川滇菱形块体中部现今构造应力场精确求解
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摘要
自Global CMT和前人文献中搜索了1973～2015年间的34条中小地震震源机制解并进行分析,根据震级对每个地震震源机制解进行加权处理,采用网格搜索法反演了川滇菱形块体中部区域现今构造应力场。结果表明,川滇菱形块体中部区域整体以走滑断层类型为主,而西部呈现正断层类型;整个区域应力场受到近NW向挤压,NE向拉张,应力形因子为0.1。该区域应力场主张应力轴方向近水平,表明有横向的拉张作用。较低的应力形因子表明几乎处于NW-SE向和垂直向的双轴挤压及NE-SW向拉张的应力状态。这种应力状态来源于2种动力作用:(1)在青藏高原物质东流和华南块体阻挡作用下呈现NW-SE向挤压和NE-SW向拉张的走滑应力状态;(2)印度板块缅甸弧对该地区深部的NEE向低角度俯冲作用导致浅部地壳物质具有NEE-SWW向的拉张分量。这2种动力的共同作用导致该地区既出现走滑型地震,又出现正断型地震。
The 34 focal mechanisms are selected from Global CMT and publications during1978-2016 and analyzed. After weighting each focal mechanism according to its magnitude, the present tectonic stress field in the central region of Sichuan-Yunnan blocks is inverted using grid search method. The results show : The focal mechanisms primarily show strike-slip types in the central region of Sichuan-Yunnan block,but normal fault type in the west. The regional stress field is nearly NW compression and NE extension; the stress shape factor is estimated to be 0.1. The extensional axis of the stress field is nearly horizontal, which shows lateral extension action in this area. Lower stress shape factor suggested nearly biaxial compressional stress in NW-SE and updown direction and larger NE-SW extensional stress. The stress state results from two effects:(1)the NW-SE compression and NE-SW extensional strike slip stress state due to the Qinghai-Tibetan Plateau's material eastward flowing and the blocking of the Southern China Block.(2) NEE-SWW extension in the shallower crust resulted from the subducting in the depth of the Burma Arc. Both the effects contribute to the occurrence of strike-slip and normal faulting earthquakes.
The 34 focal mechanisms are selected from Global CMT and publications during1978-2016 and analyzed. After weighting each focal mechanism according to its magnitude, the present tectonic stress field in the central region of Sichuan-Yunnan blocks is inverted using grid search method. The results show : The focal mechanisms primarily show strike-slip types in the central region of Sichuan-Yunnan block,but normal fault type in the west. The regional stress field is nearly NW compression and NE extension; the stress shape factor is estimated to be 0.1. The extensional axis of the stress field is nearly horizontal, which shows lateral extension action in this area. Lower stress shape factor suggested nearly biaxial compressional stress in NW-SE and updown direction and larger NE-SW extensional stress. The stress state results from two effects:(1)the NW-SE compression and NE-SW extensional strike slip stress state due to the Qinghai-Tibetan Plateau's material eastward flowing and the blocking of the Southern China Block.(2) NEE-SWW extension in the shallower crust resulted from the subducting in the depth of the Burma Arc. Both the effects contribute to the occurrence of strike-slip and normal faulting earthquakes.
引文
崔效锋、谢富仁、张红艳,2006,川滇地区现代构造应力场分区及动力学意义,地震学报,28(5),451-461.
邓起东,2007,中国活动构造图,北京:地震出版社.
杜兴信、邵辉成,1999,由震源机制解反演中国大陆现代构造应力场,地震学报,21(4),354-360.
高原、吴晶、易桂喜等,2010,从壳幔地震各向异性初探华北地区壳幔耦合关系,科学通报,55(29),2837-2843.
华祥文,1980,唐山强震前后北京、天津周围地区应力的变化过程,地震学报,2(2),130-146.
黄骥超、万永革,2015,利用小震与强震震源机制解反演首都圈现今构造应力场,地震,35(1),17-27.
阚荣举、张四昌、晏凤桐等,1977,我国西南地区现代构造应力场与现代构造活动特征的探讨,地球物理学报,20(2),96-109.
刘建中,1992,缅甸弧的俯冲作用及川滇断块的地震地质特征,中国地震,8(1),68-75.
骆佳骥、崔效锋、胡幸平等,2012,川滇地区活动块体划分与现代构造应力场分区研究综述,地震研究,35(3),309-317.
罗钧、赵翠萍、周连庆,2014,川滇块体及周边区域现今震源机制和应力场特征,地震地质,36(2),405-421.
马文涛、徐锡伟、徐平等,2004,地震三角形分类图解法与华北地区地震成因分析,地球物理学进展,19(2),379-385.
钱晓东、秦嘉政、刘丽芳,2011,云南地区现代构造应力场研究,地震地质,33(1),91-106.
盛书中、万永革、徐志国等,2013,由地震释放的地震矩叠加推导平均应力场,地震地质,35(1),92-100.
万永革,2015,联合采用定性和定量断层资料的应力张量反演方法及在乌鲁木齐地区的应用,地球物理学报,58(9),3144-3156.
万永革,2016,地震学导论,北京:科学出版社.
万永革、沈正康、兰从欣,2006,根据走滑大地震前后应力轴偏转和应力降求取偏应力量值的研究,地球物理学报,49(3),838-844.
万永革、盛书中、许雅儒等,2011,不同应力状态和摩擦系数对综合P波辐射花样影响的模拟研究,地球物理学报,54(4),994-1001.
万永革、吴忠良、周公威等,2000,根据震源的两个节面的走向角和倾角求滑动角,地震地磁观测与研究,21(5),26-30.
王晓山、吕坚、谢祖军等,2015,南北地震带震源机制解与构造应力场特征,地球物理学报,58(11),4149-4162.
吴建平、明跃红、王椿镛,2004,云南地区中小地震震源机制及构造应力场研究,地震学报,26(5),457-465.
谢富仁、陈群策、崔效锋等,2007,中国大陆地壳应力环境基础数据库,地球物理学进展,22(1),131-136.
谢富仁、崔效锋、赵建涛等,2004,中国大陆及邻区现代构造应力场分区,地球物理学报,47(4),654-662.
许忠淮、刘玉芬、张郢珍,1979,京、津、唐、张地区地震应力场的方向特征,地震学报,1(2),121-132.
许忠淮、汪素云、黄雨蕊等,1989,由大量的地震资料推断的我国大陆构造应力场,地球物理学报,32(6),636-647.
曾融生、孙为国,1992.青藏高原及其邻区的地震活动性和震源机制以及高原物质东流的讨论,地震学报,14(增刊I),534-564.
赵博、高原、黄志斌等,2013,四川芦山MS7.0地震余震序列双差定位、震源机制及应力场反演,地球物理学报,56(10),3385-3395.
钟继茂、程万正,2006,由多个地震震源机制解求川滇地区平均应力场方向,地震学报,28(4),337-346.
卓钰如、李文香、龚镇雄,1982,用多普勒效应研究中小地震的破裂面和破裂传播速度,地震学报,4(1),14-26.
Gao Y,Shi Y T, Wu J,et al, 2012, Shear-wave splitting in the crust:regional compressive stress from polarizations of fast shearwaves,Earthq Sci,25(1),35-45,.doi:10.1007/s11589-012-0829-3.
Gephart J W, Forsyth D W, 1984, An improved method for determining the regional stress tensor using earthquake focal mechanism data:application to the San Fernando earthquake sequence,J Geophys Res,89(B11),9305-9320.
Hardebeck J L, Michael A J,2006,Damped regional-scale stress inversions:methodology and examples for southern California and the Coalinga aftershock sequence,J Geophys Res,111(B11),B11310.
Lei J S,Zhao D,2016,Teleseismic P-wave tomography and mantle dynamics beneath eastern Tibet, Geochem Geophys Geosyst, 17(5),1861-1884, doi:10.1002/2016GC006262.
Shen Z K,Lu J N, Wang M,et al,2005,Contemporary crustal deformation around the southeast borderland of the Tibetan Plateau,J Geophys Res,110(B11),B11409.
Wan Y G,2010,Contemporary tectonic stress field in China,Earthq Sci,23(4),377-386.
Wan Y G,Sheng S,Huang J C, et al,2016,The grid search algorithm of tectonic stress tensor based on focal mechanism data and its application in the boundary zone of China,Vietnam and Laos,J Earth Sci,27(5),777-785.
Wessel P, Smith W H,1995,New version of the generic mapping tools released, EOS Trans, AGU,76(33),329.
Xu Z G, Huang Z C, Wang L S, et al, 2016, Crustal stress field in Yunnan:implication for crust-mantle coupling, Earthq Sci,29(2),105-115.
Zhang R Q, Wu Y, Gao Z,et al, 2017, Upper mantle discontinuity structure beneath eastern and southeastern Tibet:new constraints on the Tengchong intraplate volcano and signatures of detached lithosphere under the western Yangtze Craton,J Geophys Res, 122(2),1367-1380, doi:10.1002/2016JB013551.
Zhao L,Luo Y,Liu T Y,et al,2013, Earthquake focal mechanisms in Yunnan and their inference on the regional Stress field, Bull Seismol Soc Am,103(4),2498-2507.
Zoback M L,1992, First-and second-order patterns of stress in the lithosphere:the world stress map project, J Geophys Res, 97(B8),11703-11728.
邓起东,2007,中国活动构造图,北京:地震出版社.
杜兴信、邵辉成,1999,由震源机制解反演中国大陆现代构造应力场,地震学报,21(4),354-360.
高原、吴晶、易桂喜等,2010,从壳幔地震各向异性初探华北地区壳幔耦合关系,科学通报,55(29),2837-2843.
华祥文,1980,唐山强震前后北京、天津周围地区应力的变化过程,地震学报,2(2),130-146.
黄骥超、万永革,2015,利用小震与强震震源机制解反演首都圈现今构造应力场,地震,35(1),17-27.
阚荣举、张四昌、晏凤桐等,1977,我国西南地区现代构造应力场与现代构造活动特征的探讨,地球物理学报,20(2),96-109.
刘建中,1992,缅甸弧的俯冲作用及川滇断块的地震地质特征,中国地震,8(1),68-75.
骆佳骥、崔效锋、胡幸平等,2012,川滇地区活动块体划分与现代构造应力场分区研究综述,地震研究,35(3),309-317.
罗钧、赵翠萍、周连庆,2014,川滇块体及周边区域现今震源机制和应力场特征,地震地质,36(2),405-421.
马文涛、徐锡伟、徐平等,2004,地震三角形分类图解法与华北地区地震成因分析,地球物理学进展,19(2),379-385.
钱晓东、秦嘉政、刘丽芳,2011,云南地区现代构造应力场研究,地震地质,33(1),91-106.
盛书中、万永革、徐志国等,2013,由地震释放的地震矩叠加推导平均应力场,地震地质,35(1),92-100.
万永革,2015,联合采用定性和定量断层资料的应力张量反演方法及在乌鲁木齐地区的应用,地球物理学报,58(9),3144-3156.
万永革,2016,地震学导论,北京:科学出版社.
万永革、沈正康、兰从欣,2006,根据走滑大地震前后应力轴偏转和应力降求取偏应力量值的研究,地球物理学报,49(3),838-844.
万永革、盛书中、许雅儒等,2011,不同应力状态和摩擦系数对综合P波辐射花样影响的模拟研究,地球物理学报,54(4),994-1001.
万永革、吴忠良、周公威等,2000,根据震源的两个节面的走向角和倾角求滑动角,地震地磁观测与研究,21(5),26-30.
王晓山、吕坚、谢祖军等,2015,南北地震带震源机制解与构造应力场特征,地球物理学报,58(11),4149-4162.
吴建平、明跃红、王椿镛,2004,云南地区中小地震震源机制及构造应力场研究,地震学报,26(5),457-465.
谢富仁、陈群策、崔效锋等,2007,中国大陆地壳应力环境基础数据库,地球物理学进展,22(1),131-136.
谢富仁、崔效锋、赵建涛等,2004,中国大陆及邻区现代构造应力场分区,地球物理学报,47(4),654-662.
许忠淮、刘玉芬、张郢珍,1979,京、津、唐、张地区地震应力场的方向特征,地震学报,1(2),121-132.
许忠淮、汪素云、黄雨蕊等,1989,由大量的地震资料推断的我国大陆构造应力场,地球物理学报,32(6),636-647.
曾融生、孙为国,1992.青藏高原及其邻区的地震活动性和震源机制以及高原物质东流的讨论,地震学报,14(增刊I),534-564.
赵博、高原、黄志斌等,2013,四川芦山MS7.0地震余震序列双差定位、震源机制及应力场反演,地球物理学报,56(10),3385-3395.
钟继茂、程万正,2006,由多个地震震源机制解求川滇地区平均应力场方向,地震学报,28(4),337-346.
卓钰如、李文香、龚镇雄,1982,用多普勒效应研究中小地震的破裂面和破裂传播速度,地震学报,4(1),14-26.
Gao Y,Shi Y T, Wu J,et al, 2012, Shear-wave splitting in the crust:regional compressive stress from polarizations of fast shearwaves,Earthq Sci,25(1),35-45,.doi:10.1007/s11589-012-0829-3.
Gephart J W, Forsyth D W, 1984, An improved method for determining the regional stress tensor using earthquake focal mechanism data:application to the San Fernando earthquake sequence,J Geophys Res,89(B11),9305-9320.
Hardebeck J L, Michael A J,2006,Damped regional-scale stress inversions:methodology and examples for southern California and the Coalinga aftershock sequence,J Geophys Res,111(B11),B11310.
Lei J S,Zhao D,2016,Teleseismic P-wave tomography and mantle dynamics beneath eastern Tibet, Geochem Geophys Geosyst, 17(5),1861-1884, doi:10.1002/2016GC006262.
Shen Z K,Lu J N, Wang M,et al,2005,Contemporary crustal deformation around the southeast borderland of the Tibetan Plateau,J Geophys Res,110(B11),B11409.
Wan Y G,2010,Contemporary tectonic stress field in China,Earthq Sci,23(4),377-386.
Wan Y G,Sheng S,Huang J C, et al,2016,The grid search algorithm of tectonic stress tensor based on focal mechanism data and its application in the boundary zone of China,Vietnam and Laos,J Earth Sci,27(5),777-785.
Wessel P, Smith W H,1995,New version of the generic mapping tools released, EOS Trans, AGU,76(33),329.
Xu Z G, Huang Z C, Wang L S, et al, 2016, Crustal stress field in Yunnan:implication for crust-mantle coupling, Earthq Sci,29(2),105-115.
Zhang R Q, Wu Y, Gao Z,et al, 2017, Upper mantle discontinuity structure beneath eastern and southeastern Tibet:new constraints on the Tengchong intraplate volcano and signatures of detached lithosphere under the western Yangtze Craton,J Geophys Res, 122(2),1367-1380, doi:10.1002/2016JB013551.
Zhao L,Luo Y,Liu T Y,et al,2013, Earthquake focal mechanisms in Yunnan and their inference on the regional Stress field, Bull Seismol Soc Am,103(4),2498-2507.
Zoback M L,1992, First-and second-order patterns of stress in the lithosphere:the world stress map project, J Geophys Res, 97(B8),11703-11728.