利用GPS TEC探测2015年尼泊尔地震激发的电离层扰动

Ionospheric Disturbances Triggered by 2015 Nepal Earthquake Detected by GPS TEC

利用尼泊尔周边区域6个IGS GPS跟踪站数据,对2015-04-25尼泊尔地震激发的电离层扰动进行分析。结果表明,地震发生后,尼泊尔上空电离层总电子含量(total electron content,TEC)存在不同频率的电离层扰动,扰动中心频率约为3mHz和4mHz。前者发生在震中附近1 000km左右的范围,后者范围达2 000km,推断其分别为地震破裂产生的声重波信号以及瑞利波向上传播到电离层所激发的异常扰动信号。联合两个频率扰动信号,根据观测的扰动位置以及经验扰动速度反演震中位置,结果与实际情况符合较好。

This paper analyses the ionospheric disturbances triggered by the 25 April 2015Nepal earthquake,using data from 6IGS GPS stations in the Nepal area.The results show that there are ionosphericdisturbances with different frequencies(3 mHz and 4 mHz)above the Nepal area after the earthquake.We deduce that the disturbances with a frequency of 3mHz within 1 000 km are generated by AGW(acoustic gravity wave)produced by vertical motions of the earth's surface,and the disturbances with a frequency of 4mHz,which can reach over 2 000 km,are caused by the Raleigh wave's upward propagation.Furthermore,we invert the epicenter in the light of the observed disturbance location and empirical disturbance velocities,combining the two kinds of disturbance signals to validate our results.The inverted epicenter accords well with the real position.