scholarly journals Lake County, Tennessee, in the Heart of the New Madrid Seismic Zone

2019 ◽  
Vol 7 ◽  
Author(s):  
Taylor Weathers ◽  
Roy Van Arsdale
Keyword(s):  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Lake County ◽  
New Madrid

How Old is the New Madrid Seismic Zone?

1994 ◽  
Vol 65 (2) ◽  
pp. 172-179 ◽  
Author(s):  
Thomas L. Pratt
Keyword(s):  
Fault Zone ◽  
Fault Model ◽  
New Madrid Seismic Zone ◽  
Reverse Fault ◽  
Seismic Zone ◽  
Lake County ◽  
Recurrence Times ◽  
Analysis Techniques ◽  
Large Earthquakes ◽  
New Madrid

Abstract Current seismicity levels on the New Madrid seismic zone should produce about 0.11 cm/year of horizontal slip which, when compared with uplift of 42 m in the subsurface strata below the Lake County uplift and assuming a 31° reverse fault model, indicates that the present seismicity levels could not have been present for more than about 64,000 years. If seismicity in the region has persisted for a much longer period of time, then (1) the seismicity has moved spatially between several deformed zones (Crowley’s Ridge and the Crittenden County fault zone); (2) the seismicity is episodic in nature, and active periods similar to the present occur between long quiescent times; or (3) there have been far fewer large earthquakes than predicted by extrapolation of the Gutenberg-Richter relation to higher magnitudes. Any of these scenarios indicates that assessing the hazard from large earthquakes is more complicated than conventional analyses have assumed because either the seismicity locations or rates change or analysis techniques relying on the Gutenberg-Richter relation are invalid for estimating the recurrence times of large earthquakes in the New Madrid area.

Tectonic Deformation in the New Madrid Seismic Zone: Inferences from Boundary Element Modeling

1992 ◽  
Vol 63 (3) ◽  
pp. 407-425 ◽  
Author(s):  
J. S. Gomberg
Keyword(s):  
Boundary Element ◽  
Strain Field ◽  
Tectonic Deformation ◽  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Lake County ◽  
Element Modeling ◽  
Dimensional Boundary ◽  
Length Width ◽  
New Madrid

Abstract The lack of instrumental recordings and of obvious fault scarps associated with the 1811–1812 New Madrid earthquakes necessitates examination of more subtle indicators of the geometry and type of faulting responsible for these events. Morphologic and geologic features and the distribution of modern seismicity are used to infer the number, strike, length, width, type of faulting (strike- or dip-slip), and spatial variability of slip for the major faults in the New Madrid Seismic Zone (NMSZ). This is accomplished through two-dimensional boundary-element modeling of the strain field arising from slip on hypothetical faults that is driven by either coseismic or uniform regional strains. Tectonic deformation is reflected in the seismicity and in morphologic and geologic features including (1) the Lake County uplift, (2) Reelfoot Lake, (3) the deformed rocks of the Blytheville arch, and (4) the St. Francis Sunk Lands. Many of these features can be qualitatively explained as resulting from tectonic deformation due to slip on two left-stepping right-lateral strike-slip faults that are coincident with the northeast-trending zones of seismicity and the Blytheville arch. The morphology appears to be, at least in part, a consequence of major earthquakes that rupture these faults. The locations of the 1811–1812 and largest post-1812 earthquakes and the models are consistent with a process in which the 1811–1812 earthquakes relieved accumulated regional shear strain causing the greatest post-1812 shear strains to exist at the ends of the fault zone. Modeling results also suggest that the numerous small earthquakes in the NMSZ are not aftershocks of the 1811–1812 earthquakes but instead represent continuous localized adjustments to a uniform regional strain field. The Bootheel lineament does not appear to be significant in the shaping the morphology, geologic structure, and pattern of seismicity of the NMSZ. The inferred length of the 1811–1812 earthquake ruptures suggest that their sizes may have been overestimated. Model predicted subsidence within the St. Francis Sunk Lands suggests that tectonic deformation may also influence alluvial processes in the NMSZ.

Structure of the Lake County uplift: New Madrid seismic zone

1998 ◽  
Vol 88 (5) ◽  
pp. 1204-1211
Author(s):  
Jodi L. Purser ◽  
Roy B. Van Arsdale
Keyword(s):  
Hanging Wall ◽  
New Madrid Seismic Zone ◽  
Reverse Fault ◽  
Seismic Zone ◽  
Lake County ◽  
Western Margin ◽  
Kink Bands ◽  
Brittle Ductile Transition ◽  
Step Over ◽  
New Madrid

Abstract The central segment of the New Madrid seismic zone lies within a left step-over zone between two northeast-striking, right-lateral, strike-slip fault systems. Within this compressional step-over zone is the topographically and structurally high Lake County uplift, which includes the Tiptonville dome and Ridgely ridge. We believe these structures are a consequence of deformation in the hanging wall above the northwest-striking, southwest-dipping Reelfoot reverse fault. Reelfoot fault dips 73° from the surface to the top of the Precambrian at a depth of approximately 4 km. From 4 to 12 km depth, the fault dips 32° and is seismically active. Based on a fault-bend fold model, we believe that the Reelfoot fault becomes horizontal and aseismic at the top of the quartz brittle-ductile transition zone, at approximately 12 km depth. Our data indicate that the western margin of the Tiptonville dome-Ridgely ridge and the western margin of the Lake County uplift are bounded by east-dipping kink bands (backthrusts). Recent work suggests that the Reelfoot fault is responsible for the 7 February 1812, M 8 New Madrid earthquake. However, the Reelfoot fault has a surface area that is less than that necessary for an M 8 earthquake. A possible solution to this discrepancy between magnitude and fault plane area is that the associated backthrusts are seismogenic.

3D GEOLOGIC MAPPING IN AND ADJACENT TO THE NEW MADRID SEISMIC ZONE, CENTRAL UNITED STATES

2020 ◽  
Author(s):  
Renee M. Reichenbacher ◽  
◽  
Valarie Harrison ◽  
Taylor Andrew Weathers ◽  
Roy B. Van Arsdale ◽  
...  
Keyword(s):  
United States ◽  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Geologic Mapping ◽  
Central United States ◽  
New Madrid

POSSIBLE SURFACE WARPING ALONG THE BOOTHEEL FAULT REVEALED FROM LIDAR, NEW MADRID SEISMIC ZONE, CENTRAL US

2020 ◽  
Author(s):  
Samia Noor ◽  
◽  
Randel Tom Cox ◽  
Robert Smalley ◽  
Md Rizwanul Hasan
Keyword(s):  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
New Madrid

Stream response to repeated coseismic folding, Tiptonville dome, New Madrid seismic zone

Geomorphology ◽  
2002 ◽  
Vol 43 (3-4) ◽  
pp. 313-349 ◽  
Author(s):  
M.J Guccione ◽  
K Mueller ◽  
J Champion ◽  
S Shepherd ◽  
S.D Carlson ◽  
...  
Keyword(s):  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Stream Response ◽  
New Madrid
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