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Brief Report for Reelfoot scarp and New Madrid seismic zone (Class A) No. 1023
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citation for this record: Crone, A.J., and Schweig, E.S., compilers, 1994, Fault number 1023, Reelfoot scarp and New Madrid seismic zone, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, http://earthquakes.usgs.gov/regional/qfaults, accessed 11/24/2009 06:23 AM.
| Synopsis | In the winter of 1811-1812, at least three major earthquakes occurred in the New Madrid seismic zone, and the area remains the most seismically active area in central and eastern North America. The 1811-1812 earthquakes were among the largest historical earthquakes to occur in North America and were perhaps the largest historical intraplate earthquakes in the world. The earthquakes produced widespread liquefaction throughout the seismic zone and prominent to subtle surface deformation in several areas, but they did not produce any known surface faulting. Other than the pervasive sand blows throughout the seismic zone, the Reelfoot scarp is the most prominent geomorphic feature that has been produced by the modern tectonism. Recent studies of the scarp have provided valuable information on the recurrence of deformation on the scarp, calculated uplift rates, and the history of faulting.
The evidence of Quaternary faulting in the New Madrid region is based on the occurrence of the major earthquakes in 1811-1812, the abundant ongoing seismicity, and the surface deformation associated with Reelfoot scarp. Other than the fault associated with Reelfoot scarp, individual seismogenic faults in the New Madrid seismic zone are not expressed at the surface, and their general locations are inferred to be associated with areas of abundant microseismicity. Because individual Quaternary faults remain unidentified throughout much of the seismic zone, it is not possible to define and measure specific attributes (azimuth, length, dip, etc.) for the faults. |
| County(s) and State(s) | |
| AMS sheet(s) | Blytheville |
| Physiographic province(s) | |
| Length (km) | 0 km. |
| Average strike | |
| Sense of movement | Dextral |
| Dip Direction | V |
| Historic earthquake | |
| Most recent prehistoric deformation | Latest Quaternary (<15 ka) |
| Slip-rate category | Insufficient data |
| Date and Compiler(s) | 1994 Anthony J. Crone, U.S. Geological Survey Eugene S. Schweig, U.S. Geological Survey |
