DEVELOPING A MODEL TO MAP THE POTENTIAL AREAS FOR LANDSLIDE HAZARDS IN HAMILTON COUNTY, TN USING GIS AND REMOTE SENSING

Landslides include all forms of downslope movement of ground, and they cause substantial damage and loss of life. In the United States landslides cause about 25-50 deaths/year and damage more than $3.5 billion/year. Landslides occur when the slope changes from a stable to an unstable condition due to the imbalance between naturally occurring driving and resisting forces, but can be exaggerated by human activities. The vulnerability of a slope failure can be determined by the nature of interrelationships of certain spatio-temporal geophysical variables including the existence of slip surface, types of earth materials, slope angle and topography, vegetation coverage, and water content.

Many hillsides and steep slopes in Hamilton County, TN present areas potentially susceptible to landslide and erosion. Past landslide events have been associated with heavy rain, removing vegetation on slopes, and roadway construction. Areas adjacent to stream banks are also susceptible to severe erosion following heavy rains. Currently, no tool is available to detect and map the potential areas of landslides in Hamilton County.

GIS and remote sensing technology have been used successfully to develop models for detecting areas susceptible to landslides in different parts of the world. The preliminary results of a recent study undertaken at the University of Tennessee at Chattanooga shows promise in the development of such models to study the landslide issues in Hamilton County. This study used geology, soil type, land cover, and slope information in GIS environments in conjunction with the known locations of some of the previously recorded landslides to develop a model to identify areas that have higher potentials for landslide occurrence. The model was developed using a GIS based weighted linear combination technique. The model and the obtained results will be presented and discussed.