LANDSLIDES IN THE EASTERN KENTUCKY COAL FIELD

Colluvium and landslides are abundant, and more often than not, seem to go together in the mountains of the Eastern Kentucky Coal Field. What has not been so evident is what initiates many of these landslides. A number of the pieces to the puzzle began to come together this spring with the occurrence of a major landslide south of Hazard, Kentucky, which blocked a road, destroyed several homes, and dammed a stream, in addition to preventing several companies from getting their coal to market. The landslide seemed to be initiated by an oil company that drilled into an abandoned and flooded mine, but the full answer was not that simple. A study of underground mine maps, mined-out area maps, surface-mine maps, geologic maps, lineament maps, and landslide-susceptibility maps indicates that a complex combination of geologic factors led to the conditions that ultimately resulted in the slide. A critical factor in being able to predict the occurrence of such slides is the ability to predict where the thick wedges of colluvium will occur. Colluvium is formed from bedrock units by weathering and erosion and the slaking of the shales, but the occurrence of lineaments such as joints and faults, as well as the stratigraphy of the bedrock, may allow us to more efficiently map these thick wedges of landslide-prone material. The Kentucky Geological Survey is initiating a research project to map surficial deposits and use a combination of other derivative maps to predict the occurrence of the materials and conditions that allow these frequent and costly landslides to occur.