SEISMIC INVESTIGATION OF SURFACE DEFORMATION ASSOCIATED WITH THE KILMICHAEL DOME, MONTGOMERY COUNTY, MISSISSIPPI

The Kilmichael Dome, first identified 70 years ago, is a circular feature exposed in unconsolidated Paleocene and Eocene sediments of north-central Mississippi. The structural complexity of the area, including zones of intense faulting and uplifted strata, has led to several suggested origins for the formation of Kilmichael Dome, including meteorite impact and regional tectonics. A shallow shear-wave seismic reflection profile was collected over a complex zone of surface faults, the Salem Church Fault Zone (SCFZ) on the northern flank of the Kilmichael Dome, with the goal of imaging the subsurface expression of deformation associated with the SCFZ. Further research will explore the relationship between shear-wave anisotropy and near-surface structural deformation utilizing multicomponent reflection and downhole seismic data to investigate shallow deformation associated with the Kilmichael Dome. This data set will allow us to more accurately assess the seismic velocities of the shallow sediments and constrain any identifiable shear-wave anisotropy. Recent field studies have identified surface deformation in the Kilmichael area that suggests high fluid pressures and sediment flow. If these features have a preferred alignment, our intent is to determine their orientations using multicomponent seismic methods. In addition to increased seismic resolution gained by using shear-waves in unconsolidated, water-saturated sediments, measurement of near-surface directional polarizations may provide valuable information for identifying neotectonic deformation, evaluating associated earthquake hazards, and guiding future paleoseismologic investigations.