Arianna Soldati

The ability to rapidly disseminate scientific knowledge across the world has never been greater. This is paralleled by the ability of rumors to spread equally far and fast. Popular misconceptions can take root and, without correction, take on the appearance of facts. Commonly misunderstood topics include those with attention-grabbing phrasing (e.g. “Pacific Ring of Fire”, “supervolcanoes”, or “mega-tsunamis”), the intersection of volcanic research with high-profile science topics (climate or human health), aspirational science goals (eruption forecasts), and basic terminology (volcanic ash versus smoke, or magma “chambers”). In this paper, we describe eighteen misconceptions grouped in six themes (seismology, volcanoes and climate, systems and structures, volcanic hazards, timescales, photographs and footage) commonly encountered by volcanologists who are actively engaging with the public and media both during and between eruptions. Each misconception description is accompanied by takeaway points and summaries of recent research to assist the reader with the information necessary to describe the issues. Finally, we present seven case studies where incorrect information was widely shared and counteracted at well-known volcanoes and recent eruptions at Mount Agung (Bali, Indonesia), Mount Etna (Sicily, Italy), Kīlauea (Hawaii, U.S.A.), Tajogaite (La Palma, Spain), La Soufrière (St. Vincent), Taal Volcano (Philippines), and Yellowstone caldera (U.S.A.). This work is intended to help both volcanologists and non-specialists get the story straight, and to effectively communicate processes and scales of volcanism and volcanic hazards, impacts, and risks.

This study uses videography, image analysis, and ballistic modeling to quantify eruption source parameters and transport characteristics of pyroclasts at Fissure 17 (F17) during the 2018 lower East Rift Zone eruption of Kīlauea. The hazard posed by volcanic ballistic projectiles depends on their range and kinetic energy on impact, which, in turn depend on the source parameters of the eruption. Furthermore, analysis of clast trajectories can inform the evolution of eruption style and its subsurface drivers. F17 evolved from a ~500 m long, segmented fissure into two dominant, long-lived segments separated by ~275 m: Segment 1 (S1) in the west was characterized by discrete, archetypal (“normal”) Strombolian explosions involving andesitic magma; and Segment 4 (S4) in the east was characterized by continuous spattering to low, unsteady Hawaiian fountaining of basaltic-andesitic magma. We analyzed clasts from two observation periods (13–14 May and 18 May), quantifying their size, exit velocity, and launch angle. S1 strengthened markedly as the fissure focused from 13 to 18 May, reflected in the median exit velocity increasing from 16 m/s to 45 m/s while median clast diameter decreased from 0.33 m to 0.17 m. S4 showed a more modest shift in median exit velocities (14 to 20 m/s) with broadly stable clast sizes. Maximum modeled ballistic ranges were 338 m at S1 and 51 m at S4. We attribute the greater range of S1 clasts to their greater density (mean of 1640 kg/m3 for S1 versus 820 kg/m3 for S4), higher launch velocity, and broader launch-angle distribution than S4 clasts. These results show that vent localization can amplify eruptive vigor while preserving fundamentally different conduit flow regimes at different sites along a single fissure, and that Strombolian activity during Hawaiian fissure eruptions may pose an elevated risk compared with more typical lava fountain activity.

The fractal dimensions of lava flow margins on Earth often correlate with their flow morphologies and have been used to tentatively identify flow morphology on other rocky planets where fine‐scale observations are limited. Previous studies of lava flow margins on Venus have reported fractal dimensions ( D ) mostly within the range between 1.05 and 1.26, which, analogous to subaerial basalt flows on Earth, suggest the presence of both ‘a’ā and pahoehoe‐like morphologies. In this work, seven Venusian lava flow margins at Maat Mons (MM) and Ozza Mons (OM) were investigated, as these are volcanoes within Atla Regio that have been identified as areas with possibly recent volcanic activity. Three lava flow margins at MM are found to have D values of 1.13–1.20, consistent with values associated with pāhoehoe and transitional flows on Earth; a fourth flow with a D of only 1.05 has been determined to be topographically confined to a valley. Three flows analyzed on OM display low D values, 1.03–1.04, similar to that of the fourth MM flow. The differences in flow‐margin fractal dimensions in Atla Regio are correlated with relative age and geologic setting, with OM being older than MM and emplaced concurrently during rifting within a potentially more heavily faulted terrain. All data for D values on Venus do not reveal strong regional patterns, suggesting that, as on Earth, flow morphologies vary primarily on local scales in response to changes in eruptive and emplacement conditions.

The rising velocity of an air bubble in a non‐Newtonian shear‐thinning fluid at low Reynolds numbers is generally similar to the Newtonian case given by Stokes' law. However, when the shear‐thinning fluid is subject to mechanical oscillations, the rising velocity could significantly increase. Here, we present a series of experiments quantifying the rising velocity of single bubbles during shaking in very high‐viscosity (2,000–30,000 Pa·s) shear‐thinning silicone oils. Air bubbles (18–30 mm diameter) were injected in a tank mounted on a shaking table. The tank was horizontally oscillated, at accelerations between 0.4 and 2 g. We observed a small increase in the rising velocity of the shaking cases at our experimental conditions. The increase was larger when bubbles were large and accelerations were high. Larger accelerations experienced the largest observational errors and we emphasize the exploratory nature of our results. We also measured the change in bubble diameter during the oscillations and computed the shear rate at the bubble surface. Maximum shear rates were in the range of 0.04–0.08 s⁻¹. At these shear rates, our analysis indicates that shear thinning behavior of our analog fluids is expected to be small and compete with elastic behavior. This transitional viscous/elastic regime helps explain the small and variable results of our experiments. Our results are relevant to the study of earthquake‐volcano interactions. Most crystal‐free silicate melts would exhibit a purely viscous, shear‐thinning behavior in a natural scenario. Seismically enhanced bubble rise could offer an explanation for the observed increased degassing and unrest following large earthquakes.

Magnetite-apatite deposits are important sources of iron and other metals. A prominent example are the magnetite lavas at the El Laco volcano, Northern Chile. Their formation processes remain debated. Here, we test the genetic hypothesis that an Fe-rich melt separated from silicate magma and ascended along collapse-related fractures. We complement recent analyses with thermodynamic modelling to corroborate Fe-Si liquid immiscibility evident in melt inclusions at El Laco and present viscometry of Fe- and Si-rich melts to assess the time and length scales of immiscible liquid separation. Using a rock deformation model, we demonstrate that volcano collapse can form failure zones extending towards the edifice flanks along which the ore liquid ascends towards extrusion driven by vapour exsolution despite its high density. Our results support the proposed magmatic genesis for the El Laco deposits. Geochemical and textural similarities indicate magnetite-apatite deposits elsewhere form by similar processes.

Glass art practice is indivisible from the material behaviour of glass at a range of working conditions, providing a direct link with the science of glass and melts. The use of non-standard, non-commercial, or natural glass compositions in art usually brings with it challenges associated with unexpected or undesirable processes, such as bubble formation and growth, liquid-liquid immiscibility, heterogeneities, and devitrification. For these reasons, natural geological compositions, including obsidian, have typically been avoided in glass art, with a few pioneering exceptions. Here, we bring together the results of mutual experimentation, knowledge-exchange workshops, and successful obsidian and magma use-cases in glass art in order to constrain the usability of obsidian and the techniques most suitable for rendering the material amenable to glass art practice. We conclude by exploring opportunities for collaboration between volcanologists and glass artists, which we propose would develop both fields in novel directions.