Neotectonics of the southeastern Reelfoot rift zone margin, central United States, and implications for regional strain accommodation

Abstract

Research Article| May 01, 2001 Neotectonics of the southeastern Reelfoot rift zone margin, central United States, and implications for regional strain accommodation Randel Tom Cox; Randel Tom Cox 1Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA Search for other works by this author on: GSW Google Scholar Roy B. Van Arsdale; Roy B. Van Arsdale 1Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA Search for other works by this author on: GSW Google Scholar James B. Harris; James B. Harris 2Department of Geology, Millsaps College, Jackson, Mississippi 39210, USA Search for other works by this author on: GSW Google Scholar Daniel Larsen Daniel Larsen 3Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Randel Tom Cox 1Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA Roy B. Van Arsdale 1Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA James B. Harris 2Department of Geology, Millsaps College, Jackson, Mississippi 39210, USA Daniel Larsen 3Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA Publisher: Geological Society of America Received: 26 Sep 2000 Revision Received: 23 Jan 2001 Accepted: 29 Jan 2001 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2001) 29 (5): 419–422. https://doi.org/10.1130/0091-7613(2001)029<0419:NOTSRR>2.0.CO;2 Article history Received: 26 Sep 2000 Revision Received: 23 Jan 2001 Accepted: 29 Jan 2001 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Randel Tom Cox, Roy B. Van Arsdale, James B. Harris, Daniel Larsen; Neotectonics of the southeastern Reelfoot rift zone margin, central United States, and implications for regional strain accommodation. Geology 2001;; 29 (5): 419–422. doi: https://doi.org/10.1130/0091-7613(2001)029<0419:NOTSRR>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The northeast-striking New Madrid fault system of central North America has been described as a right-lateral strike-slip system with a left-stepping restraining-bend thrust. The fault system has one of the highest rates of seismic energy release in an intraplate setting, and it has been regarded as a zone of significant earthquake hazard. The New Madrid fault system is the central part of the wider Reelfoot rift fault system, a northeast- striking basement fault zone. Although component faults of the New Madrid system are well defined by microseismicity, recent geodetic surveys suggest that little if any strain is accumulating on the principal (southern) strike-slip arm of the fault system. Seismicity and geologic data show that the “restraining-bend” thrust continues past the southern strike-slip arm to the southeastern Reelfoot rift margin. Thus, we suggest that earthquakes defining the southern arm of the New Madrid fault system are primarily aftershocks of an earthquake on that arm during the last sequence of great earthquakes (A.D. 1811– 1812), and it is the southeastern rift-margin fault system that is currently accommodating right-lateral strain along the boundary of the thrust block. This interpretation is consistent with recent geodetic results. The southeastern rift margin coincides with a 150-km-long linear topographic scarp from near Memphis to the Tennessee-Kentucky line, and S-wave reflection profiles, auger data, and a trench excavation reveal late Wisconsin–early Holocene surface faulting and late Holocene liquefaction associated with this fault-line scarp. Variation in sense of throw along strike and flower-structure geometry suggest that this is a strike-slip fault. Recognition of this rift margin as an important element of active tectonism in the Mississippi embayment has broad implications for assessment of the seismic hazard of this and similar intraplate settings. Temporal shifts in strain accommodation may give rise to short-term seismicity patterns and/or geodetic velocities that do not reveal long-term tectonic patterns. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.