Landslide Mapping Along the I-17 Corridor, Central Arizona

Cook, Joseph P., Arizona Geological Survey, joecook@arizona.edu; Brian F. Gootee, bgootee@arizona.edu (Poster)

Landslides occur in a variety of landscapes and geologic settings throughout Arizona. Prior to 2015, our knowledge of the number and distribution of these slides was limited and scattered across many geologic maps and reports. In 2015 the Arizona Geological Survey (AZGS) compiled the Arizona Statewide Landslide Inventory Database (AzSLID) which included all known mapped and published landslide deposits throughout Arizona. Many additional, previously unmapped landslides were identified in aerial imagery and topographic data during this process. These interpreted features were included in AzSLID but no field verification was conducted. All landslide mapping is available for viewing and download on the AZGS Hazard Viewer online. In 2019, AZGS began a new project to study the character and extent of landslide deposits along I-17 from Anthem to Flagstaff, using a combination of field mapping with high-resolution topography. This study area was chosen because of the potential high impact landslides may have on existing infrastructure as well as upcoming plans to expand I-17 near Black Canyon City; an area with many mapped landslides. Damage to roadways by landslides can be catastrophic and extremely expensive to repair and mitigate. In 2008, a section of AZ State Route 87 was damaged by a reactivated portion of a larger slide cut by the road. In 2013, a similar failure within the Bittersprings landslide resulted in the destruction of a portion of US 89. Assessment, repair, and reroutes associated with these events totaled $18M, and $60M, respectively. The results of this study include verification of interpreted AzSLID landslides, more detailed mapping, description of the extent of known landslide deposits within the study area, and the discovery of additional previously unknown landslide deposits. These improvements to our knowledge of landslides in high-impact areas along I-17 will be useful for planning and hazard assessment.

Bio:

Joe Cook graduated with a MS in Geosciences with an emphasis in Geomorphology from the University of Arizona in 2006. Since then, Joe has worked as a geologist with the Environmental Geology Group at Arizona Geological Survey (AZGS) in Tucson, Arizona. Projects have included mapping of the extent of Holocene alluvium along the San Pedro and Verde Rivers, surficial geologic quadrangle mapping, earth fissure and land subsidence studies, statewide and project-specific landslide hazard mapping, and delineation of debris flow deposits along the base of the Santa Catalina Mountains. Currently, Joe is a Research Geologist with AZGS, manages the earth fissure mapping program, and continues to map throughout the state.

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