日本冲绳海槽和欧亚板块附加体二维构造应力场的有限元模拟及其构造意义初探

Finite Element Simulation and Tectonic Significance for 2D Structural Stress Field of the Okinawa Trough and the Accretionary Prism of the Eurasian Plate

应用有限元方法模拟了日本冲绳海槽和欧亚大陆板块附加体二维构造应力场,并根据库仑-摩尔准则讨论了有限元模型中断裂构造发育与变形,定量化地研究了大陆岩石圈的扩张作用以及菲律宾海板块的俯冲作用对大陆板块边缘构造应力场及其变形作用的影响。数学模拟的结果表明,大陆地壳底部的扩张作用使得冲绳海槽内发育正断层,从而导致冲绳海槽这一弧后盆地的形成。菲律宾海板块的俯冲作用引起欧亚板块附加体中形成逆掩断层。有限单元模拟实验结果与研究区地震震源机制的研究结果是一致的。

The structural stress field of the Okinawa Trough and the accretionary prism of the Eurasian Plate is simulated by means of the finite element method. The fault development of the finite element models is determined according to the Mohr -Coulomb criterion. The influence of the extensional process of the continental lithosphere and the convergence process of the Philippine Sea Plate to the stress field and fault development within the continental plate verge is studied quantificationally. The spreading diaplacement along the crustal bottom results in normal faults in the trough,and finally leads to the formation of the Okinawa Trough. The subduction of the PHS plate causes the thrust development within the accretionary prism of the Eurasia plate. The experiment is in agreement with the earthquake focal mechanism in the study area.