首都圈地区震源机制解及现今构造应力场时空变化特征研究
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摘要
基于2009年1月至2017年11月首都圈地区发生的8 061个地震事件的23 293条P波初动极性数据,采用改进的格点尝试法计算了首都圈地区单次地震的震源机制解和小震综合断层面解。在初步分析这些数据的基础上,利用计算得到的单次地震的震源机制解和搜集到的已有历史地震的震源机制解数据,运用线性反演法对首都圈地区构造应力场的时空变化特征进行了研究。结果显示:(1)研究区的地震震源机制解类型以走滑型为主,正断型次之,这些地震震源机制解的P轴方位大都为ENE向和近EW向,与该地区的构造应力场方向基本一致,仅有个别地震的P轴方位为NNW向;(2)首都圈地区的构造应力场具有较好的一致性和连续性,最大主应力轴方位由西部的ENE向至东部的近EW向呈现顺时针旋转的趋势,应力类型整体上为走滑型,这与以往的研究结果相一致;(3)通过与已有研究结果相比较认为:京西北地区现今构造应力场是相对稳定的,最大主应力轴未呈明显改变;唐山地区和北京地区的构造应力场(最大主应力轴)在1976年唐山地震前后可能发生了变化,唐山地震后一年至今(1977—2017年)是否发生变化,依据现有的计算结果尚不得而知,需要更多的研究来进一步验证.
Based on 23 293 P-wave polarities of 8 061 earthquakes occurred during the period from January 1,2009 to November 30,2017,we calculate the focal mechanism solutions of single earthquakes and composite fault plane solutions with improved grid point test method.On the basis of preliminary analysis on these data,using obtained focal mechanism solutions and the focal mechanism solutions of historical earthquakes,we discuss the spatio-temporal variation of the present tectonic stress field in Capital Circle region by linear inversion method.The result shows that the focal mechanism solutions are mainly of strike-slip type in the studied region and the second is normal-faulting type. The P axis azimuths of these focal mechanism solutions mostly trend ENE or almost EW,which is consistent with the tectonic stress field in the region;except that P axis azimuths of a few earthquakes are in NNW direction. The results by Michael's inversion method show that tectonic stress field of Capital Circle region present good consistency and continuity. The orientation of maximum principal stress axis is in ENE to nearly EW direction from west to east. On a whole,the stress is of strike-slip type,which is consistent with the results of previous scholars. Comparison with the previous research results indicates that the present stress field in northwest of Beijing is in relatively stable state,and the maximum principal stress axis has no obvious variation. But for Tangshan region and Beijing region,the tectonic stress field probably exhibits some variations before and after the 1976 Tangshan earthquake. Whether there is any variations of maximum principal stress axis since the Tangshan earthquake(1977—2017) in the studied region is unknown according to present calculation results,which need to be further verified.
Based on 23 293 P-wave polarities of 8 061 earthquakes occurred during the period from January 1,2009 to November 30,2017,we calculate the focal mechanism solutions of single earthquakes and composite fault plane solutions with improved grid point test method.On the basis of preliminary analysis on these data,using obtained focal mechanism solutions and the focal mechanism solutions of historical earthquakes,we discuss the spatio-temporal variation of the present tectonic stress field in Capital Circle region by linear inversion method.The result shows that the focal mechanism solutions are mainly of strike-slip type in the studied region and the second is normal-faulting type. The P axis azimuths of these focal mechanism solutions mostly trend ENE or almost EW,which is consistent with the tectonic stress field in the region;except that P axis azimuths of a few earthquakes are in NNW direction. The results by Michael's inversion method show that tectonic stress field of Capital Circle region present good consistency and continuity. The orientation of maximum principal stress axis is in ENE to nearly EW direction from west to east. On a whole,the stress is of strike-slip type,which is consistent with the results of previous scholars. Comparison with the previous research results indicates that the present stress field in northwest of Beijing is in relatively stable state,and the maximum principal stress axis has no obvious variation. But for Tangshan region and Beijing region,the tectonic stress field probably exhibits some variations before and after the 1976 Tangshan earthquake. Whether there is any variations of maximum principal stress axis since the Tangshan earthquake(1977—2017) in the studied region is unknown according to present calculation results,which need to be further verified.
引文
崔效锋,谢富仁. 2001. 1976年唐山地震前后华北地区现代构造应力场的时空变化特征[J].中国地震,17(3):280–288.Cui X F,Xie F R. 2001. The space-time variations of present tectonic stress field in North China before and after 1976 Tangshan earthquake[J]. Earthquake Research in China,17(3):280–288(in Chinese).
崔效锋,谢富仁,赵建涛. 2005.中国及邻区震源机制解的分区特征[J].地震地质,27(2):298–307.Cui X F,Xie F R,Zhao J T. 2005. The regional characteristics of focal mechanism solutions in China and its adjacent areas[J].Seismology and Geology,27(2):298–307(in Chinese).
崔效锋,谢富仁,李瑞莎,张红艳. 2010.华北地区构造应力场非均匀特征与煤田深部应力状态[J].岩石力学与工程学报,29 (1):2755–2761.Cui X F,Xie F R,Li R S,Zhang H Y. 2010. Heterogeneous features of state of tectonic stress filed in North China and deep stress in coal mine[J]. Chinese Journal of Rock Mechanics and Engineering,29(1):2755–2761(in Chinese).
邓起东,张培震,冉勇康,杨晓平,闵伟,楚全芝. 2002.中国活动构造基本特征[J].中国科学:D辑, 32(12):1 0 2 0–1030.Deng Q D,Zhang P Z,Ran Y K,Yang X P,Min W,Chu Q Z. 2003. Features of active tectonics in China[J]. Science in China:Series D,46(4):356–372.
胡幸平,崔效锋. 2013.华北地区中部地震精定位与构造应力场研究[J].震灾防御技术,8(4):351–360.Hu X P,Cui X F. 2013. Study on earthquake relocation and tectonic stress field in central North China[J]. Technology for Earthquake Disaster Prevention,8(4):351–360(in Chinese).
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[J].地震,35(1):17–27.Huang J C,Wan Y G. 2015. Present tectonic stress field in the capital region of China determined from small and strong earthquake focal mechanisms[J]. Earthquake,35(1):17–27(in Chinese).
赖院根,刘启元,陈九辉,刘洁,李顺成,郭飙,黄志斌. 2006.首都圈地区横波分裂与地壳应力场特征[J].地球物理学报,49(1):189–196.Lai Y G,Liu Q Y,Chen J H,Liu J,Li S C,Guo B,Huang Z B. 2006. Shear wave splitting and the features of the crustal stress field in the Capital Circle[J]. Chinese Journal of Geophysics,49(1):189–196(in Chinese).
李钦祖,靳雅敏,于新昌. 1982.华北地区的震源机制与地壳应力场[J].地震学报,4(1):55–61.Li Q Z,Jin Y M,Yu X C. 1982. Focal mechanisms and crustal stress field in North China[J]. Acta Seismologica Sinica,4(1):55 –61(in Chinese).
李瑞莎,崔效锋,刁桂苓,张红艳. 2008.华北北部地区现今应力场时空变化特征研究[J].地震学报,30(6):570–580.Li R S,Cui X F,Diao G L,Zhang H Y. 2008. Temporal and spatial variation of the present crustal stress in northern part of North China[J]. Acta Seismologica Sinica,30(6):570–580(in Chinese).
盛书中,万永革,黄骥超,卜玉菲,李祥. 2015.应用综合震源机制解法推断鄂尔多斯块体周缘现今地壳应力场的初步结果[J].地球物理学报,58(2):436–452.Sheng S Z,Wan Y G,Huang J C,Bu Y F,Li X. 2015. Present tectonic stress field in the circum-Ordos region deduced from composite focal mechanism method[J]. Chinese Journal of Geophysics,58(2):436–452(in Chinese).
万永革,沈正康,刁桂苓,王福昌,胡新亮,盛书中. 2008.利用小震分布和区域应力场确定大震断层面参数方法及其在唐山地震序列中的应用[J].地球物理学报,51(3):793–804.Wan Y G,Shen Z K,Diao G L,Wang F C,Hu X L,Sheng S Z. 2008. An algorithm of fault parameter determination using distribution of small earthquakes and parameters of regional stress field and its application to Tangshan earthquake sequence[J].Chinese Journal of Geophysics,51(3):793–804(in Chinese).
汪素云,许忠淮. 1985.中国东部大陆的地震构造应力场[J].地震学报,7(1):17–32.Wang S Y,Xu Z H. 1985. Seismo-tectonic stress field in east China[J]. Acta Seismologica Sinica,7(1):17–32(in Chinese).
王绳祖,张流. 2002.塑性流动网络控制下华北地区构造应力场与地震构造[J].地震地质,24(1):69–80.Wang S Z,Zhang L. 2002. Tectonic stress field and seismic tectonics controlled by plastic-flow network in North China[J]. Seismology and Geology,24(1):69–80(in Chinese).
武敏捷,林向东,徐平. 2011.华北北部地区震源机制解及构造应力场特征分析[J].大地测量与地球动力学,31(5):39–43.Wu M J,Lin X D,Xu P. 2011. Analysis of focal mechanism and tectonic stress field features in northern part of North China[J].Journal of Geodesy and Geodynamics,31(5):39–43(in Chinese).
谢富仁,陈群策,崔效锋,李宏,杨树新,郭启良,陈连旺,许忠淮,张彦山,窦淑芹,赵建涛,张周术,刘长义,王刚军.2007.中国大陆地壳应力环境基础数据库[J].地球物理学进展,22(1):131–136.Xie F R,Chen Q C,Cui X F,Li H,Yang S X,Guo Q L,Chen L W,Xu Z H,Zhang Y S,Dou S Q,Zhao J T,Zhang Z S,Liu C Y,Wang G J. 2007. Fundamental database of crustal stress environment in continental China[J]. Process in Geophysics,22(1):131–136(in Chinese).
谢富仁,崔效锋. 2015.中国及邻区现代构造应力场图[M].北京:中国地图出版社:1–18.Xie F R,Cui X F. 2015. The Map of Recent Tectonic Stress Field in China and Adjacent Areas[M]. Beijing:China Cartographic Publishing House:1–18(in Chinese).
徐锡伟,吴卫民,张先康,马胜利,马文涛,于贵华,顾梦林,江娃利. 2002.首都圈地区地壳最新构造变动与地震[M].北京:科学出版社:1–376.Xu X W,Wu W M,Zhang X K,Ma S L,Ma W T,Yu G H,Gu M L,Jiang W L. 2002. New Changing of Crustal Tectonic and Earthquake in Capital Circle[M]. Beijing:Science Press:1–376(in Chinese).
许忠淮,阎明,赵仲和. 1983.由多个小地震推断的华北地区构造应力场的方向[J].地震学报,5(3):268–279.Xu Z H,Yan M,Zhao Z H. 1983. Evaluation of the direction of tectonic stress in North China from recorded data of a large number of small earthquakes[J]. Acta Seismologica Sinica,5(3):268–279(in Chinese).
许忠淮,戈澍谟. 1984.用滑动方向拟合法反演富蕴地震断裂带应力场[J].地震学报,6(4):395–404.Xu Z H,Ge S M. 1984. Stress field in the Fuyun,Xinjiang earthquake fracture zone determined by fitting fault slip vector data[J]. Acta Seismologica Sinica,6(4):395–404(in Chinese).
许忠淮. 1985.用滑动方向拟合法反演唐山余震区的平均应力场[J].地震学报,7(4):349–362.Xu Z H. 1985. Mean stress field in Tangshan aftershock area obtained from focal mechanism data by fitting slip directions[J].Acta Seismologica Sinica,7(4):349–362(in Chinese).
俞春泉,陶开,崔效锋,胡幸平,宁杰远. 2009.用格点尝试法求解P波初动震源机制解及解的质量评价[J].地球物理学报,52(5):1402–1411.Yu C Q, Tao K, Cui X F, Hu X P, Ning J Y. 2009. P-wave first-motion focal mechanism solutions and their quality evaluation[J]. Chinese Journal of Geophysics,52(5):1402–1411(in Chinese).
张红艳,谢富仁,崔效锋,李瑞莎. 2009.张渤带陆地段现代构造应力场的非均匀特征[J].中国地震,25(3):314–324.Zhang H Y,Xie F R,Cui X F,Li R S. 2009. Research on heterogeneity of the present tectonic stress field at the overland part of the Zhangjiakou-Bohai fault zone[J]. Earthquake Research in China,25(3):314–324(in Chinese).
周翠英,王华林,王红卫,王梅,柳凤兰,周元夫. 2001.华北4次中、强地震前震源区及其附近应力场的变化[J].地震地质,23(1):98–110.Zhou C Y,Wang H L,Wang H W,Wang M,Liu F L,Zhou Y F. 2001. The changes of stress field in the focal region and its adjacent areas before four moderate-strong earthquakes in North China[J]. Seismology and Geology,23(1):98–110(in Chinese).
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]. 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]. J Geophys Res,111(B11):B11310.
Michael A J. 1984. Determination of stress from slip data:Faults and folds[J]. J Geophys Res,89(B13):11517–11526.
Michael A J. 1987. Use of focal mechanisms to determine stress:A control study[J]. J Geophys Res,92(B1):357–368.
Michael A J. 1991. Spatial variations in stress within the 1987 Whittier Narrows,California,aftershock sequence:New techniques and results[J]. J Geophys Res,96(B4):6303–6319.
Wan Y G,Sheng S Z,Huang J C,Li X,Chen X. 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]. J Earth Sci,27(5):777–785.
Wiemer S,Malone S. 2001. A software package to analyze seismicity:ZMAP[J]. Seismo Res Lett,7(2):373–382.
崔效锋,谢富仁,赵建涛. 2005.中国及邻区震源机制解的分区特征[J].地震地质,27(2):298–307.Cui X F,Xie F R,Zhao J T. 2005. The regional characteristics of focal mechanism solutions in China and its adjacent areas[J].Seismology and Geology,27(2):298–307(in Chinese).
崔效锋,谢富仁,李瑞莎,张红艳. 2010.华北地区构造应力场非均匀特征与煤田深部应力状态[J].岩石力学与工程学报,29 (1):2755–2761.Cui X F,Xie F R,Li R S,Zhang H Y. 2010. Heterogeneous features of state of tectonic stress filed in North China and deep stress in coal mine[J]. Chinese Journal of Rock Mechanics and Engineering,29(1):2755–2761(in Chinese).
邓起东,张培震,冉勇康,杨晓平,闵伟,楚全芝. 2002.中国活动构造基本特征[J].中国科学:D辑, 32(12):1 0 2 0–1030.Deng Q D,Zhang P Z,Ran Y K,Yang X P,Min W,Chu Q Z. 2003. Features of active tectonics in China[J]. Science in China:Series D,46(4):356–372.
胡幸平,崔效锋. 2013.华北地区中部地震精定位与构造应力场研究[J].震灾防御技术,8(4):351–360.Hu X P,Cui X F. 2013. Study on earthquake relocation and tectonic stress field in central North China[J]. Technology for Earthquake Disaster Prevention,8(4):351–360(in Chinese).
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[J].地震,35(1):17–27.Huang J C,Wan Y G. 2015. Present tectonic stress field in the capital region of China determined from small and strong earthquake focal mechanisms[J]. Earthquake,35(1):17–27(in Chinese).
赖院根,刘启元,陈九辉,刘洁,李顺成,郭飙,黄志斌. 2006.首都圈地区横波分裂与地壳应力场特征[J].地球物理学报,49(1):189–196.Lai Y G,Liu Q Y,Chen J H,Liu J,Li S C,Guo B,Huang Z B. 2006. Shear wave splitting and the features of the crustal stress field in the Capital Circle[J]. Chinese Journal of Geophysics,49(1):189–196(in Chinese).
李钦祖,靳雅敏,于新昌. 1982.华北地区的震源机制与地壳应力场[J].地震学报,4(1):55–61.Li Q Z,Jin Y M,Yu X C. 1982. Focal mechanisms and crustal stress field in North China[J]. Acta Seismologica Sinica,4(1):55 –61(in Chinese).
李瑞莎,崔效锋,刁桂苓,张红艳. 2008.华北北部地区现今应力场时空变化特征研究[J].地震学报,30(6):570–580.Li R S,Cui X F,Diao G L,Zhang H Y. 2008. Temporal and spatial variation of the present crustal stress in northern part of North China[J]. Acta Seismologica Sinica,30(6):570–580(in Chinese).
盛书中,万永革,黄骥超,卜玉菲,李祥. 2015.应用综合震源机制解法推断鄂尔多斯块体周缘现今地壳应力场的初步结果[J].地球物理学报,58(2):436–452.Sheng S Z,Wan Y G,Huang J C,Bu Y F,Li X. 2015. Present tectonic stress field in the circum-Ordos region deduced from composite focal mechanism method[J]. Chinese Journal of Geophysics,58(2):436–452(in Chinese).
万永革,沈正康,刁桂苓,王福昌,胡新亮,盛书中. 2008.利用小震分布和区域应力场确定大震断层面参数方法及其在唐山地震序列中的应用[J].地球物理学报,51(3):793–804.Wan Y G,Shen Z K,Diao G L,Wang F C,Hu X L,Sheng S Z. 2008. An algorithm of fault parameter determination using distribution of small earthquakes and parameters of regional stress field and its application to Tangshan earthquake sequence[J].Chinese Journal of Geophysics,51(3):793–804(in Chinese).
汪素云,许忠淮. 1985.中国东部大陆的地震构造应力场[J].地震学报,7(1):17–32.Wang S Y,Xu Z H. 1985. Seismo-tectonic stress field in east China[J]. Acta Seismologica Sinica,7(1):17–32(in Chinese).
王绳祖,张流. 2002.塑性流动网络控制下华北地区构造应力场与地震构造[J].地震地质,24(1):69–80.Wang S Z,Zhang L. 2002. Tectonic stress field and seismic tectonics controlled by plastic-flow network in North China[J]. Seismology and Geology,24(1):69–80(in Chinese).
武敏捷,林向东,徐平. 2011.华北北部地区震源机制解及构造应力场特征分析[J].大地测量与地球动力学,31(5):39–43.Wu M J,Lin X D,Xu P. 2011. Analysis of focal mechanism and tectonic stress field features in northern part of North China[J].Journal of Geodesy and Geodynamics,31(5):39–43(in Chinese).
谢富仁,陈群策,崔效锋,李宏,杨树新,郭启良,陈连旺,许忠淮,张彦山,窦淑芹,赵建涛,张周术,刘长义,王刚军.2007.中国大陆地壳应力环境基础数据库[J].地球物理学进展,22(1):131–136.Xie F R,Chen Q C,Cui X F,Li H,Yang S X,Guo Q L,Chen L W,Xu Z H,Zhang Y S,Dou S Q,Zhao J T,Zhang Z S,Liu C Y,Wang G J. 2007. Fundamental database of crustal stress environment in continental China[J]. Process in Geophysics,22(1):131–136(in Chinese).
谢富仁,崔效锋. 2015.中国及邻区现代构造应力场图[M].北京:中国地图出版社:1–18.Xie F R,Cui X F. 2015. The Map of Recent Tectonic Stress Field in China and Adjacent Areas[M]. Beijing:China Cartographic Publishing House:1–18(in Chinese).
徐锡伟,吴卫民,张先康,马胜利,马文涛,于贵华,顾梦林,江娃利. 2002.首都圈地区地壳最新构造变动与地震[M].北京:科学出版社:1–376.Xu X W,Wu W M,Zhang X K,Ma S L,Ma W T,Yu G H,Gu M L,Jiang W L. 2002. New Changing of Crustal Tectonic and Earthquake in Capital Circle[M]. Beijing:Science Press:1–376(in Chinese).
许忠淮,阎明,赵仲和. 1983.由多个小地震推断的华北地区构造应力场的方向[J].地震学报,5(3):268–279.Xu Z H,Yan M,Zhao Z H. 1983. Evaluation of the direction of tectonic stress in North China from recorded data of a large number of small earthquakes[J]. Acta Seismologica Sinica,5(3):268–279(in Chinese).
许忠淮,戈澍谟. 1984.用滑动方向拟合法反演富蕴地震断裂带应力场[J].地震学报,6(4):395–404.Xu Z H,Ge S M. 1984. Stress field in the Fuyun,Xinjiang earthquake fracture zone determined by fitting fault slip vector data[J]. Acta Seismologica Sinica,6(4):395–404(in Chinese).
许忠淮. 1985.用滑动方向拟合法反演唐山余震区的平均应力场[J].地震学报,7(4):349–362.Xu Z H. 1985. Mean stress field in Tangshan aftershock area obtained from focal mechanism data by fitting slip directions[J].Acta Seismologica Sinica,7(4):349–362(in Chinese).
俞春泉,陶开,崔效锋,胡幸平,宁杰远. 2009.用格点尝试法求解P波初动震源机制解及解的质量评价[J].地球物理学报,52(5):1402–1411.Yu C Q, Tao K, Cui X F, Hu X P, Ning J Y. 2009. P-wave first-motion focal mechanism solutions and their quality evaluation[J]. Chinese Journal of Geophysics,52(5):1402–1411(in Chinese).
张红艳,谢富仁,崔效锋,李瑞莎. 2009.张渤带陆地段现代构造应力场的非均匀特征[J].中国地震,25(3):314–324.Zhang H Y,Xie F R,Cui X F,Li R S. 2009. Research on heterogeneity of the present tectonic stress field at the overland part of the Zhangjiakou-Bohai fault zone[J]. Earthquake Research in China,25(3):314–324(in Chinese).
周翠英,王华林,王红卫,王梅,柳凤兰,周元夫. 2001.华北4次中、强地震前震源区及其附近应力场的变化[J].地震地质,23(1):98–110.Zhou C Y,Wang H L,Wang H W,Wang M,Liu F L,Zhou Y F. 2001. The changes of stress field in the focal region and its adjacent areas before four moderate-strong earthquakes in North China[J]. Seismology and Geology,23(1):98–110(in Chinese).
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]. 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]. J Geophys Res,111(B11):B11310.
Michael A J. 1984. Determination of stress from slip data:Faults and folds[J]. J Geophys Res,89(B13):11517–11526.
Michael A J. 1987. Use of focal mechanisms to determine stress:A control study[J]. J Geophys Res,92(B1):357–368.
Michael A J. 1991. Spatial variations in stress within the 1987 Whittier Narrows,California,aftershock sequence:New techniques and results[J]. J Geophys Res,96(B4):6303–6319.
Wan Y G,Sheng S Z,Huang J C,Li X,Chen X. 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]. J Earth Sci,27(5):777–785.
Wiemer S,Malone S. 2001. A software package to analyze seismicity:ZMAP[J]. Seismo Res Lett,7(2):373–382.