1982年日本茨城地震序列表现出的局部板块俯冲动态过程

DYNAMIC SUBDUCTION PROCESS OF LOCAL PLATE REVEALED BY IBARAKI EARTHQUAKE SEQUENCE OF 1982 IN JAPAN

板块构造的运动和动力学是地学研究的前沿课题 .板块边缘强震是板块运动的直接结果 .分析 1 982年日本茨城地震序列发现 ,震源断层面存在分阶段沿走向扩展、倾向调整的特殊图象 .结合震源机制的走向、倾向以及滑动方向等资料 ,确认属于日本海沟下方的俯冲带逆冲地震 .文中讨论了地震序列过程的成因 ,认为采用介于年尺度的空间大地测量结果与秒尺度的强震矩张量分析之间的地震序列时空分布研究 ,表明太平洋板块向欧亚板块局部下方俯冲的动态过程 .根据地震平均错距和板块运动速度 。

WT5BZ]The kinematics and dynamics of plate tectonics are the frontal subjects in geoscience, and the strong earthquake occurred along the plate boundary results directly from plate movement. By analyzing Ibaraki earthquake sequence, it has been found that the focal fault plane has a special image of grading expansion and adjustment along the directions of strike and dip, respectively. With the consideration of strike, dip and slip directions of focal mechanism, we have confirmed that Ibaraki earthquake is a thrust fault earthquake occurred under the Japan Trench. The cause of the earthquake sequence is discussed in the paper. The study on the temporal spatial distribution of the earthquake sequence with a time scale which is between the year scale spatial geodetic data and the second scale moment tenser of the strong earthquake has indicated the dynamic process of Pacific plate subduction under the Eurasia plate. According to the average slip distance of earthquake and the velocity of plate movement, it is predicted that a strong earthquake might occur in recent years.