TWO DIMENSIONAL SEISMIC REFLECTION MODELING OF SHALLOW FAULTING ASSOCIATED WITH THE ROUGH CREEK GRABEN IN WESTERN KENTUCKY

The southern portion of the Illinois Basin was tectonically altered in the Early Cambrian during a failed rifting event known as the Reelfoot Rift. The Rough Creek Fault Zone is a major fault system striking in an East-West direction in the Western Kentucky region and is associated with the Reelfoot Rift. There have been three major tectonic episodes along this fault system. The first episode occurred as normal faulting during the Early Cambrian associated with the Reelfoot Rift. Reactivations of this structure occurred as a reverse faulting episode in the Late Paleozoic and a normal faulting episode in the Mesozoic. These major offsets in the older rocks have been imaged in several previous deep seismic reflection surveys. Associated smaller offset faults have been observed in some drill holes and on some of the deep seismic profiles in the area. A recent seismic reflection survey in Western Kentucky was designed to image and to provide improved resolution of these shallow structures. Three survey lines trending in a more or less North-South direction were collected. Several coal seams in the area make good seismic reflection markers for determining if the structures observed are faults or other types of structures and for measuring the amount of offset on any small-scale faults. Two dimensional seismic reflection models of the shallow faulting will be presented for the three seismic profiles.