利用中国钻孔应变台网(20多个台站)TJ式钻孔体应变仪的观测资料,提取2004年12月26日印尼苏门答腊地震激发的地球球型振荡。通过统计分析,识别了众多振型,计算了0S9~0S16等振型的品质因子并与PREM模型进行了比较,结果十分相近。绘制了16个台站记录的球型振荡0S3-0S25的振幅谱和相位谱,结果显示低频、中频基频球型振荡的振幅总体趋势上要比高频基频球型振荡的振幅大,但是各台站频谱皆不相同。
On the basis of the observations by TJ borehole dilatometer at over twenty stations of China Borehole Dilatometer Network, the earth' s spheroidal oscillations excited by the 26 December 2004 Sumatera earthquake can be extracted. The statistic analyses of these data are done and many vibration modes are identified. The Q value for 0S9 -0S16 modes is computed and compared with that of PREM model, and it is found that the results approach to each other. The amplitude spectrum and phase spectrum of the 0S3 - 0S25 spheroidal oscillations recorded at sixteen stations are drawn. The results show that the amplitudes of the low and mid-frequency spheroidal oscillations are bigger than those of the high-frequency spheroidal oscillations, however, all of the spectra at the stations are different from each other.