ADVANCING ENGINEERING GEOLOGIC PRACTICE ALONG THE WASATCH FRONT WITH EVOLVING LANDSLIDE AND FAULT-RUPTURE DISPLACEMENT HAZARD ANALYSES AND MITIGATIONS

The increasing intensity of land use within challenging landscapes along the Wasatch Front has necessitated ever-improving practical means of geologic risk evaluations. Three areas of opportunity to advance evolving engineering geologic-risk management practices with respect to meaningful and buildable mitigation solutions for geologic hazards are provided. (1) A combination of weather events and development in steep terrain has recently resulted in property-damaging slope failures along the Wasatch Front. Successful slope stability analysis for long-term design, construction, and performance of engineered slopes is feasible when geotechnical engineering elements such as drainage, seismic design, and quality control of construction are properly implemented. (2) Fault investigations along the Wasatch Front using traditional trenching studies date back to the 1970s; however, other more modern and less destructive investigative methods such as continuous cone penetration testing, sonic borings, and/or downhole logging tied together with geophysical surveys have been found useful in evaluating fault offsets of near-surface stratigraphy in developed areas. (3) The Utah Geological Survey has recommended practical methodologies for evaluating, mitigating, and establishing setbacks from fault rupture hazards along the Wasatch Front. The availability of new fault displacement models may further inform and refine these practicable recommendations.