拉萨台重力时间变化特征及其局部动力学意义

项目名称： 拉萨台重力时间变化特征及其局部动力学意义

项目编号： No.40874038

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 建筑科学

项目作者： 徐建桥

作者单位： 中国科学院测量与地球物理研究所

项目金额： 48万元

中文摘要： 局部地壳垂直运动是全球地球动力学计划非常关注的重要研究课题，青藏高原现今隆升速率及其力学机制是大陆动力学研究的热点问题。采用国际标准分析软件对武汉和拉萨台超导重力仪（SG）和GPS观测资料进行统一的分析处理，精密确定地球潮汐参数，结合最新的重力潮汐理论模型和全球实测模型，研究拉萨重力潮汐和非潮汐变化特征，初步建立拉萨重力潮汐基准。结合数值模拟和其他观测技术的研究成果，研究大气、海洋和陆地水等环境负荷以及内部膨胀源、地震位错等局部地壳运动对拉萨台SG和GPS观测的影响特征，并从观测中剔除。以已有的高精度水准和重力梯度测量结果为约束，以FG5绝对重力仪定期对比观测确定SG的格值和漂移模型，结合GPS并址连续观测，精密确定青藏高原的现今隆升速率以及隆升过程中伴随的物质运动导致的重力变化。结合已有的区域地壳均衡（或岩石圈热均衡）、构造应力场、大陆碰撞理论模拟等研究成果，探讨青藏高原隆升的力学机制。

中文关键词： 超导重力仪；GPS；重力潮汐基准；青藏高原；隆升速率

英文摘要： Study on local vertical crustal movement and environment changes is a focused topic in the Global Geodynamics Projects. The data, recorded with the superconducting gravimeters (SG) and the GPS at Wuhan and Lasa, will be comprehensively analyzed using the international standard software packages. In consideration of the recent theoretical and experimental models for gravity tides, the characteristics of tidal and non-tidal gravity changes will be investigated and a primary reference for gravity tides will be developed at Lasa. The nature of the loading effects from local environment fluctuations, such as atmospheric pressure, ocean tides, land water and so on, in Tibetan Plateau will be revealed by means of the numerical simulation and the other measurement techniques. Comparison measurements between the SG and a FG5 will be periodically performed in order to scale accurately the SG and to stabilize the long-term behavior of the SG at Lasa. On constraint of the high-precision level and gravity gradient measurements, the present uplifting rate of Tibetan Plateau and the related gravity changes induced by the local mass adjustment in uplifting will be accurately evaluated by combining the co-site continuous measurements with the SG and GPS at Lasa while removing the effects of environment perturbations and of some local short-wave crustal movement excited by internal dilatation, earthquake dislocation and so on. The geodynamic mechanics of Tibetan Plateau uplifting will be discussed in consideration of the recent studies on isostatic adjustment of the local crust, tectonic stress field, theoretical simulations of the continental collisions and so on. The researches will provide some necessary theoretical basis and valid investigation methods for performance of the 'Monitoring Network of the Tectonic Environment in Chinese Mainland'.

英文关键词： Superconducting Gravimeter; GPS; Reference for Gravity Tides; Tibetan Plateau; Uplifting Rate