LANDSLIDE HAZARDS WITHIN THE SPRUCE PINE 7.5-MINUTE QUADRANGLE, NC: AN EVALUATION OF STRUCTURAL CONTROLS ON BEDROCK DETERIORATION

Landslides are a persistent threat to mountainous communities and a frequent occurrence in western North Carolina (WNC) due to steep slopes and heavy rainfall. The orientation of weaknesses in the rocks, such as foliations and fractures, also contribute to landslide frequency. Thus, structural patterns and geomorphological processes need to be understood to mitigate these natural hazards. Recent field and geophysical research has suggested that Miocene uplift of the Blue Ridge Mountains resulted in networks of fracture systems across WNC, called lineaments, that can increase the risk of landslide hazards. One of the lineaments, the Laurel Creek Lineament, is exposed through the town of Spruce Pine, NC. The target of this study was to constrain the location of landslides in the Spruce Pine 7.5-minute quadrangle and evaluate the role of lineament fractures in the occurrences of these landslides. Vertical joints associated with this lineament are abundant throughout the quadrangle and dominantly strike toward 260°. 63 landslides were identified in the field and from 1-m resolution LiDAR elevation models. The aspect of landslide directionality was compared to the orientation of joints and foliation. Landslide aspects ranged from 010° to 340°, with elevated frequencies parallel and perpendicular to joint strike, ~32% of the total landslides. These data indicate that lineament fractures are an important structural control on slope stability in this quadrangle.