Result of the Antarctic VLBI experiments duringJARE39 and their geodetic interpretations
Antarctica, most of which is covered with thick ice sheet, is a geologically distinct continent from the others and its characteristics have not been well revealed yet. In order to uncover interesting Antarctic tectonics, which are motion of the Antarctic plate, intra-plate deformation and uplifting...
| Main Authors: | , , |
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| Format: | Thesis |
| Language: | English |
| Published: |
2001
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| Subjects: | |
| Online Access: | https://ir.soken.ac.jp/?action=repository_uri&item_id=399 http://id.nii.ac.jp/1013/00000399/ |
| Summary: | Antarctica, most of which is covered with thick ice sheet, is a geologically distinct continent from the others and its characteristics have not been well revealed yet. In order to uncover interesting Antarctic tectonics, which are motion of the Antarctic plate, intra-plate deformation and uplifting by the Post Glacial Rebound, space geodetic methods play more important role than those for the other continents. The Antarctic plate is unique because it surrounded by the expansion area. There have been established several GPS and DORIS points in Antarctica. It has been reported that the crustal velocities in Antarctica acquired by these space geodetic points does not show the systematic residuals after subtracting fitted rigid plate motion. Also, shortness of the observation period prevents interpretations of more complicated movements. Current uplifting velocity of the Ongul Islands periphery was not clarified. Tide gauge's data that is recorded at Syowa Station shows subsiding of the sea level at a speed of 9.5mm/y. However, the observation period is not long enough to obtain a quantitative estimate. This result is larger than the averaged uplifting speed of 4mm/y, which is estimated as the Postglacial Rebound by geological survey in the Ongul Islands periphery. Syowa Station is built on a continental shield formed by old rocks. Generally, such a place is geologically very stable. Four space-geodetic techniques, which are GPS, DORIS, PRARE and VLBI, establish the observation points on the base-rock in Syowa Station. Accordingly, this Antarctic station is one of the largest space-geodetic observatories in Antarctica and plays the central role to the clarification of the Antarctic tectonics. Among the space geodetic techniques, VLBI occupies a distinct position that it can directly determine positions on the Earth's surface with respect to a quasi-inertial reference frame realized by positions of extra-galactic radio sources. Then VLBI is free from the influence by the fluctuation of the Earth's gravity center. ... |
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