基于Monte Carlo方法的由GPS观测计算地应变率的误差分析  

Error analysis of strain rates from GPS measurements based on Monte Carlo method

作　　者：朱守彪[1] 石耀霖[2] 

机构地区：[1]中国地震局地壳应力研究所,北京100085 [2]中国科学院研究生院计算地球动力学实验室,北京100049

出　　处：《地球物理学报》2007年第3期806-811,共6页Chinese Journal of Geophysics

基　　金：国家自然科学基金(40374038);地震科学联合基金(103016);北京市自然科学基金(8053020)资助

摘　　要：在利用GPS观测计算地应变率中,应变率的误差分布在地球动力学研究中非常重要.为解决这一问题,文中提出基于MonteCarlo技术,利用GPS观测的速度计算地应变率进行误差分析的方法;以青藏高原地区为例,利用带有误差的GPS观测数据进行了大量、独立的应变率重复计算,然后运用统计方法给出了应变率分量及其误差的分布.结果显示青藏高原的喜马拉雅及中东部地区地应变率的东西向、南北向及剪应变率分量的误差相对较大,但整个青藏高原及附近地区应变率结果稳定可靠;研究结果进一步表明,由GPS观测计算应变率的误差主要决定于GPS观测速度的误差,在变形小的区域(如中国东部地区),目前GPS的观测精度还不能完全满足地应变率计算的要求.The strain rate in Chinese continent has been computed from GPS data by many researchers, resulting in quite different estimates of the strain rates. Moreover, until now, researchers have not presented the errors of the strain rate yet, which are very important in geodynamics. In order to solve this problem, we propose a method to calculate the error of strain rate computed from GPS vectors with measurement errors on the base of Monte Carlo technique. Taken the Qinghai-Tibet plateau as an example, independent computation of strain rate is repeated for large numbers of times, and the components of strain rates, as well as the errors, are obtained by statistical theory. The result shows that the errors of strain rates in NS, EW directions and shear components are larger in Himalayas and in the middle and the east of the plateau than those in other places. In general, the strain rate in whole Qinghai-Tibet plateau is accurate and stable. Also the result suggests that the errors of the strain rates computed from GPS measurements are mainly originated from the errors of GPS data. The accuracy of GPS survey does not meet the requirements for precisely computing the strain rates in the region of small deformation, for example in east China.

关 键 词：应变率 误差分析 MONTE CARLO方法 GPS观测 青藏高原 

分 类 号：P541[天文地球—构造地质学]