The Ground Beneath Sweden Is Rising – Scientists Uncover Gravity Shift
Scientists at Sweden’s KTH Royal Institute of Technology have made significant advancements in measuring post-glacial rebound in Fennoscandinavia, revealing a denser-than-expected landmass and a rise rate of up to one centimeter per year. As the Nordic region continues to recover from the weight of Ice Age glaciers, its landmass is gradually rising above sea level, prompting researchers to refine their understanding of how this uplift affects Earth’s gravitational pull over time.
For decades, KTH scientists Mohammad Bagherbandi and Lars Sjöberg have focused on the post-glacial rebound effect in Fennoscandinavia, which encompasses Sweden, Norway, Finland, and parts of Russia. Their latest research introduces a more precise measurement technique that combines satellite remote sensing, terrestrial gravity data, and 3D positioning from GPS and similar satellite-based systems.
The researchers discovered that the density of the upper mantle in the region is approximately 3,546 kilograms per cubic meter, slightly higher than previously reported figures. It is widely accepted that the landmass is rising by as much as one centimeter per year, a phenomenon that has significant implications for understanding geological processes.
Bagherbandi, a researcher in geodesy and land surveying at KTH, emphasizes the importance of satellite data in this field. Geodesy involves accurately measuring and understanding the Earth’s geometric shape, orientation in space, and gravity field. He notes, “Beginning 60 years ago, scientists were using terrestrial gravimeters to establish gravity reference systems and study temporal changes in gravity associated with glacial isostatic adjustment (GIA). Our study presents an alternative technique to investigate this phenomenon.”
This innovative approach allows researchers to create alternative and comparable models of how the land and gravity are changing over time in the region. Bagherbandi explains, “This discovery helps us understand the slow ‘bounce-back’ of land after the Ice Age. It also highlights the importance of the Global Geodetic Observing System (GGOS) in learning about Earth’s movements and gravity changes.”
A similar study is currently underway in the U.S., where scientists are evaluating a larger region of North America known to be rising. Understanding these geological changes is valuable not only for geodesy but also for improving tools used to study Earth’s geodynamics. The insights gained can aid in preparing for rising sea levels and understanding natural disasters.
As researchers continue to explore the implications of post-glacial rebound and its effects on gravity, the findings from KTH Royal Institute of Technology contribute to a deeper understanding of the dynamic processes shaping our planet.
