Effects of liquefaction extended about 200 km northeast of the New Madrid seismic zone in White County, Illinois, 240 km to the north-northwest near St. Louis, Missouri, and 250 km to the south near the mouth of the Arkansas River. In the New Madrid region, sand blows can still be seen on the surface today.
The New Madrid Seismic Zone, sometimes called the New Madrid Fault Line, is a major seismic zone and a prolific source of intraplate earthquakes in the Southern and Midwestern United States, stretching to the southwest from New Madrid, Missouri. The New Madrid fault system was responsible for the 1811–12 New Madrid earthquakes, and has the potential to produce large earthquakes in the future. Since 1812, frequent smaller earthquakes have been recorded in the area. Earthquakes that occur in ...
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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.
Alternative Titles: Mississippi Valley fault system, New Madrid Fault 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.
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. Faults result from cracks and breaks in rock formations.
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.
- The Cascadia Subduction Zone, Pacific Northwest
- The New Madrid Seismic Zone, Missouri, Arkansas, Tennessee, Kentucky, Illinois
- The Ramapo Seismic Zone, Pennsylvania, New Jersey, and New York
- The Hayward Fault, California
- The Denali Fault System, Alaska
- San Andreas Fault, California
By the time Lewis and Clark arrived on the West Coast in 1805, it had been 105 years since the Cascadia Subduction Zone last ruptured, sending a large portion of the Pacific Ocean roaring toward the coast. The few remaining Native Americans in the area spoke of the earth shaking and ocean rising to consume the land. Many tribes even left the region permanently. However, it wasn’t until the discovery of the Cascadia Fault in the 1960s that modern settlers truly understood the dangers they faced. Running 680 miles along the Pacific Northwest coastline, the Cascadia Fault directly threatens 3 major metropolitan areas: Portland, Seattle, and Vancouver. With Cascadia capable of producing a magnitude 9.0 earthquake, the Pacific Northwest may soon face shaking 16 times more powerful than San Francisco’s devastating 1906 earthquake, lasting 4 minutes and delivering a mighty tsunami of unimaginable proportions.
It’s not just the West Coast that needs to watch out for tectonic obliteration. The New Madrid Seismic Zone spans southeastern Missouri, northeastern Arkansas, western Tennessee, western Kentucky, and southern Illinois. It’s the most active earthquake zone east of the Rocky Mountains. Between 1811 and 1812, this zone experienced some of the largest quakes in history. And although they originated in the Mississippi Valley, they rang church bells in Boston and shook New York City — over 1,000 miles away! Even then-President James Madison and his wife Dolley reportedly felt shaking at the White House. After one particularly large rupture in the fault, the mighty Mississippi River was forced to run backward for several hours, devastating acres of forest and creating 2 temporary waterfalls. Fortunately the Mississippi Valley was sparsely populated back then. Today millions of people live in densely populated urban areas like St. Louis and Memphis, making this zone one of the biggest conc...
In 1884, Brooklyn was rattled by an earthquake originating near the Ramapo Fault System. Toppling chimneys in New York City and felt as far away as Maine and Virginia, the magnitude 5.2 earthquake was a sudden wake-up call for settlers in the region. Running through Pennsylvania, New Jersey, and New York, the Ramapo has remained quiet for about 200 years. While studies have shown that a quake greater than 5.0 to 5.5 in magnitude is unlikely, urbanization in the tristate region leaves the area extremely vulnerable. A mid-magnitude earthquake in the right place could cause devastating damage. One of the faults in the Ramapo system even crosses New York City around 125th Street. A magnitude 5.0 rupture lasting more than a minute or 2 could cause intense structural damage to numerous Manhattan skyscrapers, most of which are not designed to withstand such tectonic activity.
This very unstable fault in Californiahas been threatening the San Francisco Bay Area for generations. It’s capable of producing quakes ranging from 7.0 to 8.0 in magnitude. The last major movement along the Hayward Fault occurred on October 21, 1868, virtually destroying downtown Hayward. In fact, it was considered the “great earthquake” until the San Andreas Fault tore San Francisco apart 38 years later. Running for nearly 74 miles through cities including Fremont, Hayward, Oakland, Berkeley, and Richmond, the Hayward Fault has the potential to wreak more havoc than most California faults. Over 2.4 million people live within close proximity to the fault today, not to mention the key infrastructure developments, including a major public transit system and the Caldecott Tunnel that run precariously through the fault.
If we’re talking sheer magnitude, the largest recorded earthquake on North American soil hit Alaska on November 3, 2002. Starting on the Susitna Glacier Thrust Fault, the rupture raced along the Denali Fault System and continued 220 kilometers until it reached the Totschunda Fault, rattling 70 more kilometers. Here a video about the 1964 Alaskan earthquake, also known as the Great Alaskan earthquake and Good Friday earthquake, which occurred at 5:36 PM AST on Good Friday, March 27, 1964. The estimated magnitude of this earthquake ranged from 7.0 to 7.9 with a surface wave magnitude of close to 8.5. This almighty quake caused extensive damage to the transportation systems in central Alaska. Multiple landslides and rock avalanches occurred in the Alaska Range and Black Rapids Glacier. This event was literally felt across the nation, even causing waves in pools and lakes in Texas and Louisiana!
California sits at the border between two major tectonic plates — the Pacific plate, which is moving northwest, and the North American plate, which is sliding past it to the southeast. The two plates don’t just meet at a single line, and the state is crisscrossed with dozens of earthquake faults. The San Andreas is the most worrisome, because it generates the quakes that are really dangerous to California residents. The fault indeed slices California in two from Cape Mendocino to the Mexican border. San Diego, Los Angeles and Big Sur are on the Pacific Plate. San Francisco, Sacramento and the Sierra Nevada are on the North American Plate. While San Andreas does not go through San Francisco, it crosses Desert Hot Springs, San Bernardino, Wrightwood, Palmdale, Gorman, Frazier Park, Daly City, Point Reyes Station and Bodega Bay, (or just a few other million people). The northern San Andreas leveled San Francisco in 1906, but it’s been a lot longer since the southern part of the fault r...
Dec 14, 2019 · The New Madrid Seismic Zone This 150 mile-long series of faults stretches under five states: Illinois, Missouri, Arkansas, Tennessee and Kentucky, and is responsible for four of the largest...
2 days ago · Once upon a time in North America almost divided along a very deep subsurface rift. Today, that rift system and the faults associated with it are known as the New Madrid fault zone. This fault zone is six times larger than the San Andreas fault zone in California and it covers portions of Illinois, Indiana, Missouri, Arkansas, Kentucky, Tennessee and Mississippi.
https://www.facebook.com/roya.ericksonjr/posts/672225519471039 [bunk] (Leaked US Navy Map) This is what the continent of the USA will look like once the New Madrid Fault line is hit with a massive HAARP frequency impulse in the nearing future. Get informed and get ready.