全球地壳运动的背景场及其研究进展

THE BACKGROUND FIELD OF GLOBAL CRUSTAL MOTIONS AND ITS STUDYING PROGRESS

全球地壳运动是在全球地壳运动背景场中发生的 ,其背景场的运动参数是表征地壳运动的最基本特征。由于现今板块运动模型ITRF序列均忽略板块边界部分 ,并且板块以NUVEL1A模型来划分 ,由此建立的全球板块运动模型不能作为一个严格的全球地壳运动背景场。利用区域速度场和ITRF2 0 0 0速度场建立一个包括非刚体的板块边界区域和刚体板块的全球地壳运动模型 ,其板块总角动量 |L| =0 .131°/Ma ,即不为零 ,存在整体旋转 ,由此建立无整体旋转 (NNR)模型 。

The global crust is moving in the background field of global crustal motions, whose Euler parameter is a basic character of plate motion. A significant portion of the Earth's surface consists of zones of diffuse deformation, whose interior regions move at distinctly different velocities from that of adjacent plates, and, because of their complexities, have been ignored in previous models, such as ITRF 96VEL,ITRF 97VEL and ITRF 2000VEL We have calculated a new NNR model that incorporates both rigid plate and plate boundary zones with ITRF 2000 velocity field and local GPS field. The total angular momentum of the 22 tectonic plates is 0.131 o/Ma, which shows the ITRF 2000 is not sufficient accordant with the definition of CTRF. The inconsistency will influence the long term maintenance and highly accurate application of ITRF 2000 and long term variation of the Earth Rotation Parameters, so we infer an accurate No Net Rotation model that differences from previous NNR models and consists the diffuse boundary zone, such as the central and southeast Asia, the extending belts of north America plate. At last we remark on the progress of the plate motion model.