Dynamics of volcanic explosive eruptions
Geneva, Switzerland, 29-31 January 2014
Organisers: C. Bonadonna (Geneva, Switzerland), R. Cioni (INGV, Pisa), A. Costa (INGV, Bologna) and T. Druitt (Clermont-Ferrand, France). Contact: C. Bonadonna (Costanza.Bonadonna@unige.ch)
This workshop served to indentify open questions and research priorities that could help improve our understanding of volcanic explosive eruptions. In particular: i) We identified the main parameters and processes characterizing volcanic eruptions that include initial conditions, conduit-related magma dynamics, eruptive processes and parameters, external forces; ii) We reviewed most existing “global” classification schemes (general classification schemes that are not based on specific volcanoes) in order to identify main shortcomings and most widely-used terminology. We found that existing classification schemes fail to collate all volcanic eruptions in one simple diagrammatic form, and do not account for all volcanic behaviours and products; iii) Classification schemes need to be objective driven (e.g. scientific understanding, hazard/risk assessment, communication with public and scientific community) and simple enough to promote transfer of knowledge and scientific exchange; iv) Currently we do not have a system that can be used for all eruptions. It might be possible in the future to have a more comprehensive classification scheme, but it is more likely that it will be associated with a different way of measuring eruptions (e.g. energy balance) instead of evolving from existing schemes; v) None of the existing schemes consider the distinction between steady and unsteady processes. We identified that unsteadiness is, in fact, a key factor for describing volcanic eruptions, but also concluded that we do not yet have effective means of classifying unsteadiness itself. Future eruption classification schemes should incorporate the concept of unsteadiness; vi) Classification schemes should also describe a variety of volcanic products, such as PDCs, lava flows and gas; vii) Open questions, processes and parameters that need to be addressed and better characterised in order and to develop more comprehensive classification schemes and to progress in our understanding of volcanic eruptions include: abrupt transitions in eruption regime, conduit processes and dynamics, unsteadiness, eruption energy and energy balance.
A Consensual Document from the meeting is available below, and will be submitted for publication to an international journal. An additional outcome of the workshop was the VHub forum open to the whole volcanological community that will provide an important opportunity to extend the effort and brainstorm forward on the topic of understanding of explosive volcanism and eruption classification: https://vhub.org/groups/eruption_dynamics.