Gravity Measurements Using Absolute Gravimeter FG5 and Secular Gravity Changes at Syowa Station, Antarctica

Abstract

Absolute gravity measurements were carried out as a part of activities in 2011-2012 austral summer season of the 53rd Japanese Antarctic Research Expedition (JARE53) at Syowa Station, Antarctica. Obtained absolute gravity value was 982524322.7±0.1 μgal (1 μgal=10^-8ms^-2) using an absolute gravimeter FG5#210. Absolute gravity measurements using FG5 gravimeter have been conducted 5 times at Syowa Station. Comparing the previous obtained gravity values, we had confirmed instrumental offset among employed three FG5 absolute gravimeters. The gravity values after the correction of instrumental offset show a gravity decreasing rate of about 0.24 μgal/year. This secular gravity changes are consistent with the crustal uplift associated with Glacial Isostatic Adjustment (GIA) observed around Syowa Station, Antarctica.