New Madrid earthquakes anniversary

by Anonymous on Dec. 16th, 2011

New Madrid earthquakes: Earthquake fissure filled with intruded sand in Mississippi County, Missouri, formed at the time of the New Madrid earthquake. 1904 photograph by M. L. Fuller.
New Madrid earthquakes: Earthquake fissure filled with intruded sand in Mississippi County, Missouri, formed at the time of the New Madrid earthquake. 1904 photograph by M. L. Fuller.Courtesy US Geological Survey Photographic Library
Today marks the bicentennial of the start of the historic New Madrid earthquake series, which began at 2am on December 16, in 1811. The quakes were so powerful, large areas of land uplifted and sank creating new lakes and swamps, and causing islands to disappear. Large waves spawned by the tremors raked across the banks of the Mississippi causing massive landslides, and even briefly changing the course of the mighty river.

Named after the nearby river village of New Madrid in the then Louisiana Territory (now Missouri), the quake and its many aftershocks affected an area 10 times larger than the famous 1906 San Francisco earthquake. Luckily, the New Madrid area was sparsely populated when the line of strong earthquakes took place, as they were the strongest recorded earthquakes ever to take place east of the Rocky Mountains.

Earthquakes of such magnitude as those that struck New Madrid (~ 7.0) typically occur along plate boundaries - areas where one tectonic plate is colliding with another, such as along the West Coast's San Andreas Fault. The mid-section of the country sets on only one plate - the normally stable North American plate. Faults do run through it, such as the Cottonwood Grove and the Reelfoot faults which some scientists hypotheisze were responsible for the New Madrid series.

But researchers don't agree on what caused the strong intraplate earthquakes. They could have been triggered by other distant earthquakes or by the release of energy built up by the heating of the crust from an upper mantle magma plume or from isostatic rebound - that is the release of stresses caused by the retreat of glaciers that once covered the region.

Whatever the cause and despite new data being gathered by present day geologists, the New Madrid earthquakes were an historic anomaly that remain wrapped in mystery.

LINKS
Earth magazine story
More about the New Madrid earthquakes

Your Comments, Thoughts, Questions, Ideas

Abby Diekmann's picture
Abby Diekmann says:

Very interesting article. I read about the New Madrid earthquake quite some time ago .

posted on Thu, 12/29/2011 - 3:51pm
Dawson Petersen's picture
Dawson Petersen says:

That is sick

posted on Mon, 03/26/2012 - 10:40am

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