GEOLOGIC MAPPING OF DYER COUNTY, TENNESSEE WITHIN THE NEW MADRID SEISMIC ZONE

Dyer County, Tennessee, lies within the New Madrid seismic zone of the central Mississippi River valley and is one of five Tennessee counties being geologically mapped in a Disaster Resilience Competition grant from the U.S. Department of Housing and Urban Development. New Madrid seismic zone earthquakes are concentrated along the northwest-trending Lake County uplift and Tiptonville dome, which extends in northwestern Tennessee from Lake County through Obion County and into Dyer County. The stratigraphy and structure of Dyer County was mapped in three dimensions as fundamental input to subsequent scenario earthquake ground motion determinations and liquefaction potential mapping. Subsurface stratigraphy and structure were mapped using lignite exploration wells, water wells, US Army Corps of Engineers borings, and seismic reflection data. Structure contour maps of the tops of the Paleozoic, Cretaceous, and Eocene sections reveal displacement across the eastern margin of the Reelfoot rift and the structure contour map of the top of the Eocene also reveals displacement across the bounding faults of the Tiptonville dome and Lake County uplift.