A COORDINATED, MULTI-AGENCY, COMMUNITY-SUPPORTED MAPPING EFFORT IN THE KENTUCKY-INDIANA-ILLINOIS TRI-STATE AREA

The Ohio River Valley is an area of outstanding resources, and carries more than 35 percent of the Nation’s waterborne commerce. The Ohio and its thick associated deposits of unconsolidated materials provide water supplies for numerous communities. Industrial minerals such as sand, gravel, limestone, and abundant coal, oil, and gas are found in the area. Geologically, the river forms a rough boundary between the glaciated areas to the north and the unglaciated areas to the south.

The lower Ohio River Valley is also a focal point for geologic hazards, cutting between two major seismic zones: the Wabash Valley to the north and the New Madrid to the south. The 4.5-magnitude earthquakes west of Evansville, Ind., in 2002, and near Bardwell, Ky., in 2003 served as reminders of the hazard. Frequent flooding, bank erosion, landslides, and mine subsidence are other common hazards in the area. Detailed mapping and a comprehensive study of the area, in cooperation with the U.S. Geological Survey, have long been a goal of the state geological surveys in the tri-state area, but funding has been a major obstacle. A grassroots effort focusing primarily on hazards and led by the Building Commissioner of Evansville, Ind.; the Southwest Indiana Disaster Resistant Community Corporation; and state and U.S. geological surveys has led to a major cooperative mapping program. Among the final products will be maps of surface and subsurface geology, geological and geotechnical databases, and maps showing earthquake liquifaction susceptibiliby and ground motion (including both scenario and probability maps). The planning and execution of the mapping is done in consultation with advisory groups such as engineers, emergency managers, and government and private-sector employees in the tri-state area. In addition, the products will serve as focal points for community outreach and mitigation activities.