PALEOLIQUEFACTION EVIDENCE FOR A STRONG HOLOCENE EARTHQUAKE IN SOUTH-CENTRAL INDIANA

Earthquake-induced paleoliquefaction features in Holocene sediments in south-central Indiana are evidence for strong shaking in the recent p rehistoric past in an area where only infrequent, low-magnitude earthq uakes have occurred during the 200 yr of the historic record. Distribu tion of liquefaction features and geotechnical analyses of liquefied s ediments are the basis for estimating that an earthquake with a magnit ude of similar to 6.9 was centered near Vallonia, Indiana. Radiometric , archaeologic, and stratigraphic relations bracket the event to betwe en similar to 3.7 ka and 4.2 ka B.P. Evidence for a local source for s trong shaking requires reassessment of earthquakes hazards in the sout hern Indiana-northern Kentucky-southwestern Ohio area.