抄録
The Chandler wobble can be considered to be a succession of free damped nutations of the earth excited by some unknown causes. Bearing this in mind, we apply a linear filtering theory of multichannel time series to the analysis of polar motions. Designing a 2-channel prediction error operator, we calculate the prediction error time series y1(t) and y2(t) corresponding to the x1(t) and x2(t) terms in polar motions. The occurrence of large earthquakes is well correlative with abrupt changes of the prediction error. To clarify this relation, prediction error changes D(t)=[{y1(t)-y1(t-1)}2+{y2(t)-y2(t-1)2}]1/2 are calculated and shown in Fig. 3. It is suggested that Earthquakes excite the Chandler wobble. In order to confirm this, we must calculate the excitation function from the occurrence mechanism of each earthquake. It will be the subject for a future study.
