Study Area

The principle objective of this task is to contribute to the development of a regional tectonic framework for the corridor between St. Louis and Memphis. The primary application of this work addresses neotectonic issues and regional seismic potential questions:

• Where have neotectonic events occurred in the Mid-Continent outside of the New Madrid seismic zone?
• What is the nature of this deformation and when did it occur?
• What is the seismic potential of the Mid-Continent?

The overall strategy is to use geologic mapping and subsurface investigations to address the above issues and objectives. The basic approach will be through detailed geologic mapping of 7.5-minute quadrangles and compilation at 1:100,000 scale supported by coordinated paleontological and geophysical investigations, fault-exploration trenching, and drilling. Deformational histories and nature of active and recent faulting will be evaluated through analysis of fault kinematics and temporal constraints on episodes of movement.

This is the final year of this study which originated in 1996. Planned work includes:

• Completion of the Cape Girardeau 1:100,000 sheet in cooperation with personnel of the Illinois State Geological Survey.
• Investigations of faulting in the Smithland, KY area in cooperation with personnel from the Kentucky Geological Survey and the Illinois State Geological Survey. This area contains northeast-striking faults that have thousands of feet of separation of Paleozoic strata and are known to cut both Cretaceous and late Tertiary deposits. Reconnaissance work suggests that they may cut late Pleistocene surficial deposits. In addition, this faulting is an online projection of the northeast arm of New Madrid seismicity. After target sites have been delineated, our intention is to excavate fault-exploration trenches to evaluate possible Quaternary deformation.
• Participation in the Geologic Mapping of Memphis Task under the Earthquake Loss Reduction in the Central and Eastern United States Project is planned on a consulting, advisory basis.
• Interaction with FEMA's Project Impact in Cape Girardeau will continue. This will include evaluation of possible neotectonic activity within the city limits by providing guidance and supervision to a graduate student studying this possible activity.