北京地震台gPhone重力仪对尼泊尔M8.1强震所激发地球自由振荡的探测

利用北京地震台gPhone重力仪观测资料，采用功率谱密度估计方法，检测2015-04-25尼泊尔M8.1地震激发的0S0～0S60之间的地球球型自由振荡，并与地球初步参考模型(PREM)的理论自由振荡周期进行对比。结果表明，0S2～0S56基频自由振荡的实测周期值与PREM 模型的理论值基本一致，证实了gPhone重力仪能有效检测出地球自由振荡信号。

Detecting the Earth Free Oscillations Excited by the Nepal M8.1 Earthquake by Using gPhone Gravimeter at Beijing Seismic Station

Using the gPhone gravimeter digital observation data recorded at Beijing seismic station, we detect spherical modes of 0S0-0S60 of the earth free oscillation stimulated by the M8.1 earthquake that occurred on April 25,2015 in Nepal. In our process, the method of power spectral density(PSD) is used．In comparison with the periods of free oscillations of the PREM model, the observed periods coincide well with the theoretical values.The results verify that gPhone gravimeter can detect the earth’s free oscillation.