Notes on the New Madrid Seismic Zone

Early this morning, USGS reported a 4.0 earthquake in Southeastern Missouri along the New Madrid seismic zone.

While Missouri, Kentucky and Tennessee are not areas that one usually associates with major earthquakes, The New Madrid, MO series of four quakes that occurred in December, 1811 and January, 1812, hold the recorded historical record for the most powerful earthquakes to hit the eastern United States.

The New Madrid seismic zone is active today, and holds potential for future large earthquakes:

In a report filed in November 2008, The U.S. Federal Emergency Management Agency warned that a serious earthquake in the New Madrid Seismic Zone could result in “the highest economic losses due to a natural disaster in the United States,” further predicting “widespread and catastrophic” damage across Alabama, Arkansas, Illinois, Indiana, Kansas, Kentucky, Mississippi, Missouri, Oklahoma, Texas, and particularly Tennessee, where a 7.7 magnitude quake or greater would cause damage to tens of thousands of structures affecting water distribution, transportation systems, and other vital infrastructure.[22] The earthquake is expected to also result in many thousands of fatalities, with more than 4,000 of the fatalities expected in Memphis alone.

Source.

More information from USGS.

NMSZ Expert Panel Report to NEPEC, April 16, 2011

Related images

New Madrid and Wabash seizmic zones-USGS

This map of the New Madrid and Wabash Valley seismic zones shows earthquakes as circles. Red circles indicate earthquakes that occurred from 1974 to 2002 with magnitudes larger than 2.5 located using modern instruments (University of Memphis). Green circles denote earthquakes that occurred prior to 1974 (USGS Professional Paper 1527). Larger earthquakes are represented by larger circles.

New Madrid quakes

Earthquakes recorded in the New Madrid seismic zone since 1974. Credit: USGS; Image: Wikimedia Commons

NMSZ Vergleich

Comparison of the earthquake spread of the San Andreas fault and the New Madrid Seismic Zone (NMSZ); Image: Wikimedia commons

Soil liquefaction

Soil liquefaction occurs when the spaces between soil particles become filled with water, causing soil to lose its strength and liquefy. The phenomenon is associated with earthquakes, because the shaking can cause rapid shifts in water pressure. Soil liquefaction occurred during the 2011 Christchurch earthquake and also in the 2011 Japan earthquake. Such an event remains a concern along the New Madrid seismic zone, due to its location along the Mississippi River flood plain. USGS states the concern as follows:

Venting of large quantities of water, sand, and mud as
a result of liquefaction could flood fields and roads and disrupt
agriculture for weeks to months.

Memphis is of particular concern:

The City of Memphis and the surrounding metropolitan
area of more than one million people would be severely
impacted. Memphis has an aging infrastructure, and many of
its large buildings, including unreinforced schools and fire and
police stations, would be particularly vulnerable when subjected
to severe ground shaking. Relatively few buildings were built
using building codes that have provisions for seismic-resistant
design.

Source.

Here is a video from Japan showing soil liquefaction:

New Madrid Earthquake Marker
New Madrid Earthquake Marker

“Located at intersection of KY 94 and Fulton County Road 1282 near the Sassafras Ridge community.” Image by jimmywayne under Creative Commons on flickr.

note: I found it interesting to read the personal accounts of the historic New Madrid quake. Some mentioned reactions of the animals such as birds and farm animals. Can animals sense earthquakes? Here is an article.

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Comments
  1. I have corrected the dates of the New Madrid quake, which occurred in 1811-1812, and not 1911-1912, as I originally misstated.

  2. If anyone happened to miss this video, it is mind blowing. “2011 earthquakes, plotted and animated with sound intensity.” USGS data was used for the video. This thing puts the enormity of the Japan quake into perspective; take a look at March:

    Also, How many earthquakes occur each year? Several million, according to USGS estimates:

    http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php

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