Investigating Source Conditions and Controlling Parameters of Explosive Eruptions: Some Experimental-Observational- Modelling Case Studies

Abstract

Explosive volcanic eruptions are complex systems that can generate a variety of hazardous phenomena, for example, the injection of volcanic ash into the atmosphere or the generation of pyroclastic density currents. Explosive eruptions occur when a turbulent multiphase mixture, initially predominantly composedf of fragmented magma and gases, is injected from the volcanic vent into the atmosphere. For plume modelling purposes, a specific volcanic eruption scenario based on eruption type, style or magnitude is strictly linked to magmatic and vent conditions, despite the subsequent evolution of the plume being influenced by the interaction of the erupted material with the atmosphere. In this chapter, different methodologies for investigating eruptive source conditions and the subsequent evolution of the eruptive plumes are presented. The methodologies range from observational techniques to large-scale experiments and numerical models. Results confirm the relevance of measuring and observing source conditions, as such studies can improve predictions of the hazards of eruptive columns. The results also demonstrate the need for fundamental future research specifically tailored to answer some of the still open questions: the effect of unsteady flow conditions at the source on the eruptive column dynamics and the interaction between a convective plume and wind.

Quantifying the Effect of Wind on Volcanic Plumes: Implications for Plume Modeling

“…Since ash can be harmful in several ways in modern society, for example, for aviation, infrastructure, agriculture, water supply, or human health (e.g., Blake et al., 2017; Blong et al., 2017; Giehl et al., 2017; Grindle & Burcham, 2002; Jenkins et al., 2015) monitoring eruptive plumes in real‐time is an important task for prompt hazard mitigation. One of the key parameters required to predict the eruptive plume dynamics and the subsequent atmospheric dispersal of the erupted tephra is the mass eruption rate (MER), that is, the mass flux (kg s −1 ) of tephra injected into the atmosphere (e.g., Bonadonna et al., 2016; Dioguardi et al., 2016; Mastin et al., 2009; Sparks et al., 1997; Wilson & Walker, 1987). Plume models of various degrees of complexity exist to estimate the current MER at the source based on the top plume height h (for overview see Costa et al., 2016), but only 0D and 1D models are at present fast enough to be applicable for mass flux assessment in real‐time.…”

The effect of wind and plume height reconstruction methods on the accuracy of simple plume models — a second look at the 2010 Eyjafjallajökull eruption

“…Next to direct observations of the ash cloud (e.g. satellite imagery and lidar retrievals) predictions of movement of volcanic ash clouds are based on atmospheric ash dispersion models (Dacre et al 2011;Kristiansen et al 2012;Dioguardi et al 2016Dioguardi et al , 2020. Inaccurate predictions can on one hand lead to severe damage to and even loss of aircraft (Guffanti et al 2010), or the other hand to airport closures framed or perceived as over-cautious (Harris et al 2012;Harris 2015) and flight diversions or cancellations, which involve large preventable costs (e.g., Brannigan 2011;Macrae 2011;Ragona et al 2011).…”

The Impact of Eruption Source Parameter Uncertainties on Ash Dispersion Forecasts During Explosive Volcanic Eruptions

“…Over the last year, REFIR has been substantially improved to enable more flexibility and its application to study past eruptions in order to obtain time series of ESPs. In this manuscript, we present the new capabilities of REFIR and results of their application to the 2010 Eyjafjallajökull eruption (Dellino et al, 2012; Dioguardi et al, 2016; Dürig, Gudmundsson, & Dellino, 2015; Dürig, Gudmundsson, Karmann, et al, 2015; Gudmundsson et al, 2012). In particular, Dürig, Gudmundsson, and Dellino (2015) estimated MER in the period 8–10 May by applying video analysis of footages of the erupted ash cloud from the crater.…”