The Fennoscandian Land Uplift Gravity Lines 1966–2003

Abstract

The Fennoscandian Land Uplift Gravity Lines (sometimes called Nordic Land Uplift Gravity Lines) consist of four east-west profiles across the Fennoscandian postglacial rebound area, along the approximate latitudes 65°, 63°, 61°, and 56°N. Repeated relative gravity measurements have been so far performed 1975–2000 (65°N), 1966–2003 (63°N), 1976–1983 (61°N), and 1977–2003 (56°N). The line 63°N has most observations. From the measurements along it up to 1993, Ekman and Mäkinen (1996) deduced the ratio −0.20 μgal/mm between surface gravity change and uplift relative to the Earth’s center of mass. Since that time, more gravity measurements have been taken. On the eastern part of the line 63°N, they result in slightly smaller estimates for the rate of gravity. New estimates of uplift and model predictions are also available. The updated gravity change combined with various estimates of uplift gives ratios between −0.16 and −0.20 μgal/mm. On the western part of the line 63°N an apparently anomalous change in gravity difference requires further study. In the future, the measurements will be performed using absolute gravity techniques.