Abstract:

Based on the analysis of the orientational migration of 184 earthquakes of M_s≥7³/4 orgreater along 6 seismic zones which are of a global scale,we found the phenomenom of global ori-entational migration of earthquakes。Generally the migrations take place from the western to theeastern,with their velocities ranging from 700km/a to 140km/a.The global orientational migration of major earthquakes can be interpreted by various geedynamic processes such as the P waveshaped oscillation propagation of the movement of the upper mantle material from the western tothe eastern caused by intermittent extensional break along the Alantic ridge.It can also be interpreted by eastward propagation of strain wave caused by the sequent SW-NE compression on theEurasia seismic zone from the Africa,Arabia,and India plates；and the NW and NE orientatedoblique compression of the oceanic plate on the both sides of the Pacific ridge.

Key words: Global seismic zones, Orientational migration, Geodynamic interpretation

摘要：

对全球尺度的6条大地震带内1900～1990年中184次M_s≥7³/4级地震进行了沿地震带方向定向迁移的分析,获得了全球统一的地震定向迁移规律,总体是由西向东,迁移速度由700km/a变为150km/a,此现象可以作多种暂态地球动力作用过程的推论,如以大西洋脊间歇式张裂引起上地幔软流物质自西向东运动,呈现纵波式的振荡传播；也可解释为非洲板块、阿拉伯板块和印度板块自西南向东北对欧亚地震带依次的推压引起向东的应变波的传播；太平洋脊两侧洋底板块向西北和东北两侧的斜向推压,可能是造成两侧地震带地震向北迁移的触发源。

关键词: 全球地震带, 定向迁移, 地球动力学