以震源精确定位结果分析张北地震序列的破裂特征
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摘要
利用远场和近场数字地震观测记录 ,重新测定了张北地震序列ML≥ 3级地震的震源位置 ,结合修订后的震源机制、宏观烈度分布资料 ,给出了张北地震序列的破裂特征。地震序列由走向NWW、倾向NNE、倾角 4 4°、长 11.5km的左旋走向滑动的主破裂面 ,2条NNE走向、高倾角、右旋走滑的次要破裂面组合而成。NWW和NNE走向的破裂面共轭展布 ,2条NNE向的破裂面呈右阶斜列 ,3条破裂面先后依次出现。破裂面埋深 1.4～ 7.6km ,在地壳的浅部。研究表明 ,在没有发现活动断裂的“构造稳定区” ,利用精确可靠的强震序列震源位置、震源机制和宏观烈度分布资料 ,从三维空间分析研究强震序列的震源断层 ,是一条可行的途径
Based upon the far-field and near-field digital seismic records, the hypocenter locations of M L≥3 earthquakes of the Zhangbei earthquake sequence occurred during January, 1998-March, 1999 have been re-determined by using relative locating method. The results show that the process of the earthquake sequence can be divided into three stages. The first stage occurred in January 1988, which is the stage of the occurrence and adjustment of the main shocks. The seismic activity in this stage occurred mostly along NWW-SEE direction. The second stage occurred during February ～August 1998, which is the active period of moderate aftershocks occurred mostly along NNE direction. The third stage was represented by the occurrence of M5.6 earthquake on March 11, 1999, the hypocenter of which was aligned also along NNE direction, but was out of the hypocenter area of the main shock. It seems that the two hypocenters were not connected with each other. The rupture characteristics of the Zhangbei earthquake sequence is given on the basis of the relocation of the hypocenters and the revised focal mechanisms, as well as macroscopic intensity distribution data of this earthquake sequence. It is suggested that the earthquake sequence consists of one main left-lateral strike-slip rupture plane, and 2 right-lateral strike slip secondary rupture planes. The main rupture plane is NWW-trending, NNE-dipping at an angle of 44°, and 11.5km in length. The two secondary rupture planes are NNE-trending with a high dip angle. The main rupture plane is conjugate with the NNE-trending secondary rupture planes while the two NNE-trending rupture planes are aligned in right-step en ecelon. The three rupture planes occurred sequentially, the depth of the which is 1.4～7.6 km at shallow part of the crust. The present study shows that it is a doable approach to research the focal rupture of a strong earthquake sequence from three dimensional space by using exact hypocenter 1ocation, focal mechanism and macro-intensity distribution data in "tectonically stable area" where no active fault is found.
Based upon the far-field and near-field digital seismic records, the hypocenter locations of M L≥3 earthquakes of the Zhangbei earthquake sequence occurred during January, 1998-March, 1999 have been re-determined by using relative locating method. The results show that the process of the earthquake sequence can be divided into three stages. The first stage occurred in January 1988, which is the stage of the occurrence and adjustment of the main shocks. The seismic activity in this stage occurred mostly along NWW-SEE direction. The second stage occurred during February ～August 1998, which is the active period of moderate aftershocks occurred mostly along NNE direction. The third stage was represented by the occurrence of M5.6 earthquake on March 11, 1999, the hypocenter of which was aligned also along NNE direction, but was out of the hypocenter area of the main shock. It seems that the two hypocenters were not connected with each other. The rupture characteristics of the Zhangbei earthquake sequence is given on the basis of the relocation of the hypocenters and the revised focal mechanisms, as well as macroscopic intensity distribution data of this earthquake sequence. It is suggested that the earthquake sequence consists of one main left-lateral strike-slip rupture plane, and 2 right-lateral strike slip secondary rupture planes. The main rupture plane is NWW-trending, NNE-dipping at an angle of 44°, and 11.5km in length. The two secondary rupture planes are NNE-trending with a high dip angle. The main rupture plane is conjugate with the NNE-trending secondary rupture planes while the two NNE-trending rupture planes are aligned in right-step en ecelon. The three rupture planes occurred sequentially, the depth of the which is 1.4～7.6 km at shallow part of the crust. The present study shows that it is a doable approach to research the focal rupture of a strong earthquake sequence from three dimensional space by using exact hypocenter 1ocation, focal mechanism and macro-intensity distribution data in "tectonically stable area" where no active fault is found.
引文
成瑾,陈培善,白彤霞.1998.利用区域数字地震台网的宽频带全波资料确定张北地震及部分余震的震源机制.见:中国地震学会第七次学术大会论文摘要集〔Z〕.北京:地震出版社.17.
HENGJin,CHENPei shan,BAITong xia.1998.FocalmechanismsolutionoftheJan.1998Zhangbeiearth quakeandsomeafter shocksdeterminedfrombroadbanddigitaldataofBeijingregionalseismicnetwork〔Z〕.In:AbstractVolumeofthe7thSymposiumofChinaSeismologicalSociety.Beijing:SeismologicalPress,17(inChi nese).
陈培善.1998.全球大震和中国及邻区中强震地震活动(1997年12月～1998年1月)〔J〕.地震学报,20:(3):332～333.
CHENPei shan.1998.StrongearthquakeactivityallovertheWorldandstrong moderateearthquakeactivitywithinandnearChina(December1997～January1998)〔J〕.ActaSeismologicaSinica,20(3):332～333(inChi nese).
刁桂苓,蔡华昌,刁建新,等.2001.1998年张北6.2级地震宏观烈度〔J〕.华北地震科学,19(1):23～30.
DIAOGui ling,CAIHua chang,DIAOJian xin,etal.2001.ThemacrointensityoftheZhangbeiMS62earth quakein1998〔J〕.NorthChinaEarthquakeSciences,19(1):23～30(inChinese).
刁桂苓,张四昌,朱艾斓.1998.张北6.2级地震发生在小震条带上〔J〕.华北地震科学,16(3):34～38.
DIAOGui ling,ZHANGSi chang,ZHUAi lan.1998.TheZhangbeiearthquakeoccurredonaweakearthquakebelt〔J〕.NorthChinaEarthquakeSciences,16(3):34～38(inChinese).
高景春,胡斌,张从珍.1999.用相对定位法精细测定张北地震序列的时空参数〔J〕.华北地震科学,17(1):42～46.
GAOJing chun,HUBin,ZHANGCong zhen.1999.AccuratedeterminationofthetemporalandspatialparametersoftheZhangbeiearthquakesequencebytherelativelocatingmethod〔J〕.NorthChinaEarthquakeSciences,17(1):42～46(inChinese).
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.
LIQin zu,JINYa min,YUXin chang.1982.FocalmechanismsandcrustalstressfieldinNorthChina〔J〕.ActaSeismologicaSinica,4(1):55～61(inChinese).
刘瑞峰,陈运泰,周公威,等.1999.地震矩张量反演在地震快速反应中的应用〔J〕.地震学报,21(2):115～122.
LIURui feng,CHENYun tai,ZHOUGong wei,etal.1999.Inversionofseismicmomenttensoranditsuseinquickresponsetoearthquakes〔J〕.ActaSeismologicaSinica,21(2):115～122(inChinese).
刘志辉,刁建新.2000.张北5.6级强余震宏观烈度考察〔J〕.华北地震科学,18(2):25～29.
LIUZhi hui,DIAOJian xin.2000.InvestigationonthemacroscopicintensityofZhangbeiMS5.6strongafter shock〔J〕.NorthChinaEarthquakeSciences,18(2):25～29(inChinese).
马淑田,陈会忠,王松,等.1998.1998年1月10日河北张北-尚义MS6.2地震震源机制的初步研究〔J〕.地球物理学报,41(5):724～728
MAShu tian,CHENHui zhong,WANGSong,etal.1998.ApreliminarystudyoffocalmechanismofMS6.2earthquakeonJanuary10,1998,inZhangbeiShangyiregion〔J〕.ActaGeophysicaSinica,41(5):724～728(inChinese)
石金虎,赖晓玲,段永红,等.1999.张北地震近场观测资料的初步解释〔J〕.中国地震,15(2):151～158
SHIJin hu,LAIXiao ling,DUANYong hong,etal.1999.Apreliminaryinterpretationofnear fieldearthquakerecordsinZhangbeiearthquakeregion〔J〕.EarthquakeResearchinChina,15(2):151～158(inChinese).
徐锡伟,冉勇康.1999.张北地震构造背景〔J〕.见:中国地震局监测预报司编.1998年张北地震.北京:地震出版社.11～28
XUXi wei,RANYong kang.1999.SeismotectonicsoftheZhangbeiearthquake〔J〕.In:DepartmentofEarthquakeMonitoringandPrediction,ed.TheZhangbeiEarthquakeof1998.BeiJing:SeismologicalPress,11～28(inChinese)
徐锡伟,冉勇康,周本刚,等.1998.张北-尚义地震的构造环境与宏观破坏特征〔J〕.地震地质,20(2):135～145.
XUXi wei,RANYong kang,ZHOUBen gang,etal.1998.Seismotectonicsandmacro damagefeaturesoftheZhangbeiShangyiearthquake〔J〕.SeismologyandGeology,20(2):135～145(inChinese)
杨智娴,陈运泰,张宏志.1999.张北-尚义地震序列的重新定位〔J〕.地震地磁观测与研究,20(6):6～9.
YANGZhi xian,CHENYun tai,ZHANGHong zhi.1999.RelocationoftheZhangbeiShangyiearthquakesequence〔J〕.SeimologicalandGeomagneticObservationandResearch,20(6):6～9(inChinese)
张国民,张永仙.1999.张北地震的科学问题及反思〔A〕.见:中国地震局监测预报司编.1998年张北地震.北京:地震出版社.231～232.
ZHANGGuo min,ZHANGYong xian.1999.ScientificquestionandponderingonZhangbeiearthquake〔A〕.In:DepartmentofEarthquakeMonitoringandPrediction,ed.TheZhangbeiEarthquakeof1998.Beijing:Seismo logicalPress,231～232(inChinese).
张四昌.1979.大地震与共轭性构造活动〔J〕.地震地质,1(3):41～46.
ZHANGSi chang.1979.Thegreatearthquakeandtheconjugatetectonicmotion〔J〕.SeismologyandGeology,1(3):41～46(inChinese).
郑秀芬,丁晗,张宏志,等.1998.张北-尚义地震序列的空间分布、构造活动性初探〔J〕.地震地磁观测与研究,19(6):24～27.
ZHENGXiu fen,DINGHan,ZHANGHong zhi,etal.1998.Thepreliminarystudyonepicenterdistributionandtec tonicactivityofZhangbeiShangyiearthquakesequence〔J〕.SeimologicalandGeomagneticObservationandRe search,19(6):24～27(inChinese).
中国地震局监测预报司.1999.1998年张北地震〔M〕.北京:地震出版社
DepartmentofEarthquakeMonitoringandPrediction,ChinaSeismologicalBureau,ed.1999.TheZhangbeiEarth quakeof1998〔M〕.BeiJing:SeismologicalPress(inChinese).
KrishinaVG ,RaoCVRK ,GuptaHK ,etal.1999.CrustalseismicstructureintheepicentralregionoftheLaturearthquake(September29,1993),southernIndia:inferencesfrommodelingoftheaftershockseismograms〔J〕.Tectonophysics,304,241～255.
HENGJin,CHENPei shan,BAITong xia.1998.FocalmechanismsolutionoftheJan.1998Zhangbeiearth quakeandsomeafter shocksdeterminedfrombroadbanddigitaldataofBeijingregionalseismicnetwork〔Z〕.In:AbstractVolumeofthe7thSymposiumofChinaSeismologicalSociety.Beijing:SeismologicalPress,17(inChi nese).
陈培善.1998.全球大震和中国及邻区中强震地震活动(1997年12月～1998年1月)〔J〕.地震学报,20:(3):332～333.
CHENPei shan.1998.StrongearthquakeactivityallovertheWorldandstrong moderateearthquakeactivitywithinandnearChina(December1997～January1998)〔J〕.ActaSeismologicaSinica,20(3):332～333(inChi nese).
刁桂苓,蔡华昌,刁建新,等.2001.1998年张北6.2级地震宏观烈度〔J〕.华北地震科学,19(1):23～30.
DIAOGui ling,CAIHua chang,DIAOJian xin,etal.2001.ThemacrointensityoftheZhangbeiMS62earth quakein1998〔J〕.NorthChinaEarthquakeSciences,19(1):23～30(inChinese).
刁桂苓,张四昌,朱艾斓.1998.张北6.2级地震发生在小震条带上〔J〕.华北地震科学,16(3):34～38.
DIAOGui ling,ZHANGSi chang,ZHUAi lan.1998.TheZhangbeiearthquakeoccurredonaweakearthquakebelt〔J〕.NorthChinaEarthquakeSciences,16(3):34～38(inChinese).
高景春,胡斌,张从珍.1999.用相对定位法精细测定张北地震序列的时空参数〔J〕.华北地震科学,17(1):42～46.
GAOJing chun,HUBin,ZHANGCong zhen.1999.AccuratedeterminationofthetemporalandspatialparametersoftheZhangbeiearthquakesequencebytherelativelocatingmethod〔J〕.NorthChinaEarthquakeSciences,17(1):42～46(inChinese).
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.
LIQin zu,JINYa min,YUXin chang.1982.FocalmechanismsandcrustalstressfieldinNorthChina〔J〕.ActaSeismologicaSinica,4(1):55～61(inChinese).
刘瑞峰,陈运泰,周公威,等.1999.地震矩张量反演在地震快速反应中的应用〔J〕.地震学报,21(2):115～122.
LIURui feng,CHENYun tai,ZHOUGong wei,etal.1999.Inversionofseismicmomenttensoranditsuseinquickresponsetoearthquakes〔J〕.ActaSeismologicaSinica,21(2):115～122(inChinese).
刘志辉,刁建新.2000.张北5.6级强余震宏观烈度考察〔J〕.华北地震科学,18(2):25～29.
LIUZhi hui,DIAOJian xin.2000.InvestigationonthemacroscopicintensityofZhangbeiMS5.6strongafter shock〔J〕.NorthChinaEarthquakeSciences,18(2):25～29(inChinese).
马淑田,陈会忠,王松,等.1998.1998年1月10日河北张北-尚义MS6.2地震震源机制的初步研究〔J〕.地球物理学报,41(5):724～728
MAShu tian,CHENHui zhong,WANGSong,etal.1998.ApreliminarystudyoffocalmechanismofMS6.2earthquakeonJanuary10,1998,inZhangbeiShangyiregion〔J〕.ActaGeophysicaSinica,41(5):724～728(inChinese)
石金虎,赖晓玲,段永红,等.1999.张北地震近场观测资料的初步解释〔J〕.中国地震,15(2):151～158
SHIJin hu,LAIXiao ling,DUANYong hong,etal.1999.Apreliminaryinterpretationofnear fieldearthquakerecordsinZhangbeiearthquakeregion〔J〕.EarthquakeResearchinChina,15(2):151～158(inChinese).
徐锡伟,冉勇康.1999.张北地震构造背景〔J〕.见:中国地震局监测预报司编.1998年张北地震.北京:地震出版社.11～28
XUXi wei,RANYong kang.1999.SeismotectonicsoftheZhangbeiearthquake〔J〕.In:DepartmentofEarthquakeMonitoringandPrediction,ed.TheZhangbeiEarthquakeof1998.BeiJing:SeismologicalPress,11～28(inChinese)
徐锡伟,冉勇康,周本刚,等.1998.张北-尚义地震的构造环境与宏观破坏特征〔J〕.地震地质,20(2):135～145.
XUXi wei,RANYong kang,ZHOUBen gang,etal.1998.Seismotectonicsandmacro damagefeaturesoftheZhangbeiShangyiearthquake〔J〕.SeismologyandGeology,20(2):135～145(inChinese)
杨智娴,陈运泰,张宏志.1999.张北-尚义地震序列的重新定位〔J〕.地震地磁观测与研究,20(6):6～9.
YANGZhi xian,CHENYun tai,ZHANGHong zhi.1999.RelocationoftheZhangbeiShangyiearthquakesequence〔J〕.SeimologicalandGeomagneticObservationandResearch,20(6):6～9(inChinese)
张国民,张永仙.1999.张北地震的科学问题及反思〔A〕.见:中国地震局监测预报司编.1998年张北地震.北京:地震出版社.231～232.
ZHANGGuo min,ZHANGYong xian.1999.ScientificquestionandponderingonZhangbeiearthquake〔A〕.In:DepartmentofEarthquakeMonitoringandPrediction,ed.TheZhangbeiEarthquakeof1998.Beijing:Seismo logicalPress,231～232(inChinese).
张四昌.1979.大地震与共轭性构造活动〔J〕.地震地质,1(3):41～46.
ZHANGSi chang.1979.Thegreatearthquakeandtheconjugatetectonicmotion〔J〕.SeismologyandGeology,1(3):41～46(inChinese).
郑秀芬,丁晗,张宏志,等.1998.张北-尚义地震序列的空间分布、构造活动性初探〔J〕.地震地磁观测与研究,19(6):24～27.
ZHENGXiu fen,DINGHan,ZHANGHong zhi,etal.1998.Thepreliminarystudyonepicenterdistributionandtec tonicactivityofZhangbeiShangyiearthquakesequence〔J〕.SeimologicalandGeomagneticObservationandRe search,19(6):24～27(inChinese).
中国地震局监测预报司.1999.1998年张北地震〔M〕.北京:地震出版社
DepartmentofEarthquakeMonitoringandPrediction,ChinaSeismologicalBureau,ed.1999.TheZhangbeiEarth quakeof1998〔M〕.BeiJing:SeismologicalPress(inChinese).
KrishinaVG ,RaoCVRK ,GuptaHK ,etal.1999.CrustalseismicstructureintheepicentralregionoftheLaturearthquake(September29,1993),southernIndia:inferencesfrommodelingoftheaftershockseismograms〔J〕.Tectonophysics,304,241～255.
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