IDENTIFYING THE ORIGIN OF A PROMINENT TOPOGRAPHIC LINEAMENT NEAR THE NEW MADRID SEISMIC ZONE IN THE NORTHERN MISSISSIPPI EMBAYMENT

A prominent topographic lineament located peripheral to North America’s New Madrid Seismic Zone (NMSZ) remains poorly understood despite vast amounts of geologic research having been conducted throughout the NMSZ over the last century. The NMSZ is the most seismically active region in the United States east of the Rocky Mountains and is responsible for generating three of the most powerful earthquakes in North American history. Most topographic lineaments in the NMSZ correspond to magnetic and gravitational anomalies that were originally identified by Hildenbrand and Hendricks (1995) and are likely related to a network of faults associated with the Reelfoot Rift. One such lineament was identified by Fisk (1944) and corroborated by Wyatt and Stearns (1988). The lineament extends 150 km from eastern Arkansas through western Tennessee and into southern Kentucky along the southeastern margin of the Reelfoot Rift. Paleoseismological studies suggest the southern segment of the lineament corresponds to a pair of steeply dipping strike-slip faults that may have originated as normal faults during rifting in the Cambrian. The northern segment of the lineament was determined to be a fluvial “Hatchie” terrace by Saucier (1987) and is seismically quiescent, so it’s origin and nature have never been thoroughly investigated. In order to identify whether or not the origin of the lineament’s northern segment is structurally related to the Reelfoot Rift similar to its southern counterpart, a series of statistical and mathematical analysis techniques were used to quantify the concavity of the lineament’s slope in addition to several known fault scarp and terrace riser slopes. Average concavity values for the lineament, fault scarp, and terrace riser slopes were then compared to one another in order to identify morphological similarities and differences between each. Results suggest fluvial terrace riser slopes are significantly more concave on average than fault scarp slopes, and that the lineament has a slope significantly more similar to that of a fault scarp than a fluvial terrace riser.