Segmentation of the Eastern Reelfoot Rift Margin: Reinterpretation of the Northeastern Reelfoot Rift Fault Geometry and Seismic Potential

Abstract

Abstract The eastern Reelfoot rift margin (ERRM) poses a significant seismic hazard to the city of Memphis, Tennessee, and may be capable of generating moment magnitude 7 earthquakes. The goal of this study is to refine the fault structure and geometry of the ERRM, to improve understanding of the associated seismic hazard. We apply multiple filters (e.g., reduction-to-pole and horizontal-gradient) to aeromagnetic intensity data, to visualize the magnetic signature of ERRM basement rocks. To remove ambiguity in our fault interpretations from the magnetic data, we restrict our interpretations to magnetic gradients that correspond to geologic and geophysical evidence of faulting and rank faults on a confidence scheme. From near Covington, Tennessee, to Dyersburg, Tennessee, we interpret the ERRM to be segmented into nine intersecting faults that trend northeast, north-northeast, and north-northwest (two high confidence, four intermediate confidence, and three low confidence). We calculate the moment magnitude potential of each fault based on the estimated fault length. The minimum moment magnitude potential is 6.0, and the maximum is 7.0.