福建及其邻区背景噪声面波群速度层析成像
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摘要
基于福建及邻区108个宽频带地震台站2016年6月到7月两个月垂直和水平分量波形连续记录,利用相位加权叠加算法提高信噪比,计算得到108个台站对的高质量经验格林函数。对所获取的经验格林函数,采用时频分析的方法在1~20s频段内量取了大量高质量的Rayleigh波和Love波群速度频散数据。在此基础上,采用基于射线追踪的二维层析成像方法反演得到了福建及其邻区1~20s的Rayleigh波和Love波群速度分布。分辨率测试结果表明群速度分布的分辨率能达50km。成像结果显示1~10s的群速度分布与地壳中上部地质特征有很好的一致性,区内的福州盆地和漳州盆地在浅层结构中表现出明显的低速异常。长周期的群速度则揭示了漳州西北的高地热区内中下地壳低速体,政和-大埔断裂两侧的速度差异,表明其可能是一个深大断裂,并呈现明显的东西差异。
Based on continuous waveform recording of vertical and horizontal component of broadband stations in June and July of 2016 in Fujian and its adjacent areas,we used the phase-weight stack algorithm to improve the signal to noise ratio(SNR).We obtain high quality Empirical Green Functions(EGF)of 108 stations.Applying time-frequency analysis technique from symmetrical component of EGF,we measured a large number of high quality Rayleigh and Love wave group velocity dispersion curves in the 1~20 s.To reduce error of straight ray-path assumption in 2 Dtomography of group velocity map,the traveltime field was computed with a finite-difference scheme and the ray-path was tracing on the travel-time field.The checkerboard test suggests the resolution of 2 Dtomography is up to50 km.We obtain the Rayleigh and Love wave group velocity map of Fujian province and adjacent areas in the 1~20 s.The results show that the group velocity distribution of 1~10 sis consistent with the upper and middle geological features of the crust,and the Fuzhou and Zhangzhou basins are imaged as obvious low velocity bodies at the periods.The long period group velocity results suggest a high geothermal region at the northwest of Zhangzhou in the middle and lower crust,and the velocity difference between the two sides of Zhenghe—Dapu fault that suggest it maybe a deep and large fault and have an obvious velocity difference between east and west.The general pattern of our model crust is consistent with geological units in this region.
Based on continuous waveform recording of vertical and horizontal component of broadband stations in June and July of 2016 in Fujian and its adjacent areas,we used the phase-weight stack algorithm to improve the signal to noise ratio(SNR).We obtain high quality Empirical Green Functions(EGF)of 108 stations.Applying time-frequency analysis technique from symmetrical component of EGF,we measured a large number of high quality Rayleigh and Love wave group velocity dispersion curves in the 1~20 s.To reduce error of straight ray-path assumption in 2 Dtomography of group velocity map,the traveltime field was computed with a finite-difference scheme and the ray-path was tracing on the travel-time field.The checkerboard test suggests the resolution of 2 Dtomography is up to50 km.We obtain the Rayleigh and Love wave group velocity map of Fujian province and adjacent areas in the 1~20 s.The results show that the group velocity distribution of 1~10 sis consistent with the upper and middle geological features of the crust,and the Fuzhou and Zhangzhou basins are imaged as obvious low velocity bodies at the periods.The long period group velocity results suggest a high geothermal region at the northwest of Zhangzhou in the middle and lower crust,and the velocity difference between the two sides of Zhenghe—Dapu fault that suggest it maybe a deep and large fault and have an obvious velocity difference between east and west.The general pattern of our model crust is consistent with geological units in this region.
引文
[1]福建省地质矿产局.福建省区域地质志[M].北京:地质出版社,1985.
[2]廖其林,吴宁远,丘陶兴,等.福州盆地及其周围地区地壳深部结构与构造的初步研究[J].地球物理学报,1990,33(2):163-173.
[3]熊绍柏,金东敏,孙克忠,等.福建漳州地热田及其邻近地区的地壳深部构造特征[J].地球物理学报,1991,34(1):55-63.
[4]王椿镛,林中洋,陈学波.青海门源—福建宁德地学断面综合地球物理研究[J].地球物理学报,1995,38(5):590-598.
[5]朱金芳,方盛明,张先康,等.漳州盆地及其邻区地壳深部结构的探测与研究[J].中国地震,2006,22(4):405-417.
[6]Zheng H W,Gao R,Li T D,et al.Collisional tectonics between the Eurasian and Philippine Sea plates from tomography evidences in Southeast China[J].Tectonophysics,2013,606:14-23.
[7]蔡辉腾,金星,王善雄.福建地区地壳上地幔速度结构研究进展[J].地球物理学进展,2014,29(4):1 485-1 490.
[8]丁学仁,吴长江.福建及其沿海地区中强以上地震的震源机制研究[J].大地测量与地球动力学,1999,19(1):95-97.
[9]邱毅,郑斯华,鲍挺,等.利用地震台网宽频带地震记录计算福建中等强度地震的震源机制解[J].地震,2013,33(1):65-73.
[10]段刚.CAP方法反演福建仙游ML5.0、ML4.5级地震震源机制解[J].地球物理学进展,2016,31(4):1 432-1 437.
[11]Shapiro N,Campillo M.Emergence of broadband Rayleigh waves from correlations of the ambient seismic noise[J].Geophys Res Lett,2004,31:L07614.
[12]Shapiro N,Campillo M,Stehly L.High-resolution surface wave tomography from ambient seismic noise[J].Scien M.ce,2005,307:1 615-1 618.
[13]Yao H,vander Hilst R D,e HoopM.V.d.Surface-wave array tomography in SE Tibet from ambient seismic noise and two-station analysis-I.Phase velocity maps[J].Geophys J Int,2006,166:732-744.
[14]Lin F C,Ritzwoller M H,Townend J.Ambient noise Rayleigh wave tomography of New Zealand[J].Geophys J Int,2007.170(2):649-666
[15]Zheng S H,Sun X L,Song X D,et al.Surface wave tomography of China from ambient seismic noise correlation[J].Geochem Geophys Geosyst,2008,9:Q05020.
[16]Yang Y,Ritzwoller M H,Lin F C,et al.Structure of the crust and uppermost mantle beneath the western United States revealed by ambient noise and earthquake tomography[J].J Geophys Res,2008a,113:B12310.
[17]房立华,吴建平,吕作勇.华北地区基于噪声的瑞利面波群速度层析成像[J].地球物理学报,2009,52:663-671.
[18]Guo Z,Gao X,Yao H,Li J,Wang W.Midcrustal low-velocity layer beneath the central Himalaya and southern Tibet revealed by ambient noise array tomography[J].Geochem Geophys Geosyst,2009,10:Q05007.
[19]李昱,姚华建,刘启元,等.川西地区台阵环境噪声瑞利波相速度层析成像[J].地球物理学报,2010,53:842-852.
[20]Zhou L,Xie J,Shen W,et al.The structure of the crust and uppermost mantle beneath South China from ambient noise and earthquake tomography[J].Geophys J Int,2012,189:1 565-1 583.
[21]金星,李军,林树,等.利用双台脉动记录的相关系数估计福建地区瑞雷面波的群速度[J].中国地震,2007,23(4):249-358.
[22]李军,金星,鲍挺,等.利用噪声记录估计福建地区中上地壳体波速度结构[J].中国地震,2011,27(3):226-234.
[23]梁富华,金星,李军,等.福建地区环境噪声瑞利波群速度层析成像[J].中国地震,2012,28(1):22-32.
[24]姚晟锞.福建地区背景噪声勒夫面波层析成像研究[D].2013.硕士论文中国地震局工程力学研究所
[25]Bensen G D,Ritzwoller M H,Barmin M P.Processing seismic ambient noise data to obtain reliable broad-band surface wave dispersion measurements[J].Geophys J Int,2007,169:1 239-1 260.
[26]Zeng X,Thurber C H.A Graphics Processing Unit Implementation for Time-Frequency PhaseWeighted Stacking[J].Seismological Research Letters,2016,87(2A):358-362.
[27]Schimmel M,Gallart J.Frequency-dependent phase coherence for noise suppression in seismic array data[J].J Geophys Res,2007,112:B04303.
[28]邱毅,金星,蔡辉腾,等.利用人工地震研究福建地壳一维速度结构[J].地震工程与工程振动,2014,34:1 071-1 076.
[29]黄晖,米宁,徐鸣洁,等.福建地区地壳上地幔S波速度结构与泊松比[J].高校地质学报,2010,16(4):465-474.
[2]廖其林,吴宁远,丘陶兴,等.福州盆地及其周围地区地壳深部结构与构造的初步研究[J].地球物理学报,1990,33(2):163-173.
[3]熊绍柏,金东敏,孙克忠,等.福建漳州地热田及其邻近地区的地壳深部构造特征[J].地球物理学报,1991,34(1):55-63.
[4]王椿镛,林中洋,陈学波.青海门源—福建宁德地学断面综合地球物理研究[J].地球物理学报,1995,38(5):590-598.
[5]朱金芳,方盛明,张先康,等.漳州盆地及其邻区地壳深部结构的探测与研究[J].中国地震,2006,22(4):405-417.
[6]Zheng H W,Gao R,Li T D,et al.Collisional tectonics between the Eurasian and Philippine Sea plates from tomography evidences in Southeast China[J].Tectonophysics,2013,606:14-23.
[7]蔡辉腾,金星,王善雄.福建地区地壳上地幔速度结构研究进展[J].地球物理学进展,2014,29(4):1 485-1 490.
[8]丁学仁,吴长江.福建及其沿海地区中强以上地震的震源机制研究[J].大地测量与地球动力学,1999,19(1):95-97.
[9]邱毅,郑斯华,鲍挺,等.利用地震台网宽频带地震记录计算福建中等强度地震的震源机制解[J].地震,2013,33(1):65-73.
[10]段刚.CAP方法反演福建仙游ML5.0、ML4.5级地震震源机制解[J].地球物理学进展,2016,31(4):1 432-1 437.
[11]Shapiro N,Campillo M.Emergence of broadband Rayleigh waves from correlations of the ambient seismic noise[J].Geophys Res Lett,2004,31:L07614.
[12]Shapiro N,Campillo M,Stehly L.High-resolution surface wave tomography from ambient seismic noise[J].Scien M.ce,2005,307:1 615-1 618.
[13]Yao H,vander Hilst R D,e HoopM.V.d.Surface-wave array tomography in SE Tibet from ambient seismic noise and two-station analysis-I.Phase velocity maps[J].Geophys J Int,2006,166:732-744.
[14]Lin F C,Ritzwoller M H,Townend J.Ambient noise Rayleigh wave tomography of New Zealand[J].Geophys J Int,2007.170(2):649-666
[15]Zheng S H,Sun X L,Song X D,et al.Surface wave tomography of China from ambient seismic noise correlation[J].Geochem Geophys Geosyst,2008,9:Q05020.
[16]Yang Y,Ritzwoller M H,Lin F C,et al.Structure of the crust and uppermost mantle beneath the western United States revealed by ambient noise and earthquake tomography[J].J Geophys Res,2008a,113:B12310.
[17]房立华,吴建平,吕作勇.华北地区基于噪声的瑞利面波群速度层析成像[J].地球物理学报,2009,52:663-671.
[18]Guo Z,Gao X,Yao H,Li J,Wang W.Midcrustal low-velocity layer beneath the central Himalaya and southern Tibet revealed by ambient noise array tomography[J].Geochem Geophys Geosyst,2009,10:Q05007.
[19]李昱,姚华建,刘启元,等.川西地区台阵环境噪声瑞利波相速度层析成像[J].地球物理学报,2010,53:842-852.
[20]Zhou L,Xie J,Shen W,et al.The structure of the crust and uppermost mantle beneath South China from ambient noise and earthquake tomography[J].Geophys J Int,2012,189:1 565-1 583.
[21]金星,李军,林树,等.利用双台脉动记录的相关系数估计福建地区瑞雷面波的群速度[J].中国地震,2007,23(4):249-358.
[22]李军,金星,鲍挺,等.利用噪声记录估计福建地区中上地壳体波速度结构[J].中国地震,2011,27(3):226-234.
[23]梁富华,金星,李军,等.福建地区环境噪声瑞利波群速度层析成像[J].中国地震,2012,28(1):22-32.
[24]姚晟锞.福建地区背景噪声勒夫面波层析成像研究[D].2013.硕士论文中国地震局工程力学研究所
[25]Bensen G D,Ritzwoller M H,Barmin M P.Processing seismic ambient noise data to obtain reliable broad-band surface wave dispersion measurements[J].Geophys J Int,2007,169:1 239-1 260.
[26]Zeng X,Thurber C H.A Graphics Processing Unit Implementation for Time-Frequency PhaseWeighted Stacking[J].Seismological Research Letters,2016,87(2A):358-362.
[27]Schimmel M,Gallart J.Frequency-dependent phase coherence for noise suppression in seismic array data[J].J Geophys Res,2007,112:B04303.
[28]邱毅,金星,蔡辉腾,等.利用人工地震研究福建地壳一维速度结构[J].地震工程与工程振动,2014,34:1 071-1 076.
[29]黄晖,米宁,徐鸣洁,等.福建地区地壳上地幔S波速度结构与泊松比[J].高校地质学报,2010,16(4):465-474.