全球级三个地震构造系统和大地水准面
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摘要
据全球地震活动和活动构造的综合研究，全球地震构造可归总为３个大系统：（１）环太平洋深俯冲地震构造系（Ｐ系）；（２）以大西洋为代表的大洋中脊裂谷地震构造系（Ａ系）；（３）大陆剪切网络地震构造系（Ｃ系）。这３个系统与大地水准面相对于理想旋转椭球面的畸变之间有重要的动力学联系。用构造变形和地震机制资料对３大系统作对比分析。Ａ系以面状伸展破裂为特征，Ｐ系与大西洋（０°）半球岩石圈相对于太平洋（１８０°）半球岩石圈的反俯冲或逆冲有密切关系。Ａ系总体反映了南半球的膨胀，而Ｃ系代表了北半球的收缩，环南极洋脊和Ｃ系的相互关系可能与径向对流有关。
Based on the comprehensive studies of the global sesmicity and active tectonics, the global seismotectonics is summarized with three great systems:(1)the circum-Pacific seismotectonicsystem of deep subduction(the P system);(2)the Atlantic seismotectonic system of mid-oceanic ridge rifts(the A system );and(3)the continental seismotectonic system of shear nets(the C system).There is important dynamic correlation between the distribution of these three systems on the earth’s surface and the deflection of the geoid relative to the ideal roatating ellipsoid.Comparative analyses are made for the three systems by using the data of tectonic deformation and earthquake mechanism. The A system is characterized by planar extensional fractures. The P system demonstraces obduction and overthrusting of the Atlantic(0°)hemisphere lithosphere to the Pacific(180°)hemisphere lithosphere. The A system representsdilatation of the south hemisphere ,while the C system indicates contraction of the northhemisphere. The relationship between the circum-antarctic oceanic ridge and the C system isprobably assoriated with the longitudinal flow of the mantle.
Based on the comprehensive studies of the global sesmicity and active tectonics, the global seismotectonics is summarized with three great systems:(1)the circum-Pacific seismotectonicsystem of deep subduction(the P system);(2)the Atlantic seismotectonic system of mid-oceanic ridge rifts(the A system );and(3)the continental seismotectonic system of shear nets(the C system).There is important dynamic correlation between the distribution of these three systems on the earth’s surface and the deflection of the geoid relative to the ideal roatating ellipsoid.Comparative analyses are made for the three systems by using the data of tectonic deformation and earthquake mechanism. The A system is characterized by planar extensional fractures. The P system demonstraces obduction and overthrusting of the Atlantic(0°)hemisphere lithosphere to the Pacific(180°)hemisphere lithosphere. The A system representsdilatation of the south hemisphere ,while the C system indicates contraction of the northhemisphere. The relationship between the circum-antarctic oceanic ridge and the C system isprobably assoriated with the longitudinal flow of the mantle.
引文
1傅承义．地球十讲．北京：科学出版社，1976．2MaZongjinetal．Thebasiccharacteristicsofthecontinentalearthquakes．in：ACollectionofPaporsof1stSCSEP，Beijing．Beijing：SeismologicalPress，1982．299－312．3GaposchkinEM（ed．）．SmithsonianstandardEarth（III）SmithsonianAstrophysicalObservatorySpecialRept．Cambridge，Mass．，1973，353．4PollackHNandChapmanDS．Ontheregionalvariationofheatflow．geothermsandlithosphericthickness．Tectonophysics，1977，38：279－296．5MaZongJinandChanQing．GlobalseismotectonicsystemsandtheEarth＇sasymmetry．ScienceinChina（SeriesB），1990．33（1）：121－128．6GrippAEandGordonRG．CurrentplatevelocitiesrelativetothehotspotsincorporatingtheNUVEL－1globalplatemotionmodel．Gepphys．Res．Let．，1990，17：1109－1112．
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