Aeromagnetic map and associated depth map of the Upper Mississippi Embayment region

The purpose of these maps is to present recently compiled aeromagnetic data and associated depth estimates to magnetic basement in the upper Mississippi embayment region.  This area is one of the most seismically active regions in the eastern United States.  In 1974, the U.S. Geological Survey initiated magnetic surveys to delineate major geologic or tectonic features that may be responsible for the geration or control of seismic energy.