1811–1812 New Madrid earthquakes

Events

• December 16, 1811, 08:15 UTC (02:15 am local time): M 7.2–8.2, epicenter in what is now northeast Arkansas. It caused only slight damage to man-made structures, mainly because of the sparse population in the epicentral area. The future location of Memphis, Tennessee, experienced level IX shaking on the Mercalli intensity scale. A seismic seiche propagated upriver, and Little Prairie (a village that was on the site of the former Fort San Fernando, near the site of present-day Caruthersville, Missouri) was heavily damaged by soil liquefaction. Modified Mercalli intensity VII or greater was observed over a 600,000 km2 area.
• December 16, 1811 (aftershock), 13:15 UTC (07:15 am local time): M 7.4, epicenter in southeast Missouri. This shock followed the first earthquake by six hours and was similar in intensity.
• January 23, 1812, 15:15 UTC (09:15 am local time): M 7.0–8.0, epicenter in the Missouri Bootheel. The meizoseismal area was characterized by general ground warping, ejections, fissuring, severe landslides, and caving of stream banks. Johnston and Schweig attributed this earthquake to a rupture on the New Madrid North Fault. This may have placed strain on the Reelfoot Fault.
• February 7, 1812, 09:45 UTC (03:45 am local time): M 7.4–8.6, epicenter near New Madrid, Missouri. The town of New Madrid was destroyed. In St. Louis, Missouri, many houses were severely damaged and their chimneys were toppled. This shock was definitively attributed to the Reelfoot Fault by Johnston and Schweig. Uplift along a segment of this reverse fault created temporary waterfalls on the Mississippi at Kentucky Bend, created waves that propagated upstream, and caused the formation of Reelfoot Lake by obstructing streams in what is now Lake County, Tennessee. The maximum Modified Mercalli intensity observed was XII.

Eyewitness accounts

John Bradbury, a fellow of the Linnean Society, was on the Mississippi on the night of December 15, 1811, and describes the tremors in great detail in his Travels in the Interior of America in the Years 1809, 1810 and 1811, published in 1817:

By the time we could get to our fire, which was on a large flag in the stern of the boat, the shock had ceased; but immediately the perpendicular banks, both above and below us, began to fall into the river in such vast masses, as nearly to sink our boat by the swell they occasioned ... At day-light we had counted twenty-seven shocks.}}

Eliza Bryan in New Madrid, Missouri Territory, wrote the following eyewitness account in March 1812:

John Reynolds, the fourth governor of Illinois, among other political posts, mentions the earthquake in his biography My Own Times: Embracing Also the History of My Life (1855):

The Shaker diarist Samuel Swan McClelland described the effects of the earthquake on the Shaker settlement at West Union (Busro), Indiana, where the earthquakes contributed to the temporary abandonment of the westernmost Shaker community.

Geologic setting

Main article: New Madrid seismic zone

The underlying cause of the earthquakes is not well understood, but modern faulting seems to be related to an ancient geologic feature buried under the Mississippi River alluvial plain, known as the Reelfoot Rift. The New Madrid seismic zone 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). Faults were created along the rift, and igneous rocks formed from magma that was being pushed towards the surface. The resulting rift system failed to split the plate, but has remained as an aulacogen (a scar or weak zone) deep underground.

In recent decades, minor earthquakes have continued. The epicenters of over 4,000 earthquakes can be identified from seismic measurements since 1974, originating from the seismic activity of the Reelfoot Rift. USGS Forecasts made in 2003 estimated a 7–10% chance of a major earthquake like those of 1811–1812, and a 25–40% chance of a quake of magnitude 6 or greater, within the next 50 years.

In a report filed in November 2008, the U.S. Federal Emergency Management Agency warns that a serious earthquake in the New Madrid seismic zone could inflict "the highest economic losses due to a natural disaster in the United States", further predicting "widespread and catastrophic" damage across Alabama, Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri, and particularly Tennessee, where a 7.7 or greater magnitude quake would cause damage to tens of thousands of structures affecting water distribution, transportation systems, and other vital infrastructure.

Aftermath

The quakes caused extensive changes to the region's topography. Subsidence, uplift, fissures, landslides and riverbank collapses were common. Trees were uprooted by the intense shaking. Reelfoot Lake was formed in Tennessee by subsidence of 1.5 meters to 6 meters in some places. Lake St. Francis in eastern Arkansas was expanded by subsidence, with sand and coal being ejected from fissures in the adjacent swamps as water levels rose by 8 to 9 meters. Waves on the Mississippi River caused boats to wash ashore; river banks rose, sand bars were destroyed, and some islands completely disappeared. Sand blows occurred in Missouri, Tennessee, and Arkansas, covering farmland.

The number of people who died is unknown; as a frontier area, the region was sparsely populated, and communications and records were poor. The predominantly wooden buildings resisted collapse, though the intense shaking caused many chimneys to fall, wood structures to crack, and trees to fall on buildings, particularly in the epicentral area during the first earthquake on December 16, 1811. Additionally, people drowned when subsided land began to flood. A Methodist chaplain traveling with Andrew Jackson on his Natchez Expedition of 1813 recorded in his journal: "The fishers [fissures] produced in the earth about Madrid look awful on both sides of the River and the earth continues to shake at times, fears are ascertained that the worst is to come, it is said that there where about one thousand inhabitants in the Town of New Madrid previous to the Earth Quake – but many alarmed went off that at this time there only about 300."

Rated at VII on the Mercalli Intensity Scale, the New Madrid earthquakes remain the strongest recorded North American earthquakes east of the Rocky Mountains. The earthquakes strengthened the Shawnee prophet Tenskwatawa after the defeat at the Battle of Tippecanoe and the destruction of Prophetstown, with local Native Americans seeing it as a vindication of his teachings and of the warnings of his brother Tecumseh. Cherokee settlements along the St. Francis River were flooded and abandoned and the Cherokee moved to the Arkansas River valley.

Gallery

Image:NMSZ_Erdbeben.jpg|Reelfoot Rift and NMSZ Image:NMSZ_Vergleich.jpg|Damage-range comparison between a moderate New Madrid zone earthquake (1895, magnitude 6.8), and a similar Los Angeles event (1994, magnitude 6.7).

References

References

1. "M 6.3 – Near Marked Tree, Arkansas". United States Geological Survey.
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6. (1988). "Trail of Tears: The Rise and Fall of the Cherokee Nation". Knopf Doubleday Publishing.
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8. (October 2, 2019). "Summary of 1811–1812 New Madrid Earthquakes Sequence". United States Geological Survey.
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18. Bradbury, John. (2003). "Bradbury's Travels in the interior of America, 1809–1811". [[Applewood Books]].
19. Letter of Eliza Bryan found in ''[http://www.hsv.com/genlintr/newmadrd/accnt1.htm Lorenzo Dow's Journal]'', Published By Joshua Martin, Printed By John B. Wolff, 1849, p. 344. Accessed September 17, 2009. [https://web.archive.org/web/20091004215057/http://www.hsv.com/genlintr/newmadrd/accnt1.htm Archived] September 21, 2009.
20. Reynolds, John. (1855). "My own times: embracing also the history of my life". B. H. Perryman and H. L. Davison.
21. Diary of Samuel Swan McClelland, in "Shakers of Eagle and Straight Creeks," Shakers of Ohio: Fugitive Papers Concerning the Shakers of Ohio, with unpublished manuscripts, [[John Patterson MacLean. J. P. MacLean]], ed. Columbus, Ohio, 1907.
22. (1995). "Fact Sheet". United States Geological Survey.
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27. Phelps, Dawson A.. (1953). "The Diary of a Chaplain in Andrew Jackson's Army: The Journal of the Reverend Mr. Learner Blackman—December 28, 1812 – April 4, 1813". Tennessee Historical Quarterly.
28. Cozzens, Peter. (2021). "The Warrior and the Prophet: The Epic Story of the Brothers Who Led the Native American Resistance".
29. (2018). "Cherokee Renascence in the New Republic". Princeton University Press.