Lateral Extent of Pyroclastic Surge Deposits at Ubehebe Crater (Death Valley, California) and Implications for Hazards in Monogenetic Volcanic Fields

Hazard assessments in monogenetic volcanic fields require estimates of the runout pyroclastic surges that result from phreatomagmatic explosive activity. Previous used distances 1–4 km, with large cases up to 6 km. Surge deposits at Ubehebe Crater (∼2100 y.b.p., Death Valley, California) have been traced ∼9 km crater center, and likely originally extended 1–3 farther. There is no evidence activity was unusually energetic; rather, its distal are better preserved than those most maar volcanoes because young age arid environment. Numerical simulations illustrate how low temperatures facilitate long due reduced expansion entrained air compared hot surges, allowing cool retain higher densities ambient air. We suggest hazard for phreatomagmatic, maar-forming eruptions should consider range 10–15