A geophysical interpretation of the secular displacement and gravity rates observed at Ny-Ålesund, Svalbard in the Arctic-effects of post-glacial rebound and present-day ice melting

作者：Tadahiro Sato, Jun’ichi Okuno, Jacques Hinderer, Daniel S. MacMillan, Hans‐Peter Plag, Olivier Francis, Reinhard Falk, Yoichi Fukuda · 发表于：Geophysical Journal International · 年份：2006 · DOI：10.1111/j.1365-246x.2006.02992.x · 被引用次数：55 · 研究领域：Geophysics and Gravity Measurements、earthquake and tectonic studies、Methane Hydrates and Related Phenomena

We have analysed the Ny-Ålesund very long baseline interferometry (VLBI) data over the period 1994 August to 2004 May, and we obtain secular displacement rates relative to a NNR-NUVEL-1A reference frame of 0.2 ± 0.5 mm yr−1, −1.7 ± 0.5 mm yr−1 and 4.8 ± 1.1 mm yr−1 for the north, east and vertical directions, respectively. The corresponding global positioning system (GPS) station displacement rates relative to the same reference frame for the north, east, and vertical directions are 0.2 ± 0.6 mm yr−1, −2.3 ± 0.6 mm yr−1, and 6.4 ± 1.5 mm yr−1 at NYA1 and -−0.1 ± 0.5 mm yr−1, −1.6 ± 0.5 mm yr−1, and 6.9 ± 0.9 mm yr−1 at NALL, where these GPS rates were derived from the ITRF2000 velocity solution of Heflin. From the comparison at 25 globally distributed collocated sites, we found that the difference in uplift rate between VLBI and GPS at Ny-Ålesund is mainly due to a GPS reference frame scale rate error corresponding to 1.6 mm yr−1 in the GPS vertical rates. The uplift rate was estimated to be 5.2 ± 0.3 mm yr−1 from the analysis of the tide gauge data at Ny-Ålesund. Hence the uplift rates obtained from three different kinds of data are very consistent each other. The absolute gravity (AG) measurements at Ny-Ålesund, which were carried out four times (period: 1998–2002) by three different FG5 absolute gravimeters, lead to a decreasing secular rate of −2.5 ± 0.9 μGal yr−1 (1 μGal = 10−8 m s−2). In this analysis, the actual data obtained from a superconducting gravimeter at Ny-Åle...