Abstract: From the Earth’s polar motion time series (IERS 08 C04, since 1981), after removal of seasonal variation byband-pass filtering, we acquired Earth’s free Eulerian motion (Chandler wobble) time series. By successive least squareerror fittings on it, we analyzed amplitude and phase variation of Chandler wobble. We attempted to identify anyprecursory behavior of the pole before large earthquakes but only to fail. Unlike Smylie’s conjecture there was noappreciable motion of the Earth’s pole detected at around the each times of recent six largest earthquakes of magnitudeover 8.5. Keywords: Polar Motion, Earthquake Precursor요약: 지구의 극운동 자료(IERS 08 C04, 1981년 이후)로부터 1 년 주기 성분을 제거한 뒤 얻어진 시계열에 대하여 최소제곱법을 적용하여 지구의 자유-오일러 운동(찬들러 워블) 시계열을 얻었으며, 이의 진폭과 위상 등의 변화를 조사하였다. 한편 대지진 발생 전의 전조현상으로서의 극의 움직임을 찾아보았으나 발견하지 못하였다. 스마일리의 추측과는 달리,규모 8.5 이상의 최근 지진 여섯 개의 발생시점 부근에서 극운동의 특별한 징후가 없었다. 주요어: 극운동, 지진전조현상 Introduction The Earth’s spin rotation is quite stable: however, the poleshows ceaseless and complicated movement. The precessionof the Earth, which is caused by luni-solar torque exerted onthe Earth’s equatorial bulge, exists in large amount. In fact, themagnitude of precession (50 arcsec per year) surpasses allother kinds of variations in the Earth’s spin rotation. Wehereby are concerned with the polar motion, which is torque-free motion aside from the forced precession and nutation, andrefers to the slow relative change of the Earth’s rotational polewith respect to the observer on the Earth itself. Chandlerwobble and annual wobble, both of a few hundred milliarcsecradii, are the dominant periodic components of the Earth’spolar motion, and they together show conspicuous beating of6.4 year period (Fig. 1a-b). While annual wobble is a drivenmotion, Chandler wobble can be regarded as authenticoscillating mode of the spinning Earth, and its period is about433 days. Aside from these periodic variations, there existssteady pole drift about 10 centimeters per year along 70W(Fig. 1a-b) due to ‘glacial isostatic adjustment’, which is alsoknown as ‘post glacial rebound.’ It is obvious that seasonalvariations of diverse processes of the Earth should beassociated with the annual periodic components of the polarmotion. Likewise there must be certain energy source to excite