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Carol Stewart

Publications and source records attributed to Carol Stewart.

10 recordsLinked to original sources
USGS2026

Getting the story straight: Common misconceptions around volcanoes and eruptions with case studies of recent events

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.

Journal of Applied Volcanology↗
USGS2025

The communication of volcano information in New Zealand - A narrative review

Communication of volcano information is critical for effective volcanic risk management. A variety of information is communicated to inform decisions and guide actions for planning, preparedness, and response. Such information needs to be reliable, and fit-for-purpose across different stages of volcanic activity (quiescence, unrest, short or long-term eruptive stages, and the post-eruptive stage). However, an understanding of communication across these different stages of volcanic activity remains limited. We undertook a narrative review of New Zealand literature to explore what information is communicated about volcanoes, across which stages of activity and by whom. Results highlight that NZ literature only documents certain aspects of volcano information and communication, specifically regarding certain locations, stages of volcanic activity (i.e. quiescence or unrest), or hazards. Literature gaps exist regarding volcano communication during unrest and post-eruptive stages, as well as how volcano information evolves between these phases, and how decision-makers use such information. Additional work would be useful to document existing examples of volcano information for different stages of activity. Further research could help in understanding the information needs of decision-makers during each of these stages to improve information and communication.

New Zealand Journal of Geology and Geophysics↗
USGS2023

Physicochemical hazard assessment of ash and dome rock from the 2021 eruption of La Soufrière, St Vincent, for the assessment of respiratory health impacts and water contamination

La Soufrière, St Vincent, began an extrusive eruption on 27 December 2020. The lava dome was destroyed, along with much of the pre-existing 1979 dome, in explosive eruptions from 9 to 22 April 2021. Lava domes generate crystalline silica – inhalation of which can cause silicosis in occupational settings – which can become hazardous when dome material is incorporated into volcanic ash. La Soufrière ash (17 samples) was analysed, according to IVHHN protocols, to rapidly quantify crystalline silica and test for other health-relevant properties. The basaltic andesitic ash contained <5 wt% crystalline silica, which agrees with previous analyses of ash of similar compositions and mirrors the low quantities measured in dome samples (2 area %). It contained substantial inhalable material (7–21 vol% <10 µm). Few fibre-like particles were observed, reducing concern about particle shape. Leaching assays found low concentrations of potentially toxic elements, which indicates low potential to impact health, contaminate drinking-water sources or harm grazing animals through ingestion. Collectively, these data indicate that the primary health concern from this eruption was the potential for fine-grained ash to increase ambient particulate matter, an environmental risk factor for respiratory and cardiovascular morbidity and mortality. Precautionary measures were advised to minimize exposure.

La Soufrière↗
USGS2021

From anecdotes to quantification: Advances in characterizing volcanic eruption impacts on the built environment

Over the past 20 years, our understanding of volcanic eruption impacts on the built environment has transformed from being primarily observational with small datasets to one grounded in field investigations, laboratory experiments, and quantitative modeling, with an emphasis on stakeholder collaboration and co-creation. Here, we summarize key advances and knowledge gaps of impacts across volcanic hazards and built environment types from the past 20 + years. Studies have concentrated on impacts from tephra fall (ash) and to buildings, with less examination of other hazards’ impacts to critical infrastructure. As we look to the next decade, we speculate on likely research directions, including the increasing role of new technologies, higher resolution modeling, transdisciplinary collaborations, and evidence-based mitigative solutions.

Bulletin of Volcanology↗
USGS2021

Volcanic air pollution and human health: Recent advances and future directions

Volcanic air pollution from both explosive and effusive activity can affect large populations as far as thousands of kilometers away from the source, for days to decades or even centuries. Here, we summarize key advances and prospects in the assessment of health hazards, effects, risk, and management. Recent advances include standardized ash assessment methods to characterize the multiple physicochemical characteristics that might influence toxicity; the rise of community-based air quality monitoring networks using low-cost gas and particulate sensors; the development of forecasting methods for ground-level concentrations and associated public advisories; the development of risk and impact assessment methods to explore health consequences of future eruptions; and the development of evidence-based, locally specific measures for health protection. However, it remains problematic that the health effects of many major and sometimes long-duration eruptions near large populations have gone completely unmonitored. Similarly, effects of prolonged degassing on exposed populations have received very little attention relative to explosive eruptions. Furthermore, very few studies have longitudinally followed populations chronically exposed to volcanic emissions; thus, knowledge gaps remain about whether chronic exposures can trigger development of potentially fatal diseases. Instigating such studies will be facilitated by continued co-development of standardized protocols, supporting local study teams and procuring equipment, funding, and ethical permissions. Relationship building between visiting researchers and host country academic, observatory, and agency partners is vital and can, in turn, support the effective communication of health impacts of volcanic air pollution to populations, health practitioners, and emergency managers.

Bulletin of Volcanology↗
USGS2021

Development of a simulated lung fluid leaching method to assess the release of potentially toxic elements from volcanic ash

Freshly erupted volcanic ash contains a range of soluble elements, some of which can generate harmful effects in living cells and are considered potentially toxic elements (PTEs). This work investigates the leaching dynamics of ash-associated PTEs in order to optimize a method for volcanic ash respiratory hazard assessment. Using three pristine (unaffected by precipitation) ash samples, we quantify the release of PTEs (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn) and major cations typical of ash leachates (Mg, Na, Ca, K) in multiple simulated lung fluid (SLF) preparations and under varying experimental parameters (contact time and solid to liquid ratio). Data are compared to a standard water leach (WL) to ascertain whether the WL can be used as a simple proxy for SLF leaching. The main findings are: PTE concentrations reach steady-state dissolution by 24 h, and a relatively short contact time (10 min) approximates maximum dissolution; PTE dissolution is comparatively stable at low solid to liquid ratios (1:100 to 1:1000); inclusion of commonly used macromolecules has element-specific effects, and addition of a lung surfactant has little impact on extraction efficiency. These observations indicate that a WL can be used to approximate lung bioaccessible PTEs in an eruption response situation. This is a useful step towards standardizing in vitro methods to determine the soluble-element hazard from inhaled ash.

Chemosphere↗
USGS2021

Report on geochemical characterisation of volcanic ash from Cumbre Vieja, La Palma, for the assessment of respiratory health hazard

Volcanic ash has several hazardous characteristics that may impact human and animal health. We report the results of a geochemical assessment of key hazardous characteristics of 16 volcanic ash samples erupted from Cumbre Vieja, La Palma, between 19 September – 16 October 2021. The analyses are an essential first step in assessing health risk from volcanic eruptions because they allow a rapid screening of the physicochemical characteristics that have the potential to cause harm. The report is in two sections: Part 1 presents analyses related to respiratory hazard, while Part 2 presents analyses relevant for contamination of drinking water and ingestion hazards for livestock. The main authors (Horwell, Damby & Stewart) are directors of the International Volcanic Health Hazard Network (www.ivhhn.org) and have conducted and published extensive research to develop and test techniques for rapid analysis of volcanic ash for health hazard assessment.

Cumbre Vieja, La Palma↗
USGS2020

Assessment of leachable elements in volcanic ashfall: A review and evaluation of a standardized protocol for ash hazard characterization

Volcanic ash presents a widespread and common hazard during and after eruptions. Complex interactions between solid ash surfaces and volcanic gases lead to the formation of soluble salts that may be mobilized in aqueous environments. A variety of stakeholders may be concerned about the effects of ash on human and animal health, drinking water supplies, crops, soils and surface runoff. As part of the immediate emergency response, rapid dissemination of information regarding potentially hazardous concentrations of soluble species is critical. However, substantial variability in the methods used to characterize leachable elements makes it challenging to compare datasets and eruption impacts. To address these challenges, the International Volcanic Health Hazard Network ( www.ivhhn.org ) organized a two-day workshop to define appropriate methods for hazard assessment. The outcome of this workshop was a ‘consensus protocol’ for analysis of volcanic ash samples for rapid assessment of hazards from leachable elements, which was subsequently ratified by leading volcanological organizations. The purpose of this protocol is to recommend clear, standard and reliable methods applicable to a range of purposes during eruption response, such as assessing impacts on drinking-water supplies and ingestion hazards to livestock, and also applicable to research purposes. Where possible, it is intended that the methods make use of commonly available equipment and require little training. To evaluate method transferability, an interlaboratory comparison exercise was organized among six laboratories worldwide. Each laboratory received a split of pristine ash, and independently analyzed it according to the protocol for a wide range of elements. Collated results indicate good repeatability and reproducibility for most elements, thus indicating that the development of this protocol is a useful step towards providing standardized and reliable methods for ash hazard characterization. In this article, we review recent ash leachate studies, report the outcomes of the comparison exercise and present a revised and updated protocol based on the experiences and recommendations of the exercise participants. The adoption of standardized methods will improve and facilitate the comparability of results among studies and enable the ongoing development of a global database of leachate information relevant for informing volcanic health hazards assessment.

Journal of Volcanology and Geothermal Research↗