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Title:: Non-tectonic Gravity Effect of Absolute Gravity Observation Stations in Southern Margin of Qinghai-Tibetan Plateau

Author(s):: ZHU Chuandong; LIU Jinzhao; ZHAN Wei; CHEN Zhaohui; LI Jingwei; (The First Monitoring and Application Center,China Earthquake Administration,Tianjin 300180,China)

Keywords:: southern margin of Qinghai-Tibet Plateau; absolute gravity; non-tectonic gravity effect

摘要:: 基于2002—2017年的ECMWF Interim三维大气再分析资料、GRACE时变重力场模型和GPS数据,分析了青藏高原南缘的拉萨、日喀则、仲巴、噶尔4个绝对重力测站的非构造重力效应。结果表明:ECMWF Interim大气负荷重力效应主要表现为季节性变化特征,最大周年振幅可达到1.4 μGal; GRACE陆地水负荷重力效应和GPS地壳垂直位移引起的重力效应均存在较为明显的季节性及长期趋势变化特征,二者的最大周年振幅和长期趋势分别达到2.6 μGal,-0.6 μGal/a和1.8 μGal,-0.3 μGal/a; GRACE与GPS的比较分析结果表明青藏高原南缘的非构造重力效应会受到局部流体质量负荷的显著影响。

Abstract:: Based on three-dimensional ECMWF interim reanalysis data,GRACE time variable gravity model and GPS data from 2002 to 2017,we analyzed the nontectonic gravity effects of absolute gravity observation stations in southern margin of Qinghai-Tibetan Plateau.The results show that the ECMWF Interim atmospheric gravity effect mainly presents seasonal characteristics.Its maximum annual amplitude is 1.4 μGal.The GRACE hydrological gravity effect and gravity effect caused by the vertical crustal deformation from GPS show obvious seasonal and long-term trend characteristics.The maximum annual amplitude and long-term trend can reach 2.6 μGal and -0.6 μGal/a,1.8 μGal and 0.3 μGal/a,respectively.The comparative analysis of GRACE and GPS show that the nontectonic gravity effects in southern margin of Qinghai-Tibetan Plateau can be significantly affected by the local fluid mass load.