Working towards a safer more resilient Arizona Pilot Study: Assessing Unreinforced Masonry Buildings in Flagstaff & Yuma, Arizona

Arizona is prone to moderate- to rare large-magnitude earthquakes. Communities in earthquake-prone parts of Arizona possess a potentially large number of unreinforced masonry (URM) buildings. In 2021-2022, the Arizona Geological Survey (AZGS) initiated a pilot program to assess the URM building stock of the Cities of Flagstaff and Yuma. To do so we collaborated with staff of the two cities responsible for managing building stock data. Retrieving pre-1976 building data of potential URM buildings was challenging because neither Flagstaff nor Yuma possesses or manages those data; that is the province of Coconino and Yuma Counties, respectively. Teasing out URM building stock for both cities was fraught with difficulty due to the structure of the databases and ambiguities regarding principal building material. URM building stock identified in this study include: commercial, residential, and private/public facilities (K-20 schools, churches, theaters, and more). In Flagstaff we identified more than 2,200 potential URM buildings; in Yuma we identified more than 1,600 potential URM buildings. Validating the veracity of URM building stock parameters (e.g., year built, physical address, among other things) with the National Register for Historic Places showed considerable discrepancies between both cities and the National Register. A definitive assessment of URM stock in Flagstaff and Yuma would require a physical survey of suspected URM building stock by structural or civil engineers.Documents in the AZGS Documents Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact azgs-info@email.arizona.edu