Earthquakes and the New Madrid Fault LineSeismic activity, maps, information
New Madrid region with recent quakes - map updated by CERI, University of Memphis. Tighter map
The New Madrid (MAD'rud) Seismic Zone, midway between St. Louis and Memphis, has a history of shaking violently, about every 500 years. When it shook for three months in 1811-12, this was the western frontier, and the population was sparse. If it shook with that magnitude again, the devastation would make Hurricane Katrina look "like a Sunday School picnic." The New Madrid fault system is a series of faults several miles below the surface. Experts say we're overdue for a "6" like the one in 1895 which shook down buildings in the Charleston, Mo. area. The "big ones" of 1811-12 were probably high "7"s, accompanied by a few thousand smaller ones over 4-6 months.
Two sharply conflicting press releases were issued within four minutes of each other on Dec. 11th. 2006:
Silent Night, nine days before Christmas, 1811The famous earthquakes of the New Madrid region began early on December 16th, 1811. The weather was "indian summer," a mild 45 degrees (Yes, people were keeping diaries). The stars were almost brighter than the visible sliver of the new moon. Without warning, after 2 a.m. the rocks violently shifted, a few miles below the surface, west of the present Blytheville, Arkansas. map At 8 a.m., another large shift took place, near the present Cooter and Steele, Missouri. Then at 11 a.m., beneath the present Caruthersville, it happened again. These quakes are in the magnitude range of 7.3 - 8.0 for the 3 main shocks of the 1811-12 sequence (CERI, 2005). Big Lake, just west of Blytheville, was formed on this day.
The population on this western end of the country was still sparse. St. Louis had about 1,200 people, all living in the rock-base Laclede's Landing area now between its arch and the river. The future Memphis would not be handed over from the Chickasaws until 1818. Jan. 1812Five weeks later, about 8 a.m. January 23, 1812, another big shake struck, north of Caruthersville. The town of Point Pleasant, southeast of Marston, on a point of land sticking into the Mississippi River, completely crashed into the river and was swept away without a trace. The townspeople had all fled, a month earlier. because of the tremors. Eyewitnesses. Little Prairie, near Caruthersville, had a similar fate. The Granddaddy Quake - Feb. 1812
Researcher Otto Nuttli wrote that this quake caused 60 miles of the New Madrid Fault to rupture. This caused waterfalls on the Mississippi, and the river to run backwards for several hours, [map] in the river bends just northeast of New Madrid. This quake also created Reelfoot Lake in Northwest Tennessee. Today an 800-foot power generation smokestack in St. Jude Industrial Park at Marston (just south of New Madrid, good photo) marks the approximate center of that quake. This could someday become a monument to dumb engineering. There are others. An AECI - Associated Electric - power plant worker told us they feel a quake in the plant about once a month, amid the turbines and industrial atmosphere, but "everyone is used to it." The power plant employs 200, and can burn a train car load of coal per day. A huge Noranda aluminum processing plant alongside, directly employs more than 1100 people. "Constant Shaking" for five monthsThere may have been two thousand quakes during these five months of 1811-12. Researchers Ray Knox and David Stewart, in "The New Madrid Fault Finders Guide" say any one of them would make front-page news today. The book describes land deformations from the quakes that may not be obvious to a new observer. There were no seismographs then. Researchers estimate the strength by studying damage accounts and sandboils. Older texts refer to the the 1811-12 quakes as above 8 on the Richter scale. The Richter scale saturates and does not read the highest intensities, well. A revised magnitude scale estimates them as high 7's. The tectonic plate under the New Madrid area was almost pulled apart perhaps more than once, hundreds of millions of years ago. The pulling created a weak zone called a "failed rift". If it had been separated, the New Madrid area might be on the Atlantic seaboard, and the southeastern US might be attached to Africa. A more recent rift is the Red Sea, separating Africa from Saudi Arabia. 150 Rattles A Year
A quake of magnitude four starts making serious news. A "four" quake can be expected every couple of years. A quake with a six reading on the magnitude scale is serious within 50-100 miles. A six is expected every hundred years. The three "big ones" of the winter of 1811-12 (magnitudes above seven) were felt in Massachusetts and Virginia. There's one report that President James Madison felt the 1811-12 quakes and thought intruders were in the White House. A catastrophic quake, above magnitude seven, can be expected about every 500 years, though scientists say there's about a ten percent chance of one happening anytime in any 50-year period. Scientists find evidence of big quakes dating to 4000 BC even though the river has washed away much of the older evidence. source It is not uncommon to have perhaps three small quakes, magnitude 1.5 - 2.0 reported in this area in a single day in the counties surrounding New Madrid and across the river in Lake or Dyer County, Tn. Few people notice. Here's the last week's worth. A resident just north of New Madrid may have a typical reaction to the threat. She told us she "never" feels quakes and is not concerned. She sees the weekly quake list in the local paper, and calmly says "most are over in Tennessee," perhaps thinking of the 90-minute drive by car. But the prime Tennessee earthquake counties are only 15 air miles from her home. See http://en.wikipedia.org/wiki/New_Madrid_Fault Sand boils, liquefaction, disappearing highwaysLiquefaction is difficult for newcomers to grasp. It can cause a section of heavy interstate highway, or your house to disappear into the sandy soil when the subsurface sand becomes water-saturated, loses its friction, and pressure is applied. Builders also are slow to learn the lesson. Human casualties could be in the thousands, per county.
PipelinesSome major refined oil and natural gas pipelines go in and near the area (see map), connecting the petroleum fields of Louisiana and Oklahoma to the chilly northeastern states. The MO emergency planning folks say three major lines run through Missouri's Bootheel. Two pipelines pass through Dexter. Highway engineers in 2005 replaced a section of Interstate highway near Charleston, Mo. with pre-cast sections trucked from Memphis. The method may be used again in case of Bootheel liquefaction. Rail, air, trucking, river distribution of goods in Memphis area is key to the nation. Tennessee's first commission devoted to dealing with a major earthquake began reviewing disaster preparations in June 2007. Memphis building codes didn't require designs to resist earthquake forces until 1992. Arkansas legislature Jan. 2008 is considering tightening building requirements for quake resistance, and encountering economic resistance. Builders and Safety folks disagree. The 200th anniversary of the New Madrid earthquakes will be recognized in 2011 and 2012. Preliminary plans have recently begun, including ambitious plans for a PBS special, numerous outreach efforts and field trips, and the National Earthquake Conference. Wrinkling the mattress?
The National Park Service says a continental glacier covered North America 18,000 years ago. Its gradual melting period from 12,000 to 7,500 years ago, was the last in a series of continental glaciers that have formed and then receded over the last 25 million years. --nps.gov
7.7 fake quake, 34 seconds, 11 statesThe Spill of National Significance emergency exercise in June 2007 simulated multiple oil and hazardous materials spills caused by a strong earthquake along the New Madrid fault line. Here are damage estimates (PDF) to bridges and the river itself. Losses can exceed a billion dollars per county.
Powered by Show-Me.net
|
The New Madrid Seismic Zone was revised to include updated fault geometry and earthquake information and the possibility of several large earthquakes taking place within a few years or less,
Most earthquakes happen when the edges of continent-sized pieces of rock called "tectonic plates" rub against each other. But New Madrid is in the middle of such a plate.
Perhaps the biggest quake came two weeks later, in the early hours of February 7th, 1812. The 
The New Madrid Fault now rattles its area 
Planners expect sections of I-55 which connects St. Louis and Memphis to be 
Glaciers, 
