Investigating Risks Related to Unstable Slopes in Great Smoky Mountains National Park

O’Shea, Thomas, East Tennessee State University, OSHEAT@mail.etsu.edu; Samantha Farmer; Arpita Nandi

Rockfalls are frequent events in the Southern Appalachians, United States, initiated in highly weathered, fractured metasedimentary rocks. In this study, the Unstable Slope Management Program for Federal Land Management Agencies (USMP for FLMA) protocols were utilized to create an inventory of unstable slopes and evaluate their current hazard and risk conditions along the paved transportation corridors in Great Smoky Mountains National Park (GRSM). Kernel Density Estimations (KDE) and weighted overlay analyses were used to identify clusters of unstable slopes along transportation corridors and select sites for detailed rockfall and environmental impact assessments. A total of 253 unstable slopes were studied along 186 miles of roadway, of which 223 slopes were designated as localized rockfall, dominated by wedge and planar failure mechanisms. Five clusters concentrated along primary roads were identified by KDE which used the USMP for FLMA risk and hazard values as the intensity fields. Weighted overlay analysis was then used as an intermediate step to refine site selection. Six variables were used in the weighted overlay analysis: KDE raster layers, slope, distance to map-scale faulting, distance to roadway, and the predicted acid-producing potential of geologic units. Based on the results of the weighted overlay analysis, seven sites were selected for detailed site assessments which will include rockfall simulations and acid-base accounting. The research provides a case study on how to prioritize areas for site-specific investigations with the ultimate aim to improve safety for GRSM visitors and commuters.


Thomas O’Shea is a Geologist-in-Training and master’s student in the Department of Geosciences at East Tennessee State University (ETSU) in Johnson City, TN. He is currently working with a team to conduct a risk-based assessment of unstable slopes along transportation corridors in Great Smoky Mountains National Park as part of an NPS task agreement.

Thomas’ first work experiences came from working as the assistant geologist for a junior exploration company in Chesterfield County, SC. He later worked as an environmental field technician for an analytical lab and environmental services company where he conducted a wide range of water- and soil-sampling tasks in Western North Carolina.

Thomas plans to become a licensed geologist and looks forward to developing his career in applied geology with a company dedicated to technical excellence and creating value for clients while promoting environmental stewardship.

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