Volcanological Community Research Articles

A Case for Improved Global Coordination of Volcano Observatories

The distribution of volcano monitoring networks and volcano expertise does not correlate well with the global distribution of volcanic risk. All countries have cultural, financial, bureaucratic, political, and logistical barriers to effective risk reduction. The lack of parity amongst volcano observatories jeopardizes public safety and curtails scientific research and understanding. Having global data compiled daily to retain a full record of volcanic unrest would lead to large and meaningful improvements in future eruption forecasts. To make progress on these issues, the volcanological community needs greater collaboration, standardization, and support..

The global volcano monitoring infrastructure database (GVMID)

Monitoring volcanoes is of the most importance in volcano risk mitigation to safeguard lives and economies. Thanks to recent technological advances, both on-ground and in space, our understanding of volcanic processes has improved significantly. Though there is no one-system-fits-all, optimizing infrastructure for efficient monitoring stands as key objective. The impacts of volcanic hazards can span from local to global scales, affecting us both in the short and long term. This highlights the worldwide significance of improving volcano monitoring. Previously reliant on local ground-based instruments, today’s monitoring approach is enhanced by remote and space-based techniques such as satellite remote sensing, scanning-Differential Optical Absorption Spectroscopy (DOAS), and infrasound. Designing an effective monitoring infrastructure for volcano observatories involves careful consideration of various factors such as network coverage, type of sensors, data transmission, and power supply to ensure that the targeted parameters meet the specific needs of each volcano (e.g., type of activities, early warning systems). Additionally, fostering collaboration and information sharing within the global scientific community is essential for addressing the current challenges in volcanology. In line with this, we’ve established the Global Volcano Monitoring Infrastructure Database (GVMID) to compile data from volcano monitoring across the globe. Global Volcano Monitoring Infrastructure Database serves as an integral component of WOVOdat, the global volcano unrest database, aiming to enhance our understanding of eruptive processes and improve eruption forecasts. The database incorporates monitoring metadata comprising networks, stations, and instruments, all standardized and managed using a MySQL relational database management system. Accessed through a web-based interface (https://wovodat.org/gvmid/home.php), GVMID offers an informative snapshot and foundational overview of the techniques and instruments in place at diverse volcanoes. This interactive platform allows for queries, visualizations, and downloads, serving as a valuable resource for the volcano community. GVMID can assist observatories in various ways, by: (a) Facilitating the setup or enhancement of monitoring systems for specific volcanoes. (b) Providing insights into the latest monitoring technologies and instrumentation. (c) Identifying existing monitoring gaps that could be addressed through remote sensing infrastructure and future instrument deployments. We extend an invitation to the global volcano community to actively participate in the development and enrichment of GVMID. Our aim is for it to become a continually updated and indispensable resource that caters to diverse needs within the volcanology community.

Lessons learned from the 2022 CONVERSE Monogenetic Volcanism Response Scenario Exercise

When volcanic unrest occurs, the scientific community can advance fundamental understanding of volcanic systems, but only with coordination before, during, and after the event across academic and governmental agencies. To develop a coordinated response plan, the Community Network for Volcanic Eruption Response (CONVERSE) orchestrated a scenario exercise centered around a hypothetical volcanic crisis in Arizona’s San Francisco Volcanic Field (SFVF). The exercise ran virtually from February 4 to March 4, 2022. Over 60 scientists from both academic and governmental spheres participated. The scenario exercise was assessed for its effectiveness in supporting collaborative production of knowledge, catalyzing transdisciplinary collaboration, supporting researcher confidence, and fostering a culture of inclusion within the volcanology community. This identified a need to support early career researchers through community and allyship. Overall, the 2022 CONVERSE exercise demonstrated how a fully remote, extended scenario can be authentically implemented and help broaden participation within the volcano science community.

The Volcanic Hazard Maps Database: an initiative of the IAVCEI Commission on Volcanic Hazards and Risk

In this work we present the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) Commission on Volcanic Hazards and Risk (CVHR) Volcanic Hazard Maps Database and the accompanying volcanichazardmaps.org website. Using input from a series of IAVCEI CVHR Working Group on Hazard Mapping workshops, we developed a classification scheme and terminology framework for categorizing, discussing, naming, and searching for hazard maps. ≥ The database and website aim to serve as a resource for the volcanology community to explore how different aspects of hazard map development and design have been addressed in different countries, for different hazard processes, and for different intended purposes and audiences. Additionally, they act as a tool for presenting hazard map options to stakeholder groups and serve as a learning resource that can be incorporated into educational materials and training courses. In this work, we present the database and website, discuss the classification scheme, explore the enormous diversity of hazard maps, and suggest ways that the database and website can be used by the volcanic hazard mapping community.

Making sense of brittle deformation in rhyolitic lavas: Insights from Obsidian Dome, California, USA

AbstractThe scarcity of observed active extrusive rhyolitic lava flows has skewed research to extensively focus on prehistoric lavas for information about their eruptive and emplacement dynamics. The first ever witnessed silicic lava eruptive events, Chaitén (2008) and Cordón Caulle (2011–2012) in Chile, were illuminating to the volcanology community because they featured a range of emplacement processes (endogenous versus exogenous), movement limiting modes, and eruptive behaviors (explosive versus effusive) that were often regarded as acting independently throughout an eruptive event. In this study, we documented evidence of a continuum of brittle and brittle-ductile deformation and fracture-induced outgassing during the emplacement of the ~600-yr-old silicic lava from Obsidian Dome, California, USA. This study focused on mapping the textural-structural relationships of the upper surface of the lava onto high-resolution (<10 cm2/pixel) orthorectified color base maps. We found that the upper surface is characterized by small (<1 m) mode 1 tensile fractures that grew and initiated new cracks, which linked together to form larger tensile fractures (1–5 m), which in turn penetrated deeper into the lava. We recorded ornamentations on these fracture surfaces that allow snapshot views into the rheological and outgassing conditions during the lava’s effusion. The largest fractures developed during single, large fracture events in the final stages of the lava’s emplacement. Ornamentations preserved on the fractured surfaces record degassing and explosive fragmentation away from the vent throughout the lava’s emplacement, suggesting explosive activity was occurring during the effusive emplacement. Field-based cataloguing of the complexities of fracture surfaces provides qualitative constraints for the future mechanical modeling of effusive lavas.

An Inside Sun: Lickanantay Volcanology in the Salar de Atacama

The need of establishing more substantive dialogs between the mainstream and Indigenous knowledge on volcanoes has been increasingly recognized. To contribute to this endeavor, in this article we present the basic volcanological understandings of the Lickanantay people in the Salar de Atacama Basin. The Salar de Atacama Basin is an active volcanic territory within the Central Volcanic Zone of the Andes (CVZA). From the El Tatio geothermal field to Socompa volcano, more than 19 active volcanoes surround the territory that the Lickanantay (Atacameño) people have inhabited for more than 11,000 years. Living around and with the geological dynamism of the CVZA for millennia, the Lickanantay communities have accumulated rich observational and ceremonial data on volcanoes and volcanism. Paradoxically, however, while the Atacameño people have thoroughly characterized the CVZA, the volcanology community has not been properly introduced to the ancestral knowledge articulated in the territory. In order to make traditional Atacameño perspectives on volcanoes, volcanic risk, and geo-cosmic interdependence more amply available to the volcanology community, in this article, we present a basic description of what we call Atacameño volcanology. By Atacameño volcanology, we understand the ancestral principles by which volcanoes are known and understood as partaking in larger processes of a cosmo-ecological formation. Specifically, we describe the basic volcanological notions arising from the Lickanantay ancestral knowledge—volcanic formation, functions, and behavior. Second, we focus on the El Tatio geothermal field to offer a situated example. Finally, we delineate some relevant elements of human–volcano interactions and volcanic risk management from an Atacameño perspective. In our conclusions we suggest that volcanology, particularly in the context of the Andes, needs to engage more substantially with the Atacameño or other ancestral systems of knowledge production to expand volcanological insights and respond to the call for decolonizing science.

The integrated multidisciplinary European volcano infrastructure: from the conception to the implementation

Recent decades have highlighted the increasing need to connect and strengthen the volcanology community at European level. Indeed, research in the volcanology field is highly qualified in Europe and the volcano monitoring infrastructures have achieved valuable know-how, becoming the state-of-the-art in the world. However, the lack of common good practices in sciences and technologies, missing standards, as well as a significant fragmentation of the community requires coordination to move forward and guarantee a trans-national harmonisation. The European Plate Observing System (EPOS) represented the first opportunity to initiate this process of coordination by encouraging the creation of a European volcanological scientific infrastructure for data and service sharing. During the preparation and the design of EPOS, the volcanology community identified the objectives and the needs of the community building, the services to be provided and the work plan to implement the infrastructure. To achieve this aim, the contribution from three European projects FUTUREVOLC, MED-SUV and EUROVOLC was essential. This paper presents the main steps performed during the last years for building the community and implementing the infrastructure. This paper also describes the strategic choices and actions taken to realise the infrastructure such as the establishment of the Volcano Observation Thematic Core Service (TCS), whose structure and activity are described.

Eruptions and Social Media: Communication and Public Outreach About Volcanoes and Volcanic Activity in Italy

Italy is the land of iconic volcanoes, whose activity has been witnessed, described and portrayed for centuries. This legacy has greatly contributed to shaping the public perception of volcanoes and their impact, well beyond the national borders. Stories about famous eruptions overlap and nowadays easily mix up with the impressive footage that is readily available from ongoing eruptions worldwide. As a result, the public discourse may flatten the wide spectrum of possible phenomena into an oversimplified sketch of volcanic eruptions and their impact, where all events seem equally probable and look alike. Actual volcanoes differ in size, eruption magnitude, state of activity, eruptive style, geographical position, and each is located within a specific social and cultural context. All these elements combine in defining the consequences of volcanic activity as well as in determining the severity of the damage and the size of the impacted area. How can we convey such a complexity to the general public? Can social media contribute to raise awareness and build a more resilient society? An effective hazard communication should propose a comprehensible yet realistic description of volcanic settings and provide adequate tools to recognize and understand the specific features of each phenomenon and volcanic area. As we write, two Italian volcanoes display persistent eruptive activity, while other two are going through unrest phases that started in 2012, at Campi Flegrei, and in late summer of 2021, at Vulcano Island. Other active volcanoes (Vesuvius, Ischia, Colli Albani, Lipari, and Pantelleria) have been dormant for tens, hundreds, or thousands of years. Communication in these different contexts also require different approaches that take into account the specific needs of local communities. Social media may provide a unique opportunity to quickly share relevant news and information. Yet, this type of communication has its challenges and volcano observatories can rarely rely on expert social media managers. Sharing experiences and lessons learned is a key to ensure the growth of the volcanological community and improve its ability to connect and engage local residents. Here we discuss the online communication strategies implemented by the Istituto Nazionale di Geofisica e Vulcanologia (INGV) since 2018 to inform Internet and social media users about volcanoes, volcanology, and ongoing volcanic activity, both in Italy and abroad. We describe the internal procedures that we developed and practiced and the experience gathered so far, during both quiet periods and a few volcanic crises. Our experience confirms previous indications about the importance of a steady online presence and suggests that public interest is not always easily predictable.

Thermal Budgets of Magma Storage Constrained by Diffusion Chronometry: the Cerro Galán Ignimbrite

Abstract The long-term thermochemical conditions at which large bodies of silicic magma are stored in the crust is integral to our understanding of the timing, frequency, and intensity of volcanic eruptions and provides important context for interpreting volcano monitoring data. Despite this, however, individual magmatic systems may exhibit a range of time–temperature paths, or thermal histories, that are the result of many complex and, in some cases, competing processes. This complexity contributes to an incomplete understanding of the long-term thermal evolution of magma stored within the Earth’s crust. Of recent interest to the volcanology community is the length of time large volumes of rheologically eruptible and geophysically detectable magma exist within the crust prior to their eruption. Here we use a combination of diffusion chronometry, trace element, and thermodynamic modeling to quantify the long-term thermal evolution of the 2.08 Ma, 630 km3 Cerro Galán Ignimbrite (CGI) in NW Argentina; one of the largest explosive volcanic eruptions in the recent geologic record. We find that diffusion of both Mg and Sr in plagioclase indicate that erupted magmatic material only spent decades to centuries at or above temperatures (~750°C) required to maintain significant volumes of stored eruptible magma. Calculated plagioclase equilibrium compositions reveal an array of liquids that is controlled overall by fractionation of plagioclase + biotite + sanidine, although high-resolution trace element transects record a diversity of fractionation pathways. Overall, we suggest that there is compelling evidence that the magma erupted from the CGI magmatic system spent most of its upper crustal residence in a largely uneruptible state and was rapidly remobilized shortly before eruption.

Volcanologists—who are we and where are we going?

Equity, diversity and inclusivity (EDI) are principles all scientific groups and organisations should strive to achieve as they secure working conditions, policies and practices that not only promote high-quality scientific output but also well-being in their communities. In this article, we reflect on the progress of EDI in volcanology by presenting data related to memberships of international volcanology organisations, positions on volcanology committees, volcanology awards and lead-authorship on volcanology papers. The sparse demographic data available means our analysis focuses mainly on gender identity discrimination, but we show that discrimination related to ethnicity, sexual orientation, religion, physical ability and socio-economic background is also occurring, with the intersection of these discriminations further exacerbating marginalisation within the volcanology community. We share suggestions and recommendations from other disciplines on how individuals, research groups and organisations can promote, develop and implement new initiatives to call out and tackle discrimination and advance EDI in the volcanological community. There is a lot of potential for improvement if we all see our role in creating a more equitable, diverse and inclusive volcanology community. This requires (1) awareness: acknowledgement of the problem, (2) commitment: through the statement of EDI core values and the development of action plans, codes of conducts and guidelines, (3) action: aiming for representation of all groups, and (4) reflection: development through critical self-reflection and a willingness to address shortcomings.

PlumeTraP: A New MATLAB-Based Algorithm to Detect and Parametrize Volcanic Plumes from Visible-Wavelength Images

Tephra plumes from explosive volcanic eruptions can be hazardous for the lives and livelihoods of people living in the proximity of volcanoes. Monitoring and forecasting tephra plumes play essential roles in the detection, characterization and hazard assessment of explosive volcanic events. However, advanced monitoring instruments, e.g., thermal cameras, can be expensive and are not always available in monitoring networks. Conversely, visible-wavelength cameras are significantly cheaper and much more widely available. This paper proposes an innovative approach to the detection and parametrization of tephra plumes, utilizing videos recorded in the visible wavelengths. Specifically, we have developed an algorithm with the objectives of: (i) identifying and isolating plume-containing pixels through image processing techniques; (ii) extracting the main geometrical parameters of the eruptive column, such as the height and width, as functions of time; and (iii) determining quantitative information related to the plume motion (e.g., the rise velocity and acceleration) using the physical quantities obtained through the first-order analysis. The resulting MATLAB-based software, named Plume Tracking and Parametrization (PlumeTraP), semi-automatically tracks the plume and is also capable of automatically calculating the associated geometric parameters. Through application of the algorithm to the case study of Vulcanian explosions from Sabancaya volcano (Peru), we verify that the eruptive column boundaries are well recognized, and that the calculated parameters are reliable. The developed software can be of significant use to the wider volcanological community, enabling research into the dynamics of explosive volcanic eruptions, as well as potentially improving the use of visible-wavelength cameras as part of the monitoring networks of active volcanoes. Furthermore, PlumeTraP could potentially find a broader application for the analysis of any other plume-shaped natural or anthropogenic phenomena in visible wavelengths.

Big volcano science: needs and perspectives

Volcano science has been deeply developing during last decades, from a branch of descriptive natural sciences to a highly multi-disciplinary, technologically advanced, quantitative sector of the geosciences. While the progress has been continuous and substantial, the volcanological community still lacks big scientific endeavors comparable in size and objectives to many that characterize other scientific fields. Examples include large infrastructures such as the LHC in Geneva for sub-atomic particle physics or the Hubble telescope for astrophysics, as well as deeply coordinated, highly funded, decadal projects such as the Human Genome Project for life sciences. Here we argue that a similar big science approach will increasingly concern volcano science, and briefly describe three examples of developments in volcanology requiring such an approach, and that we believe will characterize the current decade (2020–2030): the Krafla Magma Testbed initiative; the development of a Global Volcano Simulator; and the emerging relevance of big data in volcano science.

Post-Caldera Eruptions at Chalupas Caldera, Ecuador: Determining the Timing of Lava Dome Collapse, Hummock Emplacement and Dome Rejuvenation

Determining the lithology, extent, origin, and age of hummocks can be challenging, especially if these are covered by successive deposits and lush vegetation. At Chalupas caldera, a late-Pleistocene silicic center that lies astride the Eastern Cordillera of northern Ecuador, we have tried to overcome these difficulties by combining geological observations and sampling, laboratory analysis (geochemistry, scanning electron microscope analysis and radiometric dating) and remote sensing techniques. Chalupas is the second largest caldera in the Northern Volcanic Zone of South America and its VEI 7 eruption, which occurred ∼0.21 Ma, has garnered the attention of the volcanological community. Our research highlights new observations of the post-caldera activity at Chalupas, beginning with the growth of Quilindaña stratovolcano (∼0.170 Ma), followed by the formation of Buenavista dome that is located 5 km eastward of Quilindaña’s summit. At the eastern foot of Buenavista dome we identify hummocky terrain covering an area of ∼20 km2. Collectively, the suite of techniques that we used helped to highlight geological features that shed light on the provenance of the hummocks and demonstrate that this topography may have originated from gravitational breccia flows from Buenavista lava dome. Numerical simulations were also performed to represent breccia flow transit and emplacement over the present caldera landscape and to view the potential hazard footprints of a future Buenavista dome collapse. For modeling we employed volumes of 20–120 Mm3 to visualize the consecutive traces of mass flow deposition and how the traces correspond to the hummocky landscape. Following the partial collapse of Buenavista lava dome, its rejuvenation is represented by tephra layers of several small eruptions that are dated at about 40 ky BP. These tephras represent some of the youngest eruptive activity recognized at Chalupas caldera. Our results contribute to the overall knowledge about Chalupas and demonstrate that eruptions at this important caldera are more recent than was previously reported.

Long-Term Probabilistic Volcanic Hazard Assessment Using Open and Non-open Data: Observations and Current Issues

Probabilistic volcanic hazard assessment (PVHA) has become the paradigm to quantify volcanic hazard over the last decades. Substantial aleatory and epistemic uncertainties in PVHA arise from complexity of physico-chemical processes, impossibility of their direct observation and, importantly, a severe scarcity of observables from past eruptions. One factor responsible for data scarcity is the infrequency of moderate/large eruptions; other factors include lack of discoverability and accessibility to volcanological data. Open-access databases can help alleviate data scarcity and have significantly contributed to long-term PVHA of eruption onset and size, while are less common for data required in other PVHA components (e.g. vent opening). Making datasets open is complicated by economical, technological, ethical and/or policy-related challenges. International synergies (e.g. Global Volcanism Program, WOVOdat, Global Volcano Model, EPOS) will be key to facilitate the creation and maintenance of open-access databases that support Next-Generation PVHA. Additionally, clarification of some misconceptions about PVHA can also help progress. Firstly, PVHA should be understood as an expansion of deterministic, scenario-based hazard assessments. Secondly, a successful PVHA should sometimes be evaluated by its ability to deliver useful and usable hazard-related messages that help mitigate volcanic risk. Thirdly, PVHA is not simply an end product but a driver for research: identifying the most relevant sources of epistemic uncertainty can guide future efforts to reduce the overall uncertainty. Broadening of the volcanological community expertise to statistics or engineering has already brought major breakthroughs in long-term PVHA. A vital next step is developing and maintaining more open-access datasets that support PVHA worldwide.

Thermal Remote Sensing for Global Volcano Monitoring: Experiences From the MIROVA System

MIROVA (Middle Infrared Observation of Volcanic Activity) is an automatic volcano hot spot detection system, based on the analysis of MODIS data (Moderate Resolution Imaging Spectroradiometer). The system is able to detect, locate and quantify thermal anomalies in near real-time, by providing, on a dedicated website (www.mirovaweb.it), infrared images and thermal flux time-series on over 200 volcanoes worldwide. Thanks to its simple interface and intuitive representation of the data, MIROVA is currently used by several volcano observatories for daily monitoring activities and reporting. In this paper, we present the architecture of the system and its use for operational volcano monitoring and research. Particular emphasis will be given to the contribution that the thermal data has provided in order to detect volcanic unrest, to forecast eruptions and to depict trends and patterns during eruptive crisis. The current limits and requirements to improve the quality of the data, their distribution and interpretation are also discussed, in the light of the experience gained in recent years within the volcanological community. The results presented clearly demonstrate how the open access of satellite data and the sharing of derived products allow a better understanding of ongoing volcanic phenomena, and therefore constitute an essential requirement for the assessment of volcanic hazards.

TROPOMI enables high resolution SO2 flux observations from Mt. Etna, Italy, and beyond

The newly launched imaging spectrometer TROPOMI onboard the Sentinel-5 Precursor satellite provides atmospheric column measurements of sulfur dioxide (SO2) and other gases with a pixel resolution of 3.5 × 7 km2. This permits mapping emission plumes from a vast number of natural and anthropogenic emitters with unprecedented sensitivity, revealing sources which were previously undetectable from space. Novel analysis using back-trajectory modelling of satellite-based SO2 columns allows calculation of SO2 flux time series, which would be of great utility and scientific interest if applied globally. Volcanic SO2 emission time series reflect magma dynamics and are used for risk assessment and calculation of the global volcanic CO2 gas flux. TROPOMI data make this flux time series reconstruction approach possible with unprecedented spatiotemporal resolution, but these new data must be tested and validated against ground-based observations. Mt. Etna (Italy) emits SO2 with fluxes ranging typically between 500 and 5000 t/day, measured automatically by the largest network of scanning UV spectrometers in the world, providing the ideal test-bed for this validation. A comparison of three SO2 flux datasets, TROPOMI (one month), ground-network (one month), and ground-traverse (two days) shows acceptable to excellent agreement for most days. The result demonstrates that reliable, nearly real-time, high temporal resolution SO2 flux time series from TROPOMI measurements are possible for Etna and, by extension, other volcanic and anthropogenic sources globally. This suggests that global automated real-time measurements of large numbers of degassing volcanoes world-wide are now possible, revolutionizing the quantity and quality of magmatic degassing data available and insights into volcanic processes to the volcanological community.

Magma Plumbing Systems: A Geophysical Perspective

Over the last few decades, significant advances in using geophysical techniques to image the structure of magma plumbing systems have enabled the identification of zones of melt accumulation, crystal mush development, and magma migration. Combining advanced geophysical observations with petrological and geochemical data has arguably revolutionised our understanding of, and afforded exciting new insights into, the development of entire magma plumbing systems. However, divisions between the scales and physical settings over which these geophysical, petrological, and geochemical methods are applied still remain. To characterise some of these differences and promote the benefits of further integration between these methodologies, we provide a review of geophysical techniques and discuss how they can be utilised to provide a structural context for and place physical limits on the chemical evolution of magma plumbing systems. For example, we examine how Interferometric Synthetic Aperture Radar (InSAR), coupled with Global Positioning System (GPS) and Global Navigation Satellite System (GNSS) data, and seismicity may be used to track magma migration in near real-time. We also discuss how seismic imaging, gravimetry and electromagnetic data can identify contemporary melt zones, magma reservoirs and/or crystal mushes. These techniques complement seismic reflection data and rock magnetic analyses that delimit the structure and emplacement of ancient magma plumbing systems. For each of these techniques, with the addition of full-waveform inversion (FWI), the use of Unmanned Aerial Vehicles (UAVs) and the integration of geophysics with numerical modelling, we discuss potential future directions. We show that approaching problems concerning magma plumbing systems from an integrated petrological, geochemical, and geophysical perspective will undoubtedly yield important scientific advances, providing exciting future opportunities for the volcanological community.

Volcanic Plumes: Impacts on the Atmosphere and Insights into Volcanic Processes

Here we introduce a Special Issue of Geosciences focused on the scientific research field of ‘Volcanic Plumes: Impacts on the atmosphere and insights into volcanic processes’ [...]

Ultraviolet Imaging of Volcanic Plumes: A New Paradigm in Volcanology

Ultraviolet imaging has been applied in volcanology over the last ten years or so. This provides considerably higher temporal and spatial resolution volcanic gas emission rate data than available previously, enabling the volcanology community to investigate a range of far faster plume degassing processes than achievable hitherto. To date, this has covered rapid oscillations in passive degassing through conduits and lava lakes, as well as puffing and explosions, facilitating exciting connections to be made for the first time between previously rather separate sub-disciplines of volcanology. Firstly, there has been corroboration between geophysical and degassing datasets at ≈1 Hz, expediting more holistic investigations of volcanic source-process behaviour. Secondly, there has been the combination of surface observations of gas release with fluid dynamic models (numerical, mathematical, and laboratory) for gas flow in conduits, in attempts to link subterranean driving flow processes to surface activity types. There has also been considerable research and development concerning the technique itself, covering error analysis and most recently the adaptation of smartphone sensors for this application, to deliver gas fluxes at a significantly lower instrumental price point than possible previously. At this decadal juncture in the application of UV imaging in volcanology, this article provides an overview of what has been achieved to date as well as a forward look to possible future research directions.

Predicting the end of lava flow-forming eruptions from space

Although the volcanological community places great emphasis on forecasting the onset of volcanic eruptions, knowing when an effusive eruption will end is just as important in terms of mitigating hazards. Wadge (J Volcanol Geotherm Res 11:139–168, 1981) postulated that the onset of an episodic, lava flow-forming basaltic eruption is characterized by a rapid increase in effusion rate to a maximum, before decaying over a longer period of time until the eruption ends. We used thermal infrared remote-sensing data acquired by NASA’s MODerate Resolution Imaging Spectroradiometer (MODIS) to derive time-averaged discharge rate (TADR) time series using the method of Harris et al. (J Geophys Res 102(B4):7985–8003, 1997) for 104 eruptions at 34 volcanoes over the last 15 years. We found that 32 eruptions followed the pattern described by Wadge (J Volcanol Geotherm Res 11:139–168, 1981). Based on the MODIS-derived maximum lava discharge rate and a decay constant that best fits the exponential waning phase (updated as each new MODIS TADR observation is added to the time series), the time at which the discharge equals zero, and thus the point at which effusion ends, can be predicted. The accuracy of the prediction improves with the number of data points so that, in the ideal case, the end of effusion can be retro-casted before half of the eruption duration has passed. This work demonstrates the possibility of predicting when an eruption will end using satellite-derived TADR time series acquired in near real time during that eruption. This prediction can be made after an eruption has reached its maximum lava discharge rate and the waning phase of the Wadge trend has begun. This approach therefore only applies to the case of eruption from a chamber undergoing an elastic release of energy during lava flow emplacement, and we provide examples of eruptions where it would not be applicable.