Seismotectonic maps in the vicinity of the lower Wabash Valley, Illinois, Indiana, and Kentucky - Digital Spatial Database: Paleoliquefaction observations between 1990 and 1994 in Indiana

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 between 1990 and 1994, Cheryl and
Pat Munson, along with several of their students, searched ditches
and river banks for evidence of liquefaction. They found numerous
banks with shaking-induced sandblows and the dikes that fed them.
This database includes the location of dikes that
the Munsons and those with them observed and measured. Dike thickness
was divided into 5 classes, 1 being the smallest at 0-4 cm, 2 = 5-14 cm,
3 = 15-29 cm, 4 = 30-59 cm, and 5 = over 60 cm.
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.