摘要
本文基于GPS、断层形变等规测资料,实现华北地区构造运动有限元数值模拟,研究其现今地壳运动及形变动力学机理.结果表明,鄂尔多斯地块、华南地块、东北亚地块等周边构造块体的相对运动基本决定了华北地区现今表面运动及应力场格局.而另一方面,当考虑区域下部岩石层较快速的"拖动"作用时,表面速度场可以得到更好模拟,并同时形成共轭分布的剪应力梯度带.可见太平洋板块的俯冲作用、印-欧板块的碰撞挤压作用等可能造成岩石层深部、浅部运动差异,从而对研究区现今地壳运动产生深刻影响.此外,地形重力作用、断层分布及区域流变结构非均匀性也对现今地壳运动具有一定影响作用,但处于次要地位.
Using GPS and across-fault deformation survey data of this region, the tectonic movement of North China Region is simulated by finite element method aimed to study its present-day crust movement and deformation dynamics. The results show that the surface movement and stress field are largely determined by the relative movement between the surrounding tectonic blocks such as Ordos block, South China block, Northeast China sub-block, et al. On the other hand, the inhomogeneous distribution feature of the surface speed field can be simulated better when considering the differential horizontal motion and bottom dragging of lithosphere which result in the conjugate shear stress gradient zones in this area at the same time. This implies that the Pacific plate subduction or the India-Eurasia collision may induce convection beneath continental lithosphere, causing the lower part moving faster than the upper part. Such differential movement fashion exerts very large influence on the regional dynamic process. The results also show that topography gravity, faults distribution and lateral inhomogeneity of the rheology structure have certain effect on the dynamic process as well. But those factors play the second role.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第6期1418-1427,共10页
Chinese Journal of Geophysics
基金
地震动力学国家重点实验室开放基金(LED2008B03)
地震科学基金(A08013)资助