利用伸缩仪观测资料检测日本9.0级大地震激发的地球自由振荡

Detection of The Earth's Free Oscillation Excited by the Japan M9.0 Earthquake by Using Observation Data of Extensometer

利用河南信阳台和河北张家口台伸缩仪的数字化观测资料,采用功率谱密度估计方法,在没有对资料进行去固体潮处理的情况下,准确获得了2011年3月11日日本9.0级大地震激发的0S4～0S39基频球型自由振荡,并与地球初步参考模型(PREM)的理论自由振荡频率进行了对比,发现实测振荡频率与PREM预测的振荡频率基本符合。

Based on the digital observation data of extensmneter of Xinyang, Henan, Seismologieal Station and Zhangjiakou, 14ebei, Seismological Station, the spheroidal free oscillation of 0 S4 N 0S39 basic frequency excited by the MAR. 11,2011 Japan earthquake of M9.0 is accurately gained by using power spectral density estimation, in the condition without eliminating solid tide of the data. The resuh is contrasted with the theoretical free oscillation frequency of PREM, found that the measured oscillation frequency mainly coincides with the oscillation frequency predicted by PREM .