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Reelfoot Rift and the New Madrid seismic zone in a 3D topographic image

Magnetic potential map of the Reelfoot Rift

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.

The New Madrid fault system was responsible for the 1811–1812 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.^[1]

Earthquakes that occur in the New Madrid seismic zone potentially threaten parts of seven American states: Illinois, Missouri, Arkansas, Kentucky, Tennessee, and to a lesser extent Mississippi and Indiana.^[2]

Location

The 150-mile (240 km)-long seismic zone, which extends into five states, stretches southward from Cairo, Illinois; through Hayti, Caruthersville, and New Madrid in Missouri; through Blytheville into Marked Tree in Arkansas. It also covers a part of West Tennessee near Reelfoot Lake, extending southeast into Dyersburg. It is southwest of the Wabash Valley seismic zone.

Geology

The faults responsible for the NMSZ are embedded in a subsurface geological feature known as the Reelfoot Rift, which likely formed during the Cambrian Period.^[3] The Reelfoot Rift was first described by Ervin and McGinnis (1975) and believed to be of late Precambrian age.^[4] The rift failed to split the North American continent, but it has remained as an aulacogen (a scar or zone of weakness) deep underground.^[3]^[5]

This relative weakness is important, as it would allow the relatively small east–west compressive forces associated with the continuing westward continental drift of the North American plate to reactivate old faults around New Madrid, making the area unusually prone to earthquakes in spite of it being far from the nearest tectonic plate boundary.^[6]

Since other ancient rifts are known to occur in North America, but not all are associated with modern earthquakes, other processes could be at work to locally increase mechanical stress on the New Madrid faults.^[7]^[8] Some form of heating in the lithosphere below the area has been suggested to be making deep rocks more plastic, which would concentrate compressive stress in the shallower subsurface area where the faulting occurs.^[9]^[10]

History

The zone had four of the largest earthquakes in recorded North American history, with moment magnitudes estimated to be as large as 7 or greater, all occurring within a 3-month period between December 1811 and February 1812. Many of the published accounts describe the cumulative effects of all the earthquakes, known as the New Madrid Sequence, so finding the individual effects of each quake can be difficult. Magnitude estimates and epicenters are based on interpretations of historical accounts and may vary.

Prehistoric earthquakes

As uplift rates associated with large New Madrid earthquakes could not have occurred continuously over geological timescales without dramatically altering the local topography, studies have concluded that the seismic activity there cannot have gone on for longer than 64,000 years, making the New Madrid seismic zone a young feature, or that earthquakes and the associated uplift migrate around the area over time, or that the NMSZ has short periods of activity interspersed with long periods of dormancy.^[11]

Archaeological studies have found from studies of sand blows and soil horizons that previous series of very large earthquakes have occurred in the NMSZ in recent prehistory. Based on artifacts found buried by sand blow deposits and from carbon-14 studies, previous large earthquakes like those of 1811–12 appear to have happened around AD 1450 and 900,^[12] as well as around AD 300. Evidence has also been found for an apparent series of large earthquakes around 2350 BC.^[13]

About 80 kilometres (50 mi) southwest of the presently defined NMSZ, but close enough to be associated with the Reelfoot Rift, near Marianna, Arkansas, two sets of liquefaction features indicative of large earthquakes have been tentatively identified and dated to 3500 and 4800 BC. These features were interpreted to have been caused by groups of large earthquakes timed closely together.^[14]

Dendrochronology (tree ring) studies conducted on the oldest bald cypress trees growing in Reelfoot Lake found evidence of the 1811–12 series in the form of fractures followed by rapid growth after their inundation, whereas cores taken from old bald cypress trees in the St. Francis sunklands showed slowed growth in the half century that followed 1812. These were interpreted as clear signals of the 1811–12 earthquake series in tree rings. As the tree ring record in Reelfoot Lake and the St. Francis sunk lands extend back to 1682 and 1321, respectively, Van Arsdale et al. interpret the lack of similar signals elsewhere in the chronology as evidence against large New Madrid earthquakes between those years and 1811.^[15]

December 25, 1699

The first known written record of an earthquake felt in the NMSZ was from a French missionary traveling up the Mississippi with a party of explorers. At 1 pm on Christmas Day 1699, at a site near the present-day location of Memphis, the party was startled by a short period of ground shaking.^[16]

1811–12 earthquake series

December 16, 1811, 0815 UTC (2:15 am); (M about 7.5)^[17] epicenter in northeast Arkansas, probably on the Cottonwood Grove fault;^[18]^{: p. 7} it caused only slight damage to man-made structures, mainly due to the sparse population in the epicentral area. The future location of Memphis, Tennessee, was shaken at Mercalli level IX intensity. A seismic seiche propagated upriver, and Little Prairie was destroyed by liquefaction.^[19] Local uplifts of the ground and the sight of water waves moving upstream gave observers the impression that the Mississippi River was flowing backwards.^[20]

At New Madrid, trees were knocked down and riverbanks collapsed. This event shook windows and furniture in Washington, DC, rang bells in Richmond, Virginia, sloshed well water and shook houses in Charleston, South Carolina, and knocked plaster off of houses in Columbia, South Carolina. In Jefferson, Indiana, furniture moved, and in Lebanon, Ohio, residents fled their homes. Observers in Herculaneum, Missouri, called it "severe" and said it had a duration of 10–12 minutes.^[21]

Aftershocks were felt every 6-10 minutes, a total of 27, in New Madrid until what was called the Daylight Shock, which was of the same intensity as the first. Many of these were also felt throughout the eastern US, though with less intensity than the initial earthquake.^[21]

December 16, 1811, sometimes termed the "Dawn Shock" or "Daylight Shock", occurred at 1315 UTC (7:15 am); (M about 7) with the epicenter in northeast Arkansas.^[17]
January 23, 1812, 1515 UTC (9:15 am); (M about 7.3) epicenter around New Madrid,^[17] although this is disputed.^[18]^{: p. 7} This was probably the smallest of the three main shocks but resulted in widespread ground deformation, landslides, fissuring, and stream-bank caving in the meizoseismal area. Johnston and Schweig attribute this earthquake to a rupture on the New Madrid North Fault.^[19]^[17] A minority viewpoint holds that this earthquake's epicenter was in southern Illinois. A 2011 expert panel urged further research to clarify this point, stating that the Illinois hypothesis would mean that an extended section of fault exists, perhaps still loaded and capable of hosting a great earthquake in the future.^[18]^{: p. 7}
February 7, 1812, 0945 UTC (3:45 am); (M about 7.5) epicenter near New Madrid, Missouri.^[17] This was the largest event in the series, and it destroyed the town of New Madrid.^[17] At St. Louis, Missouri, many houses were severely damaged, and their chimneys were toppled. It appears to have occurred on Reelfoot fault, a reverse fault segment that crosses under the Mississippi River just south of Kentucky Bend and continues to the east as the Lake County Uplift.^[18]^{: p. 7} In this event, uplift along the fault created temporary waterfalls on the Mississippi River, created a wave that propagated upstream, and caused the formation of Reelfoot Lake by damming streams.^[19]

1812–1900

Hundreds of aftershocks of the 1811–12 series followed over a period of several years. Aftershocks strong enough to be felt occurred until 1817. The largest earthquakes to have occurred since then were on January 4, 1843, and October 31, 1895, with magnitude estimates of 6.0 and 6.6, respectively. The 1895 event had its epicenter near Charleston, Missouri. The quake damaged virtually all the buildings in Charleston, created sand volcanoes by the city, cracked a pier on the Cairo Rail Bridge, and toppled chimneys in St. Louis, Missouri; Memphis, Tennessee; Gadsden, Alabama; and Evansville, Indiana.^[22]

Modern activity

The largest NMSZ earthquake of the 20th century was a 5.4-magnitude quake on November 9, 1968, near Dale, Illinois. The quake damaged the civic building at Henderson, Kentucky, and was felt in 23 states. People in Boston said their buildings swayed. At the time of the quake, it was the biggest recorded quake with an epicenter in Illinois in that state's recorded history.^[23] In 2008 in the nearby Wabash Valley seismic zone, a similar magnitude 5.4 earthquake occurred with its epicenter in Illinois near West Salem and Mount Carmel.

Instruments were installed in and around the area in 1974 to closely monitor seismic activity. Since then, more than 4,000 earthquakes have been recorded, most of which were too small to be felt. On average, one earthquake per year is large enough to be felt in the area.

Potential for future earthquakes

In a report filed in November 2008, the U.S. Federal Emergency Management Agency warns that a serious earthquake in the NMSZ 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 would cause damage to tens of thousands of structures affecting water distribution, transportation systems, and other vital infrastructure.^[24] The earthquake is expected to result in many thousands of fatalities, with more than 4,000 of the fatalities expected in Memphis alone.

The potential for the recurrence of large earthquakes and their effects today on densely populated cities in and around the seismic zone has generated much research devoted to understanding the NMSZ. By studying evidence of past quakes and closely monitoring ground motion and current earthquake activity, scientists attempt to understand their causes and recurrence intervals.

In October 2009, a team composed of University of Illinois and Virginia Tech researchers headed by Amr S. Elnashai, funded by the Federal Emergency Management Agency, considered a scenario where all three segments of the New Madrid fault ruptured simultaneously with a total earthquake magnitude of 7.7. The report found that there would be significant damage in the eight states studied – Alabama, Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri, and Tennessee – with the probability of additional damage in states farther from the NMSZ. Tennessee, Arkansas, and Missouri would be most severely impacted, and Memphis and St. Louis would be severely damaged. The report estimated 86,000 casualties, including 3,500 fatalities, 715,000 damaged buildings, and 7.2 million people displaced, with two million of those seeking shelter, primarily due to the lack of utility services. Direct economic losses, according to the report, would be at least $300 billion.^[25]

Iben Browning's 1990 prediction

Beginning in February 1989, self-proclaimed climatologist Iben Browning, who claimed to have predicted the 1980 eruption of Mount St. Helens and the 1989 Loma Prieta earthquake – predicted a 50% probability of a magnitude 6.5 to 7.5 earthquake in the New Madrid area sometime between December 1 and December 5, 1990.^[26]^[27] Browning appears to have based this prediction on particularly strong tidal forces being expected during that time, and his opinion that a New Madrid earthquake was "overdue;" however, seismologists generally agree that no correlation exists between tides and earthquakes.^[27]

The United States Geological Survey (USGS) requested an evaluation of the prediction by an advisory board of earth scientists, who concluded, "the prediction does not have scientific validity."^[27] Despite the lack of scientific support, Browning's prediction was widely reported in international media, causing public alarm. The period passed with no major earthquake activity in New Madrid or along the 120-mile (190 km) fault line.^[27]

Uncertainty over recurrence potential

The lack of apparent land movement along the New Madrid fault system has long puzzled scientists. In 2009, two studies based on eight years of GPS measurements indicated that the faults were moving at no more than 0.2 mm (0.008 in.) per year.^[28] This contrasts to the rate of slip on the San Andreas Fault, which averages up to 37 mm (1.5 in) per year across California.^[29]

On March 13, 2009, a research group based out of Northwestern University and Purdue University, funded by the USGS, reported in Science and other journals that the New Madrid system may be "shutting down" and that tectonic stress may now be accumulating elsewhere.^[28] Seth Stein, the leader of the research group, published these views in a book, Disaster Deferred, in 2008. Although some of these ideas have gained some acceptance among researchers, they have not been accepted by the National Earthquake Prediction Evaluation Council, which advises the USGS.^[30] In the November 5, 2009, issue of Nature, researchers from Northwestern University and the University of Missouri said that due to the lack of fault movement, the quakes along the faults may only be aftershocks of the 1811–12 earthquakes.^[31]

According to the USGS, a broad consensus exists that the possibility of major earthquakes in the NMSZ remains a concern, and that the GPS data do not provide a compelling case for lessening perceived earthquake hazards in the region. One concern is that the small earthquakes that still happen are not diminishing over time, as would be if they were aftershocks of the 1811–12 events; another is that the 4,500-year archaeological record of large earthquakes in the region is more significant than 10 years of direct strain measurement. The USGS issued a fact sheet in 2009 stating the estimate of a 7–10% chance of a New Madrid earthquake of magnitude comparable to one of the 1811–12 quakes within the next 50 years, and a 25–40% chance of a magnitude 6 earthquake in the same time frame.^[32] In July 2014, the USGS increased the risk assessment for the New Madrid area.^[33]

References

^ "Center for Earthquake Research and Information at the University of Memphis". University of Memphis.
^ Stelzer, C. D. (December 15, 1999). "On Shaky Ground". Riverfront Times. Retrieved October 16, 2017.
^ ^a ^b Csontos, Ryan; Van Arsdale, Roy; Waldron, Brian (2008). "Reelfoot rift and its impact on Quaternary deformation in the central Mississippi River valley". Geosphere. 4 (1): 145–158. Bibcode:2008Geosp...4..145C. doi:10.1130/GES00107.1.
^ Ervin, C. Patrick; McGinnis, L. D. (1975). "Reelfoot Rift: Reactivated Precursor to the Mississippi Embayment". GSA Bulletin. 86 (9): 1287–1295. Bibcode:1975GSAB...86.1287E. doi:10.1130/0016-7606(1975)86<1287:RRRPTT>2.0.CO;2. Retrieved October 22, 2021.
^ Hildenbrand, Thomas G.; Langenheim, Victoria E.; Schweig, Eugene; Stauffer, Peter H.; Hendley II, James W. (1996). "Uncovering Hidden Hazards in the Mississippi Valley" (PDF). U.S. Geological Survey Fact Sheet 200-96. United States Geological Survey. Retrieved October 22, 2021.
^ "USGS Earthquake Hazards Program, Earthquake Report: Kentucky". National Earthquake Information Center. June 6, 2003. Archived from the original on April 20, 2006.
^ Grollimund, Balz; Zoback, Mark D. (February 2001). "Did deglaciation trigger intraplate seismicity in the New Madrid seismic zone?". Geology. 29 (2): 175–178. Bibcode:2001Geo....29..175G. doi:10.1130/0091-7613(2001)029<0175:DDTISI>2.0.CO;2.
^ Pollitz, Fred F.; Kellogg, Louise; Bürgmann, Roland (December 2001). "Sinking Mafic Body in a Reactivated Lower Crust: A Mechanism for Stress Concentration at the New Madrid Seismic Zone". Bulletin of the Seismological Society of America. 91 (6): 1882–1897. Bibcode:2001BuSSA..91.1882P. doi:10.1785/0120000277.
^ Liu, L.; Zoback, M. D. (1997). "Lithospheric strength and intraplate seismicity in the New Madrid seismic zone". Tectonics. 16 (4): 585–595. Bibcode:1997Tecto..16..585L. doi:10.1029/97TC01467. S2CID 129287433.
^ Forte, A. M.; Mitrovica, J. X.; R. Moucha; N. A. Simmons; S. P. Grand (2007). "Descent of the ancient Farallon slab drives localized mantle flow below the New Madrid seismic zone" (PDF). Geophys. Res. Lett. 34 (4): L04308. Bibcode:2007GeoRL..34.4308F. doi:10.1029/2006GL027895. S2CID 10662775. Archived from the original (PDF) on July 6, 2011.
^ Pratt, Thomas L (April–June 1994). "How old is the New Madrid Seismic Zone?" (PDF). Seismological Research Letters. 65 (2): 172–179. Bibcode:1994SeiRL..65..172P. doi:10.1785/gssrl.65.2.172. Archived from the original (PDF) on December 10, 2013.
^ Tuttle, Martitia P.; Schweig, Eugene S.; John D. Sims; Lafferty, Robert H.; Wolf, Lorraine W.; Hayes, Marion L. (August 2002). "The Earthquake Potential of the New Madrid Seismic Zone". Bulletin of the Seismological Society of America. 92 (6): 2080–2089. Bibcode:2002BuSSA..92.2080T. doi:10.1785/0120010227.
^ Tuttle, Martitia P.; Schweig, III, Eugene S.; et al. (July–August 2005). "Evidence for New Madrid Earthquakes in A.D. 300 and 2350 B.C". Seismological Research Letters. 76 (4): 489–501. Bibcode:2005SeiRL..76..489T. doi:10.1785/gssrl.76.4.489.
^ Tuttle, MP; Al-Shukri, H; Mahdi, H (2006). "Very Large Earthquakes Centered Southwest of the New Madrid Seismic Zone 5,000–7,000 Years Ago". Seismological Research Letters. 77 (6): 755. Bibcode:2006SeiRL..77..755T. doi:10.1785/gssrl.77.6.755.
^ Van Arsdale, RB; Stahle, DW; MK Cleaveland; MJ Guccione (June 1998). "Earthquake signals in tree-ring data from the New Madrid seismic zone and implications for paleoseismicity". Geology. 26 (6): 515–518. Bibcode:1998Geo....26..515V. doi:10.1130/0091-7613(1998)026<0515:ESITRD>2.3.CO;2.
^ Feldman, Jay (2005). When the Mississippi Ran Backwards : Empire, Intrigue, Murder, and the New Madrid Earthquakes. Free Press. ISBN 978-0-7432-4278-3.
^ ^a ^b ^c ^d ^e ^f "Summary of 1811-1812 New Madrid Earthquakes Sequence". Earthquake Hazards Program. United States Geological Survey. Archived from the original on September 8, 2017. Retrieved September 8, 2017.
^ ^a ^b ^c ^d "Report of the Independent Expert Panel on New Madrid Seismic Zone Earthquake Hazards" (PDF). United States Geological Survey. Archived from the original (PDF) on September 8, 2017. Retrieved September 8, 2017.
^ ^a ^b ^c Johnston & Schweig, A. C, E. S (1996). "The Enigma of the New Madrid Earthquakes of 1811-1812". Annual Review of Earth and Planetary Sciences. 24: 339–384. Bibcode:1996AREPS..24..339J. doi:10.1146/annurev.earth.24.1.339. S2CID 16780063.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ "Historic Earthquakes". Earthquake Hazards Program. United States Geological Survey. Archived from the original on July 12, 2012.
^ ^a ^b Fuller, Myron (1912), The New Madrid Earthquake (PDF), United States Geological Survey
^ "Historic Earthquakes: Near Charleston, Mississippi County, Missouri". United States Geological Survey. Archived from the original on July 7, 2012. Retrieved September 23, 2009.
^ "Historic Quakes: Southern Illinois 1968 11 09 17:01:40.5 UTC". United States Geological Survey. Archived from the original on July 8, 2012. Retrieved September 23, 2009.
^ "Government warns of "catastrophic" U.S. quake". Reuters. November 20, 2008. Retrieved October 16, 2017.
^ "Impact of New Madrid Seismic Zone Earthquakes on the Central USA" Mid-American Earthquake Center Report 09-03. Urbana, IL: Mid-America Earthquake Center. University of Illinois at Urbana-Champaign.
^ Fowler, Glenn (July 20, 1991). "Iben Browning, 73; Researcher Studied Climate and Quakes". The New York Times. Retrieved July 2, 2011.
^ ^a ^b ^c ^d Spence, William J.; Herrmann, R. B.; Johnston, A. C.; Reagor, B. G. (1993). "Responses to Iben Browning's Prediction of a 1990 New Madrid, Missouri, Earthquake". Dept. of the Interior, U.S. Geological Survey. Archived from the original on April 18, 2015. Retrieved July 22, 2011.
^ ^a ^b Gardner, Elizabeth K. (2009). "New Madrid fault system may be shutting down". Retrieved October 16, 2017.
^ Thatcher, Wayne "Present-Day Crustal Movements and the Mechanics of Cyclic Deformation" in "The San Andreas Fault System, California." USGS Professional Paper 1515. Robert E. Wallace, editor. 1990. Retrieved December 6, 2013.
^ Monastersky, Richard. "Nature News: Seth Stein: The Quake Killer" Nature (9 November 2011)
^ "Earthquakes Actually Aftershocks Of 19th Century Quakes; Repercussions Of 1811 And 1812 New Madrid Quakes Continue To Be Felt". Science Daily. Retrieved November 4, 2009.
^ Earthquake Hazard in the New Madrid Seismic Zone Remains a Concern USGS (2009). Retrieved 12/6/13
^ Petersen, Mark D.; Moschetti, Morgan P.'; Powers, Peter M.' et al. (July 17, 2014) "Documentation for the 2014 Update of the United States National Seismic Hazard Maps" United States Geological Survey

External links

36°35′N 89°35′W / 36.58°N 89.59°W / 36.58; -89.59

[1] "Center for Earthquake Research and Information at the University of Memphis". University of Memphis.

[2] Stelzer, C. D. (December 15, 1999). "On Shaky Ground". Riverfront Times. Retrieved October 16, 2017.

[Csontos_et_al_2008-3] Csontos, Ryan; Van Arsdale, Roy; Waldron, Brian (2008). "Reelfoot rift and its impact on Quaternary deformation in the central Mississippi River valley". Geosphere. 4 (1): 145–158. Bibcode:2008Geosp...4..145C. doi:10.1130/GES00107.1.

[Ervin_and_McGinnis_1975-4] Ervin, C. Patrick; McGinnis, L. D. (1975). "Reelfoot Rift: Reactivated Precursor to the Mississippi Embayment". GSA Bulletin. 86 (9): 1287–1295. Bibcode:1975GSAB...86.1287E. doi:10.1130/0016-7606(1975)86<1287:RRRPTT>2.0.CO;2. Retrieved October 22, 2021.

[hazardsfactsheet-5] Hildenbrand, Thomas G.; Langenheim, Victoria E.; Schweig, Eugene; Stauffer, Peter H.; Hendley II, James W. (1996). "Uncovering Hidden Hazards in the Mississippi Valley" (PDF). U.S. Geological Survey Fact Sheet 200-96. United States Geological Survey. Retrieved October 22, 2021.

[6] "USGS Earthquake Hazards Program, Earthquake Report: Kentucky". National Earthquake Information Center. June 6, 2003. Archived from the original on April 20, 2006.

[7] Grollimund, Balz; Zoback, Mark D. (February 2001). "Did deglaciation trigger intraplate seismicity in the New Madrid seismic zone?". Geology. 29 (2): 175–178. Bibcode:2001Geo....29..175G. doi:10.1130/0091-7613(2001)029<0175:DDTISI>2.0.CO;2.

[8] Pollitz, Fred F.; Kellogg, Louise; Bürgmann, Roland (December 2001). "Sinking Mafic Body in a Reactivated Lower Crust: A Mechanism for Stress Concentration at the New Madrid Seismic Zone". Bulletin of the Seismological Society of America. 91 (6): 1882–1897. Bibcode:2001BuSSA..91.1882P. doi:10.1785/0120000277.

[9] Liu, L.; Zoback, M. D. (1997). "Lithospheric strength and intraplate seismicity in the New Madrid seismic zone". Tectonics. 16 (4): 585–595. Bibcode:1997Tecto..16..585L. doi:10.1029/97TC01467. S2CID 129287433.

[10] Forte, A. M.; Mitrovica, J. X.; R. Moucha; N. A. Simmons; S. P. Grand (2007). "Descent of the ancient Farallon slab drives localized mantle flow below the New Madrid seismic zone" (PDF). Geophys. Res. Lett. 34 (4): L04308. Bibcode:2007GeoRL..34.4308F. doi:10.1029/2006GL027895. S2CID 10662775. Archived from the original (PDF) on July 6, 2011.

[11] Pratt, Thomas L (April–June 1994). "How old is the New Madrid Seismic Zone?" (PDF). Seismological Research Letters. 65 (2): 172–179. Bibcode:1994SeiRL..65..172P. doi:10.1785/gssrl.65.2.172. Archived from the original (PDF) on December 10, 2013.

[12] Tuttle, Martitia P.; Schweig, Eugene S.; John D. Sims; Lafferty, Robert H.; Wolf, Lorraine W.; Hayes, Marion L. (August 2002). "The Earthquake Potential of the New Madrid Seismic Zone". Bulletin of the Seismological Society of America. 92 (6): 2080–2089. Bibcode:2002BuSSA..92.2080T. doi:10.1785/0120010227.

[13] Tuttle, Martitia P.; Schweig, III, Eugene S.; et al. (July–August 2005). "Evidence for New Madrid Earthquakes in A.D. 300 and 2350 B.C". Seismological Research Letters. 76 (4): 489–501. Bibcode:2005SeiRL..76..489T. doi:10.1785/gssrl.76.4.489.

[14] Tuttle, MP; Al-Shukri, H; Mahdi, H (2006). "Very Large Earthquakes Centered Southwest of the New Madrid Seismic Zone 5,000–7,000 Years Ago". Seismological Research Letters. 77 (6): 755. Bibcode:2006SeiRL..77..755T. doi:10.1785/gssrl.77.6.755.

[15] Van Arsdale, RB; Stahle, DW; MK Cleaveland; MJ Guccione (June 1998). "Earthquake signals in tree-ring data from the New Madrid seismic zone and implications for paleoseismicity". Geology. 26 (6): 515–518. Bibcode:1998Geo....26..515V. doi:10.1130/0091-7613(1998)026<0515:ESITRD>2.3.CO;2.

[16] Feldman, Jay (2005). When the Mississippi Ran Backwards : Empire, Intrigue, Murder, and the New Madrid Earthquakes. Free Press. ISBN 978-0-7432-4278-3.

[USGS_Summary-17] ^ ^a ^b ^c ^d ^e ^f "Summary of 1811-1812 New Madrid Earthquakes Sequence". Earthquake Hazards Program. United States Geological Survey. Archived from the original on September 8, 2017. Retrieved September 8, 2017.

[Expert_Panel-18] "Report of the Independent Expert Panel on New Madrid Seismic Zone Earthquake Hazards" (PDF). United States Geological Survey. Archived from the original (PDF) on September 8, 2017. Retrieved September 8, 2017.

[:0-19] Johnston & Schweig, A. C, E. S (1996). "The Enigma of the New Madrid Earthquakes of 1811-1812". Annual Review of Earth and Planetary Sciences. 24: 339–384. Bibcode:1996AREPS..24..339J. doi:10.1146/annurev.earth.24.1.339. S2CID 16780063.{{cite journal}}: CS1 maint: multiple names: authors list (link)

[USGS_Historic_Earthquakes-20] "Historic Earthquakes". Earthquake Hazards Program. United States Geological Survey. Archived from the original on July 12, 2012.

[:1-21] Fuller, Myron (1912), The New Madrid Earthquake (PDF), United States Geological Survey

[22] "Historic Earthquakes: Near Charleston, Mississippi County, Missouri". United States Geological Survey. Archived from the original on July 7, 2012. Retrieved September 23, 2009.

[23] "Historic Quakes: Southern Illinois 1968 11 09 17:01:40.5 UTC". United States Geological Survey. Archived from the original on July 8, 2012. Retrieved September 23, 2009.

[24] "Government warns of "catastrophic" U.S. quake". Reuters. November 20, 2008. Retrieved October 16, 2017.

[Elnashai_2009-25] "Impact of New Madrid Seismic Zone Earthquakes on the Central USA" Mid-American Earthquake Center Report 09-03. Urbana, IL: Mid-America Earthquake Center. University of Illinois at Urbana-Champaign.

[obit-26] Fowler, Glenn (July 20, 1991). "Iben Browning, 73; Researcher Studied Climate and Quakes". The New York Times. Retrieved July 2, 2011.

[USGS_Circular_1083-27] Spence, William J.; Herrmann, R. B.; Johnston, A. C.; Reagor, B. G. (1993). "Responses to Iben Browning's Prediction of a 1990 New Madrid, Missouri, Earthquake". Dept. of the Interior, U.S. Geological Survey. Archived from the original on April 18, 2015. Retrieved July 22, 2011.

[Shutting_Down-28] Gardner, Elizabeth K. (2009). "New Madrid fault system may be shutting down". Retrieved October 16, 2017.

[Cyclic_Deformation-29] Thatcher, Wayne "Present-Day Crustal Movements and the Mechanics of Cyclic Deformation" in "The San Andreas Fault System, California." USGS Professional Paper 1515. Robert E. Wallace, editor. 1990. Retrieved December 6, 2013.

[30] Monastersky, Richard. "Nature News: Seth Stein: The Quake Killer" Nature (9 November 2011)

[31] "Earthquakes Actually Aftershocks Of 19th Century Quakes; Repercussions Of 1811 And 1812 New Madrid Quakes Continue To Be Felt". Science Daily. Retrieved November 4, 2009.

[USGS_Factsheet_2009-32] Earthquake Hazard in the New Madrid Seismic Zone Remains a Concern USGS (2009). Retrieved 12/6/13

[33] Petersen, Mark D.; Moschetti, Morgan P.'; Powers, Peter M.' et al. (July 17, 2014) "Documentation for the 2014 Update of the United States National Seismic Hazard Maps" United States Geological Survey

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+{{Short description|Major seismic zone in the southern and midwestern United States}}
-[[Image:NMSZBig.gif|thumb|Seismic map New Madrid Seismic Zone.  Credit: USGS]]
+{{Use mdy dates|date=April 2024}}
-The '''New Madrid Seismic Zone''', also known as the '''Reelfoot Rift''' or the '''New Madrid Fault Line''', is a major seismic zone located in the [[Midwestern United States]].  The New Madrid fault system was responsible for the 1812 [[New Madrid Earthquake]] and has the potential to produce damaging earthquakes in coming decades.
+{{bots|deny=Citation bot}}
+{{multiple image
+ | align     = right
+ | direction = horizontal
+ | image1    = NMSZBig.gif
+ | width1    = 210
+ | caption1  = Reelfoot Rift and the New Madrid seismic zone in a 3D topographic image
+ | image2    = NMSZ Erdbeben.jpg
+ | width2    = 241
+ | caption2  = Magnetic potential map of the Reelfoot Rift
+}}
+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 earthquake]]s (earthquakes within a [[tectonic plate]]) in the [[Southern United States|Southern]] and [[Midwestern United States]], stretching to the southwest from [[New Madrid, Missouri]].
+The New Madrid fault system was responsible for the [[1811–1812 New Madrid earthquakes]] and has the potential to produce large [[earthquake]]s in the future. Since 1812, frequent smaller earthquakes have been recorded in the area.<ref>{{Cite web|url=http://www.memphis.edu/ceri/public/history.php|title=Center for Earthquake Research and Information at the University of Memphis|publisher=University of Memphis}}</ref>
+Earthquakes that occur in the New Madrid seismic zone potentially threaten parts of seven American states: [[Illinois]], [[Missouri]], [[Arkansas]], [[Kentucky]], [[Tennessee]], and to a lesser extent [[Mississippi]] and [[Indiana]].<ref>{{Cite web|url=https://www.riverfronttimes.com/stlouis/on-shaky-ground/Content?oid=2492565|title=On Shaky Ground|last=Stelzer|first=C. D.|date=December 15, 1999|website=Riverfront Times|access-date=October 16, 2017}}</ref>
+==Location==
+The {{convert|150|mi|km|adj=mid}}-long seismic zone, which extends into five states, stretches southward from [[Cairo, Illinois]]; through [[Hayti, Missouri|Hayti]], [[Caruthersville, Missouri|Caruthersville]], and [[New Madrid, Missouri|New Madrid]] in Missouri; through [[Blytheville, Arkansas|Blytheville]] into [[Marked Tree, Arkansas|Marked Tree]] in Arkansas. It also covers a part of [[West Tennessee]] near [[Reelfoot Lake]], extending southeast into [[Dyersburg, Tennessee|Dyersburg]]. It is southwest of the [[Wabash Valley seismic zone]].
 ==Geology==
+[[File:Reelfoot Rift diagram from USGS en.svg|thumb|287px|The geological structure of Reelfoot Rift, USGS, 1996]]
-The New Madrid Seismic Zone is made up of reactivated [[Geological fault|faults]] that formed when [[North America]] began to split or [[rift]] apart during the breakup of the [[supercontinent]] [[Rodinia]] in the [[Neoproterozoic]] [[Era (geology)|Era]] (about 750 million years ago). The rift failed, but remained as a scar or zone of weakness. The area was then flooded by an ancient ocean, depositing layers of sediment on the rift. During the [[Mesozoic]] [[era (geology)|Era]] (about 200 million years ago), as the [[Atlantic Ocean]] was opening in the east, rifting was once again re-activated and [[intrusive]] [[igneous]] rocks were emplaced. But again the rifting failed and the continent remained intact, although with a significant zone of weakness. The natural valley formed by collapsed rock allowed the Mississippi River to flow through, depositing more sediment on the rift. This rift is known as the Reelfoot Rift and coincides with the northernmost portion of the [[Mississippi embayment]]. Most of the [[seismic|seismicity]] is located from 5 to 25 km beneath the Earth's surface. The depth of the rift allows earthquakes' seismic waves to travel long distances through the bedrock, making them destructive when they do happen.
+The [[Fault (geology)|faults]] responsible for the NMSZ are embedded in a subsurface geological feature known as the Reelfoot Rift, which likely formed during the [[Cambrian|Cambrian Period]].<ref name="Csontos et al 2008">{{cite journal|doi=10.1130/GES00107.1 |title=Reelfoot rift and its impact on Quaternary deformation in the central Mississippi River valley |first1=Ryan |last1=Csontos |first2=Roy |last2=Van Arsdale |first3=Brian |last3=Waldron |journal=Geosphere |year=2008 |volume=4 |issue=1 |pages=145–158 |bibcode=2008Geosp...4..145C |doi-access=free}}</ref> The Reelfoot Rift was first described by Ervin and McGinnis (1975) and believed to be of late [[Precambrian]] age.<ref name="Ervin and McGinnis 1975">{{cite journal |url=https://pubs.geoscienceworld.org/gsa/gsabulletin/article/86/9/1287/201869/Reelfoot-Rift-Reactivated-Precursor-to-the |title=Reelfoot Rift: Reactivated Precursor to the Mississippi Embayment |journal=GSA Bulletin |year=1975 |volume=86 |issue=9 |first1=C. Patrick |last1=Ervin |first2=L. D. |last2=McGinnis | pages=1287–1295 |doi=10.1130/0016-7606(1975)86<1287:RRRPTT>2.0.CO;2 |bibcode=1975GSAB...86.1287E |access-date=October 22, 2021}}</ref> The [[rift]] failed to split the North American continent, but it has remained as an [[aulacogen]] (a scar or zone of weakness) deep underground.<ref name="Csontos et al 2008"/><ref name=hazardsfactsheet>{{cite web |url=https://pubs.usgs.gov/fs/1996/0200/report.pdf |title=Uncovering Hidden Hazards in the Mississippi Valley |work=U.S. Geological Survey Fact Sheet 200-96 |year=1996 |first1=Thomas G. |last1=Hildenbrand |first2=Victoria E. |last2=Langenheim |first3=Eugene |last3=Schweig |first4=Peter H. |last4=Stauffer |first5=James W. |last5=Hendley II |publisher=United States Geological Survey |access-date=October 22, 2021}}</ref>
-The 150-mile long fault system, which extends into five states, stretches southward from [[Cairo, Illinois]], through [[Hayti, Missouri|Hayti]]-[[Caruthersville, Missouri|Caruthersville]] and [[New Madrid, Missouri]], through [[Blytheville, Arkansas| Blytheville]], to [[Marked Tree, Arkansas]]. It also covers a part of [[Tennessee]], near [[Reelfoot Lake]], extending southeast into [[Dyersburg, Tennessee|Dyersburg]].
+This relative weakness is important, as it would allow the relatively small east–west compressive forces associated with the continuing westward [[continental drift]] of the [[North American plate]] to reactivate old faults around New Madrid, making the area unusually prone to earthquakes in spite of it being far from the nearest tectonic plate boundary.<ref>{{Cite web|url=http://neic.usgs.gov/neis/eq_depot/2003/eq_030606/|title=USGS Earthquake Hazards Program, Earthquake Report: Kentucky|date=June 6, 2003|website=National Earthquake Information Center|archive-url=https://web.archive.org/web/20060420141846/http://neic.usgs.gov/neis/eq_depot/2003/eq_030606/|archive-date=April 20, 2006}}</ref>
-The red zones on the map above indicate the [[epicenter]] locations of hundreds of minor [[earthquake]]s recorded since the [[1970s]]. Two trends are apparent. First is the general NE-SW trend paralleling the trend of the Reelfoot Rift. The second is the intense cross trend, NW-SE, that occurs just southwest of New Madrid. This second trend coincides with an intrusive igneous body which lies deeply buried beneath the sediments of the rift zone. Several other bodies of deeply buried intrusive rock are known to exist within the seismic zone. The depths of these igneous rock bodies closely corresponds to the depth of the seismic activity.
+Since other ancient rifts are known to occur in North America, but not all are associated with modern earthquakes, other processes could be at work to locally increase mechanical stress on the New Madrid faults.<ref>{{Cite journal |title=Did deglaciation trigger intraplate seismicity in the New Madrid seismic zone? |first1=Balz |last1=Grollimund |first2=Mark D. |last2=Zoback |journal=Geology |date=February 2001 |volume=29  |issue=2 |pages=175–178 |doi=10.1130/0091-7613(2001)029<0175:DDTISI>2.0.CO;2 |bibcode=2001Geo....29..175G}}</ref><ref>{{Cite journal |title=Sinking Mafic Body in a Reactivated Lower Crust: A Mechanism for Stress Concentration at the New Madrid Seismic Zone |first1=Fred F. |last1=Pollitz |first2=Louise |last2=Kellogg |first3=Roland |last3=Bürgmann |journal=Bulletin of the Seismological Society of America |date=December 2001 |volume=91 |issue=6 |pages=1882–1897 |doi=10.1785/0120000277 |bibcode=2001BuSSA..91.1882P |url=https://zenodo.org/record/1235774}}</ref> Some form of heating in the [[lithosphere]] below the area has been suggested to be making deep rocks more plastic, which would concentrate compressive stress in the shallower subsurface area where the faulting occurs.<ref>{{Cite journal |last1=Liu |first1=L. |first2=M. D. |last2=Zoback |year=1997 |title=Lithospheric strength and intraplate seismicity in the New Madrid seismic zone |journal=Tectonics |volume=16 |issue=4 |pages=585–595 |doi=10.1029/97TC01467 |bibcode=1997Tecto..16..585L|s2cid=129287433}}</ref><ref>{{Cite journal |url=http://gizmo.geotop.uqam.ca//forteA/Forte_et_al_GRL_2007.pdf |archive-url=https://web.archive.org/web/20110706211145/http://gizmo.geotop.uqam.ca//forteA/Forte_et_al_GRL_2007.pdf |url-status=dead |archive-date=July 6, 2011 |title=Descent of the ancient Farallon slab drives localized mantle flow below the New Madrid seismic zone |last1=Forte |first1=A. M. |first2=J. X. |last2=Mitrovica |author3=R. Moucha |author4=N. A. Simmons |author5=S. P. Grand |year=2007 |journal=Geophys. Res. Lett. |volume=34 |page=L04308 |doi=10.1029/2006GL027895 |bibcode= 2007GeoRL..34.4308F|issue=4 |s2cid=10662775}}</ref>
 ==History==
-[[Image:New Madrid quakes.png|thumb|Earthquakes in the New Madrid seismic zone since 1974. Credit: USGS]]
+[[File:New Madrid and Wabash seizmic zones-USGS.png|thumb|267px|Earthquakes in the New Madrid and Wabash Valley seismic zones from 1974 to 2002, with magnitudes larger than 2.5]]
-The zone saw four of the largest [[North America|North American]] earthquakes in recorded history, with magnitude estimates greater than 7.0 on the [[Richter scale]], all occurring in a 3 month period. Many of the published accounts describe the cumulative effects of all the earthquakes, known as the New Madrid Sequence, thus finding the individual effects of each quake can be difficult.
+The zone had four of the largest earthquakes in recorded North American history, with [[Moment magnitude scale|moment magnitudes]] estimated to be as large as 7 or greater, all occurring within a 3-month period between December 1811 and February 1812. Many of the published accounts describe the cumulative effects of all the earthquakes, known as the New Madrid Sequence, so finding the individual effects of each quake can be difficult. Magnitude estimates and epicenters are based on interpretations of historical accounts and may vary.
+===Prehistoric earthquakes===
-* '''First earthquake of [[December 16]], [[1811]]''', 0815 UTC (2:15 a.m.); 7.7 [[Moment magnitude scale|magnitude]]; epicenter in northeast Arkansas; [[Mercalli_Intensity_Scale|Mercalli XI]].  It caused only slight damage to man-made structures, mainly because of the sparse population in the epicentral area.  However, landslides and geological changes occurred along the Mississippi River, and large localized waves occurred due to fissures opening and closing below the Earth's surface.
+As uplift rates associated with large New Madrid earthquakes could not have occurred continuously over geological timescales without dramatically altering the local topography, studies have concluded that the seismic activity there cannot have gone on for longer than 64,000 years, making the New Madrid seismic zone a young feature, or that earthquakes and the associated uplift migrate around the area over time, or that the NMSZ has short periods of activity interspersed with long periods of dormancy.<ref>{{Cite journal|last=Pratt|first=Thomas L|date=April–June 1994|title=How old is the New Madrid Seismic Zone?|url=http://faculty.washington.edu/tpratt/publications/Pratt_SRL_94.pdf|journal=Seismological Research Letters|volume=65|issue=2|pages=172–179|doi=10.1785/gssrl.65.2.172|bibcode=1994SeiRL..65..172P |archive-url=https://web.archive.org/web/20131210144437/http://faculty.washington.edu/tpratt/publications/Pratt_SRL_94.pdf|archive-date=December 10, 2013}}</ref>
+Archaeological studies have found from studies of [[Sand boil|sand blows]] and soil horizons that previous series of very large earthquakes have occurred in the NMSZ in recent prehistory. Based on artifacts found buried by sand blow deposits and from carbon-14 studies, previous large earthquakes like those of 1811–12 appear to have happened around AD 1450 and 900,<ref>{{Cite journal|last1=Tuttle|first1=Martitia P.|last2=Schweig|first2=Eugene S.|author3=John D. Sims|author4=Lafferty, Robert H.|author5=Wolf, Lorraine W.|author6=Hayes, Marion L.|date=August 2002|title=The Earthquake Potential of the New Madrid Seismic Zone|journal=Bulletin of the Seismological Society of America|volume=92|issue=6|pages=2080–2089|bibcode=2002BuSSA..92.2080T|doi=10.1785/0120010227}}</ref> as well as around AD 300. Evidence has also been found for an apparent series of large earthquakes around 2350 BC.<ref>{{Cite journal |title=Evidence for New Madrid Earthquakes in A.D. 300 and 2350 B.C |first1=Martitia P. |last1=Tuttle |first2=Eugene S. |last2=Schweig, III|journal=Seismological Research Letters |date=July–August 2005 |volume=76 |pages=489–501 |doi=10.1785/gssrl.76.4.489 |issue=4 |bibcode=2005SeiRL..76..489T |display-authors=etal}}</ref>
-* '''Second earthquake of [[December 16]], [[1811]]''', 1415 UTC (8:15 a.m.); 7.0 magnitude; epicenter in northeast Arkansas; Mercalli X-XI.  This shock followed the first earthquake by six hours.
+About {{convert|80|km}} southwest of the presently defined NMSZ, but close enough to be associated with the Reelfoot Rift, near [[Marianna, Arkansas]], two sets of [[Soil liquefaction|liquefaction]] features indicative of large earthquakes have been tentatively identified and dated to 3500 and 4800 BC. These features were interpreted to have been caused by groups of large earthquakes timed closely together.<ref>{{Cite journal |title=Very Large Earthquakes Centered Southwest of the New Madrid Seismic Zone 5,000–7,000 Years Ago |first1=MP |last1=Tuttle |first2=H |last2=Al-Shukri |first3=H |last3=Mahdi |journal=Seismological Research Letters |volume=77 |pages=755 |year=2006 |doi=10.1785/gssrl.77.6.755 |issue=6|bibcode=2006SeiRL..77..755T }}</ref>
-* '''Earthquake of [[January 23]], [[1812]]''', 1500 UTC (9 a.m.); 7.6 magnitude; epicenter in Missouri Bootheel.  The meizoseismal area was characterized by general ground warping, ejections, fissuring, severe landslides, and caving of stream banks.
+[[Dendrochronology]] (tree ring) studies conducted on the oldest [[Taxodium distichum|bald cypress]] trees growing in [[Reelfoot Lake]] found evidence of the 1811–12 series in the form of fractures followed by rapid growth after their inundation, whereas cores taken from old bald cypress trees in the St. Francis sunklands showed slowed growth in the half century that followed 1812. These were interpreted as clear signals of the 1811–12 earthquake series in tree rings. As the tree ring record in Reelfoot Lake and the St. Francis sunk lands extend back to 1682 and 1321, respectively, Van Arsdale et al. interpret the lack of similar signals elsewhere in the chronology as evidence against large New Madrid earthquakes between those years and 1811.<ref>{{Cite journal |title=Earthquake signals in tree-ring data from the New Madrid seismic zone and implications for paleoseismicity |first1=RB |last1=Van Arsdale |first2=DW |last2=Stahle |author3=MK Cleaveland |author4=MJ Guccione |journal=Geology |date=June 1998 |volume=26 |issue=6 |pages=515–518 |doi=10.1130/0091-7613(1998)026<0515:ESITRD>2.3.CO;2 |bibcode=1998Geo....26..515V}}</ref>
-* '''Earthquake of [[February 7]], [[1812]] (the [[New Madrid Earthquake]])''', 0945 UTC (4:45 a.m.); 7.9 magnitude; epicenter near New Madrid, Missouri.  New Madrid was destroyed. At St. Louis, many houses were damaged severely and their chimneys were thrown down. The meizoseismal area was characterized by general ground warping, ejections, fissuring, severe landslides, and caving of stream banks.
+===December 25, 1699===
-These catastrophic earthquakes occurred during a three-month period in December [[1811]] and early [[1812]]. They caused permanent changes in the course of the [[Mississippi River]], which flowed backwards temporarily, and were felt as far away as [[New York City]] and [[Boston, Massachusetts]] where churchbells rang. Large areas sank into the earth, fissures opened, lakes permanently drained, new lakes were formed, and forests were destroyed over an area of 150,000 acres (600 km&sup2;). Many houses at New Madrid were thrown down. "Houses, gardens, and fields were swallowed up" one source notes. But fatalities and damage were low, because the area was sparsely settled. Hundreds of aftershocks followed over a period of several years. All three major quakes are generally believed to have exceeded 8.0 on the [[Richter Scale]], and some [[seismologist]]s believe the largest was 9.0 or larger.
+The first known written record of an earthquake felt in the NMSZ was from a French missionary traveling up the Mississippi with a party of explorers. At 1 pm on [[Christmas Day]] 1699, at a site near the present-day location of Memphis, the party was startled by a short period of ground shaking.<ref>{{Cite book|url=https://books.google.com/books?id=OB75l5upMJQC|title=When the Mississippi Ran Backwards : Empire, Intrigue, Murder, and the New Madrid Earthquakes|last=Feldman|first=Jay|publisher=Free Press|year=2005|isbn=978-0-7432-4278-3}}</ref>
+[[File:New Madrid Erdbeben.jpg|thumb|250px|''The Great Earthquake at New Madrid'', a 19th-century [[woodcut]] from Devens' ''Our First Century'' (1877)]]
-From what is known about the present seismicity of the area, it can be inferred that their focal depths were probably between 5 and 20 kilometers. The fault plane&mdash;or planes&mdash;on which the Earth rupture occurred are inferred to have had a NNE&ndash;SSW strike direction, more or less parallel to the Mississippi River.
+===1811–12 earthquake series===
-Aftershocks strong enough to be felt occurred until the year 1817.  The largest earthquakes to have occurred since then were on [[January 4]], [[1843]] and [[October 31]], [[1895]] with magnitude estimates of 6.0 and 6.2 respectively. In addition to these events, seven events of magnitude &ge; 5.0 have occurred in the area. From the early years of the [[1800s|Nineteenth Century]] until well after the [[American Civil War]], the citizens of [[Union City, Tennessee]] would gather every [[February 7]] for an all-night "vigil and fish fry" on the site currently occupied by the Cumberland [[Presbyterianism|Presbyterian]] Church, praying, singing and beseeching [[God|the Almighty]] to "spare the land over" for another year.
+{{main|1811–12 New Madrid earthquakes}}
+* '''December 16, 1811''', 0815 UTC (2:15&nbsp;am); (M about 7.5)<ref name="USGS Summary">{{cite web|title=Summary of 1811-1812 New Madrid Earthquakes Sequence|url=https://earthquake.usgs.gov/earthquakes/events/1811-1812newmadrid/summary.php|publisher=United States Geological Survey|department=Earthquake Hazards Program|access-date=8 September 2017|archive-url=https://archive.today/20170908010930/https://earthquake.usgs.gov/earthquakes/events/1811-1812newmadrid/summary.php|archive-date=8 September 2017|url-status=dead}}</ref> epicenter in northeast Arkansas, probably on the Cottonwood Grove fault;<ref name="Expert Panel"/>{{rp|p. 7}} it caused only slight damage to man-made structures, mainly due to the sparse population in the epicentral area. The future location of Memphis, Tennessee, was shaken at Mercalli level IX intensity. A seismic [[seiche]] propagated upriver, and Little Prairie was destroyed by [[Soil liquefaction|liquefaction]].<ref name=":0">{{Cite journal|last=Johnston & Schweig|first=A. C, E. S|date=1996|title=The Enigma of the New Madrid Earthquakes of 1811-1812|journal=Annual Review of Earth and Planetary Sciences|volume=24|pages=339–384|doi=10.1146/annurev.earth.24.1.339|bibcode=1996AREPS..24..339J|s2cid=16780063}}</ref> Local uplifts of the ground and the sight of water waves moving upstream gave observers the impression that the Mississippi River was flowing backwards.<ref name="USGS Historic Earthquakes">{{cite web|title=Historic Earthquakes|url=https://earthquake.usgs.gov/earthquakes/states/events/1811-1812.php|publisher=United States Geological Survey|department=Earthquake Hazards Program|archive-url=https://archive.today/20120712125656/http://earthquake.usgs.gov/earthquakes/states/events/1811-1812.php|archive-date=12 July 2012|url-status=dead}}</ref>
+:At New Madrid, trees were knocked down and riverbanks collapsed. This event shook windows and furniture in Washington, DC, rang bells in Richmond, Virginia, sloshed well water and shook houses in Charleston, South Carolina, and knocked plaster off of houses in Columbia, South Carolina. In Jefferson, Indiana, furniture moved, and in Lebanon, Ohio, residents fled their homes. Observers in Herculaneum, Missouri, called it "severe" and said it had a duration of 10–12 minutes.<ref name=":1">{{Citation|last=Fuller|first=Myron|date=1912|title=The New Madrid Earthquake|url=https://pubs.usgs.gov/bul/0494/report.pdf|publisher=United States Geological Survey|issue=Bulletin 494}}</ref>
+:[[Aftershock]]s were felt every 6-10 minutes, a total of 27, in New Madrid until what was called the Daylight Shock, which was of the same intensity as the first. Many of these were also felt throughout the eastern US, though with less intensity than the initial earthquake.<ref name=":1" />
+* '''December 16, 1811''', sometimes termed the "Dawn Shock" or "Daylight Shock", occurred at 1315 UTC (7:15&nbsp;am); (M about 7) with the epicenter in northeast Arkansas.<ref name="USGS Summary"/>
+* '''January 23, 1812''', 1515 UTC (9:15&nbsp;am); (M about 7.3) epicenter around New Madrid,<ref name="USGS Summary"/> although this is disputed.<ref name="Expert Panel"/>{{rp|p. 7}} This was probably the smallest of the three main shocks but resulted in widespread ground deformation, landslides, fissuring, and stream-bank caving in the [[meizoseismal area]]. Johnston and Schweig attribute this earthquake to a rupture on the New Madrid North Fault.<ref name=":0" /><ref name="USGS Summary"/> A minority viewpoint holds that this earthquake's epicenter was in southern Illinois. A 2011 expert panel urged further research to clarify this point, stating that the Illinois hypothesis would mean that an extended section of fault exists, perhaps still loaded and capable of hosting a great earthquake in the future.<ref name="Expert Panel"/>{{rp|p. 7}}
+* '''February 7, 1812''', 0945 UTC (3:45&nbsp;am); (M about 7.5) epicenter near New Madrid, Missouri.<ref name="USGS Summary"/> This was the largest event in the series, and it destroyed the town of New Madrid.<ref name="USGS Summary"/> At [[St. Louis, Missouri]], many houses were severely damaged, and their chimneys were toppled. It appears to have occurred on Reelfoot fault, a [[reverse fault]] segment that crosses under the Mississippi River just south of [[Kentucky Bend]] and continues to the east as the Lake County Uplift.<ref name="Expert Panel">{{cite web|title=Report of the Independent Expert Panel on New Madrid Seismic Zone Earthquake Hazards|url=https://earthquake.usgs.gov/aboutus/nepec/reports/NEPEC_NMSZ_expert_panel_report.pdf|publisher=United States Geological Survey|access-date=8 September 2017|archive-url=https://archive.today/20170908211408/https://earthquake.usgs.gov/aboutus/nepec/reports/NEPEC_NMSZ_expert_panel_report.pdf|archive-date=8 September 2017|url-status=dead}}</ref>{{rp|p. 7}} In this event, uplift along the fault created temporary waterfalls on the Mississippi River, created a wave that propagated upstream, and caused the formation of [[Reelfoot Lake]] by damming streams.<ref name=":0" />
+[[File:New Madrid Seismic Zone activity 1974-2011.svg|thumb|250px|A map of more than 4,000 earthquakes in the area since 1974]]
-Instruments were installed in and around this area in [[1974]] to closely monitor seismic activity. Since then, more than 4000 earthquakes have been located, most of which are too small to be felt. On average one earthquake per year will be large enough to be felt in the area.
+===1812–1900===
-In the late 1980s [[Iben Browning]] predicted that a major earthquake on the New Madrid fault line in southern Missouri would occur on [[December 3]], [[1990]]; the predicted earthquake did not occur. The prediction created a stir that was followed by scorn and ridicule.
+Hundreds of aftershocks of the 1811–12 series followed over a period of several years. Aftershocks strong enough to be felt occurred until 1817. The largest earthquakes to have occurred since then were on January 4, 1843, and [[1895 Charleston earthquake|October 31, 1895]], with magnitude estimates of 6.0 and 6.6, respectively. The 1895 event had its epicenter near [[Charleston, Missouri]]. The quake damaged virtually all the buildings in Charleston, created sand volcanoes by the city, cracked a pier on the [[Cairo Rail Bridge]], and toppled chimneys in [[St. Louis, Missouri]]; Memphis, Tennessee; [[Gadsden, Alabama]]; and [[Evansville, Indiana]].<ref>{{cite web |title=Historic Earthquakes: Near Charleston, Mississippi County, Missouri |url=https://earthquake.usgs.gov/regional/states/events/1895_10_31.php |publisher=United States Geological Survey |access-date=23 September 2009 |archive-url=https://archive.today/20120707135000/http://earthquake.usgs.gov/earthquakes/states/events/1895_10_31.php |archive-date=7 July 2012 |url-status=dead}}</ref>
+===Modern activity===
-==More quakes predicted==
+The largest NMSZ earthquake of the 20th century was [[1968 Illinois earthquake|a 5.4-magnitude quake]] on November 9, 1968, near [[Dale, Illinois]]. The quake damaged the civic building at [[Henderson, Kentucky]], and was felt in 23 states. People in [[Boston]] said their buildings swayed. At the time of the quake, it was the biggest recorded quake with an epicenter in Illinois in that state's recorded history.<ref>{{cite web|title=Historic Quakes: Southern Illinois 1968 11 09 17:01:40.5 UTC|url=https://earthquake.usgs.gov/regional/states/events/1968_11_09.php|publisher=United States Geological Survey|access-date=23 September 2009|archive-url=https://archive.today/20120708185537/http://earthquake.usgs.gov/earthquakes/states/events/1968_11_09.php|archive-date=8 July 2012|url-status=dead}}</ref> In 2008 in the nearby [[Wabash Valley seismic zone]], a similar [[2008 Illinois earthquake|magnitude 5.4 earthquake]] occurred with its epicenter in Illinois near [[West Salem, Illinois|West Salem]] and [[Mount Carmel, Illinois|Mount Carmel]].
-[[Image:Charleston1895.gif|thumb|Comparison: the 1895 Charleston, Missouri, earthquake in the New Madrid seismic zone with the 1994 Northridge, California, earthquake. Red indicates area of structural damage, yellow indicates area where shaking was felt.]]
+Instruments were installed in and around the area in 1974 to closely monitor seismic activity. Since then, more than 4,000 earthquakes have been recorded, most of which were too small to be felt. On average, one earthquake per year is large enough to be felt in the area.
-The potential for the recurrence of large earthquakes and their impact today on densely populated cities in and around the seismic zone has generated much research devoted to understanding earthquakes. Establishing the probability for an earthquake of a given magnitude is an inexact science. By studying evidence of past quakes and closely monitoring ground motion and current earthquake activity, scientists attempt to understand their causes, recurrence rates, ground motion and disaster mitigation.  The probability of magnitude 6.0 or greater in the near future is considered significant; a 90% chance of such an earthquake by the year [[2040]] has been given. In the [[June 23]], [[2005]] issue of the journal [[Nature (journal)|Nature]], the odds of another 8.0 event within 50 years were estimated to be between 7 and 10 percent.[http://www.livescience.com/forcesofnature/050622_new_madrid.html] Because of the unconsolidated sediments which are a major part of the underlying [[geology]] of the [[Mississippi embayment]] as well as the river sediments along the Mississippi and [[Ohio River]] valleys to the north and east (note the red ''fingers'' extending up these valleys in the image above), large quakes here have the potential for more widespread damage than major quakes on the west coast.
+===Potential for future earthquakes===
-The possibility of a large earthquake hitting [[Memphis, Tennessee]] was even explored on the television program [[It Could Happen Tomorrow]], on [[The Weather Channel]] in early 2006 as well as the [[History Channel]] show Mega Disasters.
+In a report filed in November 2008, the U.S. [[Federal Emergency Management Agency]] warns that a serious earthquake in the NMSZ 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 would cause damage to tens of thousands of structures affecting [[Water purification|water distribution]], [[transportation|transportation systems]], and other vital [[infrastructure]].<ref>{{Cite news|url=https://www.reuters.com/article/us-earthquake-study/government-warns-of-catastrophic-u-s-quake-idUSTRE4AJ9EV20081120|title=Government warns of "catastrophic" U.S. quake|date=November 20, 2008|agency=Reuters|access-date=October 16, 2017}}</ref> The earthquake is expected to result in many thousands of fatalities, with more than 4,000 of the fatalities expected in Memphis alone.
+<!--According to an unattributed report carried by the ''Virtual Times'', an 8.0 earthquake on the New Madrid Fault would destroy 60 percent of Memphis, killing thousands and causing over $50 billion in property damage in the city alone.<ref>http://www.hsv.com/genlintr/newmadrd/ "The Virtual Times: The New Madrid Earthquake"</ref>-->The potential for the recurrence of large earthquakes and their effects today on densely populated cities in and around the seismic zone has generated much research devoted to understanding the NMSZ. By studying evidence of past quakes and closely monitoring [[ground motion]] and current earthquake activity, scientists attempt to understand their causes and recurrence intervals.
-==Trivia==
-An eruption from the seismic zone and its potential consequences was the subject of an episode of the History Channel show ''Mega Disasters''.
+In October 2009, a team composed of [[University of Illinois]] and [[Virginia Tech]] researchers headed by Amr S. Elnashai, funded by the [[Federal Emergency Management Agency]], considered a scenario where all three segments of the New Madrid fault ruptured simultaneously with a total earthquake magnitude of 7.7. The report found that there would be significant damage in the eight states studied – Alabama, Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri, and Tennessee – with the probability of additional damage in states farther from the NMSZ. Tennessee, Arkansas, and Missouri would be most severely impacted, and Memphis and St. Louis would be severely damaged. The report estimated 86,000 casualties, including 3,500 fatalities, 715,000 damaged buildings, and 7.2 million people displaced, with two million of those seeking shelter, primarily due to the lack of utility services. Direct economic losses, according to the report, would be at least $300 billion.<ref name="Elnashai 2009">[https://www.ideals.illinois.edu/handle/2142/14810 "Impact of New Madrid Seismic Zone Earthquakes on the Central USA"] Mid-American Earthquake Center Report 09-03. Urbana, IL: Mid-America Earthquake Center. University of Illinois at Urbana-Champaign.</ref>
-The potential danger to [[Memphis, TN]] from another mega New Madrid earthquake was featured on [[The Weather Channel]]'s "It Could Happen Tomorrow".
+===Iben Browning's 1990 prediction===
+Beginning in February 1989, self-proclaimed climatologist [[Iben Browning]], who claimed to have predicted the [[1980 eruption of Mount St. Helens]] and the [[1989 Loma Prieta earthquake]] – predicted a 50% probability of a magnitude 6.5 to 7.5 earthquake in the New Madrid area sometime between December 1 and December 5, 1990.<ref name=obit>{{cite news | author=Fowler, Glenn| title=Iben Browning, 73; Researcher Studied Climate and Quakes | url=https://www.nytimes.com/1991/07/20/obituaries/iben-browning-73-researcher-studied-climate-and-quakes.html?scp=1&sq=iben%20browning&st=cse | work=The New York Times | date=July 20, 1991 | access-date=2 July 2011}}</ref><ref name="USGS Circular 1083">{{cite web|author1=Spence, William J. |author2=Herrmann, R. B. |author3=Johnston, A. C. |author4=Reagor, B. G. | title=Responses to Iben Browning's Prediction of a 1990 New Madrid, Missouri, Earthquake | url=https://pubs.er.usgs.gov/usgspubs/cir/cir1083 | publisher=Dept. of the Interior, U.S. Geological Survey | year=1993 | volume=248  |issue=1083 | access-date=22 July 2011 | archive-url=https://web.archive.org/web/20150418215612/http://pubs.er.usgs.gov/publication/cir1083 | archive-date=2015-04-18}}</ref> Browning appears to have based this prediction on particularly strong tidal forces being expected during that time, and his opinion that a New Madrid earthquake was "overdue;" however, seismologists generally agree that no correlation exists between tides and earthquakes.<ref name="USGS Circular 1083"/>
+The [[United States Geological Survey]] (USGS) requested an evaluation of the prediction by an advisory board of earth scientists, who concluded, "the prediction does not have scientific validity."<ref name="USGS Circular 1083"/> Despite the lack of scientific support, Browning's prediction was widely reported in international media, causing public alarm. The period passed with no major earthquake activity in New Madrid or along the {{convert|120|mi|km|adj=on}} fault line.<ref name="USGS Circular 1083"/>
+===Uncertainty over recurrence potential===
+The lack of apparent land movement along the New Madrid fault system has long puzzled scientists. In 2009, two studies based on eight years of GPS measurements indicated that the faults were moving at no more than 0.2&nbsp;mm (0.008 in.) per year.<ref name="Shutting Down">{{Cite news|url=http://www.physorg.com/news156169464.html|title=New Madrid fault system may be shutting down|last=Gardner|first=Elizabeth K.|year=2009|access-date=October 16, 2017}}</ref> This contrasts to the rate of slip on the [[San Andreas Fault]], which averages up to {{convert|37|mm|in|abbr=on}} per year across California.<ref name="Cyclic Deformation">[http://pubs.usgs.gov/pp/1990/1515/ Thatcher, Wayne "Present-Day Crustal Movements and the Mechanics of Cyclic Deformation"] in "The San Andreas Fault System, California." USGS Professional Paper 1515. Robert E. Wallace, editor. 1990. Retrieved December 6, 2013.</ref>
+On March 13, 2009, a research group based out of [[Northwestern University]] and [[Purdue University]], funded by the USGS, reported in [[Science (journal)|''Science'']] and other journals that the New Madrid system may be "shutting down" and that tectonic stress may now be accumulating elsewhere.<ref name="Shutting Down"/> Seth Stein, the leader of the research group, published these views in a book, ''Disaster Deferred'', in 2008. Although some of these ideas have gained some acceptance among researchers, they have not been accepted by the National Earthquake Prediction Evaluation Council, which advises the USGS.<ref>Monastersky, Richard. [http://www.nature.com/news/2011/111109/full/479166a.html "Nature News: Seth Stein: The Quake Killer"] ''[[Nature (journal)|Nature]]'' (9 November 2011)</ref> In the November 5, 2009, issue of ''[[Nature (journal)|Nature]]'', researchers from Northwestern University and the [[University of Missouri]] said that due to the lack of fault movement, the quakes along the faults may only be aftershocks of the 1811–12 earthquakes.<ref>{{cite web |title=Earthquakes Actually Aftershocks Of 19th Century Quakes; Repercussions Of 1811 And 1812 New Madrid Quakes Continue To Be Felt |url=https://www.sciencedaily.com/releases/2009/11/091104132652.htm |website=[[Science Daily]] |access-date=November 4, 2009}}</ref>
+According to the USGS, a broad consensus exists that the possibility of major earthquakes in the NMSZ remains a concern, and that the GPS data do not provide a compelling case for lessening perceived earthquake hazards in the region. One concern is that the small earthquakes that still happen are not diminishing over time, as would be if they were aftershocks of the 1811–12 events; another is that the 4,500-year archaeological record of large earthquakes in the region is more significant than 10 years of direct strain measurement. The USGS issued a fact sheet in 2009 stating the estimate of a 7–10% chance of a New Madrid earthquake of magnitude comparable to one of the 1811–12 quakes within the next 50 years, and a 25–40% chance of a magnitude 6 earthquake in the same time frame.<ref name="USGS Factsheet 2009">[http://pubs.usgs.gov/fs/2009/3071/pdf/FS09-3071.pdf Earthquake Hazard in the New Madrid Seismic Zone Remains a Concern USGS (2009).] Retrieved 12/6/13</ref> In July 2014, the USGS increased the risk assessment for the New Madrid area.<ref>Petersen, Mark D.; Moschetti, Morgan P.'; Powers, Peter M.' et al. (July 17, 2014) [http://pubs.usgs.gov/of/2014/1091/ "Documentation for the 2014 Update of the United States National Seismic Hazard Maps"] [[United States Geological Survey]]</ref>
 ==See also==
+* {{annotated link|Crowley's Ridge}}
-*[[Earthquake]]
+* {{annotated link|Earthquake prediction}}
-*[[Disaster preparedness]]
+* {{annotated link|Eastern Tennessee seismic zone}}
-*[[Household seismic safety]]
+* {{annotated link|Guy-Greenbrier earthquake swarm}}
-*[[Plate tectonics]]
+* {{annotated link|Marianna Fault}}
-*[[Seismic retrofit]]
-*[[Soil liquefaction]]
 ==References==
+{{Reflist}}
-*[[United States Geological Survey]] ([[October 15]], [[2003]]). [http://wwwneic.cr.usgs.gov/neis/eq_depot/usa/1811-1812.html "USGS Earthquake Hazards Program: 1811 - 1812 Earthquakes in the New Madrid Seismic Zone"]. Retrieved [[May 3]], [[2005]].
-*[http://wwwneic.cr.usgs.gov/neis/new_madrid/new_madrid.html USGS New Madrid]
+==Further reading==
-*[http://quake.wr.usgs.gov/prepare/factsheets/NewMadrid/ U.S. Geologic Survey site discusses the New Madrid seismic zone.]
+* Boyd, K.F. (1995). ''Geomorphic evidence of deformation in the northern part of the New Madrid seismic zone'' [U.S. Geological Survey Professional Paper 1538-R]. Washington, DC: U.S. Department of the Interior, U.S. Geological Survey.
-*[http://quake.wr.usgs.gov/prepare/factsheets/HiddenHazs/ Uncovering Hidden Hazards in the Mississippi Valley]
+* Langenheim, V.E. (1995). ''Gravity of the New Madrid seismic zone : a preliminary study'' [U.S. Geological Survey Professional Paper 1538-L]. Washington, DC: U.S. Department of the Interior, U.S. Geological Survey.
-*[http://www.cusec.org Central US Earthquake Consortium]
+* Odum, J.K., et al. (1995). ''High-resolution, shallow, seismic reflection surveys of the northwest Reelfoot rift boundary near Marston, Missouri'' [U.S. Geological Survey Professional Paper 1538-P]. Washington, DC: U.S. Department of the Interior, U.S. Geological Survey.
-*[http://www.ceri.memphis.edu/compendium/ U. Memphis, TN, Center for Earthquake Research and Information (CERI) comprehensive references for the 1811–1812 earthquakes]
+* Potter, C.J., et al. (1995). ''Structure of the Reelfoot-Rough Creek rift system, fluorspar area fault complex and Hicks dome, southern Illinois and western Kentucky : new constraints from regional seismic reflection data'' [U.S. Geological Survey Professional Paper 1538-Q]. Washington, DC: U.S. Department of the Interior, U.S. Geological Survey.
-*[http://hsv.com/genlintr/newmadrd/ Links to eyewitness descriptions of the three 1811-12 earthquakes, and results of the earthquakes as seen in photographs of 1904.]
+* Rodriguez, B.D. (1995). ''Axial structures within the Reelfoot rift delineated with magnetotelluric surveys'' [U.S. Geological Survey Professional Paper 1538-K]. Washington, DC: U.S. Department of the Interior, U.S. Geological Survey.
-*[http://rockhoundingar.com/geology/fault.html Your Fault, My Fault, and the New Madrid Fault]
+* Stein, Seth. ''Disaster Deferred: A New View of Earthquake Hazards in the New Madrid Seismic Zone'' Columbia University Press, 2012.
+* Stephenson, W.J., K.M. Shedlock, and J.K. Odum. (1995). ''Characterization of the Cottonwood Grove and Ridgely faults near Reelfoot Lake, Tennessee, from high-resolution seismic reflection data'' [U.S. Geological Survey Professional Paper 1538-I]. Washington, DC: U.S. Department of the Interior, U.S. Geological Survey.
+* Valencius, Conevery Bolton. ''The Lost History of the New Madrid Earthquakes. ''Chicago: University of Chicago Press, 2013.
+==External links==
+* [http://www.cusec.org Central US Earthquake Consortium]
+* [http://pubs.usgs.gov/fs/2009/3071/pdf/FS09-3071.pdf Earthquake Hazard in the New Madrid Seismic Zone Remains a Concern] – United States Geological Survey
+* [http://search.usa.gov/search?affiliate=usgs&utf8=%E2%9C%93&query=New+Madrid&commit=Search USGS New Madrid]
+* [https://pubs.usgs.gov/fs/1996/0200/report.pdf "Uncovering Hidden Hazards in the Mississippi Valley"]
+* [http://www.memphis.edu/ceri/compendium/ U. Memphis, TN, Center for Earthquake Research and Information (CERI) comprehensive references for the 1811–1812 earthquakes]
+* [http://web.mst.edu/~rogersda/nmsz/Space%20geodetic%20evidence%20for%20rapid%20strain%20rates%20in%20the%20New%20Madrid%20seismic%20zone%20of%20Central%20USA.pdf Space geodetic evidence for rapid strain rates in the New Madrid seismic zone of Central USA (PDF) ]
+{{Faults|state=collapsed}}
+{{Coord|36.58|N|89.59|W|source:placeopedia|display=title}}
-[[Category:Earthquakes]]
+[[Category:Aulacogens]]
-[[Category:Geography of Arkansas]]
+[[Category:Geographic areas of seismological interest]]
-[[Category:Geography of Missouri]]
+[[Category:Geology of Arkansas]]
+[[Category:Geology of Illinois]]
+[[Category:Geology of Indiana]]
+[[Category:Geology of Kentucky]]
+[[Category:Geology of Mississippi]]
+[[Category:Geology of Missouri]]
+[[Category:Geology of Tennessee]]
+[[Category:Mississippi embayment]]
 [[Category:Plate tectonics]]
-[[Category:Rift valleys]]
+[[Category:Seismic faults of the United States]]
-[[Category:Seismic faults]]
+[[Category:Seismic zones of the United States]]
-[[Category:Seismology]]