数字化水位仪观测的苏门答腊大地震激发的地球球型自由振荡

Earth's Free Spheroidal Oscillations of the Great Sumatra Earthquake Observed with Digital Water Level Meter

利用LN-3型数字化水位仪的观测资料,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,获得了2004年12月26日苏门答腊大地震激发的0S3～0S30基频球型自由振荡,并检测到2S1、1S2、1S3、2S5和2S6等5个谐频球型振荡,同时记录到一些明显的振型的谱线分裂现象。用水位观测资料提取了0S3、0S4和2S1等3个振型的谱线分裂周期,虽然3个振型均只得到2个单峰,但地球自由振荡谱线分裂现象的检测为研究地球的深内部结构提供了新的、不同类型的观测资料。研究表明,用数字化水位仪的观测资料可以提取到苏门答腊大地震激发的地球球型振荡,为地球自由振荡的研究提供了一种新的观测手段。

Firstly, by means of LN-3 digital water level meter data and power spectral density estimation method, in the absence of information to deal with the tidal case, we gained the 0S3 - 0S30 free-oscillation frequency of Su- matra earthquake on 26 December 2004, and also detected 2S1, 1S2, 1S3, 2S5, 2S6 5 months spherical har- monic oscillation. Recorded a number of significant modes of the line splitting, the first time the water level data extracted 0S3, 0S4, 2S1 three modes of splitting of the line cycle, although the three modes are only two sin- gle-peak, but the Earth＇s free oscillation spectrum of split testing to study the phenomenon of the deep internal structure of the Earth provides a new method. Studies have shown that the water level instrument digital data can be extracted is true to the Sumatra earthquake excited oscillation of the Earth＇s sphere, which for the Study of Earth＇s free oscillations and provides a new method of observing instruments. The use of digital water level data of the Earth＇s free oscillations research issue has a bright future.