GEOLOGICAL MAPPING IN LAKE COUNTY, TENNESSEE

The purpose of this project is to develop surface and subsurface geological maps of Lake County, Tennessee, which lies within the New Madrid seismic zone. This work is part of a 5-year project focused on mapping seismic hazards and liquefaction potential in five counties in west Tennessee. Both geologic and seismic-hazard mapping has been done on a regional scale, but it has not been done on a county scale, except for Shelby County. Lidar imagery, soil maps, lignite boring logs, water well logs, petroleum exploration logs, engineering logs, and seismic reflection lines were interpreted to map the stratigraphy and structural features of Lake County. This included producing structure contour maps of the tops of the Paleozoic, Cretaceous, and Eocene. Other maps that were made include isopachous maps of the Quaternary alluvial deposits, and their facies, within the Mississippi River Floodplain. Finally, a 3-D geological model was produced for Lake County, which shows the structure throughout Lake County as well as the stratigraphy from the Quaternary to the Paleozoic. The resulting maps and models from this project provide a better visualization of the deformation that has occurred in Lake County and a baseline from which seismic-hazard maps can be produced to predict earthquake ground motion and liquefaction occurrence in the event of a large future earthquake.