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The New Madrid seismic zone (NMSZ), sometimes called the New Madrid fault line (or fault zone or fault system), is a major seismic zone and a prolific source of intraplate earthquakes (earthquakes within a tectonic plate) in the Southern and Midwestern United States, stretching to the southwest from New Madrid, Missouri.
Locations of quakes magnitude 2.5 or greater in the Wabash Valley (upper right) and New Madrid (lower left) Seismic Zones. The Wabash Valley seismic zone (also known as the Wabash Valley fault system or fault zone) is a tectonic region located in the Midwestern United States, centered on the valley of the lower Wabash River, along the state line between southeastern Illinois and southwestern ...
The 1811–1812 New Madrid earthquakes were a series of intense intraplate earthquakes beginning with an initial earthquake of moment magnitude 7.2–8.2 on December 16, 1811, followed by a moment magnitude 7.4 aftershock on the same day. Two additional earthquakes of similar magnitude followed in January and February 1812.
English: Earthquakes recorded in the New Madrid Seismic Zone — in the Mississippi River Valley. Located primarily through Arkansas, Missouri, and Tennessee in the central United States from June 1974 to July 2011. Without indicication of magnitude. Most of the tremors represented on the map were below the threshold of human sensitivity.
Pressure on the fault where the 1811–1812 New Madrid earthquakes occurred was believed to be increasing, [23] but a later study by Eric Calais of Purdue University and other experts concluded the land adjacent to the New Madrid fault was moving less than 0.2 mm (0.0079 in) a year, increasing the span between expected earthquakes on the fault ...
Examples of intraplate earthquakes include those in Mineral, Virginia, in 2011 (estimated magnitude 5.8), Newcastle, New South Wales in 1989, New Madrid in 1811 and 1812 (estimated magnitude as high as 8.6), [6] the Boston (Cape Ann) earthquake of 1755 (estimated magnitude 6.0 to 6.3), earthquakes felt in New York City in 1737 and 1884 (both ...
It was also possible that the rupture involved more than one fault. Inferred aftershock locations suggest compatibility with the latter model, and agrees with the intensity distribution which suggest a northeast-propagating rupture. All three models indicate the earthquake was a buried rupture event along a 5–20 km (3.1–12.4 mi) fault. [2]
The New Madrid Seismic Zone lies at the northern end of the embayment. It was the site of the large New Madrid earthquakes of 1811-12. The area is underlain by some anomalous geology. The Reelfoot Rift is an ancient failed continental rift, an aulacogen, which dates back to the Precambrian break-up of the supercontinent Rodinia.