宁夏地区上地幔地震各向异性特征
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摘要
利用宁夏6个三分向宽频带数字地震台记录的震中距在85°—110°,震级大于6级的远震SKS波震相作了偏振分析,采用Silver-Chan方法求得了分裂参数,获得了宁夏地区上地幔各向异性图像.结果表明,宁夏地区上地幔各向异性普遍存在,本区盐池台(YCI)所在的鄂尔多斯块体下方的各向异性可归结为"化石"各向异性,其它地区的各向异性特征则反映了正在进行的构造运动,由此可为贺兰山脉东西两侧复杂的运动图像提供深部证据.最后推测本区的青藏高原东北缘—阿拉善块体及银川断陷区壳、幔的运动是耦合的,而鄂尔多斯块体地区壳、幔的运动型式尚不明朗.
A polarization analysis has been carried out on teleseismic SKS phases with epicentral distance between 85°and 110°and from M≥6.0 earthquakes recorded by 6 digital broadband seismic stations with 3 components in Ningxia region,China. The splitting parameters have been obtained by using the Silver-Chan method and the anisotropy feature of the upper mantle in Ningxia region has been obtained. The result shows that in Ningxia region there widely exists the upper mantle anisotropy.The anisotropy beneath the Erdos block,where the YCI station is located,could be classified as "fossil" anisotropy,while the anisotropy in other regions reflects tectonic movement undergoing,having also provided the deep evidence about the complex kinetic figure of the Helanshan Mountain and its double sides. Finally,it is inferred that in this region the movement between the crust and upper mantle from the northeast edge of the Qingzang Plateau to the Alashan Block and the Yinchuan broken region is coupled,and the Erdos Block region has not been clear yet.
A polarization analysis has been carried out on teleseismic SKS phases with epicentral distance between 85°and 110°and from M≥6.0 earthquakes recorded by 6 digital broadband seismic stations with 3 components in Ningxia region,China. The splitting parameters have been obtained by using the Silver-Chan method and the anisotropy feature of the upper mantle in Ningxia region has been obtained. The result shows that in Ningxia region there widely exists the upper mantle anisotropy.The anisotropy beneath the Erdos block,where the YCI station is located,could be classified as "fossil" anisotropy,while the anisotropy in other regions reflects tectonic movement undergoing,having also provided the deep evidence about the complex kinetic figure of the Helanshan Mountain and its double sides. Finally,it is inferred that in this region the movement between the crust and upper mantle from the northeast edge of the Qingzang Plateau to the Alashan Block and the Yinchuan broken region is coupled,and the Erdos Block region has not been clear yet.
引文
①柴炽章,杜鹏,沈卫华.2005.《贺兰山西麓活动断裂带晚第四纪活动精细研究》.宁夏回族自治区地震局研究报告.
[1]张培震.2008.《汶川8.0级强震控震构造———南北地震带的结构、运动模型及危险性》(注:原报告题目中8.0级为7.8级).中国地震局地质研究所内部报告.
常利军,王椿镛,丁志峰.2006.云南地区SKS波分裂研究[J].地球物理学报,49(1):197-204.
常利军,王椿镛,丁志峰.2008a.首都圈地区SKS波分裂研究[J].地震学报,30(6):551-559.
常利军,王椿镛,丁志峰,周民都,杨建思,徐智强,姜旭东,郑秀芬.2008b.青藏高原东北缘上地幔各向异性研究[J].地球物理学报,51(2):431-438.
丁志峰,曾融生.1996.青藏高原横波分裂的观测研究[J].地球物理学报,39(2):211-220.
董英君,薛光琦,马开义,姜枚.1999.阿尔金断裂系及邻区剪切波各向异性研究[J].地球物理学进展,14(4):58-65.
付金华,万丛礼.2004.鄂尔多斯盆地构造:热事件与古生界天然气聚集[J].西北大学学报(自然科学网络版),2(8):1-7.
姜枚,许志琴,Hirn A,刘妍,董英君,薛光琦,钱辉.2001.青藏高原及其部分邻区地震各向异性和上地幔特征[J].地球学报,22(2):111-116.
李清河,郭守年,吕德徽.1999.鄂尔多斯西缘与西南缘深部结构与构造[M].北京:地震出版社:200-203.
刘堃,张中杰,胡家富,滕吉文,孙克忠.2001.中国陆区S波分裂与上地幔地震各向异性[J].地球物理学进展,16(2):81-87.
罗艳,黄忠贤,彭艳菊,郑月军.2004.中国大陆及邻区SKS波分裂研究[J].地球物理学报,47(5):812-821.
阮爱国,王椿镛.2002.云南地区上地幔各向异性研究[J].地震学报,21(3):260-267.
王椿镛,常利军,吕智勇,秦嘉政,苏伟.2007.青藏高原东部上地幔各向异性及相关的壳幔耦合型式[J].中国科学:D辑,37(4):495-503.
谢富仁,舒塞兵,窦素芹.2000.海原、六盘山断裂带至银川断陷第四纪构造应力场分析[J].地震地质学报,22(2):139-146.
杨明芝,马禾青,廖玉华.2007.宁夏地震活动与研究[M].北京:地震出版社:41-68.
郑斯华,高原.1994.中国大陆岩石层的方位各向异性[J].地震学报,16(2):131-140.
Anderson ML,Zandt G,Triep E,Fouch M,Beck S.2004.Anisotropy and mantle flowin the Chile-Argentina subduc-tion zone fromshear wave splitting analysis[J].Geophys Res Lett,31:L23608.
Ando M,Ishikawa Y,Wada H.1980.S-wave anisotropyinthe upper mantle under a volcanic areain Japan[J].Nature,286:43-46.
Ando M,Ishikawa Y,Yamazaki F.1983.Shear wave polarization anisotropyinthe upper mantle beneath Honshu,Japan[J].J Geophys Res,88(B7):5850-5864.
Ando M.1984.ScS polarization anisotropy around the Pacific Ocean[J].J Phys Earth,32:179-195.
Bowman J R,Ando M.1987.Shear-wave splittinginthe upper-mantle wedge above the Tonga subduction zone[J].Geo-phys J Royal Astron Soc,88:25-41.
Bormann P,Grnthal G,Kind R.1996.Upper mantle anisotropy beneath central Europe from SKS wave splitting:effects of absolute plate motion andlithosphere-asthenosphere boundarytopography?[J].J Geodynamics,22(1-2):11-32.
Flesch ML,Holt WE,Silver P G,Stephenson M,Wang C Y,Chan W W.2005.Constrainingthe extent of crust-mantle cou-plingin central Asia using GPS,geologic,and shear wave splitting data[J].Earth Planet Sci Lett,238:248-268.
Liu K H,Gao S S,Gao Y.2008.Shear wave splitting and mantle flowassociated with the deflected Pacific slab beneathnortheast Asia[J].J Geophys Res,113:B01305.
Ricard Y,Ricards M A.Lithgow-Nertelloni,C,Yves L S.1993.A geodynamic model of mantle density heterogeneity[J].J Geophys Res,98:21895-21909.
Richardson R M.1992.Ridge forces,absolute plate motions,and the intraplate stress field[J].J Geophys Res,97:11739-11748.
Silver P G,Chan W W.1988.I mplications for continental structure and evolution fromseismic anisotropy[J].Nature,335:34-39.
Silver P G,Chan W W.1991.Share wave splitting and subcontinental mantle deformation[J].J Geophys Res,96(10):16429-16454.
Vinnik L P,Farra V,Romanowicz B.1989.Azi muthal anisotropyinthe Earthfromobservations of SKS at Geoscope andNARS broadband stations[J].Bull Sesi m Soc Amer,79:1452-1558.
Vinnik L P,Makeyeva L,Milev A,Usenko A Y.1992.Global patterns of azi muthal anisotropy and deformationin thecontinental mantle[J].Geophys J Int,111:433-447.
Zhao L,Zheng T Y.2005.Using shear wave splitting measurement to investigate the upper mantle anisotropy beneaththe North China Craton[J].Geophys Res Lett,32:L10309.
[1]张培震.2008.《汶川8.0级强震控震构造———南北地震带的结构、运动模型及危险性》(注:原报告题目中8.0级为7.8级).中国地震局地质研究所内部报告.
常利军,王椿镛,丁志峰.2006.云南地区SKS波分裂研究[J].地球物理学报,49(1):197-204.
常利军,王椿镛,丁志峰.2008a.首都圈地区SKS波分裂研究[J].地震学报,30(6):551-559.
常利军,王椿镛,丁志峰,周民都,杨建思,徐智强,姜旭东,郑秀芬.2008b.青藏高原东北缘上地幔各向异性研究[J].地球物理学报,51(2):431-438.
丁志峰,曾融生.1996.青藏高原横波分裂的观测研究[J].地球物理学报,39(2):211-220.
董英君,薛光琦,马开义,姜枚.1999.阿尔金断裂系及邻区剪切波各向异性研究[J].地球物理学进展,14(4):58-65.
付金华,万丛礼.2004.鄂尔多斯盆地构造:热事件与古生界天然气聚集[J].西北大学学报(自然科学网络版),2(8):1-7.
姜枚,许志琴,Hirn A,刘妍,董英君,薛光琦,钱辉.2001.青藏高原及其部分邻区地震各向异性和上地幔特征[J].地球学报,22(2):111-116.
李清河,郭守年,吕德徽.1999.鄂尔多斯西缘与西南缘深部结构与构造[M].北京:地震出版社:200-203.
刘堃,张中杰,胡家富,滕吉文,孙克忠.2001.中国陆区S波分裂与上地幔地震各向异性[J].地球物理学进展,16(2):81-87.
罗艳,黄忠贤,彭艳菊,郑月军.2004.中国大陆及邻区SKS波分裂研究[J].地球物理学报,47(5):812-821.
阮爱国,王椿镛.2002.云南地区上地幔各向异性研究[J].地震学报,21(3):260-267.
王椿镛,常利军,吕智勇,秦嘉政,苏伟.2007.青藏高原东部上地幔各向异性及相关的壳幔耦合型式[J].中国科学:D辑,37(4):495-503.
谢富仁,舒塞兵,窦素芹.2000.海原、六盘山断裂带至银川断陷第四纪构造应力场分析[J].地震地质学报,22(2):139-146.
杨明芝,马禾青,廖玉华.2007.宁夏地震活动与研究[M].北京:地震出版社:41-68.
郑斯华,高原.1994.中国大陆岩石层的方位各向异性[J].地震学报,16(2):131-140.
Anderson ML,Zandt G,Triep E,Fouch M,Beck S.2004.Anisotropy and mantle flowin the Chile-Argentina subduc-tion zone fromshear wave splitting analysis[J].Geophys Res Lett,31:L23608.
Ando M,Ishikawa Y,Wada H.1980.S-wave anisotropyinthe upper mantle under a volcanic areain Japan[J].Nature,286:43-46.
Ando M,Ishikawa Y,Yamazaki F.1983.Shear wave polarization anisotropyinthe upper mantle beneath Honshu,Japan[J].J Geophys Res,88(B7):5850-5864.
Ando M.1984.ScS polarization anisotropy around the Pacific Ocean[J].J Phys Earth,32:179-195.
Bowman J R,Ando M.1987.Shear-wave splittinginthe upper-mantle wedge above the Tonga subduction zone[J].Geo-phys J Royal Astron Soc,88:25-41.
Bormann P,Grnthal G,Kind R.1996.Upper mantle anisotropy beneath central Europe from SKS wave splitting:effects of absolute plate motion andlithosphere-asthenosphere boundarytopography?[J].J Geodynamics,22(1-2):11-32.
Flesch ML,Holt WE,Silver P G,Stephenson M,Wang C Y,Chan W W.2005.Constrainingthe extent of crust-mantle cou-plingin central Asia using GPS,geologic,and shear wave splitting data[J].Earth Planet Sci Lett,238:248-268.
Liu K H,Gao S S,Gao Y.2008.Shear wave splitting and mantle flowassociated with the deflected Pacific slab beneathnortheast Asia[J].J Geophys Res,113:B01305.
Ricard Y,Ricards M A.Lithgow-Nertelloni,C,Yves L S.1993.A geodynamic model of mantle density heterogeneity[J].J Geophys Res,98:21895-21909.
Richardson R M.1992.Ridge forces,absolute plate motions,and the intraplate stress field[J].J Geophys Res,97:11739-11748.
Silver P G,Chan W W.1988.I mplications for continental structure and evolution fromseismic anisotropy[J].Nature,335:34-39.
Silver P G,Chan W W.1991.Share wave splitting and subcontinental mantle deformation[J].J Geophys Res,96(10):16429-16454.
Vinnik L P,Farra V,Romanowicz B.1989.Azi muthal anisotropyinthe Earthfromobservations of SKS at Geoscope andNARS broadband stations[J].Bull Sesi m Soc Amer,79:1452-1558.
Vinnik L P,Makeyeva L,Milev A,Usenko A Y.1992.Global patterns of azi muthal anisotropy and deformationin thecontinental mantle[J].Geophys J Int,111:433-447.
Zhao L,Zheng T Y.2005.Using shear wave splitting measurement to investigate the upper mantle anisotropy beneaththe North China Craton[J].Geophys Res Lett,32:L10309.
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