Reproducing pyroclastic density current deposits of the 79 CE eruption of the Somma–Vesuvius volcano using the box-model approach

Abstract. We use PyBox, a new numerical implementation of the box-model approach, to reproduce pyroclastic density current (PDC) deposits from Somma–Vesuvius volcano (Italy). Our simplified model assumes inertial flow front dynamics and mass deposition equations axisymmetric conditions inside circular sectors. Tephra volume total grain size distribution EU3pf EU4b/c, two well-studied PDC units different phases 79 CE Pompeii eruption, are used as input parameters. Such correspond variably dilute, turbulent PDCs. perform quantitative comparison uncertainty quantification outputs with respect observed data unit thickness, inundation areas function radial distance source. The simulations consider (i) polydisperse conditions, given by deposit, or monodisperse mean Sauter diameter deposit; (ii) collapses either covering whole 360? (round angle) divided into obtain range plausible initial concentrations solid particles 2.5 % 6 %, depending on sector. Optimal modelling results extent deposit thickness reached EU4b/c in sectorialized situation, indicating that using particle densities close possible real significantly improves performance PyBox code. study findings suggest approach has promise for applications constraining parameters more computationally expensive models. This could be done due relatively fast computational time code, which allows exploration physical space