The 1811 or 1812 New Madrid Earthquake is one of the largest successions of earthquakes, including the most intensive ever indirectly inferred (not recorded) in the contiguous United States, beginning with an initial pair of very large earthquakes on December 16, 1811, plus aftershocks and other large related quakes separated by a succession of smaller aftershock quakes with the largest event classified as a Mega-quake of greater than 8.0 on the Richter scale occurring on February 7, 1812. It got its name from its primary location in the New Madrid Seismic Zone, near New Madrid, Louisiana Territory (now Missouri), where a stretch of land five miles (8 km) deep spanning from Arkansas to Illinois shifted and slipped. The fault is believed to generate a slip every 250-400 years.
This earthquake was preceded by three other major quakes: two on December 16, 1811, and one on January 23, 1812. These earthquakes destroyed approximately half the town of New Madrid. There were also numerous aftershocks in the area for the rest of that winter with research indicating a series of some 2,000 earthquakes overall that affected the lands of what would become eight of today's heartland states of the United States.
There are estimates that the earthquakes were felt strongly over roughly 130,000 sq km (50,000 sq mi), and moderately across nearly three million sq km (1 million sq mi). The historic 1906 San Francisco earthquake, by comparison, was felt moderately over roughly 16,000 sq km (6000 sq mi).
On the 22nd March 2008 an earthquake swarm began focusing just south of the town of New Madrid, 100 miles north of Memphis. On the first day there were 230 quakes ranging in size from 2.2 to 5.6 on the Richter scale.
The earthquake swarm continued for the next two months until on 18th April 2008 at 3.06pm there is a massive 8.2 earthquake 22 miles north of Memphis. Damage is considerable 99% of buildings with 100 miles have some structural damage, buildings within 50 miles have a 80-85% collapse rate any buildings with 15 miles collapse. Death tolls are difficult to calculate as many farmsteads collapse and catch fire destroying any bodies in them, but general consensus estimates that between 15,000 and 20,000 die, many are children caught in collapsing school buildings.
There are hundreds of aftershocks ranging up to 6.8 on the Richter scale over the next three months.
On the 5th July 2008 at 4.15am there is another massive 8.5 earthquake. Roughly located 126 miles north west of the original quake site. The quake causes the surrounding 500 sq mi to drop by anything up to 40 feet. The Mississippi changes course and floods these low lying areas forming five new lakes on of which is the largest in the state at 23 sq mi. Many building damaged in the 18th April quake collapse as well a thousands of newly damaged buildings. Buildings are damaged as far away as Florida and New Mexico.
Seismologists determine that the long known, but inactive, Reelfoot rift zone had re-activated. The States of Tennessee, Mississippi, Missouri and Arkansas are told that they should expect more earthquakes ranging up to 7 on the richter scale for anything up to ten years every few months. The states' governors choose to evacuate the major cities effected, Memphis and Tupelo and the surrounding areas are evacuated.
Between July 2008 and December 2008 there are 4 earthquakes above 6.5 on the Richter scale. the earthquake zones have now extended north to the Great Lakes area, west to Kansas and Nebraska, east to Florida and Kentucky. GPS measurements showed that the land levels surrounding the New Madrid area have sunk by 250 feet, the land surrounding has also sunk by substantial amount.
In January 2009 scientists announce that the central USA is sinking at such a rate that by 2020 the ocean will invade up to the Canadian border by 2050.