GREENBELT, Md., Aug. 2 (UPI) -- U.S. scientists have found that melting glaciers in southern Alaska could cause future earthquakes in that region by lessening the load on tectonic plates.
Researchers at NASA and the U.S. Geological Survey have discovered that rapidly melting glaciers lighten the overburden on tectonic plates, allowing them to move more freely, potentially to cause future earthquakes.
"Historically, when big ice masses started to retreat, the number of earthquakes increased," said Jeanne Sauber of NASA's Goddard Space Flight Center, citing melting ice sheets in Canada as the cause for earthquakes there nearly 10,000 years ago.
Higher temperatures and changes in precipitation seem to have caused many glaciers in southern Alaska to shrink or disappear completely over the past 100 years. Researchers suspect a severe 1979 earthquake in St. Elias -- with a magnitude of 7.9 on the Richter scale -- was abetted by these melting glaciers.
Heavy glaciers can help stabilize active earthquake areas, but as their weight dwindles, earthquakes may become more likely, the researchers said.
Earthquakes in southern Alaska are caused by a build-up of pressure along the Pacific Ocean tectonic plate, which is slowly moving under the North American plate.
