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Todo se oscureció: uniting remote sensing observations and human experiences to understand recent eruptive activity of Volcán de Fuego, Guatemala
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This thesis presents an interdisciplinary case study of the active Volcán de Fuego in southern Guatemala to examine: (1) the physical behaviours and volcanic hazards that characterize eruptions occurring in recent years, and (2) the factors that influence local residents’ decision to evacuate from these eruptions. The thesis presents different answers to these issues depending on the data sources studied: satellite observations, geophysical and gas timeseries, and observations of and interviews with local residents and authorities. The thesis begins by presenting Fuego as an ideal subject for an interdisciplinary volcanology PhD, and establishes the philosophical positions and methodological approaches that were necessary to consider in order to undertake both physical and social science research within this PhD. The first results of this thesis are satellite observations of Fuego’s activity between January 2015 and June 2018. These observations, supplemented by other data, identify a new eruptive regime characterized by frequent explosive eruptions ("paroxysms") consistently preceded by lava flow effusion. Thresholds for determining eruption are debated. Physical results are juxtaposed with qualitative narratives of previous eruptions of Fuego and evacuations of communities as told by both authorities and local residents of rural communities around the volcano. These narratives reveal that an eruption at Fuego is not a consistent phenomenon, but is experienced differently by different observers based on their previous experiences, knowledge, resources, and priorities. Finally, quantitative and qualitative data are integrated through analysis of timeframes of eruption and response for several recent eruptions. Quantitative timescales and their qualitative counterpart, timelines, provide detailed chronologies of times and uncertainties involved in forecasting eruptions of Fuego and of deciding, warning, responding to, and evacuating from eruption. Ultimately, this thesis concludes that the lives of local residents cannot be reliably protected from hazards of Fuego without integration of the monitoring and risk mitigation efforts of INSIVUMEH and CONRED. This integration mirrors that of physical and social drivers of volcanic risk explored within this work. This thesis demonstrates the value of integrating physical and social research methods in a single interdisciplinary project, and contributes to volcanological literature with findings that volcanic risk is both spatially and temporally variable around a single volcano.
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... However, national media later highlighted the disconnect between these authorities supposedly fulfilling their responsibilities and the high death toll. In partic-Fireside tales: Volcán de Fuego Naismith et al., 2020 ular, media focussed on the different fates of geographically close communities: why did the private golf resort of La Reunión successfully evacuate, yet Los Lotes, two kilometres further south, suffer such extensive human loss [Tobar 2018]?. This question relates to the larger issue of the ability and willingness of communities to evacuate from eruptive crisis. ...
... The most effective action to mitigate risk to life from most volcanic hazards is evacuation. The decision Fireside tales: Volcán de Fuego Naismith et al., 2020 to evacuate is often difficult to make because all choices may have negative consequences. An individual may decide to reduce personal risk when an eruption reaches its climax. ...
... Therefore, interviews provided an opportunity for better understanding of "[a] phenomenon about which little is yet known . . . to gain more in-depth information that may be difficult to convey quantitatively" [Hoepfl 1997]. Our paper is published from the results of the lead author's thesis, which includes theoretical assumptions and philosophical stance involved in her research [Naismith 2020]. ...
Volcán de Fuego (Guatemala) is an active stratovolcano capable of large (VEI~>2) explosive eruptions like that of 3rd June 2018, which triggered pyroclastic flows that devastated the community of San Miguel Los Lotes and caused hundreds of fatalities and severe long-term socioeconomic impacts. Future volcanic risk mitigation efforts are likely to involve temporary evacuation of local communities, the success of which requires cooperation between locals, scientists, and decision-makers. However, locals' experiences of eruptive activity, and how these experiences influence their responses to evacuation, have not been studied in detail. In 2019 we conducted an investigation of these themes through qualitative research methods involving semi-structured interviews that focussed on direct experience as opposed to volcanic risk perception. We found substantial differences between scientists' and locals' observations of Fuego's activity. Furthermore, a clear disparity emerged between communities on Fuego's west and east flanks in terms of direct prior experience of eruptions and communication with authorities. These findings have serious implications for future evacuation efforts at Fuego and at other highly populated active volcanoes.
Ash cloud surges are capable to cause huge devastation and mortality around volcanoes, and temperature is a crucial parameter in assessing their lethal power. Reflectance analysis on carbonized wood from ancient Herculaneum allowed a new reconstruction of the thermal events that impacted buildings and humans during the 79CE Vesuvius eruption. Here we show that the first pyroclastic flow to enter the town was a short-lived ash cloud surge, detached from high concentration currents, with temperatures of 555 − 495°C capable of causing instant death of people, while leaving only a few decimeters of ash on ground. The subsequent pyroclastic currents progressively buried the town at temperatures between 465 − 390 and 350 − 315°C. Charcoal proved to be the only proxy capable of recording multiple, ephemeral extreme thermal events, allowing us to reveal for the first time the real thermal impact of the 79CE eruption. The lethal impact detected for ash cloud surges produced during ancient and recent volcanic eruptions suggests that such hazard deserves much more consideration at Vesuvius and elsewhere.
p>Modern satellite networks with rapid image acquisition cycles allow for near-real-Time imaging of areas impacted by natural hazards such as mass wasting, flooding, and volcanic eruptions. Publicly accessible multi-spectral datasets (e.g., Landsat, Sentinel-2) are particularly helpful in analyzing the spatial extent of disturbances, however, the datasets are large and require intensive processing on high-powered computers by trained analysts. HazMapper is an open-Access hazard mapping application developed in Google Earth Engine that allows users to derive map and GIS-based products from Sentinel or Landsat datasets without the time-and cost-intensive resources required for traditional analysis. The first iteration of HazMapper relies on a vegetation-based metric, the relative difference in the normalized difference vegetation index (rdNDVI), to identify areas on the landscape where vegetation was removed following a natural disaster. Because of the vegetation-based metric, the tool is typically not suitable for use in desert or polar regions. HazMapper is not a semi-Automated routine but makes rapid and repeatable analysis and visualization feasible for both recent and historical natural disasters. Case studies are included for the identification of landslides and debris flows, wildfires, pyroclastic flows, and lava flow inundation. HazMapper is intended for use by both scientists and non-scientists, such as emergency managers and public safety decision-makers.
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Monitoring volcanic unrest and understanding seismic and acoustic signals associated with eruptive activity is key to mitigate its impacts on population and infrastructure. On June 3, 2018, Volcán de Fuego, Guatemala, produced a violent eruption with very little warning. The paroxysmal phase of this event generated pyroclastic density currents (PDC) that impacted nearby settlements resulting in 169 fatalities, 256 missing, and nearly 13,000 permanently displaced from their homes. Since then, Volcán de Fuego has been instrumented with an extensive network of seismic and infrasound sensors. Infrasound is a new monitoring tool in Guatemala. A key step toward its effective use in volcano monitoring at Volcán de Fuego is establishing a baseline for the interpretation of the recorded signals. Here, we present the first comprehensive characterization of acoustic signals at Volcán de Fuego for the whole range of surface activity observed at the volcano. We use data collected during temporary deployments in 2018 and from the permanent infrasound network. Infrasound at Fuego is dominated by the occurrence of short-duration acoustic transients linked to both ash-rich and gas-rich explosions, at times associated with the generation of shock waves. The rich acoustic record at Fuego includes broadband and harmonic tremor, and episodes of chugging. We explore the occurrence of these signals in relation to visual observations of surface activity, and we investigate their source mechanisms within the shallow conduit system. This study provides a reference for the interpretation of acoustic signals at Volcán de Fuego and a baseline for real-time monitoring of its eruptive activity using infrasound data. Our results suggest that changes in the style of activity and morphology of the summit crater are reflected in the acoustic signature of eruption; as such our study provides a reference for the interpretation of acoustic signals at Volcán de Fuego and a baseline for real-time monitoring of its eruptive activity using infrasound.
The estimation of the volume of volcanic flows during an ongoing eruption is challenging but this information is crucial for improving risk assessment and for forecasting future events. Although previous studies have shown the ability of TanDEM-X satellite data to derive the thickness and the volume of lava flow fields during effusive eruptions, the method has not been explored yet for pyroclastic flows. Using bi-static interferometry, we produce TanDEM-X DEM on Fuego volcano (Guatemala) to measure the significant topographic changes caused by the 3rd June 2018 eruption, which destroyed the town of San Miguel Los Lotes. We estimate the volume of the Pyroclastic Density Currents (PDCs) to be 15.1 ± 4.2 × 106 m3. The deposits are likely to be the source of lahars during future rainy seasons. We identify the main channel of deposition (positive elevation changes) and the source region of pyroclastic material, areas of significant substrate erosion, and vegetation destruction (negative elevation changes). Our results show that the June 3rd 2018 pyroclastic flow was predominantly composed of material which had gravitationally collapsed from a location close to the vent. The eroded material increased the volume of the flow (bulking) and likely caused the run-out distance of the 2018 PDC to be larger than previous eruptions (1999–2017). This study highlights the potential of remote sensing techniques for actively monitoring topography changes in inaccessible locations and to rapidly derive deposit volumes.
The definition of a suite of analogue volcanoes, or volcanoes that are considered to share enough characteristics as to be considered exchangeable to a certain extent, is becoming a key component of volcanic hazard assessment. This is particularly the case for volcanoes where data are lacking or scarce. Moreover, volcano comparisons have often been based on similarities and differences inferred through expert judgement and not necessarily informed by volcano characteristics from global datasets. These similarities can be based on a range of features, from very simplified (e.g. statrovolcanoes) to very specific (e.g. detailed eruption chronologies), and may be strongly influenced by the personal experience of individuals or teams conducting the analogue analysis. In this work, we present VOLCANS (VOLCano ANalogues Search)—an objective, structured and reproducible method to identify sets of analogue volcanoes from global volcanological databases. Five overarching criteria (tectonic setting, rock geochemistry, volcano morphology, eruption size and eruption style), and a structured combination of them, are used to quantify overall multi-criteria volcano analogy. This innovative method is complementary to expert-derived sets of analogue volcanoes and provides the user with full flexibility to weigh the criteria and identify analogue volcanoes applicable to varied purposes. Some results are illustrated for three volcanoes with diverse features and significant recent and/or ongoing eruptions: Kı̄lauea (USA), Fuego (Guatemala) and Sinabung (Indonesia). The identified analogue volcanoes correspond well with a priori analogue volcanoes derived from expert knowledge. In some cases, single-criterion searches may not be able to isolate a reduced set of analogue volcanoes but any multi-criteria search can provide high degrees of granularity in the sets of analogue volcanoes obtained. Data quality and quantity can be important factors, especially for single-criterion searches and volcanoes with very scarce data (e.g. Sinabung). Nevertheless, the method gives stable results overall across multi-criteria searches of analogue volcanoes. Potential uses of VOLCANS range from quantitative volcanic hazard assessment to promoting fundamental understanding of volcanic processes.
Fuego volcano (Guatemala) is one of the most active and hazardous volcanoes in the world. Its persistent activity generates lava flows, pyroclastic density currents (PDCs), and lahars that threaten the surrounding areas and produce frequent morphological change. Fuego’s eruption deposits are often rapidly eroded or remobilized by heavy rains and its constant activity and inaccessible terrain makes ground-based assessment of recent eruptive deposits very challenging. Earth-orbiting satellites can provide unique observations of volcanoes during eruptive activity, when ground-based techniques may be too hazardous, and also during inter-eruptive phases, but have typically been hindered by relatively low spatial and temporal resolution. Here, we use a new source of Earth observation data for volcano monitoring: high resolution (~3 m pixel size) images acquired from a constellation of over 150 CubeSats (‘Doves’) operated by Planet Labs Inc. The Planet Labs constellation provides high spatial resolution at high cadence (<1–72 h), permitting space-based tracking of volcanic activity with unprecedented detail. We show how PlanetScope images collected before, during, and after an eruption can be applied for mapping ash clouds, PDCs, lava flows, or the analysis of morphological change. We assess the utility of the PlanetScope data as a tool for volcano monitoring and rapid deposit mapping that could assist volcanic hazard mitigation efforts in Guatemala and other active volcanic regions.
Originally prepared for the United Nations Office for Disaster Risk Reduction, this is the first comprehensive assessment of global volcanic hazards and risk, presenting the state of the art in our understanding of global volcanic activity. It examines our assessment and management capabilities, and considers the preparedness of the global scientific community and government agencies to manage volcanic hazards and risk. Particular attention is paid to volcanic ash, the most frequent and wide-ranging volcanic hazard. Of interest to government officials, the private sector, students and researchers, this book is a key resource for the disaster risk reduction community and for those interested in volcanology and natural hazards. A non-technical summary is included for policy makers. Regional volcanic hazard profiles, with invaluable information on volcanic hazards and risk at the local, national and global scale, are provided online. This title is available as an Open Access eBook via Cambridge Books Online.
This book provides a comprehensive overview of volcanic crisis research, the goal being to establish ways of successfully applying volcanology in practice and to identify areas that need to be addressed for future progress. It shows how volcano crises are managed in practice, and helps to establish best practices. Consequently the book brings together authors from all over the globe who work with volcanoes, ranging from observatory volcanologists, disaster practitioners and government officials to NGO-based and government practitioners to address three key aspects of volcanic crises.
First, the book explores the unique nature of volcanic hazards, which makes them a particularly challenging threat to forecast and manage, due in part to their varying spatial and temporal characteristics. Second, it presents lessons learned on how to best manage volcanic events based on a number of crises that have shaped our understanding of volcanic hazards and crises management. Third, it discusses the diverse and wide-ranging aspects of communication involved in crises, which merge old practices and new technologies to accommodate an increasingly challenging and globalised world.
The information and insights presented here are essential to tapping established knowledge, moving towards more robust volcanic crises management, and understanding how the volcanic world is perceived from a range of standpoints and contexts around the globe.
Paroxysmal activity represents an end-member in the common range of activity at mafic arc volcanoes, characterised by rapid transitions across the effusive-explosive interface and thus posing significant challenges to hazard assessment. Conceptual models to explain changes in the frequency and magnitude of these paroxys-mal events are based either on magma recharge or an increase in gas flux, largely framed in the context of two-phase flow. Gas-and magma-driven models are both viable mechanisms to explain the varying styles of parox-ysmal behaviour observed in mafic systems; however, each has different implications for future activity. We present time series petrologic data for ash and lava samples collected at Volcán de Fuego, Guatemala, during par-oxysmal eruptions between 2011 and 2018. We show that a step-change in glass composition occurred between 2015 and 2016, reflecting an increase in magma temperature and a reduction in pre-eruptive crystallisation, concurrent with an escalation in the frequency of paroxysmal activity. There was no change in the bulk or phase compositions during this period. To explain these observations, we propose that the increase in frequency of paroxysmal eruptions is modulated by the supply of exsolved volatiles from lower crustal degassing magmas, without invoking repeated transfer of new, primitive magma to a shallow reservoir. Protracted lava effusion, accompanied by more vigorous and more frequent Strombolian explosions and gas 'chugging', prior to the transition to sustained fountaining suggests that gas retention in crystal-rich magma may modulate the height of the magma column as gas supply increases. Slow decompression associated with effusion may determine the timing of effusive to explosive transitions in mafic arc systems more generally. A large paroxysmal eruption of Fuego on 3 June 2018, notable for the rapid escalation in eruptive intensity several hours into the eruption, produced ash with a range of textures and glass compositions consistent with magma evacuation over a range of depths and decompression rates. Given the protracted repose time between paroxysms before this event, we suggest that a shallow crystallised plug degraded , and ultimately failed, several hours into the eruption of 3 June 2018, triggering top-down decompression of magma in the conduit synchronous with the observed rapid acceleration in eruption rate. Ultimately, we propose that the frequency of paroxysms at Fuego is broadly proportional to the gas supply rate, while the range in glass compositions is related to the repose time prior to eruptive activity. Our data illustrate the potential of pet-rologic monitoring to distinguish between gas-and magma-driven paroxysm triggers and to anticipate future events, especially when interpreted in the context of geophysical observations and implemented within community-based ash collection initiatives.