REMOTE SENSING STUDIES, CARROLL COUNTY, INDIANA PROVIDE BACKGROUND FOR ASSESSING GEOLOGIC CONSTRAINTS

Geologic constraints in the Midwest involve the following: slope stability, landfill siting, septic tank placement, construction material shortage, bedrock excavation, compressible soils, loess/lacustrine deposits, karst terrain, expansive soils, active faults, groundwater concerns, reactive aggregates, soil erosion/siltation and local flooding (West, 1995, p. 496). Each requires detailed knowledge of the geologic terrain. Two remote sensing studies were conducted in Carroll County, northcentral Indiana on Wisconsin age ground moraine. The 34 km square county is dissected by the Wabash River and its tributaries. The first study (H.Liu), a soil texture classification using Landsat Thermatic Mapper data involved two analysis methods, multi-category logistic regression and Support Vector Machines (SVMs) consisting of two types, polynomical and Radial Basis Function. Training fields 8x4.8 km were selected to train and evaluate models. The Maximum Likelihood Method was also used to provide a classification for comparison. The second study (Y.Sui) involved site evaluation for relocation of State Highway 25 through Carroll County. A new four-lane highway (northeast-southwest orientation) will be located near the center of the County. Four alternate routes were evaluated based on engineering soils properties, topography and groundwater. Thematic Mapper data were analyzed and compared to SSURGO, the State Soil Survey Geographic data base for Carroll County, a digitized data base of agricultural soils. Studies of the four alternates were conducted and the preferred route designated. These two remote sensing studies of Carroll County are examples of how to provide useful information for geologic hazards evaluation.