利用重力卫星监测尼泊尔Ms8.1地震前后重力变化

利用重力恢复与气候实验(Gravity Recovery and Climate Explorer, GRACE)卫星时变重力场数据获取尼泊尔地震震源区周缘震前震后重力变化。根据地震发生前后震源区及周边重力变化的时空分布特征,探求地震孕震机制及地表物质迁移情况,详细分析了震前5年和震后2年年际变化和季度变化,并提取了5个重力变化显著的特征点和震中点进行时间序列分析。结果表明：正负重力变化信号以震中为中心呈现出明显的出四象限分布特征,同时地震通常发生在重力变化的零值线处。通过对5个特征点及震中点重力变化时间序列的分析发现：每个点在震后1-2个月内均出现了较大的跃迁现象,其振幅有所不同,这可能是震后地球内部物质均衡调整造成的。

The Gravity Changes of Before and After the Nepal Ms8.1 Earthquake from Gravity satellite

The gravity changes of before and after Nepal earthquake around the epicentre area were obtained by using the time-variable gravity field data of Gravity Recovery and Climate Explorer(GRACE). And according to the spatial and temporal distribution characteristics of gravity changes around the earthquake source areas before and after the earthquake, the mechanism of earthquake preparation and surface mass changes were investigated. The internanual and quarterly gravity changes in five years before and two years after the earthquake were analyzed in detail. The five points with significant gravity changes have time series analysis. The results show that the positive and negative gravity changes signals has obvious distribution characteristics with the four quadrants centered on the epicenter, and the earthquake usually occurs at the zero value line. By the analysis of gravity changes time series of five characteristic points and epicenter, each point has a large transition phenomenon within 1-2 months after the earthquake with different amplitude, caused by the material balance adjustment in the Earth after earthquake.