Abstract
Active volcanoes are typically subject to frequent substantial topographic changes as well as variable eruption intensity, style and/or directionality. Gravitational instabilities and local accumulation of pyroclasts affect conditions at the active vents, through which gas-particle jets are released. In turn, the vent geometry strongly impacts the eruption characteristics. Here, we compare five high-resolution topographic data sets (<4 cm/pixel) of volcanic craters and vents from Stromboli volcano, Italy, that were acquired by unoccupied aerial vehicle (UAV) during five field campaigns between May 2019 and January 2020. This period includes two paroxysmal explosions (3 July and 28 August 2019) and exhibited significant changes on day-to-month timescales. Our results highlight changes to vent geometry and their strong control on the directionality of explosions. Recurrent UAV surveys enable the monitoring of temporal morphologic changes and aid the interpretation of observed changes in eruption style. Ultimately, this may contribute to repeatedly revised risk areas on permanently active volcanoes, especially those that are important tourist destinations.
Highlights
Vent evolution is a critical parameter for volcanic hazard assessment as shifts of vent geometry and position can be linked to shifts in eruptive mechanisms [Graettinger et al 2015; Taddeucci et al 2013a; Valade et al 2016]
Our results show that the morphology of Stromboli’s crater terrace and the geometry of craters and vents are transient on timescales of days to months
The comparison between May and June 2019 and between September 2019 and January 2020 show the changes caused by ‘normal’ and elevated levels of activity, while changes between June and August 2019 and between August and September 2019 were dominated by the two paroxysms and the effusive episode after the 3 July paroxysm
Summary
Vent evolution is a critical parameter for volcanic hazard assessment as shifts of vent geometry and position can be linked to shifts in eruptive mechanisms [Graettinger et al 2015; Taddeucci et al 2013a; Valade et al 2016]. Direct observations detecting changes in the activity at persistently active volcanoes can provide insights into the shallow conduit system, which, in turn, improves hazard assessment [Capponi et al 2016; Salvatore et al 2018; Simons et al 2020]. Can the geometry be affected by the eruptive activity but vent geometry can modulate the dynamics of volcanic explosions. While vent geometry can be measured directly, our knowledge about conduit geometry has been constrained based on inactive fissures, eroded volcanoes, laboratory experiments or through indirect geophysical methods [e.g.
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