江苏地区波速比与泊松比分布特征
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摘要
将江苏地区(30.5°～35.5°N, 116°～122°E)按1°×1°分成18个子区,搜集整理了江苏数字地震台网2009年1月1日至2017年12月31日产出的震相观测报告,采用多台和达法计算了各子区域的平均波速比,分析研究了全区波速比和泊松比分布特征。结果表明:①各区的波速比均值介于1.68～1.73之间,相关系数均在0.99以上,全区平均波速比值为1.71,较全球大陆地壳平均值偏低;②全区平均泊松比值为0.24,研究区域没有熔融的介质性质,与该区地质构造以花岗岩为主的特征一致;③从泊松比与地壳厚度的相关性来看,江苏地区的泊松比与地壳厚度整体上呈现负相关的关系,北高南低、东高西低,在33°N附近,泊松比高低相间,变化复杂,可能与研究区内复杂的地质构造有关。
In this paper, we divided the Jiangsu area(30.5°N ～35.5°N, 116°E ～122°E) into 18 sections in which each section has the range of 1°×1°. We collected the phase data of Jiangsu Digital Seismic Network from January 1, 2009 to December 31, 2017. Using the multi-station methods, we calculated the velocity ratio and possion's ratio of the 18 sections. The results show that: ① In 18 sections, the mean velocity ratio ranges from 1.68 to 1.73, the correlation coefficients are above 0.99, the average velocity ratio value of the whole are is 1.71, which is lower than the average value of the global continental crust. ② The average poisson's ratio value is 0.24. This shows that there is no melting medium property in the study area, consistent with the crust medium which mainly consist of granite. ③ From the relevance of poisson's ratio and crust thickness, there is a negative correlation between the poisson's ratio and crust thickness in Jiangsu area, which is higher in the north and lower in the south, higher in the east and lower in the east. The Poisson's ratio of some sub-regions near 33°N, alternates high and low and changes complicatedly, which may be related to complex geological structure in the study area.
In this paper, we divided the Jiangsu area(30.5°N ～35.5°N, 116°E ～122°E) into 18 sections in which each section has the range of 1°×1°. We collected the phase data of Jiangsu Digital Seismic Network from January 1, 2009 to December 31, 2017. Using the multi-station methods, we calculated the velocity ratio and possion's ratio of the 18 sections. The results show that: ① In 18 sections, the mean velocity ratio ranges from 1.68 to 1.73, the correlation coefficients are above 0.99, the average velocity ratio value of the whole are is 1.71, which is lower than the average value of the global continental crust. ② The average poisson's ratio value is 0.24. This shows that there is no melting medium property in the study area, consistent with the crust medium which mainly consist of granite. ③ From the relevance of poisson's ratio and crust thickness, there is a negative correlation between the poisson's ratio and crust thickness in Jiangsu area, which is higher in the north and lower in the south, higher in the east and lower in the east. The Poisson's ratio of some sub-regions near 33°N, alternates high and low and changes complicatedly, which may be related to complex geological structure in the study area.
引文
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[14] 胥颐,李雪垒,汪晟.腾冲火山区的地壳厚度和平均泊松比研究[J].地球物理学报,2017,60(6):2256-2264.
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[17] 黄耘,李清河,孙业君,等.江苏及邻区地壳上地幔结构研究[J].西北地震学报,2006,28(4):369-375.
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[2] 赵晋明,胡毅力,杨润海,等.岩石临破坏前波速奇异变化的再研究[J].地震研究,2001,24(2):136-139.
[3] 黎明晓,张晓东.应用多台法测定华北地区地壳的平均波速比[J].地震,2004,24(1):163-169.
[4] 张学民,张天中,李永红,等.山东地区多台波速比研究[J].地震地质,2007,29(1):95-104.
[5] 刘文邦,万玉杰,李玮杰.2016年青海门源6.4级地震前后波速比变化研究[J].地震研究,2016,39(S1):49-54.
[6] 王林瑛,李艳娥,李芳,等.汶川地震前后地震波速比和视速度变化特征的研究[J].地震学报,2011,33(1):1-14.
[7] 钱晓东,苏有锦.2008年攀枝花6.1级地震前后波速比变化研究[J].地震研究,2013,36(1):15-23.
[8] 王林瑛,李艳娥,郑需要,等.芦山MS7.0强震前单台波速比变化特征研究[J].地震学报,2014,36(1):42-58.
[9] 翁钊强,梁向军,吴昊昱,等.单台多震和达法研究山西地区的波速比变化特征[J].中国地震,2015,31(1):89-100.
[10] 王亚茹,王想,宫猛,等.河北及邻区平均波速比变化特征分析[J].中国地震,2016,32(4):747-755.
[11] 嵇少丞,王茜,杨文采.华北克拉通泊松比与地壳厚度的关系及其大地构造意义[J].地质学报,2009,83(3):324-330.
[12] 张小涛,韩丽萍,张新东,等.河北邯郸-邢台地区波速比和泊松比分布特征研究[J].西北地震学报,2012,34(1):84-87.
[13] 邓嘉美,陈佳,高琼,等.云南宾川地区的地壳厚度和泊松比分布特征研究[J].地震,2016,36(3):99-108.
[14] 胥颐,李雪垒,汪晟.腾冲火山区的地壳厚度和平均泊松比研究[J].地球物理学报,2017,60(6):2256-2264.
[15] 傅征祥,程燕.北京和张家口地区地壳平均波速比的联合测定[J].地震,1988,8(4):28-34.
[16] 黄耘,李清河,张元生,等.郯庐断裂带鲁苏皖段及邻区地壳速度结构[J].地球物理学报,2011,54(10):2549-2559.
[17] 黄耘,李清河,孙业君,等.江苏及邻区地壳上地幔结构研究[J].西北地震学报,2006,28(4):369-375.
[18] Christensen N I,Mooney W D.Seismic velocity structure and composition of the continental crust:a global view[J].J Geophys.Res.,1995,100:9761-9788.
[19] Watanabe T.Effects of water and melt on seismic velocities and their application to characterization of seismic reflectors[J].Geophys.Res.Lett.,1993,20:2933-2936.