3D GEOLOGY AND SEISMIC HAZARDS OF LAUDERDALE AND TIPTON COUNTIES, TENNESSEE

As a part of an ongoing seismic and liquefaction hazard mapping project funded by the U.S. Department of Housing and Urban Development under a Disaster Resilience Competition grant, detailed surface and subsurface geology of five western Tennessee counties have been mapped. Here we present the results for Lauderdale and Tipton counties. County 3D geologic models were constructed to assess earthquake ground motion and liquefaction potential. Borehole, water well, seismic reflection data, and S-wave data were compiled for these counties. The resulting datasets provide thickness and elevation of the top of the Eocene Jackson Formation, Eocene Memphis Sand Formation (regional aquifer), Cretaceous Owl Creek Formation, and the elevation of the Paleozoic Knox Group. For each stratigraphic formation, an un-faulted and faulted structure contour map was made. The isopach data provide important information for the assessment of ground motion in the event of a large magnitude proximal earthquake. The 3D model also reveals windows through the Jackson Formation that may expose the underlying Memphis Sand regional aquifer to surface pollution.