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terça-feira, 26 de abril de 2011

@TheEarthScience: #Earthquakes

TheEarthScience Earthquakes: A threat not to be taken lightly, but odds of one occurring are ...

One possible guide to that future is found in a frightening past. New Madrid spawned the largest quakes ever recorded east of the Rocky Mountains. The four shocks, striking between December 1811 and February 1812, have become the stuff of local legend. People were rumored to have been awakened as far away as New York City, church bells rang in Boston and the president felt the quakes in the nation's capital. Regional lore even has it that the Mississippi River briefly flowed backward. The official webpage of New Madrid says the quakes are estimated to have clocked in at between 7.8 and 8.8 on the Richter Scale.

But the actual intensity is still a matter of some debate, especially since tools weren't around at the time to create proper measurements. Generally, they are thought to have been smaller than folklore suggests. The U.S. Geological Survey approximates the New Madrid quakes in the 7.0-7.7 range. In recent findings released to the Seismological Society of America, one expert estimated the most powerful of the quakes right around the 7.0 mark.