Geophysical Setting of the Wabash Valley Fault System

Abstract

Research Article| July 01, 1997 Geophysical Setting of the Wabash Valley Fault System Thomas G. Hildenbrand; Thomas G. Hildenbrand U.S. Geological Survey MS 989 345 Middlefield Road Menlo Park, CA 94025 (T.G.H.) Search for other works by this author on: GSW Google Scholar Dhananjay Ravat Dhananjay Ravat Southern Illinois University at Carbondale Dept. of Geology, MS 4324 Carbondale, IL 62901 (D.R.) Search for other works by this author on: GSW Google Scholar Seismological Research Letters (1997) 68 (4): 567–585. https://doi.org/10.1785/gssrl.68.4.567 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Thomas G. Hildenbrand, Dhananjay Ravat; Geophysical Setting of the Wabash Valley Fault System. Seismological Research Letters 1997;; 68 (4): 567–585. doi: https://doi.org/10.1785/gssrl.68.4.567 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 SocietySeismological Research Letters Search Advanced Search Abstract Interpretation of existing regional magnetic and gravity data and new local high-resolution aeromagnetic data provides new insights on the tectonic history and structural development of the Wabash Valley Fault System in Illinois and Indiana. Enhancement of short-wavelength magnetic anomalies reveal numerous NW- to NNE-trending ultramafic dikes and six intrusive complexes (including those at Hicks Dome and Omaha Dome). Inversion models indicate that the interpreted dikes are narrow (≤3 m), lie at shallow depths (<200 m) and are steeply dipping. Some of the interpreted dikes closely follow mapped faults; their abundance suggests that the Wabash Valley Fault System contains many more faults than those mapped. Both the interpreted dike pattern and mapped Wabash Valley Fault System terminate near the Reelfoot-Rough Creek-Rome rift system.Based on the interpretation of both the regional magnetic and gravity data and the high-resolution magnetic data, we propose that the shallow faults and deep-seated rift structures in the Wabash Valley terminate at or near the Rough Creek-Shawneetown Fault System. The Grayville Graben (∼20 km wide, ∼700 m maximum basement relief, and <40 km long [Bear et al., this volume]) underlying the Wabash Valley developed during rifting, perhaps in response to stress concentrations generated by a bend in the Reelfoot-Rough Creek-Rome rift system. We therefore hypothesize that although the Reelfoot Rift and Rough Creek Graben represent tectonic intraplate structures of large areal extent (>500 km long and generally >50 km wide) and with deep basins (locally >3 km thick), the ancestral Wabash Valley faults express, in comparison, minor tectonic structures and probably do not represent a failed rift arm.There is a lack of any obvious relation between the Wabash Valley Fault System and the epicenters of historic and prehistoric earthquakes. Five prehistoric earthquakes lie conspicuously near structures associated with the Commerce geophysical lineament, a NE-trending magnetic and gravity lineament lying oblique to the Wabash Valley Fault System and possibly extending over 600 km from NE Arkansas to central Indiana. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.