低纬度环球带和环太平洋带大地震的幕式活动分析
|
摘要
统计分析低纬度环球带(E带)和环太平洋带(P带)在1900～2008年问M_W≥7.5地震的时空分布,进一步证实两者本身和两者之间都存在15～18年的幕式交替活动.将这两大地震带分别划分为5个地震区,发现这些分区地震幕式活动互不相同,但E带各区奇数幕与偶数幕年均地震数之比OER均大于1.58,而P带各区的OER均小于0.93,显示出前者以奇数幕活跃为特征,后者以偶数幕活跃为特征.对这些地震区的组合分析进一步证明,从幕式活动的共性看,中太平洋地区宜纳入E带.本文推论:低纬度环球带是另一条全球尺度地震带;大地震幕式活动的成因应归因于板块运动有几十年时间尺度的非平稳幕式运动;未来5～8年,E带的大地震还会比P带多.
We have analyzed the temporal-spatial distributions of M_W≥7. 5 earthquakes for 1900～2008 in the low-latitude circum-earth zone (E zone) and circum-Pacific zone (P zone). The result shows that there are alternating episodes of events in each zone and between the two zones. We divide these two zones into five subregions, respectively, and find that these subregions have distinct episodes of great quakes. In the E zone, the ratio of earthquake number of the odd episode to that of the even episode (OER) for each subregion is greater than 1. 58, while that in the P zone is all less than 0, 93. It means that the E zone is featured by active odd episodes and the P zone characterized by active even episodes. Combined analysis of these subregions indicates that the middle section of the circum-Pacific seismic zone can be placed into the E zone in view of the episode feature. This study infers that the low-latitude circum-earth zone is another seismic belt of global scale. The episodes of great earthquakes are likely attributed to unstable episodes of plate motions on a scale of several tens years. It is estimated that the E zone will suffer more great earthquakes than the P zone in future 5～8 years.
We have analyzed the temporal-spatial distributions of M_W≥7. 5 earthquakes for 1900～2008 in the low-latitude circum-earth zone (E zone) and circum-Pacific zone (P zone). The result shows that there are alternating episodes of events in each zone and between the two zones. We divide these two zones into five subregions, respectively, and find that these subregions have distinct episodes of great quakes. In the E zone, the ratio of earthquake number of the odd episode to that of the even episode (OER) for each subregion is greater than 1. 58, while that in the P zone is all less than 0, 93. It means that the E zone is featured by active odd episodes and the P zone characterized by active even episodes. Combined analysis of these subregions indicates that the middle section of the circum-Pacific seismic zone can be placed into the E zone in view of the episode feature. This study infers that the low-latitude circum-earth zone is another seismic belt of global scale. The episodes of great earthquakes are likely attributed to unstable episodes of plate motions on a scale of several tens years. It is estimated that the E zone will suffer more great earthquakes than the P zone in future 5～8 years.
引文
[1] Mogi K.Active periods in the world's chief seismic belts.Tectonophysics,1974,22:265～282
[2] Fedotov S A,Sobolev G A,Boldyrev S A,et al.Long-and short-time earthquake prediction in Kamchatka.Tectonophysics,1979,37:(2) :305～321
[3] Kilston S,Knopoff L.Lunar solar periodicities of large earthquake in southern California.Nature,1983,304(5921) :21～25
[4] Ma Z,Fu Z,Zhang Y,et al.Earthquake Prediction,Nine Major Earthquake in China(1966～1976) .Beijing and Berlin:Seismological Press and Springer-Verlag,1989． 201～310
[5] Ma Z,Jiang M.Strong earthquake period and episodes in China.Earthquake Research in China,1987,1(4) :505～510
[6] 马宗晋,杜品仁,任金卫等.低纬度环球剪切带及其与环太平洋带大地震的幕式活动.中国科学(D辑),2006,36(4) :326～331 Ma Z J,Du P R,Ren J W,et al.A circum-earth shear zone at low-latitudes and episodic large earthquakes in it and the circum-Pacific seismic zone.Science in China Series D,2006,49(9) :897～303
[7] Kanamori H.The energy release in great earthquakes.Jour.Geophys.Res.,1977,82:2982～2983
[8] Pacheco J F,Sykes L R.Seismic moment catalog of large shallow earthquakes,1900 to 1989． Bull.Seism.Soc.Am.,1992,82(3) :1306～1349
[9] Pollitz F F.Episodic North America and Pacific plate motions.Tectonics,1987,7(4) :711～726
[10] Royden L H,Burchfiel B C,van der Hilst R D.The Geological Evolution of the Tibetan Plateau.Science,2008,321(5892) :1054～1058
[2] Fedotov S A,Sobolev G A,Boldyrev S A,et al.Long-and short-time earthquake prediction in Kamchatka.Tectonophysics,1979,37:(2) :305～321
[3] Kilston S,Knopoff L.Lunar solar periodicities of large earthquake in southern California.Nature,1983,304(5921) :21～25
[4] Ma Z,Fu Z,Zhang Y,et al.Earthquake Prediction,Nine Major Earthquake in China(1966～1976) .Beijing and Berlin:Seismological Press and Springer-Verlag,1989． 201～310
[5] Ma Z,Jiang M.Strong earthquake period and episodes in China.Earthquake Research in China,1987,1(4) :505～510
[6] 马宗晋,杜品仁,任金卫等.低纬度环球剪切带及其与环太平洋带大地震的幕式活动.中国科学(D辑),2006,36(4) :326～331 Ma Z J,Du P R,Ren J W,et al.A circum-earth shear zone at low-latitudes and episodic large earthquakes in it and the circum-Pacific seismic zone.Science in China Series D,2006,49(9) :897～303
[7] Kanamori H.The energy release in great earthquakes.Jour.Geophys.Res.,1977,82:2982～2983
[8] Pacheco J F,Sykes L R.Seismic moment catalog of large shallow earthquakes,1900 to 1989． Bull.Seism.Soc.Am.,1992,82(3) :1306～1349
[9] Pollitz F F.Episodic North America and Pacific plate motions.Tectonics,1987,7(4) :711～726
[10] Royden L H,Burchfiel B C,van der Hilst R D.The Geological Evolution of the Tibetan Plateau.Science,2008,321(5892) :1054～1058
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心