Monday, January 31, 2011

Does climate change have an effect on earthquakes?

There are actually two questions here to ponder: the former and vice versa. As for earthquakes having any effect on climate change, studies have found some evidence but not influential enough to currently make long-standing connections. Climate change effecting earthquakes, on the other hand, has been gathering evidence and provisional links are beginning to be made.

Melting glaciers and rising sea levels are the first and foremost base of reason concerning this connection, with the weight distribution along the earth’s crust and over fault lines changing slowly with time. The weight allocation relieves pressure on some parts of the crust and applies it to others, implementing plate shifts as sections of the crust strained by ice rise in a process called isostatic rebound. This same reason can change the weight over undersea volcanoes which have been reported to associate with eruptions, which are then related to earthquakes.

Isostatic Rebound
     This isn’t about a couple hundred pounds of ice melting and leaving polar bears scrambling in a panic for still ground, this is about unloading the weight of a sheet of ice a kilometer thick onto a continent, which subsequently can cause serious damage in the way of, no surprise, mega thrust earthquakes. For example, the St. Elias earthquake of 1979 in southern Alaska (magnitude 7.2) had been promoted by melting glaciers in the area. These glaciers near the fault zone had melted substantially since 1899 to be hundreds of meters thinner and many had even disappeared, applying increased pressure on the fault line where the Pacific plate slides under the Continental plate.


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