GEOPHYSICAL AND GEOTECHNICAL FIELD CORRELATIONS OF THE DOE RUN LANDSLIDE, NORTHERN KENTUCKY

Landslide characterization and hazard assessments require multidisciplinary approaches that connect geologic processes with geotechnical behavior. Preexisting landslide activity, geology and geomorphology, landslide structure, soil strength, and hydrologic conditions are complex factors that affect landslide hazard assessments. Often, the connections between these factors is not made for hazard assessments, forecasting, or slope stability modeling. Therefore, geologic, geophysical, and geotechnical data sets for landslides are typically investigated independently.

This study aims to bring together different data sets and techniques to create a methodology that connects electrical measurements and shear strength. We collected field data from a shallow colluvial landslide in northern Kentucky, including volumetric water content, soil water potential (suction), electrical conductivity, and landslide movement. These are pertinent to investigating the stability of colluvial landslides that are triggered or reactivated by rainfall. Suction stresses, along with moisture, porosity, and clayey lithologies, affect slope stability, but also are some of the same factors that affect the physics of electrical current flow. Field work includes repeated surface electrical resistivity surveys to support the interpretation of depth to failure and lithologic differences, and to compare with the insitu electrical measurements. We hypothesize that the observed changes in saturation and soil water potential are detected within inverted electrical resistivity survey profiles and thus can be correlated with shear strength. The results from this study could provide a technical framework for landslide hazard assessment that geologists and engineers can use to assess and communicate landslide hazards.