Residents of the central and eastern United States and Canada have become accustomed to the idea that the land on which they live, once visited a kilometer glaciers that covered these places 18,000 years ago. But they, perhaps, be surprised to learn that today an international group of geologists from Northwestern University with the help of Global Positioning System satellites monitors the rise as land — in some places to a centimeter a year — as the she recovers from the pressure of the glacier.
After collecting data from 200 points across the continent, the researchers found remarkable regularity. While in Canada, the land rises (around Hudson Bay, where the ice layer was the thickest, it rises faster than most) American cities to the south of the Great Lakes inexplicably omitted. This movement is a manifestation of post-glacial recovery is still going on in those places, where 18,000 years ago the ice sheets are squeezed heavy mantle. These movements, in particular, may be the cause of the mysterious earthquakes occurring in the central part of the North American continent.
Battery News, 18.05.2004 15:22