利用琼中台重力观测资料检测智利地震所激发的地球自由振荡

Detection of Free Oscillations Following Chile Earthquake By using Gravity Observations at Qiongzhong Station

基于琼中PET重力仪的数字化观测资料,利用功率谱密度估计方法,在没有对重力资料进行任何(固体潮、气压)改正的情况下,准确获取了2010年2月27日智利发生巨大地震激发的0S8～0S29基频球型自由振荡。并与PREM模型理论自由振荡的周期进行对比分析,实测周期与PREM预测振荡周期是相吻合的,除0S10周期的相对误差为0.28%,其余周期误差均小于0.1%。结论对进一步研究地球的内部结构和震源机制具有一定的意义。

This paper accurately obtains 0S8-0S29-pitch spheroidal free oscillation produced by huge earthquake in Chile on February 27, 2010. Digital observation data of Qiongzhong PET gravimeter and method of power spectral density （Earth tide, atmospheric pressure） correction. Co estimation are used, without any gravity data mpared with the period of free oscillations of PREM model, their periods are consistent, and relative errors of periods are less than 0.1% except oSl0 Which is 0.28%. Conclusions are significant for further studies on the internal structure of the earth and focal mechanisms.