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Lava Flow Hazard Assessment for Flagstaff and Surrounding Areas in the San Francisco Volcanic Field (Arizona, U.S.A.)

Loÿc Vanderkluysen 1, Christina Liu1, Aurélie Germa2, Jacob Brauner1, Aleeza Wilkins3, Jean-François Smekens4, Laura Connor2, Charles B. Connor2

  • Affiliations: 1Dept. of Biodiversity, Earth & Environmental Science, Drexel University, Philadelphia, U.S.A; 2School of Geosciences, University of South Floria, Tampa, U.S.A.; 3United States Geological Survey, Reston, U.S.A.; 4Dept. of Astronomy and Planetary Science, Northern Arizona University, Flagstaff, U.S.A.

  • Presentation type: Talk

  • Presentation time: Tuesday 15:45 - 16:00, Room R290

  • Programme No: 6.3.5

  • Theme 6 > Session 3

Abstract

The San Francisco Volcanic Field (SFVF) in northern Arizona (USA) contains over 600 basaltic cinder cones, along with several larger volcanic structures. The most recent eruption, at Sunset Crater in ~1085 CE, impacted the local Sinagua population and is remembered in Native American oral traditions. Flagstaff, with a population exceeding 76,000, is the largest urban area within the SFVF. Given Flagstaff's rapid population growth, assessing lava flow hazards from future eruptions is essential. In this study, we identify 585 basaltic vents from satellite imagery and categorize them into three age groups based on magnetic chronologies. We characterize 30 lava flows using field observations and digital elevation models (DEMs) to estimate their size and extent. In combination with estimates of the spatial probability of future vent opening, these data are used to simulate lava flow inundation probabilities using the MrLavaLoba and MOLASSES models, with median flow areas of 7.5 km² and volumes of 0.24 km³. Our results suggest a low probability (~few percent) of lava flows reaching Flagstaff, with some vents potentially located within city limits. However, the probability of lava inundation in residential areas northeast of Flagstaff, such as Doney Park, is higher, potentially affecting over 5,000 residents. With an eruptive recurrence interval of ~1 per 10,000 years, lava flow hazards to Flagstaff are low but should be considered in urban planning.