Characterizing Landslide Susceptibility in a Potentially Active Fault Area: A Case Study of the Guaje Mountain Quadrangle, New Mexico

The Pajarito fault system has long been a focus area for natural hazards studies due to its proximity to Los Alamos National Laboratory, a major federal research facility located in Los Alamos, New Mexico. While landslide susceptibility analyses in the Guaje Mountain identify locations and spatial extent features, these analyses do not assess the mechanism or mechanisms that triggered them. To characterize areas of landslide risk, we performed geospatial terrain analyses to investigate the relationship between potential landslide locations and six related factors: slope, aspect, distance to drainages, distance to faults, lithology, and soils. We qualitatively weight, rank and classify these factors into instability categories, ranging from very low to very high. Based on the six factors, proximity to active faults was the most important factor in occurrence of landslides in the study area, suggesting it is the primary mechanism for landscape instability. In addition, there was moderate slope instability in areas where loose clay, silt and sand deposits exist on moderate slope angles. These landslide instability maps would be useful for decision-makers in mitigating landslide hazards and stabilizing landscapes.