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Abstract

About 10% of the world's population live within 100 km of an historically-active volcano and the potential for great loss of life and economic disruption due to violent eruptions has emerged as a major problem. Developing the capacities to better understand volcano dynamics and to forecast and mitigate hazards are therefore principal scientific priorities in order to reach a sustainable development of the exposed regions. Nevertheless, understanding of explosive eruption dynamics and assessment of their hazards continue to represent challenging issues to the present-day volcanology community. This presentation illustrates some contributions to the reaching of these challenging goals through the development and application of physical-mathematical models of explosive volcanic eruptions. In particular, transient, 2D/3D, and multiphase flow models were recently developed implementing state-of-the-art formulations of the physics with high-performance computational techniques. Numerical simulations produced by such codes have allowed to better understand and fairly accurately reproduce well-documented volcanic events, and provide key insights in comprehending the complex and often non-intuitive dynamics of explosive eruptions - such as convective plumes, ash dispersal and deposition, collapsing columns and pyroclastic density currents, short-lived explosions, etc. Simplified models based on a reduction of the system complexity have been also proved useful, combined with Monte Carlo and statistical methods, to generate quantitative probabilistic hazard maps at different space and time scales, some including the quantification of uncertainty. Examples of numerical simulations and quantitative hazard mapping of explosive phenomena developed for high-risk volcanoes will be given.