Scientists at Sweden’s KTH Royal Institute of Technology have refined a method to measure 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 rebound from the weight of Ice Age glaciers, its landmass is gradually rising above sea level. Researchers at Sweden’s KTH Royal Institute of Technology have developed a more precise method for measuring and predicting how this slow uplift affects Earth’s gravitational pull over time. Their findings reveal that the landmass of the Fennoscandinavian Peninsula is denser than previously thought.
For decades, KTH scientists Mohammad Bagherbandi and Lars Sjöberg have studied the post-glacial rebound effect in Fennoscandinavia, which includes Sweden, Norway, Finland, and part of Russia. Their latest research introduces a refined measurement technique that integrates satellite remote sensing, terrestrial gravity data, and 3D positioning from GPS and similar satellite-based systems.
The KTH researchers found that the density of the upper mantle is about 3,546 kilograms per cubic meter—slightly more than reported in earlier studies. It is widely believed the land mass rises by as much as 1 cm per year.
The Role of Satellite Data in Geodesy
Bagherbandi, a researcher in geodesy and land surveying at KTH, says the new technique highlights the value of satellite data in the field of geodesy, the science of accurately measuring and understanding the Earth’s geometric shape, orientation in space, and gravity field
“Beginning 60 years ago, scientists were using terrestrial gravimeters to establish gravity reference system and study temporal changes in gravity associated with glacial isostatic adjustment (GIA),” Bagherbandi says. “Our study is an alternative technique to study this phenomenon.”
This means researchers can now create alternative and comparable models of how the land and gravity are changing over time in the region, he says.
“This discovery helps us understand the slow ‘bounce-back’ of land after the Ice Age,” Bagherbandi says. “It also shows how important the Global Geodetic Observing System (GGOS) are for learning about Earth’s movements and gravity changes.”
A similar study is underway in the U.S., where scientists are evaluating an even larger region of North America that is known to be rising.
Bagherbandi says understanding these changes is valuable beyond the field of geodesy. It helps scientists improve their tools for studying Earth’s geodynamics. It can also help with other fields, like preparing for rising sea levels and learning about natural disasters
Reference: “A short note on GIA related surface gravity versus height changes in Fennoscandia” by Mohammad Bagherbandi, and Lars E. Sjöberg, 13 December 2024, Journal of Geodesy.
DOI: 10.1007/s00190-024-01921-7
