Melting Glaciers Contribute to Alaska Earthquakes
In a recently published research article, scientists with the University of Alaska Fairbanks Geophysical Institute found that ice loss near Glacier Bay National Park has influenced the timing and location of earthquakes with a magnitude of 5.0 or greater in the area during the past century.
Scientists have known for decades that melting glaciers have caused earthquakes in otherwise tectonically stable regions, such as Canada’s interior and Scandinavia. In Alaska, this pattern has been harder to detect, as earthquakes are common in the southern part of the state.
Alaska has some of the world’s largest glaciers, which can be thousands of feet thick and cover hundreds of square miles. The ice’s weight causes the land beneath it to sink, and, when a glacier melts, the ground springs back like a sponge. The disappearance of glaciers has also caused Southeast Alaska’s land to rise at about 1.5 inches per year.
When the earth rebounds following a glacier’s retreat, it does so much like bread rising in an oven, spreading in all directions. This effectively unclamps strike-slip faults, such as the Fairweather in Southeast Alaska, and makes it easier for the two sides to slip past one another.