日本南海海槽地震区域应力场及其板块构造动力学特征
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摘要
为了研究海沟型巨大地震发生机制及其构造动力学特征 ,详细研究了地震活动与震源机制结果 ,根据地震俯冲带几何形状及其内应力场区域特征 ,南海海槽下的俯冲带可划分为两段 :东部的四国 -纪伊半岛段和西部的九州段 .东部的菲律宾海板块地震俯冲带呈现出低角度俯冲 (10°～ 2 2°) ,且俯冲深度相当浅 (6 0～ 85km)的特征 ;而西部九州段的俯冲带为高角度俯冲 (4 0°) ,且俯冲深度较深 (16 0km) .东、西部俯冲带内部应力场也截然不同 .东部的四国大部分地区和纪伊半岛的俯冲带内表现为俯冲压缩型应力场 ,而西部的九州段则为明显的俯冲拉张型应力场 .本文在综合分析了重力异常、GPS、热流量等地球物理观测结果后指出 ,南海海槽东部 ,即四国 -纪伊半岛以南的海槽区域 ,具有与智利海沟极其相似的地震发生板块构造动力学背景和高应力积累等特征 ,属于年轻活动俯冲带的高应力型俯冲 .而西部的九州段 ,虽然也是海沟型地震活动区 ,但不具有大地震发生的构造动力学背景和高应力积累 ,不属于年轻活动俯冲带的高应力型俯冲 .俯冲带年龄的不同很可能是造成南海海槽东、西段板块构造动力学以及应力场不同的根本原因之一 .
The Nankai Trough of Japan is one of the most active seismic zones in the world. In order to understand the mechanisms of great interplate earthquakes and the tectonics, seismic activity and focal mechanism solutions are analyzed in detail in this research. Based on the geometry of slabs and state of stress within the slabs, the Nankai Trough can be divided into two parts, the eastern part (Shikoku and the Kii peninsula) and western part (Kyushu). In the east the seismic slab of the Philippine Sea plate subducts at shallow dip angels between 10°～22° and its leading edge reaches down only to about 60～85km depth beneath Shikoku and the Kii peninsula. While in the west the seismic slab with dip angle of 40° subducts and down to about 160km depth beneath Kyushu. There are two types of seismogenic stress field within the slabs of thePhilippine Sea plate in the eastern and western parts of the Nankai Trough .The type of down dip compression stress field exists in the region beneath the most of Shikoku and the Kii peninsula .On the otherhand ,the type of down dipextensionstressfieldwithintheslabisdominantbeneathKyushu .Theanalysesofgravity ,heat flow ,GPS and other geophysical data suggest that the tectonic features in the eastern part are different from that of the western part.Two types of characteristics of seismotectonics and in traslabstress field in the same trough migh tberel atedto the differences of thes labagesinth eeastern and western parts .
The Nankai Trough of Japan is one of the most active seismic zones in the world. In order to understand the mechanisms of great interplate earthquakes and the tectonics, seismic activity and focal mechanism solutions are analyzed in detail in this research. Based on the geometry of slabs and state of stress within the slabs, the Nankai Trough can be divided into two parts, the eastern part (Shikoku and the Kii peninsula) and western part (Kyushu). In the east the seismic slab of the Philippine Sea plate subducts at shallow dip angels between 10°～22° and its leading edge reaches down only to about 60～85km depth beneath Shikoku and the Kii peninsula. While in the west the seismic slab with dip angle of 40° subducts and down to about 160km depth beneath Kyushu. There are two types of seismogenic stress field within the slabs of thePhilippine Sea plate in the eastern and western parts of the Nankai Trough .The type of down dip compression stress field exists in the region beneath the most of Shikoku and the Kii peninsula .On the otherhand ,the type of down dipextensionstressfieldwithintheslabisdominantbeneathKyushu .Theanalysesofgravity ,heat flow ,GPS and other geophysical data suggest that the tectonic features in the eastern part are different from that of the western part.Two types of characteristics of seismotectonics and in traslabstress field in the same trough migh tberel atedto the differences of thes labagesinth eeastern and western parts .
引文
[1] AndoM .Anoutline:forthefutureNankaiearthquake,whatmustbedoneinJapan?ChikyuMonthly,1999,24:6～13
[2] 宇津德治.「地震の事典」.东京:朝仓书店,1996UtsuT .EncyclopediaofEarthquake(inJapanese).Tokyo:AsakuraShotenPublisher,1996
[3] NakamuraM ,WatanabeH ,KonamiT ,etal.CharacteristicactivitiesofsubcrustalearthquakesalongtheouterzoneofsouthwesternJapan.AnnualsofDisas,Prev,Res,Inst.,KyotoUniv.,1997,(40B 1):1～20
[4] IshikawaY .IntroductiontotherevisionofSEIS PC .GeologicalInformation,1986,11:65～74
[5] IshibashiK .Specificationofasoon to occurseismicfaultingintheTokaidistrict,centralJapan,baseduponseismotectonics.MauriceEwingSer.4,1981,297～332
[6] 佐藤良辅.日本の地震断层パラメタ-·ハンドブツク.东京:鹿岛出版会,1995SataR .ParameterHandbookofEarthquakeFaults,Japan(inJapanese).Tokyo:KajimaPress,1995
[7] KikuchiM .EICnewsletter.http: www.eri.u tokyo.ac.jpJhome.html,2000
[8] KodairaS ,TakahashiN ,ParkJ,etal.WesternNankaiTroughseismologeniczone:Resultfromwide angleOceanBottomSeismicsurvey.J .Geophys.Res.,2000,105:5887～5905
[9] KodairaS ,TakahashiN ,ParkJ,etal.Subductedseamountimagedintherupturezoneofthe1946Nankaidoearthquake.Science,2001,289:104～106
[10] XuJ,KonoY .SeismogenicStressFieldandItsTectonicsinandaroundtheNankaiTrough,Japan.AbstractofAGUFallMeeting,1999,137～138
[11] KinoshitaM ,YamanoM .HeatflowdistributionintheNankaiTroughregion,JapanRussiaChinaMonograph.Tokyo:TERRAPUB ,1996.77～86
[12] GeograhicalSurveyInstitute.CrustalDeformationofJapandetectedbyGEONET .http: mekira.gsi.go.jp hendounew.html,1999
[13] KanamoriH .Seismicandaseismicslipalongsubductionzonesandtheirtectonicimplications.MauriceEwingSer.1977,1:162～174
[14] IsacksBL ,MolnarP .Distributionofstressesinthedescendinglithospherefromaglobalsurveyoffocalmechanismsolutionsofmantleearthquakes.Rev.Geophys.SpacePhys.,1971,9:103～174
[15] KimuraS ,OkanoK .CharacteristicsoffocaldepthdistributionofmantelearthquakesinthecentralandwesternpartofShikoku.Zisin(inJapanese),1994,47(2):11～19
[16] ShionoK .SeismicityoftheSWJapanArcSubductionoftheYoungShikokuBasin.ModernGeology,1988,12:449～464
[17] SenoT .RegionalStressFieldsinKyushu:ImplicationstoDeepProcesses.Programandabstractsof1998FallMeeting.theSeismologicalSocietyofJapan,1998,C37
[18] RuffLJ,KanamoriH .Seismicityandthesubductionprocess.Phys.EarthPlanet.Inter.,1980,23:240～252
[19] KagamiH ,ShionoK ,TairaA .SubductingofplateandformationofaccretionaryprisminNankaitrough,FormationofJapanIslands.Tokyo:IwanamiShortenPublisher,1987.139～148
[2] 宇津德治.「地震の事典」.东京:朝仓书店,1996UtsuT .EncyclopediaofEarthquake(inJapanese).Tokyo:AsakuraShotenPublisher,1996
[3] NakamuraM ,WatanabeH ,KonamiT ,etal.CharacteristicactivitiesofsubcrustalearthquakesalongtheouterzoneofsouthwesternJapan.AnnualsofDisas,Prev,Res,Inst.,KyotoUniv.,1997,(40B 1):1～20
[4] IshikawaY .IntroductiontotherevisionofSEIS PC .GeologicalInformation,1986,11:65～74
[5] IshibashiK .Specificationofasoon to occurseismicfaultingintheTokaidistrict,centralJapan,baseduponseismotectonics.MauriceEwingSer.4,1981,297～332
[6] 佐藤良辅.日本の地震断层パラメタ-·ハンドブツク.东京:鹿岛出版会,1995SataR .ParameterHandbookofEarthquakeFaults,Japan(inJapanese).Tokyo:KajimaPress,1995
[7] KikuchiM .EICnewsletter.http: www.eri.u tokyo.ac.jpJhome.html,2000
[8] KodairaS ,TakahashiN ,ParkJ,etal.WesternNankaiTroughseismologeniczone:Resultfromwide angleOceanBottomSeismicsurvey.J .Geophys.Res.,2000,105:5887～5905
[9] KodairaS ,TakahashiN ,ParkJ,etal.Subductedseamountimagedintherupturezoneofthe1946Nankaidoearthquake.Science,2001,289:104～106
[10] XuJ,KonoY .SeismogenicStressFieldandItsTectonicsinandaroundtheNankaiTrough,Japan.AbstractofAGUFallMeeting,1999,137～138
[11] KinoshitaM ,YamanoM .HeatflowdistributionintheNankaiTroughregion,JapanRussiaChinaMonograph.Tokyo:TERRAPUB ,1996.77～86
[12] GeograhicalSurveyInstitute.CrustalDeformationofJapandetectedbyGEONET .http: mekira.gsi.go.jp hendounew.html,1999
[13] KanamoriH .Seismicandaseismicslipalongsubductionzonesandtheirtectonicimplications.MauriceEwingSer.1977,1:162～174
[14] IsacksBL ,MolnarP .Distributionofstressesinthedescendinglithospherefromaglobalsurveyoffocalmechanismsolutionsofmantleearthquakes.Rev.Geophys.SpacePhys.,1971,9:103～174
[15] KimuraS ,OkanoK .CharacteristicsoffocaldepthdistributionofmantelearthquakesinthecentralandwesternpartofShikoku.Zisin(inJapanese),1994,47(2):11～19
[16] ShionoK .SeismicityoftheSWJapanArcSubductionoftheYoungShikokuBasin.ModernGeology,1988,12:449～464
[17] SenoT .RegionalStressFieldsinKyushu:ImplicationstoDeepProcesses.Programandabstractsof1998FallMeeting.theSeismologicalSocietyofJapan,1998,C37
[18] RuffLJ,KanamoriH .Seismicityandthesubductionprocess.Phys.EarthPlanet.Inter.,1980,23:240～252
[19] KagamiH ,ShionoK ,TairaA .SubductingofplateandformationofaccretionaryprisminNankaitrough,FormationofJapanIslands.Tokyo:IwanamiShortenPublisher,1987.139～148
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