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

Note: this cover is a combination of liq94surv and liqmunsurv. 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 earthquake induced liquefaction. They found numerous banks with shaking-induced sandblows and the dikes that fed them. This database shows where they searched. 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 dikes and sandblows that feed them. 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.