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  1. New Madrid Seismic Zone - Wikipedia

    The New Madrid Seismic Zone (/ ˈmædrɪd /), sometimes called the New Madrid Fault Line, 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.

  2. The New Madrid Seismic Zone - USGS

    New Madrid seismicity is spatially associated with the Reelfoot rift and may be produced by movement on old faults in response to compressive stress related to plate motions. Geologic and seismotectonic model of the New Madrid region (modified from Braile et. al., 1984).

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  3. About the New Madrid Fault | St Charles County, MO - Official ...

    The New Madrid Fault extends approximately 120 miles southward from the area of Charleston, Missouri, and Cairo, Illinois, through Mew Madrid and Caruthersville, following Interstate 55 to Blytheville, then to Marked Tree Arkansas. It crosses 5 state lines and cuts across the Mississippi River in 3 places and the Ohio River in 2 places.

  4. 1811–1812 New Madrid earthquakes - Wikipedia–12_New_Madrid...

    The New Madrid Seismic Zone (NMSZ) is made up of reactivated faults that formed when what is now North America began to split or rift apart during the breakup of the supercontinent Rodinia in the Neoproterozoic era (about 750 million years ago).

  5. New Madrid Seismic Zone | geological feature, United States ...

    New Madrid Seismic Zone (NMSZ), region of poorly understood, deep-seated faults in Earth’s crust that zigzag southwest-northeast through Arkansas, Missouri, Tennessee, and Kentucky, U.S. Lying in the central area of the North American Plate, the seismic zone is about 45 miles (70 km) wide and about 125 miles (200 km) long.

  6. Facts about the New Madrid Seismic Zone
    • Description
    • History
    • Study of The NMSZ
    • Probability
    • Damages
    • Predicted Cost of A Seismic Event in The NMSZ
    • Impact to Business Community

    While not as well known for earthquakes as California or Alaska, the New Madrid Seismic Zone (NMSZ), located in southeastern Missouri, northeastern Arkansas, western Tennessee, western Kentucky and southern Illinois, is the most active seismic area in the United States, east of the Rocky Mountains. The area includes major cities such as Memphis, Tennessee, St. Louis, Missouri, Little Rock, Arkansas and Evansville, Indiana. Every year hundreds of small earthquakes occur in the NMSZ, however mo...

    The NMSZ is famous for a series of three major earthquakes (believed to have been magnitude 7.0 or larger) which occurred in the two month period between Dec. 16, 1811, and Feb. 7, 1812. In addition, hundreds of moderate earthquakes (magnitude 5.0 to 6.5) and thousands of smaller (5.0M to 4.0M) earthquakes occurred in between the larger earthquakes and continued shaking the area for several months. These earthquakes were felt and recorded in personal journals as far away as Louisville, Kentuc...

    Current knowledge about the faults system within the NMSZ is obtained by studying seismograph recordings of the seismic waves produced by the frequent small earthquakes. Several organizations such as St. Louis University, University of Memphis and the United States Geological Survey (USGS) operate a network of seismograph stations to monitor earthquake activity in the NMSZ and Central U.S. Scientists use this network to record and study small Microseismic earthquakes (magnitude less than 2.0M...

    Some scientists believe the probability of a large earthquake (magnitude 7.0 – 8.0) is about 10 percent in 50 years.Due to their infrequency, the recurrence interval of moderate to large earthquakes in the NMSZ is very hard to predict. In addition to seismic waves, scientists are using several other methods of research to better understand the fault system. While they cannot predict an earthquake, scientist can however provide a Probabilistic Seismic Hazard Analysis for an area. By studying t...

    The 1811-1812 earthquakes in the New Madrid Seismic Zone impacted most of the simple buildings in New Madrid and Little Prairie (Caruthersville), the two towns in the area at the time. Approximately 5,500 square miles or about 3.5 million acres of the Mississippi and Ohio river valleys were impacted by landslides, fissures, sandblows, lateral spreads, subsidence, submergence and uplift. The basic single story log buildings, which are in fact a very earthquake resistant type of construction, o...

    A 1991 Missouri State Emergency Management Agency (SEMA) and FEMA report estimates damages from a 7.6 magnitude NMSZ earthquake to the Bootheel counties of Mississippi, New Madrid and Pemiscot would be 0.2 percent to 2 percent of their population killed, 1 percent to 10 percent of their population seriously injured, 10 percent of their buildings collapsed and 30 percent of their buildings receiving severe structural damage. For Scott, Stoddard and Dunklin counties the percentage estimates are...

    According to the Federal Emergency Management Agency (FEMA) and the QuakeSmart program, small businesses account for more than 99 percent of all companies in the United States, they employ 50 percent of all private sector workers, and provide nearly 45 percent of the nation’s payroll. It is estimated that 40 percent of all small businesses will not reopen after a major disaster and of the ones that do open 25 percent of those will close within one year. Developing a disaster contingency plan...

  7. New Madrid Seismic Zone Earthquake Hazard Article and Map
    • Risks
    • Future
    • Assessment
    • Geology
    • Results
    • Effects

    There is broad agreement in the scientific community that a continuing concern exists for a major destructive earthquake in the New Madrid seismic zone. Many structures in Memphis, Tenn., St. Louis, Mo., and other communities in the central Mississippi River Valley region are vulnerable and at risk from severe ground shaking. This assessment is based on decades of research on New Madrid earthquakes and related phenomena by dozens of Federal, university, State, and consulting earth scientists.

    Considerable interest has developed recently from media reports that the New Madrid seismic zone may be shutting down. These reports stem from published research using global positioning system (GPS) instruments with results of geodetic measurements of strain in the Earths crust. Because of a lack of measurable strain at the surface in some areas of the seismic zone over the past 14 years, arguments have been advanced that there is no buildup of stress at depth within the New Madrid seismic zone and that the zone may no longer pose a significant hazard.

    As part of the consensus-building process used to develop the national seismic hazard maps, the U.S. Geological Survey convened a workshop of experts in 2006 to evaluate the latest findings in earthquake hazards in the Eastern United States. These experts considered the GPS data from New Madrid available at that time that also showed little to no ground movement at the surface. The experts did not find the GPS data to be a convincing reason to lower the assessment of earthquake hazard in the New Madrid region, especially in light of the many other types of data that are used to construct the hazard assessment, several of which are described here.

    There are historical accounts of major earthquakes in the New Madrid region during 1811-12. The geologic record of pre-1811 earthquakes also reveals that the New Madrid seismic zone has repeatedly produced sequences of major earthquakes, including several of magnitude 7 to 8, over the past 4,500 years. These prehistoric earthquakes caused severe and widespread ground failures in the New Madrid region, much like those caused by the 1811-12 earthquake sequence. The key evidence for large earthquakes that occurred in the past are sand blows that formed when underground sand and water erupted to the surface as a result of violent shaking. Numerous large sand blows over a wide area were created by strong ground shaking during the 1811-12 earthquakes. Similarly large, widespread, and abundant prehistoric sand blows were produced over the same area during ground shaking from previous clusters of large earthquakes around A.D. 1450, A.D. 900, and 2350 B.C. The sizes and areal distribution of the prehistoric sand blows indicate that the older earthquakes were similar in location and magnitude to the 1811-12 shocks. The New Madrid seismic zone is a source of continuing small and moderate earthquakes, which attest to the high stress in the region and indicate that the processes that produced the large earthquakes over the previous 4,500 years, are still operating. It is the most seismically active area of the United States east of the Rockies. There is no sign that the rate of these smaller earthquakes is decreasing with time, as would be expected if they were aftershocks of the 181112 earthquakes. It has been known for several years that GPS measurements made since about 1996 do not show significant deformation across part of the New Madrid seismic zone. The new results reported on recently are not substantially different from those derived from previous GPS data. These short-term observations, though important, must be tempered by the context of tectonic processes developed over many thousands to millions of years. Such long-term processes are unlikely to switch off in a few decades with an accompanying decrease in the earthquake hazard. The New Madrid region is located in the middle of the vast North American tectonic plate. In contrast to plate boundary settings like the coasts of California or Alaska where continuous deformation can be measured at the surface, some models predict that little deformation will occur during the period between large earthquakes in seismic areas within a plate. The geologic record of repeated large earthquakes, the historical accounts of the 1811-12 large earthquakes, and the continuing earthquake activity in the area are compelling evidence that the New Madrid region has high earthquake hazard. The preponderance of evidence leads us to conclude that earthquakes can be expected in the future as frequently and as severely as in the past 4,500 years. Such high hazard requires prudent measures such as adequate building codes to protect public safety and ensure the social and economic resilience of the region to future earthquakes.

    The USGS has carried out an extensive consensus-building process in the development and updating of the national seismic hazard maps. These maps are the basis for the seismic provisions in the model-building codes adopted in almost all of the United States. Many workshops were conducted involving hundreds of scientists and engineers, and a thorough peer review process was undertaken in the development of the seismic hazard maps. Scientists at some workshops evaluated the New Madrid GPS results of the past 12 years and debated their meaning. They also considered the clear geologic evidence of large earthquakes occurring over the past 4,500 years and the continuing moderate earthquakes in the area. It was the consensus of this broad group of scientists that (1) the evidence indicates that we can expect large earthquakes similar to the 1811-12 earthquakes to occur in the future with an average recurrence time of 500 years and that (2) magnitude 6 earthquakes, which can also cause serious damage, can be expected more frequently than the large 1811-12 shocks.

    Earthquake hazards involve more than just strong ground shaking from passing seismic waves. The 1811-12 earthquakes caused many types of ground failures including landslides along the Mississippi River bluffs from Mississippi to Kentucky. Ground failures also included lateral spreading and ground subsidence by soil liquefaction across the Mississippi River flood plain and along tributaries to the Mississippi River over at least 15,000 square kilometers. Today, a repeat event could be expected to produce similar effects in northeastern Arkansas, southeastern Missouri, western Tennessee and Kentucky, and southern Illinois. Roadways in the Mississippi Valley of Arkansas and Missouri (such as Interstate 55) could become impassable because of bridge failures and fissuring of road surfaces. 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. Flooding of farmland, where agricultural chemicals are stored onsite, could contaminate rivers and streams. Failure of levees, especially during high water, would contribute to flooding, and failures of riverbanks could make the Mississippi River and its tributaries difficult to navigate for many weeks. 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. Soil liquefaction and related ground failures are likely to occur in downtown Memphis along the Mississippi River and along the Wolf River that passes through Memphis. The older highways and railroad bridges that cross the Mississippi River, as well as older overpasses, would likely be damaged or collapse in the event of a major New Madrid earthquake. Some of the bridges and pipelines crossing the Wolf River might be damaged or destroyed. Although Memphis is likely to be the focus of major damage in the region, St. Louis, Mo., Little Rock, Ark., and many small and medium-sized cities would also sustain damage.

  8. The infamous New Madrid earthquake is overdue - Strange Sounds

    Aug 14, 2020 · The New Madrid Seismic Zone, sometimes called the New Madrid Fault Line, is a major active seismic zone in the southern and midwestern United States. As shown in the map above, it stretches to the southwest from New Madrid, Missouri.

  9. What is the New Madrid Fault? (with pictures)

    Jan 28, 2021 · The New Madrid Fault is located beneath the Mississippi River Valley in the Midwest United States. It is part of the North American tectonic plate and the major fault among four, located in this region. It is yet to be confirmed if these faults intersect or are unique to each other. The seismic zone of the New Madrid Fault includes Missouri.

  10. The New Madrid Earthquake That Will Divide The United States ...

    On Dec. 16, 1811, a magnitude 7.7 earthquake hit the New Madrid fault line, which lies on the border region of Illinois, Indiana, Missouri, Arkansas, Kentucky, Tennessee and Mississippi. It’s by far the largest earthquake ever to strike the United States east of the Rockies.

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