南海中北部OBS2006-3地震剖面中横波的识别与应用
|
摘要
纵横波联合探测可以获得丰富的地下结构信息。纵横波速比和岩石泊松比在预测岩石圈的岩性、物性等介质属性方面有重要的作用。通过对比南海中北部OBS2006-3地震剖面垂直分量和径向分量上的纵横波走时、视速度以及质点运动轨迹,识别出了转换横波震相。本文以OBS8和OBS10台站的数据为例,说明了横波识别的方法,并在拟合好的P波速度模型基础上,利用RayInvr软件对转换横波震相进行了射线追踪,确认了PwSs3、PgSs3、PmS等几组转换震相,计算了这两个站位下的波速比和泊松比。根据OBS2006-3测线下地壳高速层的P波速度(VP=7.20—7.25km·s-1)、S波速度(VS=4.20—4.23km·s-1)、泊松比(0.24)等参数,初步推断下地壳高速层是由上地幔岩浆底侵作用形成。
Applying the joint exploration of P-wave and S-wave,the complex subsurface crustal structure can be obtained.The association of P-wave velocity and S-wave velocity is very sensitive to the physical state of rocks,and is thus very useful in lithological studies.Compared with travel-time of P-wave and S-wave,apparent velocity and particle's moving trajectory in vertical-component and radical-component seismic sections,converted S-wave phases were identified in OBS8 and OBS10 along the profile OBS2006-3 in the mid-northern South China Sea.In this paper,taking these two OBSs as examples,we discussed identification and analysis of converted S-waves in detail.A few of S-wave seismic phases(e.g.,PwSs3,PgSs3,PmS) were identified based on the optimum P-wave model using the software Rayinvr and the ratio of Vp/Vs and Poisson's ratio are calculated beneath these two OBSs stations.Based on P-wave velocity(VP=7.20-7.25km·s-1),S-wave velocity(VS= 4.20-4.23km·s-1) and Poisson's ratio(0.24),we suggest that the high velocity layer in the lower crust has a mafic composition that may originate from magmatic underplating.
Applying the joint exploration of P-wave and S-wave,the complex subsurface crustal structure can be obtained.The association of P-wave velocity and S-wave velocity is very sensitive to the physical state of rocks,and is thus very useful in lithological studies.Compared with travel-time of P-wave and S-wave,apparent velocity and particle's moving trajectory in vertical-component and radical-component seismic sections,converted S-wave phases were identified in OBS8 and OBS10 along the profile OBS2006-3 in the mid-northern South China Sea.In this paper,taking these two OBSs as examples,we discussed identification and analysis of converted S-waves in detail.A few of S-wave seismic phases(e.g.,PwSs3,PgSs3,PmS) were identified based on the optimum P-wave model using the software Rayinvr and the ratio of Vp/Vs and Poisson's ratio are calculated beneath these two OBSs stations.Based on P-wave velocity(VP=7.20-7.25km·s-1),S-wave velocity(VS= 4.20-4.23km·s-1) and Poisson's ratio(0.24),we suggest that the high velocity layer in the lower crust has a mafic composition that may originate from magmatic underplating.
引文
[1]汪品先.走向地球系统科学的必由之路[J].地球科学进展,2003,18(5):795-796.
[2]中国大洋钻探学术委员会.中国加入综合大洋钻探(IODP)科学计划[J].地球科学进展,2004,18(5):662-665.
[3]丘学林,施小斌,阎贫,等.南海北部地壳结构的深地震探测和研究新进展[J].自然科学进展,2003,13(3):231-236.
[4]夏少红,丘学林,赵明辉,等.香港地区海陆地震联测及深部地壳结构研究[J].地球物理学进展,2008,23(5):1389-1397.
[5]郝天珧,黄松,徐亚,等.南海东北部及临区深部结构的综合地球物理研究[J].地球物理学报,2008,51(6):1785-1796.
[6]姚伯初,曾维军,陈艺中,等.南海北部陆缘东部的地壳结构[J].地球物理学报,1994,37(1):27-35.
[7]QIU XUE LIN,YE SAN YU,WU SHI MING,et al.Crustal structure across the Xisha Trough,northwestern South China Sea[J].Tectonophysics,2001,341:179-193.
[8]WANG TIAN KAI,CHEN MING KAI,LEE CHAO SHING,et al.Seismic imaging of the transitional crust across the northeastern margin of the South China Sea[J].Tectonohys-ics,2006,412:237-254.
[9]李湘云,吴振利,薛斌,等.SEDISⅣ型短周期自浮式海底地震仪及应用体会[J].热带海洋学报,2007,26(5):35-39.
[10]赵明辉,丘学林,夏少红,等.南海东北部三分量海底地震仪记录中横波的识别与分析[J].自然科学进展,2008,17(11):1516-1523.
[11]阮爱国,李家彪,冯占英,等.海底地震仪及其国内外发展现状[J].东海海洋,2004,22(2):19-27.
[12]吴振利,阮爱国,李家彪,等.南海中北部地壳深部结构探测新进展[J].华南地震,2008,28(1):21-28.
[13]游庆瑜,刘福田,冉崇荣,等.高频微功耗海底地震仪研制[J].地球物理学进展,2003,18(1):173-176.
[14]丘学林,王平,赵明辉,等.南海南部大陆边缘的海底地震仪探测[C]//第25届中国地球物理年会.合肥:2009.
[15]吴能友,曾维军,杜德莉,等.南海区域岩石圈的壳-幔耦合关系和纵向演化[J].海洋地质与第四纪地质,1999,19(1):31-38.
[16]YAN PIN,ZHOU DI,LIU ZHAO SHU.A crustal structure profile across the northern continental margin of the South China Sea[J].Tectonophysics,2001,338:1-21.
[17]姚伯初.南海北部陆缘的地壳结构及构造意义[J].海洋地质与第四纪地质,1998,18(2):1-16.
[18]阎全人,王宗起,李赠悦.南海北部陆缘地壳结构特征极其构造过程[J].地质论评,2000,46(4):417-423.
[19]阎贫,刘海龄.南海北部陆缘地壳结构探测结果分析[J].热带海洋学报,2002,21(2):1-12.
[20]刘安,武国忠,吴世敏.南海东北部下地壳高速层的成因探讨[J].地质论评,2008,54(5):609-616.
[21]丘学林,周蒂,夏戡原,等.南海西沙海槽地壳结构的海底地震仪探测与研究[J].热带海洋,2000,19(2):9-18.
[22]WILKENS R,SIMMONS G.,CARUSO L.The ratio Vp/Vs as a discriminant of composition for siliceouslimestones[J].Geophysics,1984,49(11):1850-1860.
[23]TINIVELLA U,ACCAINO F.Compressional velocity structure and Poisson’s ratio in marine sediments with gas hydrate and free gas by inversion of reflected and refracted seismic data(South Shetland Island,Antarctica)[J].Marine Geology,2000,164:13-27.
[24]ZELT,C A,SMITH R B.Seismic traveltime inversion for2-D crustal velocity structure[J].Geophys J Int,1992,108:16-34.
[25]KODAIRA S,BELLENBERG M,IWASAKI T.Vp/Vs ratio structure of the Lofoten continental margin,northern Norway,and its geological implications[J].Geophys J Int,1996,124:724-740.
[26]CHRISTENSEN N I.Poisson’s ratio and crustal seismology[J].J Geophy Res,1996,101(B2):3139-3156.
[27]MJELDE R,RAUM T,DIGRANES P.Vp/Vs ratio along the V-ing Margin,NE Atlantic,derived from OBS data:impli-cations on lithology and stress field[J].Tectonohysics,2003,369:175-197.
[28]阎贫.海底地震仪记录中的横波[J].海洋地质与第四纪地质,1998,18(1):115-118.
[29]DIGRANES P,MJELDE R,KODAIRA S.A regional shear-wave velocity model in the central V-ring Basin,N Norway,using three-component Ocean Bottom Seismo-graphs[J].Tectonohysics,1998,293:157-174.
[30]RICHARD L,CARLSON D.MILLER J.A new assessment of the abundance of serpentinite in the oceanic crust[J].Geophysical Research Letters,1997,24(4):457-460.
[31]RUDNICK R L,FOUNTAIN D M.Nature and composition of the continental crust:A lower crustal perspective[J].Rev Geophys,1995,33:267-309.
[32]刘明军,李松林,方盛明,等.利用地震波研究青藏高原东北缘地壳组成及其动力学[J].地球物理学报,2008,51(2):412-430.
[2]中国大洋钻探学术委员会.中国加入综合大洋钻探(IODP)科学计划[J].地球科学进展,2004,18(5):662-665.
[3]丘学林,施小斌,阎贫,等.南海北部地壳结构的深地震探测和研究新进展[J].自然科学进展,2003,13(3):231-236.
[4]夏少红,丘学林,赵明辉,等.香港地区海陆地震联测及深部地壳结构研究[J].地球物理学进展,2008,23(5):1389-1397.
[5]郝天珧,黄松,徐亚,等.南海东北部及临区深部结构的综合地球物理研究[J].地球物理学报,2008,51(6):1785-1796.
[6]姚伯初,曾维军,陈艺中,等.南海北部陆缘东部的地壳结构[J].地球物理学报,1994,37(1):27-35.
[7]QIU XUE LIN,YE SAN YU,WU SHI MING,et al.Crustal structure across the Xisha Trough,northwestern South China Sea[J].Tectonophysics,2001,341:179-193.
[8]WANG TIAN KAI,CHEN MING KAI,LEE CHAO SHING,et al.Seismic imaging of the transitional crust across the northeastern margin of the South China Sea[J].Tectonohys-ics,2006,412:237-254.
[9]李湘云,吴振利,薛斌,等.SEDISⅣ型短周期自浮式海底地震仪及应用体会[J].热带海洋学报,2007,26(5):35-39.
[10]赵明辉,丘学林,夏少红,等.南海东北部三分量海底地震仪记录中横波的识别与分析[J].自然科学进展,2008,17(11):1516-1523.
[11]阮爱国,李家彪,冯占英,等.海底地震仪及其国内外发展现状[J].东海海洋,2004,22(2):19-27.
[12]吴振利,阮爱国,李家彪,等.南海中北部地壳深部结构探测新进展[J].华南地震,2008,28(1):21-28.
[13]游庆瑜,刘福田,冉崇荣,等.高频微功耗海底地震仪研制[J].地球物理学进展,2003,18(1):173-176.
[14]丘学林,王平,赵明辉,等.南海南部大陆边缘的海底地震仪探测[C]//第25届中国地球物理年会.合肥:2009.
[15]吴能友,曾维军,杜德莉,等.南海区域岩石圈的壳-幔耦合关系和纵向演化[J].海洋地质与第四纪地质,1999,19(1):31-38.
[16]YAN PIN,ZHOU DI,LIU ZHAO SHU.A crustal structure profile across the northern continental margin of the South China Sea[J].Tectonophysics,2001,338:1-21.
[17]姚伯初.南海北部陆缘的地壳结构及构造意义[J].海洋地质与第四纪地质,1998,18(2):1-16.
[18]阎全人,王宗起,李赠悦.南海北部陆缘地壳结构特征极其构造过程[J].地质论评,2000,46(4):417-423.
[19]阎贫,刘海龄.南海北部陆缘地壳结构探测结果分析[J].热带海洋学报,2002,21(2):1-12.
[20]刘安,武国忠,吴世敏.南海东北部下地壳高速层的成因探讨[J].地质论评,2008,54(5):609-616.
[21]丘学林,周蒂,夏戡原,等.南海西沙海槽地壳结构的海底地震仪探测与研究[J].热带海洋,2000,19(2):9-18.
[22]WILKENS R,SIMMONS G.,CARUSO L.The ratio Vp/Vs as a discriminant of composition for siliceouslimestones[J].Geophysics,1984,49(11):1850-1860.
[23]TINIVELLA U,ACCAINO F.Compressional velocity structure and Poisson’s ratio in marine sediments with gas hydrate and free gas by inversion of reflected and refracted seismic data(South Shetland Island,Antarctica)[J].Marine Geology,2000,164:13-27.
[24]ZELT,C A,SMITH R B.Seismic traveltime inversion for2-D crustal velocity structure[J].Geophys J Int,1992,108:16-34.
[25]KODAIRA S,BELLENBERG M,IWASAKI T.Vp/Vs ratio structure of the Lofoten continental margin,northern Norway,and its geological implications[J].Geophys J Int,1996,124:724-740.
[26]CHRISTENSEN N I.Poisson’s ratio and crustal seismology[J].J Geophy Res,1996,101(B2):3139-3156.
[27]MJELDE R,RAUM T,DIGRANES P.Vp/Vs ratio along the V-ing Margin,NE Atlantic,derived from OBS data:impli-cations on lithology and stress field[J].Tectonohysics,2003,369:175-197.
[28]阎贫.海底地震仪记录中的横波[J].海洋地质与第四纪地质,1998,18(1):115-118.
[29]DIGRANES P,MJELDE R,KODAIRA S.A regional shear-wave velocity model in the central V-ring Basin,N Norway,using three-component Ocean Bottom Seismo-graphs[J].Tectonohysics,1998,293:157-174.
[30]RICHARD L,CARLSON D.MILLER J.A new assessment of the abundance of serpentinite in the oceanic crust[J].Geophysical Research Letters,1997,24(4):457-460.
[31]RUDNICK R L,FOUNTAIN D M.Nature and composition of the continental crust:A lower crustal perspective[J].Rev Geophys,1995,33:267-309.
[32]刘明军,李松林,方盛明,等.利用地震波研究青藏高原东北缘地壳组成及其动力学[J].地球物理学报,2008,51(2):412-430.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心