HR: 11:20h
AN: G42A-05 INVITED     [Abstracts]
TI: Earth's shape variations: Geodetic observations and Crust-Mantle-Core rotation modeling
AU: * Jin, S
EM: sgjin@kasi.re.kr
AF: Korea Astronomy and Space Science Institute, 61-1, Whaam-dong, Yusong-gu , Daejeon, 305-348, Korea, Republic of
AU: Barkin, Y
EM: yuri.barkin@ua.es
AF: Sternberg Astronomical Institute, Universitetskii pr-t, Moscow, 13, Russian Federation
AU: Park, J
EM: jupark@kasi.re.kr
AF: Korea Astronomy and Space Science Institute, 61-1, Whaam-dong, Yusong-gu , Daejeon, 305-348, Korea, Republic of
AB: The geodetically observed length variations of latitude circles of the Earth testify an asymmetry of shape variations of the Northern and Southern Hemispheres. The circles are pulled together in the Northern Hemisphere with a lesser degree than stretched in the Southern Hemisphere. Meanwhile it was also supported by the secular radial motions of geodetic observations and the secular geocenter motion trend to the North Pole of the Earth. These relative motions of the Earth shells lead to inverse changes of the Earth shape as formation of fluxes on the Earth surface as well as the intensity of many natural processes in the opposite hemispheres. The secular asymmetrical change of the Earth hemispheres is an important signal to the Earth's interior activities, e.g. relative oscillations or deformations of the core and mantle induced by the forced core-mantle interaction. The main consequence of the relative displacement is the changes of tension states of the mantle layers in opposite hemispheres. The inertia moment with respect to the polar axis of the Earth is decreasing in the Northern hemisphere, while increasing in the Southern hemisphere. Furthermore, due to the mantle deformation under a gravitational action of the displaced core, the centre of the Earth's mass is tended to the northern pole with velocity 0.9+/-0.2 mm/yr. These secular differences or drifts result in secular redistribution of masses in the Earth hemispheres, increasing in the Northern Hemisphere and decreasing in the Southern Hemisphere.
DE: 1239 Earth rotation variations
DE: 1243 Space geodetic surveys
DE: 8011 Kinematics of crustal and mantle deformation
SC: Geodesy [G]
MN: 2007 Joint Assembly