Explosive volcanic eruptions are defined as the violent ejection of gas and hot fragments from a vent in Earth's crust. Knowledge velocity is crucial for understanding modeling relevant physical processes an eruption, yet direct measurements still difficult task with largely variable results. Here we apply pioneering high‐speed imaging to measure pyroclasts Strombolian explosive unparalleled temporal resolution. Measured supersonic velocities, up 405 m/s, twice higher than previously...

Two main end-members of eruptive regimes are identified from analyses high-speed videos collected at Stromboli volcano (Italy), based on vent conditions: one where the is completely clogged by debris, and a second open, without any cover. By detailing processes for each regime, we provide first account how presence cover affects dynamics compared to open-vent explosions. For vents, explosion controlled amount grain size debris. Fine-grained covers entirely removed explosions, favouring...

Abstract. Volcanic ash advisories are produced by specialised forecasters who combine several sources of observational data and volcanic dispersion model outputs based on their subjective expertise. These used the aviation industry to make decisions about where it is safe fly. However, both observations simulations subject various uncertainties that not represented in operational forecasts. Quantification communication these fundamental for making more informed decisions. Here, we develop a...

Pressurized gas drives explosive volcanic eruptions. Existing models can predict the amount and pressure of in erupting magma, but application testing such is currently limited by accuracy input parameters from natural systems. Here, we present a new methodology, based on novel integration 1) high‐speed imaging 2) shock‐tube modeling activity order to derive estimates sub‐second variations pressure, mass, volume that drive dynamics unsteady First, validate method against laboratory‐scale...

Bubble formation and bubbling regimes are well-characterized for the cases of single-orifice bubblers industrial perforated plates. However, from with multiple in-line orifices remain poorly described. Here, we investigate dynamics bubble at both multi-orifice bubblers, one, three, five nine in an 80-cm-long bubbler. We use high-speed videography image processing to identify effects bubbler volume, number, spacing, diameter orifices, on regimes, period, time. main based synchronization among...

Strombolian volcanism is a ubiquitous form of activity, driven by the ascent and bursting bubbles slug morphology. Whilst considerable attention has been devoted to understanding behaviour individual slugs in this regime, relatively little known about how inter-slug interactions modify flow conditions. Recently, we reported on high temporal frequency strombolian activity Etna, which larger erupted masses were followed longer intervals before following explosion than smaller bursts (Pering et...

Volcanic plumes pose a hazard to health and society particular risk for aviation. Hazard mitigation relies on forecasting plume dispersion within the atmosphere over time. The accuracy of forecasts depends our understanding particle sedimentation processes, as well model input parameters, such initial size distribution concentrations volcanic particles (i.e., ash) in atmosphere. However, understating these processes accurate quantification parameters remain main sources uncertainty modeling....

Airborne ash generated by explosive volcanic eruptions presents a significant danger to aviation. Accurate modelling and predictions of the dispersal hazardous into atmosphere are currently hampered uncertainties in 'source term' parameters associated with initial eruption plume, specifically amount size particles released atmosphere. Ground based radar offers means remotely measure reflectivity, however estimation source term from reflectivity measured single frequency is limited ambiguity...

Basaltic eruptions produce lava flows that have the potential to destroy local infrastructure and emit toxic gas particles may adversely impact public health. Predicting their style evolution is therefore a key goal in volcanology. This requires an understanding of multiphase flow processes operate within sub-volcanic system. Field observations both solidified erupting basaltic fissures at Kīlauea volcano (Hawai‘i, USA) are synthesised with laboratory analogue experiments...

Abstract. Volcanic ash advisories are produced by specialised forecasters who combine several sources of observational data and volcanic dispersion model outputs based on their subjective expertise. These used the aviation industry to make decisions about where it is safe fly. However, both observations simulations subject various uncertainties that not represented in operational forecasts. Quantification communication these fundamental for making more informed decisions. Here, we develop a...

Bubbly flows occur in a wide variety of industrial and environmental settings. While there is broad literature that describes bubbly flow behavior pipes channels, high aspect ratio slot has received little attention. We describe the design construction new experimental apparatus to investigate processes associated with geometry. The designed perform scaled analog experiments magma through sub-volcanic plumbing system, but it sufficiently flexible address many other scenarios. main bubble...

Abstract Making decisions about the appropriate action to take when presented with uncertain information is difficult, particularly in an emergency response situation. Decision-makers can be influenced by factors such as how framed, their risk sensitivity, and impact of false alarms. Uncertainty arising from limited knowledge current state or future outcome event unavoidable making decisions. However, there no universally agreed method on design presentation uncertainty information. The aim...