Seismotectonic maps in the vicinity of the lower Wabash Valley, Illinois, Indiana, and Kentucky - Digital Spatial Database: Gravity and aeromagnetic surveying and modeling lines

Lines in this cover show where gravity oe aeromagnetic data have been
modelled to constrain subsurface structure. Gravity and
magnetic signatures result from deep structure, such as might be at
hypocentral depths of earthquakes. We show only the lines for which
interpretations or models are publically available. In gravmag_all,
extent of the lines outside the study boundary is retained;
in gravmag the lines have been clipped to the study boundary.