华北地区活动地块运动时空变化特征

THE TEMPORAL AND SPATIAL VARIATION CHARACTERISTICS OF CRUSTAL DEFORMATION OF ACTIVE TECTONIC BLOCKS IN NORTH CHINA

利用华北地区 1992年、1995年、1996年和 1999年 4期GPS资料研究分析了华北地区活动地块运动的时空变化特征。基于刚性块体和GPS稳定点组概念 ,分别用 1992年、1995年、1996年所得到的GPS速度场和 1996年与 1999年所得到的GPS速度场求出了华北地区活动地块的欧拉运动参数 ,反演计算各GPS观测点的背景运动速度 ,分析了华北地区活动地块边界带的运动及块体内部变形的规律。采用双三次贝塞尔样条函数模型拟合华北地区应变率场 。

Global Positioning System (GPS) observations from four measurement campaigns from 1992 to 1999 are used in a study of the temporal and spatial variation characteristics of crustal deformation of active tectonic blocks in North China. The Euler vectors for these active blocks are determined on the basis of GPS velocities of group relative stable points in 1992,1995,1996 and in 1996,1999 respectively. We study the relative motion in the boundaries between blocks and the deformation field in intra blocks. We also invert the strain rate fields for these active blocks by bi cubic spline model based on the GPS velocity field. The results show that the deformation rates in these intra blocks are different from that in boundary zones, and these deformation rates are also different in different periods; the deformational field is generally characterized by extension in intra block of North China area.