Abstract

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.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.