. The results show that the crustal thickness of the studied area ranges 29-33 km. The depth of Moho of the southeast edge of the Yangtze block has an obvious difference from that of the Cathaysia block. The depth of the Ping-xiang--Leping depression zone to the north of Pingxiang--Guangfeng fault exhi-bits obvious uplift of Moho in the deep, being the thinnest part of the studied area. The average value of Poisson's ratio obtained from H-k stacking method shows that the Poisson's ratios are as low as 0.21-0.24 beneath crust of most of the studied area. At the two sides of the Pingxiang--Guangfeng fault, the Poisson's ratio value is higher, reaching about 0.26, which means the different constitution of the rock in the deep for the disparate tectonic units. All above evidences suggest that the Pingxiang--Guangfeng fault can be considered as the extension of Jiangshan-Shaoxing coherence belt, meanwhile it is the convergent boundary of Yangtze block and Cathaysia block in the north of Jiangxi Province, therefore it is inferred that the two blocks are composed of similar material in the deep.
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图 1 研究区台站(a)及所用远震事件震中分布图(b)， 图(b)中星号代表研究区域
F1： 九江—靖安断裂； F2： 萍乡—广丰断裂； F3： 永丰—抚州断裂； F4： 于都—乐安断裂； F5： 邵武—河源断裂
Figure 1. Distribution of the seismic stations (a) and the epicenters of teleseismic events (b) used in this study， where the red star in Fig.1b indicates the studied area
F1： Jiujiang--Jing’an fault; F2： Pingxiang--Guangfeng fault; F3： Yongfeng--Fuzhou fault;F4： Yudu--Le’an fault; F5： Shaowu--Heyuan fault
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图 2 sp06(a)、 sc06(b)和sc16(c)台站的接收函数(上)和H-k扫描叠加结果(下)
Figure 2. Receiver functions (upper) and H-k stacking results (lower) of the stations sp06 (a)， sc06 (b) and sc16 (c)
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图 3 研究区CCP叠加剖面
黄色虚线表示由CCP叠加法得到的莫霍面变化， 黑色十字表示H-k扫描叠加法得到的相应台站下方的地壳厚度F1： 九江—靖安断裂； F2： 萍乡—广丰断裂； F3： 永丰—抚州断裂； F4： 于都—乐安断裂； F5： 邵武—河源断裂
Figure 3. CCP stacking profile in the studied area
The yellow dashed lines represent the depth of Moho by CCP stacking method, and the black crosses represent the crustal thickness beneath the corresponding stations by H-k stacking method. F1： Jiujiang--Jing’an fault；F2： Pingxiang--Guangfeng fault； F3： Yongfeng--Fuzhou fault；F4： Yudu--Le’an fault； F5： Shaowu--Heyuan fault
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图 4 H-k扫描叠加法获得的各台站地壳厚度(a)和泊松比(b)
Figure 4. Crustal thickness (a) and Poisson’s ratio (b) beneath the stations in the studied area obtained by H-k stacking method
表 1 H-k扫描叠加法得到的各台站下方地壳厚度H、 波速比k及泊松比σ
Table 1 Crustal thickness,vP/vS ratio and Poisson’s ratio beneath the stations obtained by H-k stacking method
台站
名称接收函
数数量H/km k σ 台站
名称接收函
数数量H/km k σ sp06 43 33.0±1.3 1.67±0.03 0.220±0.016 sc13 32 32.1±1.3 1.75±0.04 0.258±0.017 sp05 23 31.6±0.8 1.72±0.03 0.245±0.013 sc14 30 32.0±1.1 1.69±0.03 0.231±0.016 sp04 26 30.8±1.3 1.72±0.03 0.245±0.013 sc15 40 31.1±1.5 1.65±0.04 0.210±0.023 sp03 29 31.3±1.0 1.70±0.03 0.235±0.015 sc16 44 31.5±1.0 1.70±0.03 0.235±0.015 sp02 30 31.3±1.2 1.67±0.03 0.220±0.016 sc17 47 31.6±1.2 1.73±0.04 0.249±0.013 sp01 28 29.1±1.3 1.71±0.03 0.240±0.014 sc18 21 31.4±1.3 1.70±0.03 0.235±0.015 sc01 19 29.6±1.5 1.71±0.04 0.240±0.014 sc19 24 32.3±1.6 1.69±0.04 0.231±0.019 sc02 35 28.9±1.3 1.71±0.05 0.240±0.022 sc20 32 32.0±2.1 1.69±0.05 0.231±0.025 sc03 53 28.7±0.9 1.72±0.03 0.245±0.013 sc21 25 31.4±1.4 1.70±0.03 0.235±0.015 sc04 43 29.9±1.4 1.67±0.04 0.220±0.020 sc22 26 31.3±1.4 1.66±0.03 0.215±0.016 sc05 71 29.4±1.1 1.69±0.03 0.231±0.016 sc23 28 32.3±1.4 1.69±0.04 0.231±0.019 sc06 59 31.0±0.8 1.75±0.03 0.258±0.013 sc24 28 31.5±0.9 1.73±0.03 0.249±0.013 sc07 26 29.8±1.0 1.66±0.03 0.215±0.017 sc25 24 32.5±1.1 1.67±0.02 0.220±0.011 sc08 41 30.5±1.4 1.72±0.03 0.245±0.013 sc26 22 32.4±1.8 1.72±0.04 0.245±0.017 sc09 29 30.7±1.3 1.74±0.03 0.253±0.013 sc27 26 32.9±1.2 1.70±0.03 0.235±0.015 sc10 34 30.8±1.4 1.70±0.03 0.235±0.015 sc28 27 33.0±1.7 1.69±0.04 0.231±0.019 sc11 22 30.6±1.5 1.74±0.04 0.253±0.017 sc29 30 33.0±1.5 1.67±0.03 0.240±0.016 sc12 40 31.7±1.5 1.68±0.04 0.226±0.021 
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林中洋, 王椿镛, 胡鸿翔, 陈学波. 1990. 中国门源—宁德地学大断面[C]//1990年中国科学院地球物理研究所40周年所庆论文集. 北京: 地震出版社: 114-117. Lin Z Y, Wang C Y, Hu H X, Chen X B. 1990. The Menyuan-Ningde geoscience section of China[C]//The Collected Papers for the 40th Anniversary Celebration of Institute of Geophysics, Chinese Academy of Sciences in 1990. Beijing: Seismological Press: 114-117 (in Chinese).
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