지각판의 움직임은 오일러 극(Euler pole)을 중심으로 하는 회전운동으로 나타낼 수 있다. 우리는 먼저 지역적 지각판의 속도자료로부터 해당 판운동의 오일러 벡터를 근사적으로 결정하는 알고리즘을 다음과 같이 개발하였다; 1) 관측된 판속도자료로부터 평균 가상 오일러 극을 먼저 구하고, 2) 평균가상극과 관측지역의 중심을 통과하는 대원 위의 점들을 각각 극으로 설정하여, 3) 얻어지는 각 임시적 가상 모델의 판운동속도와 관측속도와의 차이의 제곱들의 합을 반복하여 구한 다음, 그 값이 최소가 되도록 보간법(interpolation)으로써 오일러 벡터를 결정함. 그런데 최근 우리는 이 와 근본적 개념은 같으나(최소제곱법), 제곱오차의 합의 편미분계수가 0이 되는 조건으로부터 곧바로 오일러 벡터를 결 정하는 알고리즘을 추가적으로 개발하였으며, 이 개선된 방법으로 판운동의 오일러 벡터를 보다 더 정확하게 산출하게 되었다. 한편 이 두 가지 방법을 최근 수년간의 한반도의 GPS 지각속도자료에 각각 적용하여 한반도 지각판의 오일러 벡터를 구하였으며, 얻어진 두 결과를 비교하였다.

대륙이동설로부터 시작되었고 이후 고지자기 및 해저퇴적물 등의 증거들에 의한 해저확장설을 통하여 정립된 판 구조론은, 지각의 운동을 몇 개의 강체 판들이 비록 느리지만 수억 년 이상의 긴 시간 동안 꾸준히 일어나는 움직임으로 서 설명하였다. 초기에는 지각판의 속도를 주로 수백만 년 동안의 고지자기 역전의 잔류 기록에 의거하여 판들 간의 상 대적 운동으로 추산하였는데, 1980년대 이후에는 우주측지 기법들을 이용하여 현재 시점의 판운동을 직접적으로 조사할 수 있게 되었고, 일부 지역에서 판의 변형이 일어나는 것도 확인하게 되었다. 본 해설에서는 (1) 초기의 상대적인 판운동 을 나타내는 모델들을 돌아보고, (2) 무회전 좌표계의 이론과 절대판운동 모델들을 요약-기술하며, (3) 판내부의 변형을 포함하는 최근의 모델을 소개하는 한편, (4) 국제 지구 기준계에 채택된 판운동 모델을 간략히 기술하였고, 끝으로 (5) 근 래에 보고된 남미, 남극, 유럽 등 몇 지역과 (6) 한반도 및 동북아의 지각판 움직임 연구를 각각 소개하였다.

Theory of Earth’s free oscillation is revisited. Firstly, we summarized the underlying formulations, such as the equation of motion and its conversion into numerically integrable form and then explained computational procedures including the treatment of inner core-outer core boundary and core-mantle boundary, while the latter information has not been explicitly given in most publications. Secondly, we re-calculated the periods of Earth’s free oscillation modes (period >200 s) for PREM model. In doing so we acquired the values of modes missing in Dziewonski and Anderson (1981). As a case observation, one seismogram after 2011 Tohoku earthquake recorded at Daejeon, Korea (KIGAM seismic station) was briefly analyzed to identify free oscillation mode excitations on its spectra. The material in this article will be most clear guide for those on calculating the Earth’s free oscillation mode.

We present our estimate of pole shift caused by the recent 31 largest earthquakes of magnitude over 8.0. After reviewing theory of perturbation in the Earth’s rotation, each co-seismic as well as post-seismic pole shifts by the earthquakes are acquired and illustrated. A total co-seismic excitation due to these earthquakes is (x1, x2)=(−3.35, 5.89) milliarcsec, which increased about twice the initial estimation when the post-seismic deformation is considered. The single largest co-seismic excitation by 2011 Japan earthquake was (x1, x2)=(−2.06, 2.36) milliarcsec, which corresponds to 9.7 cm pole shift on the surface of the Earth.

In this study, I calculate the past and future dynamical states of the Earth-Moon system by using modified Lambeck’s formulae. I find that the ocean tidal effect must have been smaller in the past compared to its present amount. Even though the Moon is already in the spin-orbit synchronous rotational state, my calculation suggest that it will not be in geostationary rotational state in the next billion years or so. This is due to the associated Earth’s obliquity increase and slow retardation of Earth’s spin and lunar orbital angular velocities. I also attempt to calculate the precessional period of the Earth in the future. To avoid uncertainties in the time scale, the future state is described by using the Earth-Moon distance ratio as independent parameter. Effects due to solar tidal dissipation are included in all calculations.

Being a torque free motion of the rotating Earth, Chandler wobble is the major component in the Earth’s polar motion with amplitude about 0.05-0.2 arcsec and period about 430-435 days. Free core nutation, also called nearly diurnal free wobble, exists due to the elliptical core-mantle boundary in the Earth and takes almost the whole part of un-modelled variation of the Earth’s pole in the celestial sphere beside precession and nutation. We hereby present a brief summary of their theories and report their recent features acquired from updated datasets (EOP C04 and ECMWF) by using Fourier transform, modelling, and wavelet analysis. Our new findings include (1) period-instability of free core nutation between 420 and 450 days as well as its large amplitude-variation, (2) re-determined Chandler period and its quality factor, (3) fast decrease in Chandler amplitude after 2010.

The atmosphere strongly affects the Earth’s spin rotation in wide range of timescale from daily to annual. Its dominant role in the seasonal perturbations of both the pole position and spinning rate of the Earth is once again confirmed by a comparison of two recent data sets; i) the Earth orientation parameter and ii) the global atmospheric state. The atmospheric semi-diurnal tide has been known to be a source of the Earth’s spin acceleration, and its magnitude is re-estimated by using an enhanced formulation and an up-dated empirical atmospheric S2 tide model. During the last twenty years, an unusual eastward drift of the Earth’s pole has been observed. The change in the Earth’s inertia tensor due to glacier mass redistribution is directly assessed, and the recent eastward movement of the pole is ascribed to this change. Furthermore, the associated changes in the length of day and UT1 are estimated.

The motivation of this study is the recent advancement of the Straddle Carrier (S/C). Previously Straddle Carrier (S/C) system was used focusing on container lift on/off due to its lower driving speed than that of (Y/T). Shuttle Carrier is evaluated as an upgraded Straddle Carrier. Recently, however, the driving speed of (S/C) has been improved to the level of Yard Tractor and Trailer systems (Y/T), which is 30Km per hour which makes (S/C) qualified as terminal in-yard transportation equipment. This paper, therefore, aims to evaluate three types of terminal in-yard transportation equipments such as (Y/T), (AGV) and the advanced (S/C) from economic perspective. The results revealed that by observing the total costs of equipment, (S/C) is a cheaper option than (Y/T) over 20 years, and than (AGV) over 6 years.