The radius of the umbrella cloud helps characterize large explosive volcanic eruptions

Abstract Eruption source parameters (in particular erupted volume and column height) are used by volcanologists to inform volcanic hazard assessments classify explosive eruptions. Estimations of associated with large uncertainties due various factors, including complex tephra sedimentation patterns from gravitationally spreading umbrella clouds. We modify an advection-diffusion model investigate this effect. Using model, for the climactic phase 2450 BP eruption Pululagua, Ecuador, different respect previous estimates (erupted mass: 1.5–5 × 10 11 kg, cloud radius: 10–14 km, plume height: 20–30 km). suggest eruptions better classified radius instead or height alone. Volume can be successfully estimated deposit data using one numerical when direct observations (e.g., satellite images) not available.