Volcanoes through multiple lenses
Discussions at a recent meeting highlighted how novel and multipronged approaches are providing new insights into volcanic processes and their associated hazards and impacts
Volcanic research encompasses the study of subsurface magmatic systems, eruptive, surface and atmospheric processes, as well as their impacts on society. The Volcanic and Magmatic Studies Group (VMSG) annual meeting (https://vmsg-2023.org/), which was held in London, UK, in January 2023, brought together scientists from across various natural and social science disciplines to facilitate discussion of physical volcanology, igneous geochemistry and petrology, and volcanic hazard management, among other topics.
Having hosted the VMSG conference online for the previous two years, a hybrid approach was adopted this year. Most delegates attended in person, but full provisions were made for remote attendees. VMSG is a friendly community in which students and early career researchers thrive; the quality of presentations from these groups are consistently high. Of the 217 delegates, 109 were students and 27 out of the 43 oral presentations were given by students.
Various lenses
An overarching theme from the conference was the highly (and necessarily) multidisciplinary nature of volcanological research, with new insights gained by using novel, multipronged approaches. For example, a number of presentations on the 2021 La Palma, Canary Islands eruption highlighted how one event could be viewed through many different lenses. For this event, petrological analyses were used to reconstruct the three-stage evolution of this eruption (Jane Scarrow, University of Granada, Spain, and colleagues), gas plume composition measurements provided insights into the spatial and temporal evolution of magma degassing (Ana Pardo Cofrades, University of Manchester, UK, and colleagues), while historical accounts and memorialisation of an earlier eruption in 1971 were used to better understand community response and resilience during the 2021 event (Rosie Rice, University of Cambridge, UK, and colleagues). Additionally, work by Sharon Backhouse (GeoTenerife Ltd, UK) and colleagues highlighted the important role of open-access web resources (in this case, VolcanoStories) in facilitating the compilation of and easy access to diverse data sets, ranging from drone model data to eye-witness accounts and educational resources.
While it is impossible for us to cover the full range of methods discussed at the meeting, here we highlight three presentations that exemplified such novel and multidisciplinary approaches to volcanological research.
Eruptions and climate
Explosive volcanic eruptions are an important driver of natural climate variability, due to the different volcanic gases that are erupted into the atmosphere. A standout presentation by May Chim (University of Cambridge, UK) emphasised that our current climate projections likely underestimate the strength of future volcanic forcing and the associated climatic effects. The core message of Chim’s talk was that lower-magnitude eruptions are key drivers of global climate change, yet these smaller-scale eruptions are not currently included in global climate forecasts, such as those used to produce reports for the Intergovernmental Panel on Climate Change. Such reports use estimates of the rate and magnitude of past eruptions that are well preserved in geological deposits, meaning that there is a bias towards large eruptions (which are better preserved in the rock record) over smaller-scale eruptions.
Observations of volcanoes erupting in the historical era, based on resampling of state-of-the-art ice-core, satellite, and geological records of volcanic activity in the Holocene, show that smaller-magnitude events occur at a much higher frequency than currently inferred from the geological record. By including these lower-magnitude events in numerical models of the climatic response to volcanic eruptions across a range of potential scenarios, Chim and colleagues found that these eruptions form a substantial portion of the total climate forcing from volcanic activity, though this is still dwarfed by recent anthropogenic forcing.
The research clearly identifies an important omission from current global climate models – a result that will hopefully be incorporated into future climate reports. Chim’s enthusiastic, accessible and clear talk resulted in the award of runner-up prize for best student presentation – always a competitive field at VMSG meetings!
Oxygen proxy
Hydrothermal alteration generally decreases the strength and stiffness of rock, therefore increasing the chance of volcanic flank collapse, making deposits in these locations difficult and risky to study. Mike Heap (University of Strasbourg, France) discussed the use of oxygen isotope ratios as a proxy for the strength and stiffness of hydrothermally altered rocks.
This novel approach gives volcanologists another tool in their arsenal to understand and model volcanic flank collapse and the associated hazards, such as tsunamis.
Oxygen isotope ratios have many applications in geoscience, such as for understanding how climate has changed over time based on ice-core analysis, but they have never been used in this context before. Heap and colleagues found that oxygen isotope ratios were sensitive to several rock properties, such as degree of alteration, tensile strength, and Young’s modulus, implying that they can be used as a proxy for the properties of hydrothermally altered rocks. Only a small sample of the hydrothermally altered rock (<1 g) is needed for analysis, which is advantageous for areas where greater amounts of material cannot be collected.
This novel approach gives volcanologists another tool in their arsenal to understand and model volcanic flank collapse and the associated hazards, such as tsunamis.
Drones and geoscience
Drones are a revolutionary technology for the geosciences as a whole. For example, following the success of Mars 2020’s proof-of-concept helicopter, Ingenuity, NASA is planning to collect samples from Mars using drones and to explore Saturn’s largest moon, Titan, using a rotorcraft mission, Dragonfly. In the field of volcanology, the use of drones is expanding to include detailed mapping of lava flows and otherwise impossible-to-collect gas measurements in volcanic plumes.
Over the course of the conference, at least five presentations utilised drones in their methodology. Perhaps the most fascinating was that presented by Anna Hicks (British Geological Survey, UK) and Neil Golding (Aquarius Survey and Mapping, UK). They transported us to the remote volcanic island of Tristan da Cunha in the middle of the South Atlantic Ocean, home of the most isolated permanent settlement in the world, Edinburgh of the Seven Seas (locally known as “The Settlement”). Located a staggering 2,450 km from the nearest community found on St. Helena, the island is entirely volcanic and rises to an imposing 2,062 m.
The most recent eruption occurred in 1961, when a parasitic cone opened less than 300 metres from The Settlement, summoning forth a lava flow that forced evacuation of the island. This event forms a key part of the islanders’ history because, for a year, considerable uncertainty surrounded their ability to return. Eruptions are not the only hazard concomitant with living beside this active volcano: landslips can occur on the steep-sided flanks because loose layers of lava and ash that form the volcanic edifice are easily eroded by the drainage of over 3,000 mm per year of rainfall. In several locations, this drainage has caused cliff failures affecting The Settlement’s roads, crops, and water supply.
Working with locals from The Settlement in September 2022, Hicks and Golding captured baseline aerial images of these landslips using lightweight drones. They processed the images using structure-from-motion techniques, reconstructing detailed 3D models of the terrain using the parallax differences between overlapping sequential images. These models allow future expeditions to calculate the rate of erosion by comparing new drone images with Hicks and Golding’s baseline images. Such comparisons will inform risk forecasts, allowing more well-informed decisions on when infrastructure investment is needed.
Drones will likely be increasingly deployed by volcanologists
Drones will likely be increasingly deployed by volcanologists, as technology advances and they become more adept at using drone-based techniques. This approach will be especially important in remote communities that previously had no means to quantitively monitor landslips.
Ongoing advances
Recent technological and methodological advances mean that we now have more detailed insights into volcanoes, their behaviour and their impacts on people than ever before. It was wonderful to see geoscientists working across a broad range of sub-disciplines coming together to discuss how different approaches to volcanic and magmatic research are contributing to this understanding – and it will be fascinating to see how these tools and techniques continue to evolve.
Authors
Ben Esse, postdoctoral researcher, University of Manchester, UK.
Marissa Lo, Assistant Editor, Geoscientist Magazine, Geological Society of London, UK.
Matthew Varnam, postdoctoral researcher, University of Arizona, USA.
VMSG (https://vmsg.org.uk/) is a hub of researchers who aim to promote and advance the study of physical volcanology, igneous geochemistry and petrology, volcanic hazard management, and related subjects, in the UK. VMSG is a special interest group of the Geological Society of London and the Mineralogical Society of Great Britain and Ireland, and has a history spanning back to the 1960s. The 2023 VMSG annual conference was hosted by Volcanologists of London, a committee comprised of researchers from the Natural History Museum, Birkbeck, Imperial College, and University College London.