华南地区时变重力场建模实验和异常分析

陆面时变重力测量是监测地壳内部密度变化和物质运移的重要手段.为确定华南时变重力观测网络的场源监测能力和重力场变化特征,本文采用球面六面体单元构建重力场模型,开展重力场建模实验,对比不同建模方法与噪声条件下的局部重力场恢复效果,并对2015-2017年来5期实测流动重力观测数据进行计算和分析.结果表明,最小二乘配置方法的...

Modeling Experiment and Anomaly Analysis of Time-varying Gravity Field in South China

The terrestrial time-varying gravity measurement has been used for monitoring the density changes and tectonic movements associated with earthquakes.In order to determine the field source monitoring capability and gravity field characteristics of South China region,a gravity model was constructed based on spherical tesseroid units.To assess the quality of recovered gravity field by different modeling methods,gravity field source modeling experiments and noise tests were carried out.The variation of observed gravitational field was calculated and recovered from 2015 to 2017 using least square collocation method.Overall,it can be concluded that the least squares configuration method performs better gravity field recovering effect and anti-noise ability.The spatial resolution capability of the South China Gravity Survey Network is about 55 km,and the equivalent observable signal is about 30×10^-8 m/s^2.The accumulative temporal and spatial characteristics of the gravity field between 2015 and 2017 is actually consistent.Negative gravity anomalies continue to increase and accumulate at different time scales,and there are periodic changes in positive and negative fluctuations locally.The results have important value for evaluating the quality of terrestrial gravity data,guiding the transformation and upgrading of gravity observation network,while advancing our standing of the interpretation of gravity field changes,analyzing strong earthquakes and geophysical field changes.