Seismotectonic maps in the vicinity of the lower Wabash Valley, Illinois, Indiana, and Kentucky - Digital Spatial Database: Neotectonic features

Although many faults are detected at the surface and in deep structures, they
are important in evaluating present seismic hazard only if they show evidence
of having recent slip. Older faults may have healed, or movement may have
occurred under a different stress orientation than currently exists, or
seismic activity may wax and wane at intervals longer than the historic
record. In this cover, we show locations of known or suspected recent
faulting. Features were identified in
trenches, auger holes, wells, or on the surface.