Understanding volcanic systems and their dynamics combining field and physical volcanology with petrology studies

Abstract

Hazard assessment and definition of the eruptive scenarios at active volcanoes are mostly based on the elaboration of a large set of information collected with different disciplines and multiple analytical approaches. We discuss here how the reconstruction of the main processes acting at a volcano during its life should be based on the direct knowledge of its activity and products, in the view that each volcano is characterized by its own «personality». Comparison with analogue volcanoes can add further important information on the expected variability of the different processes, but this should never substitute specific data collection at the volcano of interest. Field volcanology and petrology studies are the base for collecting large datasets on past, recent and on-going activity and products. Based on these data, intensive and extensive physical parameters which control the dynamics of the activity can then be derived through focused physical volcanology investigations. Experimental petrology on the products of well-characterized

Deep Magma Transport Control on the Size and Evolution of Explosive Volcanic Eruptions

“…In fact, mass flow-rate increase during initial eruption stages may reflect other factors and processes, like progressive wall rock erosion and establishment of the volcanic conduit (Aravena et al, 2017), progressive tapping of more water-rich, less chemically evolved (thus less viscous) magma (Papale et al, 1998), and others that can affect to various degrees the stages preceding and accompanying full development of a Plinian volcanic column. Many of these processes can be identified and reconstructed from the analysis of the associated volcanic deposits [e.g., Cioni et al (2021)], but are difficult to constrain while the eruption is on-going. With the above limitations, in light of the present results we suggest that for those cases where the eruption mass flow-rate is seen to increase over hours, then it may be wise to consider an increased likelihood of established deep-controlled regime conditions, as well as the possibility of a long eruption duration of order days to weeks with comparably large accumulation of volcanic ash, potentially ending up with large caldera collapse and generation of large pyroclastic flows.…”