A whole lot of shakin' goin' on

At 2:15 PM local time on December 16, 1811, a massive earthquake traditionally estimated above 8.0 on the Richter scale struck the New Madrid Faul, located midway between Memphis and St. Louis.

There were some two thousand aftershocks, four of which have also been historically believed to have been stronger than 8.0. Some experts today believe that most were in fact not quite that strong. The largest of them, in any case, all occurred on February 7. 1812. This dip-slip quake caused the Mississippi River to run backward (with consequences depicted on the above, on the left), cracked walls in Boston, and rang church bells in Montreal. It is believed to be the largest earthquake ever in the contiguous United States. Alaska has experienced more powerful ones still.

Bear in mind that for every point on the Richter scale, the force of the quake is multiplied by ten. The earthquake which caused the tsunami which has devastated the coast of Japan- and moved that coastline by eight feet- was nine times as powerful as the strongest of the New Madrid quakes.

The force of such an earthquake is nearly impossible to imagine. But to give some idea of how strong the recent quake was, it moved the Earth's axis by nearly four inches.

HT: Drudge