2008年6月10日内蒙古鄂伦春自治旗M5.2地震的震源机制、震源深度和发震构造
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摘要
2008年6月10日14时5分,内蒙古鄂伦春自治旗发生M5.2地震,该地震处于大兴安岭梯度带北段,是内蒙古东北部地区近年来发生的最大地震。基于内蒙古地震台网观测资料,使用TDMT方法、CAP方法、PTD方法和sPn-Pn等方法测定此次地震的震源机制解和震源深度。结合已有数据资料,分析震源区域地震的时空分布特征和构造应力特征,并探讨该地震的发震构造。此次地震震源深度较浅,位于上地壳,结合震源机制解结果、地震分布特征和构造背景分析认为,此次地震为右旋走滑类型,走向NNE,主压应力方向为SWW。
The M5.2 earthquake that occurred in Oroqen on 10 June,2008,was the largest earthquake effecting northeastern Inner Mongolia in recent years.In this study,the focal mechanisms and focal depth of this earthquake are determined using the TDMT method,CAP method,PTD method,and sPn-Pn method.Results using the CAP and TDMT methods are inconsistent with each other,and show that the focal depth of the earthquake is shallow and that the source is located in the upper crust.Combined with existing data,the spatial and temporal distribution characteristics and tectonic stress characteristics of earthquakes in the area near the epicenter of this earthquake are analyzed,and the seismogenic structure of this M5.2 earthquake is discussed.Using a combination of the focal mechanism solution,earthquake distribution characteristics,and tectonic background,the M5.2 earthquake is determined as a dextral strike-slip faulting event with a NNE strike and a SWW principal compressive stress direction.The seismic activities of earthquakes in this area were significantly enhanced after the M5.2 earthquake.Focal mechanism solutions in the northern section of the Greater Khingan Range gradient zone show that the Greater Khingan Range fracture is controlled by NEE-SSW horizontal compressional stress,with a strike-slip feature.
The M5.2 earthquake that occurred in Oroqen on 10 June,2008,was the largest earthquake effecting northeastern Inner Mongolia in recent years.In this study,the focal mechanisms and focal depth of this earthquake are determined using the TDMT method,CAP method,PTD method,and sPn-Pn method.Results using the CAP and TDMT methods are inconsistent with each other,and show that the focal depth of the earthquake is shallow and that the source is located in the upper crust.Combined with existing data,the spatial and temporal distribution characteristics and tectonic stress characteristics of earthquakes in the area near the epicenter of this earthquake are analyzed,and the seismogenic structure of this M5.2 earthquake is discussed.Using a combination of the focal mechanism solution,earthquake distribution characteristics,and tectonic background,the M5.2 earthquake is determined as a dextral strike-slip faulting event with a NNE strike and a SWW principal compressive stress direction.The seismic activities of earthquakes in this area were significantly enhanced after the M5.2 earthquake.Focal mechanism solutions in the northern section of the Greater Khingan Range gradient zone show that the Greater Khingan Range fracture is controlled by NEE-SSW horizontal compressional stress,with a strike-slip feature.
引文
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[10]韦生吉,倪四道,崇加军,等.2003年8月16日赤峰地震:一个可能发生在下地壳的地震?[J].地球物理学报,2009,52(1):111-119.WEI Shengji,NI Sidao,CHONG Jiajun,et al.The 16August2003Chifeng Earthquake:Is It a Lower Crust Earthquake[J].Chinese Journal Geophysics,2009,52(1):111-119.
[11]韩晓明,刘芳,张帆,等.2015年阿拉善左旗MS5.8地震的震源机制和重定位[J].地震学报,2015,37(6):1059-1063.HAN Xiaoming,LIU Fang,ZHANG Fan,et al.Source Mechanism of The 2015Alxa Zuoqi MS5.8Earthquake and Its Relocation[J].Acta Seismologica Sinica,2015,37(6):1059-1063.
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[14]钱程,崔天日,李林川,等.ASTER—GDEM数据在大兴安岭北段地貌形态分析中的应用[J].地质力学学报,2013,19(1):82-92.QIAN Cheng,CUI Tianri,LI Linchuan,et al.Application of ASTER—GDEM Data in the Geomorphic Characteristics Analysis of Northern Great Higgnan Ling Mountains[J].Journal of Geomechanics,2013,19(1):82-92.
[15]杨宝俊,刘万崧,王喜臣,等.中国东部大兴安岭重力梯级带域地球物理场特征及其成因[J].地球物理学报,2005,48(1):86-97.YANG Baojun,LIU Wansong,WANG Xichen,et al.Geophysical Characteristics of Daxinganling Gravitational Gradient Zone in the East China and Its Geodynamic Mechanism[J].Chinese Journal Geophysics,2005,48(1):86-97.
[16]于清水,张凤旭,曾昭发.大兴安岭北段的地球物理场研究[J].世界地质,2015,34(1):187-193.YU Qingshui,ZHANG Fengxu,ZENG Shaofa.Research on Geophysical Field in Northern Part of Da Hinggan Mountains[J].Global Geology,2015,34(1):187-193.
[17]ZHU L,RIVERA L A.A Note on the Dynamic and Static Displacements from a Point Source in Multilayered Media[J].Geophysical Journal International,2002,148(3):619-627.
[18]DREGER D S,HELMBERGER D V.Determination of Source Parameters at Regional Distances with Three-component Sparse Network Data[J].Journal of Geophysical Research Atmospheres,1993,98(98):8107-8125.
[19]ZOBACK M L.First-and Second-order Patterns of Stress in the Lithosphere:The World Stress Map Project[J].Journal of Geophysical Research,1992,97(B8):11703-11728.
[20]KNOPOFF L,RANDALL M J.The Compensated Linear-vector Dipole:A Possible Mechanism for Deep Earthquakes[J].Journal of Geophysical Research,1970,75(26):4957-4963.
[21]朱元清,石耀林,李平.一种确定震源深度的新方法[J].地震地磁观测与研究,1990,11(2):4-12.ZHU Yuanqing,SHI Yaolin,LI Ping.A New Method to Determine the Focal Depth[J].Seismological and Geomagnetic Observation and Research,1990,11(2):4-12.
[22]朱元清,夏俊平,李平.确定震源深度的PTD方法及其应用[J].地震地磁观测与研究,1997,18(3):21-29.ZHU Yuanqing,XIA Junping,LI Ping.A PTD Method A New Method for Determinating Focal Depth and Its Application[J].Seismological and Geomagnetic Observation and Research,1997,18(3):21-29.
[23]高立新,刘芳,赵蒙生,等.用sPn震相计算震源深度的初步分析与应用[J].西北地震学报,2007,29(3):213-217.GAO Lixin,LIU Fang,ZHAO Mengsheng,et al.Primary Analysis on The Seismic Source Depth Determination Using sPn Phase and Its Application[J].Northwestern Seismological Journal,2007,29(3):213-217.
[24]洪星,叶雯燕,邵平荣,等.台湾海峡南部一次5.0级地震的sPn震相分析[J].地震地磁观测与研究,2006,27(1):26-31.HONG Xing,YE Wenyan,SHAO Pingrong,et al.sPn Seismic Phase Analysis for A ML5.0Earthquake in Southern Taiwan Strait[J].Seismological and Geomagnetic Observation and Research,2006,27(1):26-31.
[25]王兆国,刘财,冯晅,等.中国东北地区地震空问分布与主要断裂带、深部构造及应力场关系[J].世界地质,2009,28(4):513-519.WANG Zhaoguo,LIU Cai,FENG Xuan,et al.Earthquake Space Distribution and Its Relationships with Main Faults,Deep Structure and Stress Field in Northeast China[J].Global Geology,2009,28(4):513-519.
[26]刘玉琢,梁海庆,刘建中.我国东北地区新生代构造应力场的时空变化与地震活动[J].东北地震研究,1989(1):17-24.LIU Yuzhuo,LIANG Haiqing,LIU Jianzhong.The Stress Field Change in Time and Space in Northeast China and Seismological Activity[J].Seismological Research of Northeast China,1989(1):17-24.
[27]张弘弢,安钢.1980年博克图5.6级地震前地震活动的某些特征[J].东北地震研究,1987,3(3):51-57.ZHANG Hongtao,AN Gang.Some Characteristics of the Seismic Activity before Boketu Earthquake(MS=5.6),1980[J].Seismological Research of Northeast China,1987,3(3):51-57.
[28]刘芳.2005年9月19日陈巴尔虎旗-牙克石市间5.0级地震特征分析[J].东北地震研究,2007,23(3):45-51.LIU Fang.Character Analysis on MS5.0Earthquake between Chenbaerhuqi and Yakeshi on Sep.19,2005[J].Seismological Research of Northeast China,2007,23(3):45-51.
[2]俞春泉,陶开,崔效锋,等.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,2009,52(5):1402-1411.YU Chunquan,TAO Kai,CUI Xiaofeng,et al.P-wave Firstmotion Focal Mechanism Solutions and Their Quality Evaluation[J].Chinese Journal Geophysics,2009,52(5):1402-1411.
[3]NAKAMURA M.Determination of Focal Mechanism Solution Using Initial Motion Polarity of P and S Waves[J].Physics of the Earth and Planetary Interiors,2002,130(1-2):17-29.
[4]梁尚鸿,李幼铭,束沛镒,等.利用区域地震台网P-、S-振幅比资料测定小震震源参数[J].地球物理学报,1984,27(3):249-257.LIANG Shanghong,LI Youming,SHU Peiyi,et al.On The Determining of Source Parameters of Small Earthquakes by Using Amplituderatios of P and S from Regional Network Observations[J].Chinese Journal Geophysics,1984,27(3):249-257.
[5]胡新亮,刁桂苓,马瑾,等.利用数字地震记录的P-,S-振幅比资料测定小震震源机制解的可靠性分析[J].地震地质,2004,26(2):347-354.HU Xinliang,DIAO Guiling,MA Jin,et al.Reliability Analysis of Focal Mechanism Solutions of Micro-earthquakes Determined from Amplitude Ratio of P-and S-recorded by Digital Seismograph[J].Seismology and Geology,2004,26(2):347-354.
[6]HARDEBEEK J L,SHEARER P M.A New Method for Determining First-motion Focal Mechanisms[J].Bul1 Seism Soc Am,2002,92(6):2264-2276.
[7]SNOKE J A,MUNSEY J W,TEAGUE A G,et al.A Program for Focal Mechanism Determination by Combined Use of Polarity and SV-P Amplitude Ratio Data[J].Earthquake Notes,1984,55(3):15-20.
[8]ZHU L P,HELMBERGER D V.Advancement in Source Estimation Techniques Using Broadband Regional Seismograms[J].Bull Seism Soc Amer,1996,86(5):1634-1641.
[9]ZHAO L S,HELMBERGER D V.Source Estimation from Broadband Regional Seismograms[J].Bulletin of the Seismological Society of America,1994,84(1):91-104.
[10]韦生吉,倪四道,崇加军,等.2003年8月16日赤峰地震:一个可能发生在下地壳的地震?[J].地球物理学报,2009,52(1):111-119.WEI Shengji,NI Sidao,CHONG Jiajun,et al.The 16August2003Chifeng Earthquake:Is It a Lower Crust Earthquake[J].Chinese Journal Geophysics,2009,52(1):111-119.
[11]韩晓明,刘芳,张帆,等.2015年阿拉善左旗MS5.8地震的震源机制和重定位[J].地震学报,2015,37(6):1059-1063.HAN Xiaoming,LIU Fang,ZHANG Fan,et al.Source Mechanism of The 2015Alxa Zuoqi MS5.8Earthquake and Its Relocation[J].Acta Seismologica Sinica,2015,37(6):1059-1063.
[12]韩晓明,刘芳,张文韬,等.基于震源机制资料分析河套地震带的应力场变化特征[J].地震地质,2015,37(4):1030-1042.HAN Xiaoming,LIU Fang,ZHANG Wentao,et al.Analyzing the Variation Characteristics of Stress Field in Hetao Seismic Belt Using Focal Mechanism Data[J].Seismology and Geology,2015,37(4):1030-1042.
[13]MINSON S E,DREGER D S.Inversions for Complete Moment Tensors[J].Geophysical Journal International,2008,174(2):585-592.
[14]钱程,崔天日,李林川,等.ASTER—GDEM数据在大兴安岭北段地貌形态分析中的应用[J].地质力学学报,2013,19(1):82-92.QIAN Cheng,CUI Tianri,LI Linchuan,et al.Application of ASTER—GDEM Data in the Geomorphic Characteristics Analysis of Northern Great Higgnan Ling Mountains[J].Journal of Geomechanics,2013,19(1):82-92.
[15]杨宝俊,刘万崧,王喜臣,等.中国东部大兴安岭重力梯级带域地球物理场特征及其成因[J].地球物理学报,2005,48(1):86-97.YANG Baojun,LIU Wansong,WANG Xichen,et al.Geophysical Characteristics of Daxinganling Gravitational Gradient Zone in the East China and Its Geodynamic Mechanism[J].Chinese Journal Geophysics,2005,48(1):86-97.
[16]于清水,张凤旭,曾昭发.大兴安岭北段的地球物理场研究[J].世界地质,2015,34(1):187-193.YU Qingshui,ZHANG Fengxu,ZENG Shaofa.Research on Geophysical Field in Northern Part of Da Hinggan Mountains[J].Global Geology,2015,34(1):187-193.
[17]ZHU L,RIVERA L A.A Note on the Dynamic and Static Displacements from a Point Source in Multilayered Media[J].Geophysical Journal International,2002,148(3):619-627.
[18]DREGER D S,HELMBERGER D V.Determination of Source Parameters at Regional Distances with Three-component Sparse Network Data[J].Journal of Geophysical Research Atmospheres,1993,98(98):8107-8125.
[19]ZOBACK M L.First-and Second-order Patterns of Stress in the Lithosphere:The World Stress Map Project[J].Journal of Geophysical Research,1992,97(B8):11703-11728.
[20]KNOPOFF L,RANDALL M J.The Compensated Linear-vector Dipole:A Possible Mechanism for Deep Earthquakes[J].Journal of Geophysical Research,1970,75(26):4957-4963.
[21]朱元清,石耀林,李平.一种确定震源深度的新方法[J].地震地磁观测与研究,1990,11(2):4-12.ZHU Yuanqing,SHI Yaolin,LI Ping.A New Method to Determine the Focal Depth[J].Seismological and Geomagnetic Observation and Research,1990,11(2):4-12.
[22]朱元清,夏俊平,李平.确定震源深度的PTD方法及其应用[J].地震地磁观测与研究,1997,18(3):21-29.ZHU Yuanqing,XIA Junping,LI Ping.A PTD Method A New Method for Determinating Focal Depth and Its Application[J].Seismological and Geomagnetic Observation and Research,1997,18(3):21-29.
[23]高立新,刘芳,赵蒙生,等.用sPn震相计算震源深度的初步分析与应用[J].西北地震学报,2007,29(3):213-217.GAO Lixin,LIU Fang,ZHAO Mengsheng,et al.Primary Analysis on The Seismic Source Depth Determination Using sPn Phase and Its Application[J].Northwestern Seismological Journal,2007,29(3):213-217.
[24]洪星,叶雯燕,邵平荣,等.台湾海峡南部一次5.0级地震的sPn震相分析[J].地震地磁观测与研究,2006,27(1):26-31.HONG Xing,YE Wenyan,SHAO Pingrong,et al.sPn Seismic Phase Analysis for A ML5.0Earthquake in Southern Taiwan Strait[J].Seismological and Geomagnetic Observation and Research,2006,27(1):26-31.
[25]王兆国,刘财,冯晅,等.中国东北地区地震空问分布与主要断裂带、深部构造及应力场关系[J].世界地质,2009,28(4):513-519.WANG Zhaoguo,LIU Cai,FENG Xuan,et al.Earthquake Space Distribution and Its Relationships with Main Faults,Deep Structure and Stress Field in Northeast China[J].Global Geology,2009,28(4):513-519.
[26]刘玉琢,梁海庆,刘建中.我国东北地区新生代构造应力场的时空变化与地震活动[J].东北地震研究,1989(1):17-24.LIU Yuzhuo,LIANG Haiqing,LIU Jianzhong.The Stress Field Change in Time and Space in Northeast China and Seismological Activity[J].Seismological Research of Northeast China,1989(1):17-24.
[27]张弘弢,安钢.1980年博克图5.6级地震前地震活动的某些特征[J].东北地震研究,1987,3(3):51-57.ZHANG Hongtao,AN Gang.Some Characteristics of the Seismic Activity before Boketu Earthquake(MS=5.6),1980[J].Seismological Research of Northeast China,1987,3(3):51-57.
[28]刘芳.2005年9月19日陈巴尔虎旗-牙克石市间5.0级地震特征分析[J].东北地震研究,2007,23(3):45-51.LIU Fang.Character Analysis on MS5.0Earthquake between Chenbaerhuqi and Yakeshi on Sep.19,2005[J].Seismological Research of Northeast China,2007,23(3):45-51.