Multiphase Flow Modeling of Explosive Volcanic Eruptions

Abstract

Understanding explosive eruption dynamics and assessment of their hazards continue to represent challenging issues to the present-day volcanology community. This is largely due to the complex and diverse nature of the phenomena, the variability and unpredictability of volcanic processes, and the difficulty of measuring them in the field and fully reproducing them at the laboratory scale. Nevertheless, important and continuing progress has been made in the last few decades in understanding the fundamental processes and forecasting the occurrences of these phenomena, thanks to significant advances in field, experimental, and theoretical modeling investigations. For more than four decades, for example, volcanologists have made major progress in the description of the nature of explosive eruptions, considerably aided by the development, improvement, and application of physical-mathematical models. First, integral steady-state homogeneous flow models were used to investigate the different controlling mechanisms and to infer the genesis and evolution of the phenomena. Through continuous improvements and quantum-leap developments, a variety of transient one/multi-dimensional multiphase flow models of volcanic phenomena now can implement state-of-the-art formulations of the underlying physics, new-generation analytical and experimental data, as well as high-performance computational techniques. These numerical models have proved to be able to provide key insights in the understanding of the dynamics of explosive eruptions (e.g., volcanic jets and blasts, convective plumes, collapsing columns, pyroclastic density currents, short-lived explosions, ballistic ejecta, etc., just to limit the phenomena to the atmospheric domain), as well as to represent a valuable tool in the quantification of potential eruptive scenarios and associated hazards.