The Fault the Instruments Say Is Quiet

At about three in the morning on 7 February 1812, a boatman named Mathias Speed cut his boat loose on the Mississippi because the sandbar his rope was tied to was sinking under it. Hours later he went through a waterfall that had not been there the day before. His letter gives the reason: the ground downstream had been "raised so high as to stop the progress of the river". Three earthquakes above magnitude 7 struck the middle of the North American continent between 16 December 1811 and 7 February 1812, nowhere near a plate boundary, around a river town of a few hundred people called New Madrid in Missouri Territory. Nothing measured them. Every magnitude is an estimate worked backward out of letters and newspapers. The famous part of this story is the Mississippi running backwards, and four sources disagree about it. The USGS calls the upstream flow an illusion. The IRIS and EarthScope animation says uplifted land forced the water up river, only long enough to find a new route. Eliza Bryan gives it "a few minutes". Mathias Speed describes a river that had been stopped. "For several hours" is in none of the four. Sand-blow dating puts very large earthquakes at about A.D. 900 and about A.D. 1450 as well as 1811-12, with intervals "as short as 200 years and as long as 800 years, with an average of 500". Satellite positioning has found little or no motion since 1999, and the 2009 release ran the headline "New Madrid fault system may be shutting down". The USGS answered the same year: its experts "did not find the GPS data to be a convincing reason to lower the assessment of earthquake hazard". No death toll is given: no reliable count survives, and no source read names anyone who died. No earthquake is predicted. Where the sources disagree, the video says which one says what. SOURCES USGS, "Summary of 1811-1812 New Madrid Earthquakes Sequence", usgs.gov, read in full. Dates, magnitudes, the "illusion that the river was flowing upstream", Nuttli's aftershock counts. Mathias Speed, letter, Bardstown Repository, 1812, CERI New Madrid Compendium, digitalcommons.memphis.edu. "raised so high as to stop the progress of the river", and the falls. Eliza Bryan, letter to Lorenzo Dow, 1816, CERI index, read at msnucleus.org. "retrograde for a few minutes, owing as is supposed, to an irruption in its bed". IRIS and EarthScope, "New Madrid Earthquake: A River Runs Backward", iris.edu. "the land was forced up", "only long enough to find a new route". Odum, Stephenson, Shedlock and Pratt, GSA Bulletin 110(2), 1998, abstract. The Reelfoot thrust fault, ground "uplifted at least 0.5 m". Tuttle, Schweig, Sims, Lafferty, Wolf and Haynes, BSSA, 2002, abstract. "A.D. 900 ± 100 years and A.D. 1450 ± 150 years", and the 200-800 year interval. Hough, Armbruster, Seeber and Hough, JGR 105(B10), 2000, abstract. Mw 7.2-7.3, 7.0 and 7.4-7.5 for the three mainshocks. Newman, Stein, Weber, Engeln, Mao and Dixon, "Slow Deformation and Lower Seismic Hazard at the New Madrid Seismic Zone", Science 284(5414), 1999, pp. 619-621, abstract read at digitalcommons.usf.edu. "show little, if any, motion"; the hazard "appears to be overestimated". Purdue and Northwestern release, 13 March 2009, purdue.edu, read in full. "New Madrid fault system may be shutting down", under 0.2 mm a year. Calais and Stein, "Time-Variable Deformation in the New Madrid Seismic Zone", Science 323(5920), 2009. Not read; metadata verified. Seth Stein, "New Madrid Seismic Zone: A cold, dying fault?", sites.northwestern.edu, read in full. "thousands of years or longer". Frankel, Applegate, Tuttle and Williams, USGS Fact Sheet 2009-3071, landing page read. The hazard sentence above. PDF not read. Gomberg and Schweig, USGS Fact Sheet 131-02, 2002, p. 4, read. Over 50 years, "Probability of a magnitude 6.0 or larger = 25 - 40%". Page and Hough, Science, 23 January 2014, via Scott Neuman, NPR, 24 January 2014, read at kpbs.org. Omori's Law; "not aftershocks". Calais, Camelbeeck, Stein, Liu and Craig, GRL 43(20), 2016, abstract. They "need not repeat, since the tectonic loading rate is close to zero". Fuller, "The New Madrid earthquake", USGS Bulletin 494, 1912, 119 p. Citation only; not read. Missouri Encyclopedia, "New Madrid Earthquakes, 1811-1812", William E. Foley, read. Death estimates "at a mere handful". NASA Earth Observatory, "A Lake Born Out of an Earthquake", 22 December 2023, read. Submerged pre-flood stumps. Produced with AI narration and AI-assembled footage. Research, script, editorial judgement, timeline edit and thumbnail are human. EP024