利用随机噪声研究华南地区瑞利波相速度特征
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摘要
基于2009~2010年国家、区域测震台网的387个宽频带台站数据,通过互相关方法提取到可靠的瑞利波经验格林函数,利用相位匹配滤波时频分析技术测量瑞利波相速度频散曲线,最后采用噪声层析成像方法获得了华南地区不同周期的瑞利波相速度分布图。结果显示,华南地区速度结构横向变化幅度较小,反映了华南地区作为一个整体较为稳定,与华南地区自晚中生代以来未发生过强烈构造活动的特征基本一致;虽然华南地区整个岩石圈速度结构较为均匀,但扬子块体西部、四川盆地与扬子块体东部、华夏块体间存在明显的速度差异,体现在周期为8~10s时华夏块体相速度大于扬子块体西部、川滇块体以及四川盆地,由于沉积层较厚四川盆地速度最低;周期为10~30s时华夏块体面波相速度大于扬子块体西部和四川盆地,而川滇块体速度最低;周期为35s时扬子块体、华夏块体、四川盆地的速度基本一致,且高于川滇块体,这与华南地区地壳厚度明显小于川滇块体的特征相符。
The data used in this study are continuous seismic waveforms recorded at broadband seismic stations including the 387 stations of China National and Regional Seismic Network in 2009 and 2010. Cross-correlations are computed in daily segment to retrieve the reliably empirical Rayleigh wave Green 's function. Rayleigh wave phase velocity dispersion curves are measured using a phase-matched filter and frequency time analysis technique. We apply seismic ambient noise tomography to image the different period phase velocity maps of South China. Our results indicate that the phase velocity of the whole lithosphere in South China is relatively uniform,which also reflects that South China as a whole is characterized of the relative stability. Our results agree that there have been no intense tectonic activities in South China since late Mesozoic. Although the velocity structure of the whole lithosphere in South China is relatively uniform,distinct velocity differences appear in the west of the Yangtze Block,Sichuan Basin,the east of Yangtze Block and Cathaysia Block,namely,the 8-10 s period phase velocity of Cathaysia Block is higher than the west of the Yangtze Block,Sichuan-Yunnan region and Sichuan Basin. The Sichuan Basin has the lowest velocity because of the relatively thick sedimentary layer. The velocity of the Cathaysia Block in the 10-30 s period phase is higher than those of the Yangtze Block and Sichuan Basin and the Sichuan-Yunnan region has the lowest velocity. In the 35 s period phase,the velocities of the Yangtze Block and Cathaysia Block and Sichuan Basin are basically the same and higher than that of the Sichuan-Yunnan region. This is consistent with the feature that the crustal thickness in South China is obviously smaller than that of the Sichuan-Yunnan region.
The data used in this study are continuous seismic waveforms recorded at broadband seismic stations including the 387 stations of China National and Regional Seismic Network in 2009 and 2010. Cross-correlations are computed in daily segment to retrieve the reliably empirical Rayleigh wave Green 's function. Rayleigh wave phase velocity dispersion curves are measured using a phase-matched filter and frequency time analysis technique. We apply seismic ambient noise tomography to image the different period phase velocity maps of South China. Our results indicate that the phase velocity of the whole lithosphere in South China is relatively uniform,which also reflects that South China as a whole is characterized of the relative stability. Our results agree that there have been no intense tectonic activities in South China since late Mesozoic. Although the velocity structure of the whole lithosphere in South China is relatively uniform,distinct velocity differences appear in the west of the Yangtze Block,Sichuan Basin,the east of Yangtze Block and Cathaysia Block,namely,the 8-10 s period phase velocity of Cathaysia Block is higher than the west of the Yangtze Block,Sichuan-Yunnan region and Sichuan Basin. The Sichuan Basin has the lowest velocity because of the relatively thick sedimentary layer. The velocity of the Cathaysia Block in the 10-30 s period phase is higher than those of the Yangtze Block and Sichuan Basin and the Sichuan-Yunnan region has the lowest velocity. In the 35 s period phase,the velocities of the Yangtze Block and Cathaysia Block and Sichuan Basin are basically the same and higher than that of the Sichuan-Yunnan region. This is consistent with the feature that the crustal thickness in South China is obviously smaller than that of the Sichuan-Yunnan region.
引文
房立华、吴建平、吕作勇,2009,华北地区基于噪声的瑞利面波群速度层析成像,地球物理学报,52(3) ,663~671.
刘建华、吴华、刘福田,1996,华南及其海域三维速度分布特征与岩石层结构,地球物理学报,39(4) ,483~492.
滕吉文、张中杰、胡家富等,2001,中国东南大陆及陆缘地带的瑞利波频散与剪切波三维速度结构,地球物理学报,44(5) ,663 ~ 677.
舒良树,2012,华南构造演化的基本特征,地质通报,31(7) ,1035~1053.
易桂喜、姚华建、朱介寿等,2010,用 Rayleigh 面波方位各向异性研究中国大陆岩石圈形变特征,地球物理学报,53(2) ,256 ~ 268,doi: 10.3969 / j.issn.00015733.2010.02.004.
郑秀芬、欧阳飚、张东宁等,2009,“国家数字测震台网数据备份中心”技术系统建设及其对汶川大地震研究的数据支撑,地球物理学报,52(5) ,1412~1417,doi: 10.3969 /j.issn.00015733.2009.05.031.
Barmin M P,Ritzwoller M H,Levshin A L,2001,A fast and reliable method for surface wave tomography,Pure Appl Geophys,158,1351 ~ 1375.
Bensen G D,Ritzwoller M H,Barmin M P,et al,2007,Processing seismic ambient noise data to obtain reliable broad-band surface wave dispersion measurements,Geophys J Int,169,1239 ~ 1260.
Fang L H,Wu J P,Ding Z F,et al,2010,High resolution Rayleigh wave group velocity tomography in North China from ambient seismic noise,Geophys J Int,181(2) ,1171 ~ 1182.
Faure M,Lin W,Scharer U,et al,2003,Continental subduction and exhumation of UHP rocks: Structural and geochronological insights from the Dabieshan(East China) ,Lithos,70,213 ~ 241.
Guo L Z,Shi Y S,Lu H F,et al,1989,The pre-Devonian tectonic patterns and evolution of South China,J SE Asian Earth Sci,3,87 ~ 93.
Hacker B R,Ratschbacher L,Webb L,et al,1998,U-Pb zircon ages constrain the architecture of the ultrahigh-pressure Qinling-Dabie Orogen,China,Earth Planet Sci Lett,161,215 ~ 230.
Huang J,Zhao D,2006,High-resolution mantle tomography of China and surrounding regions. J Geophys Res,111,B09305. doi: 10.1029 / 2005JB004066.
Humphreys E,Clayton R W,1988,Adaptation of back projection tomography to seismic travel time problems,J Geophys Res,93,1073 ~ 1085.
Inoue H,Fukao Y,Tanabe K,et a1,1990,Whole mantle P-wave travel time tomography,Phys Earth Planet Inter,59,294 ~ 328.
Lin F,Moschetti M P,Ritzwoller M H,2008,Surface wave tomography of the western United States from ambient seismic noise:Rayleigh and Love wave phase velocity maps,Geophys J Int,doi: 10.1111 / j1365-246X.2008.03720.x.
Shu L S,Faure M,Wang B,et al,2008,Late Paleozoic-Early Mesozoic Geological Features of South China: Response to the Indosinian Collision Event in Southeast Asia,C R Geosci,340,151 ~ 165.
Wang D Z,Shu L S,2012,Late Mesozoic Basin and range tectonics and related magmatism in Southeast China,Geoscience Frontier,3(2) ,109 ~ 124.
Wang H Z,Mo X X,1995,An outline of the tectonic evolution of China,Episodes,18(1 / 2) ,6 ~ 16.
Zhang P Z,Deng Q D,Zhang G M,et al,2003,Active tectonic blocks and strong earthquakes in the continent of China,Sci China:Ser D,46(Sup) ,13 ~ 24.
Zhang Z M,Liu J G,Coleman R G,1984,An outline of the plate tectonics of China,Geol Soc Am Bull,95,295 ~ 312.
Zheng S H,Sun X L,Song X D,et al,2008,Surface wave tomography of China from ambient seismic noise correlation,Geochem Geophys Geosyst,9,Q05020. doi: 10.1029 / 2008GC001981.
Zhou L Q,Xie J Y,Shen W S,et al,2012,The structure of the crust and uppermost mantle beneath South China from ambient noise and earthquake tomography,Geophys J Int,189,1565 ~ 1583.
刘建华、吴华、刘福田,1996,华南及其海域三维速度分布特征与岩石层结构,地球物理学报,39(4) ,483~492.
滕吉文、张中杰、胡家富等,2001,中国东南大陆及陆缘地带的瑞利波频散与剪切波三维速度结构,地球物理学报,44(5) ,663 ~ 677.
舒良树,2012,华南构造演化的基本特征,地质通报,31(7) ,1035~1053.
易桂喜、姚华建、朱介寿等,2010,用 Rayleigh 面波方位各向异性研究中国大陆岩石圈形变特征,地球物理学报,53(2) ,256 ~ 268,doi: 10.3969 / j.issn.00015733.2010.02.004.
郑秀芬、欧阳飚、张东宁等,2009,“国家数字测震台网数据备份中心”技术系统建设及其对汶川大地震研究的数据支撑,地球物理学报,52(5) ,1412~1417,doi: 10.3969 /j.issn.00015733.2009.05.031.
Barmin M P,Ritzwoller M H,Levshin A L,2001,A fast and reliable method for surface wave tomography,Pure Appl Geophys,158,1351 ~ 1375.
Bensen G D,Ritzwoller M H,Barmin M P,et al,2007,Processing seismic ambient noise data to obtain reliable broad-band surface wave dispersion measurements,Geophys J Int,169,1239 ~ 1260.
Fang L H,Wu J P,Ding Z F,et al,2010,High resolution Rayleigh wave group velocity tomography in North China from ambient seismic noise,Geophys J Int,181(2) ,1171 ~ 1182.
Faure M,Lin W,Scharer U,et al,2003,Continental subduction and exhumation of UHP rocks: Structural and geochronological insights from the Dabieshan(East China) ,Lithos,70,213 ~ 241.
Guo L Z,Shi Y S,Lu H F,et al,1989,The pre-Devonian tectonic patterns and evolution of South China,J SE Asian Earth Sci,3,87 ~ 93.
Hacker B R,Ratschbacher L,Webb L,et al,1998,U-Pb zircon ages constrain the architecture of the ultrahigh-pressure Qinling-Dabie Orogen,China,Earth Planet Sci Lett,161,215 ~ 230.
Huang J,Zhao D,2006,High-resolution mantle tomography of China and surrounding regions. J Geophys Res,111,B09305. doi: 10.1029 / 2005JB004066.
Humphreys E,Clayton R W,1988,Adaptation of back projection tomography to seismic travel time problems,J Geophys Res,93,1073 ~ 1085.
Inoue H,Fukao Y,Tanabe K,et a1,1990,Whole mantle P-wave travel time tomography,Phys Earth Planet Inter,59,294 ~ 328.
Lin F,Moschetti M P,Ritzwoller M H,2008,Surface wave tomography of the western United States from ambient seismic noise:Rayleigh and Love wave phase velocity maps,Geophys J Int,doi: 10.1111 / j1365-246X.2008.03720.x.
Shu L S,Faure M,Wang B,et al,2008,Late Paleozoic-Early Mesozoic Geological Features of South China: Response to the Indosinian Collision Event in Southeast Asia,C R Geosci,340,151 ~ 165.
Wang D Z,Shu L S,2012,Late Mesozoic Basin and range tectonics and related magmatism in Southeast China,Geoscience Frontier,3(2) ,109 ~ 124.
Wang H Z,Mo X X,1995,An outline of the tectonic evolution of China,Episodes,18(1 / 2) ,6 ~ 16.
Zhang P Z,Deng Q D,Zhang G M,et al,2003,Active tectonic blocks and strong earthquakes in the continent of China,Sci China:Ser D,46(Sup) ,13 ~ 24.
Zhang Z M,Liu J G,Coleman R G,1984,An outline of the plate tectonics of China,Geol Soc Am Bull,95,295 ~ 312.
Zheng S H,Sun X L,Song X D,et al,2008,Surface wave tomography of China from ambient seismic noise correlation,Geochem Geophys Geosyst,9,Q05020. doi: 10.1029 / 2008GC001981.
Zhou L Q,Xie J Y,Shen W S,et al,2012,The structure of the crust and uppermost mantle beneath South China from ambient noise and earthquake tomography,Geophys J Int,189,1565 ~ 1583.