南極大陸のダイナミクス測地学的研究の幕開けとしての1990年代の貢献

抄録

The Japanese Antarctic station, Syowa (69.0°S, 39.6°E) was established for International Geophysical Year (IGY) in East Ongul Island, Lutzow-Holm Bay, East Antarctica on Jan. 29, 1957. Since then Japanese Antarctic Research Expedition (DARE) has carried on many scientific items in and around Syowa Station. JARE has carried out geographical surveys in the area and had published more than 100 sheets of geographical maps. The station geophysics such as gravity, geomagnetism, seismology etc. has been observed during the last half century. The observation of tide gauge was started in 1966 and has been continued four decades. Syowa Station was nominated one of the A stations of the International Absolute Gravity Baseline Network (IAGBN) in 1987 . The absolute gravity measurements have repeated and obtained the absolute gravity value as g=982524.3269 mGal ± 0.0001 mGal. A super conductivity gravity meter (SG) was installed at Syowa Station in 1993. Free oscillation of the earth incessantly excited by coupling between atmosphere and geosphere was found using the data of SG at Syowa Station. Since 1990 the geodetic Very Long Baseline Interferometry (VLBI) observations were made on baselines among Syowa Station, O'Higgins Station in Antarctica, Stations in Australia, South Africa and Japan. The dynamics of the Antarctic plate become to be discussed by the data of VLBI and GPS. The relation between crustal uplift of the Antarctic continent and seismic activity are discussed.