Seismotectonic maps in the vicinity of the lower Wabash Valley, Illinois, Indiana, and Kentucky - Digital Spatial Database: Paleoliquefaction locations observed in 1995 in Illinois

The northern part of the map area and large adjacent regions have
been severely shaken by one or more moderate to large prehistoric
earthquakes. The evidence of these takes the form of
paleoliquefaction features, including shaking-induced sandblows and
dikes that fed them.
Over several summer field seasons from 1990 through 1994,
several workers searched ditches and river banks for evidence
of liquefaction. They found numerous dikes and sandblows.
This database includes the locations and descriptions of dikes they
observed and measured.
The most widespread paleoliquefaction is attributed to a
mid-Holocene earthquake near what is now Vicennes, IN, with an
estimated moment- magnitude of about 7.5. Stratigraphic,
geomorphological, pedological, archealogical, and geochronologic
evidence indicates that probably some of the paleoliquefaction was
caused by several additional, smaller earthquakes during the
Holocene and late Pleistocene.