Basaltic volcanism is the most common form of volcanism in the solar system. On Earth, eruptions can impact global and regional climate, and threaten populations living in their shadow, through a combination of ash, gas and lava emissions. The specific risk to the UK from an Icelandic eruption is recognized as one of the four 'highest priority risks' in the National Risk Register of Civil Emergencies. The impact of an eruption is determined by both intensity and style, ranging from explosive and ash-rich (impacting on air-space access and climate) to effusive and gas-rich (affecting public health and crops/livestock locally and distally). Understanding these eruptive styles, and their evolution in time and space is key to forecasting the impacts of eruptions. Eruption style is controlled by the degree of coupling between gas and magma during magma ascent, with strong coupling leading to enhanced fragmentation and ash production. This coupling is controlled by the interplay and feedback among several non-linear processes: multi-phase magma viscosity evolution, crystallisation, gas exsolution, permeability, magma ascent velocity and fragmentation within a dynamic magma plumbing system. Such non-linearity produces complex behaviour. Understanding the processes controlling eruptive style is therefore critical for volcanology and eruption forecasting. A crucial limitation of previous work is that it has been predicated almost exclusively on the assumption of equilibrium between melt, crystals and volatiles. In other words, the volcanology community has conventionally assumed that the processes of magma degassing and solidification/crystallisation occur nearly instantaneously in response to depressurisation during magma ascent and eruption. However, it is now recognised that the timescales required to achieve equilibrium for both crystal growth and volatile exsolution are similar to or longer than ascent times for erupting basaltic magmas, and therefore disequilibria are ubiquitous. Disequilibrium processes are therefore a key missing link preventing quantitative modelling and understanding of volcanic processes, and their impacts. The core aim of the NERC-NSF DisEqm project is to create an empirically-constrained quantitative description of disequilibrium processes in basaltic volcanism, and to apply this to address key volcanological problems through a new numerical modelling framework In order to meet this aim, we bring together a world-leading team to perform experiments using new, ground-breaking synchrotron X-ray imaging and rheometric techniques to visualise and quantify crystallisation, degassing and multiphase, HPHT (high-pressure, high-temperature) viscosity evolution, revolutionising the fields of HPHT experimental petrology and HPHT rheometry. Geochemical constraints will be achieved by applying state of the art petrological analytical techniques to samples produced both on the beamline and in benchtop quench experiments. We will perform large-scale fluid dynamics simulations to inform and validate the 3D numerical modelling, and we will constrain fragmentation and eruption column processes with empirical field studies. Results will be integrated into a state-of-the-art numerical model, and applied to impact-focussed case studies for Icelandic, US and Italian basaltic eruptions. In conclusion, our project will produce a paradigm shift in our understanding of disequilibrium processes during magma ascent and our capacity for modelling basaltic eruption phenomena, creating a step-change in our ability to forecast and quantify the impacts of basaltic eruptions.

Eyjafjallajokull, a 1666 m high, glacier-clad, stratovolcano in southern Iceland, is known to have erupted on four previous occasions in the historic record: ~500 AD, ~920 AD, 1612 AD and 1821-23 AD. Each eruption has resulted in rapid and large-scale glacier ice melt, generating very large jokulhlaups (glacier outburst floods) with peak discharges of 10^3-10^4 m^3s^-1 inundating the surrounding populated lowlands. On March 3rd 2010, the Icelandic Meteorological Office (IMO) informed us of a period of enhanced seismic activity under Eyjafjallajokull (since the beginning of January 2010). Based on the assumption that the exponential increase in both seismic activity and rates of ground deformation represented pre-eruption behaviour and intrusion of a magma tongue into the Earth's crust at this location, we collected pre-eruption Terrestrial Laser Scanner and dGPS survey data from a number of probable jökulhlaup routeways between March 9th and 16th 2010. Five days after the end of this data acquisition period (on March 20th 2010), the magma reached the surface along a newly formed 500 m-long fissure located north of Fimmvorduháls pass and directly east of the Eyjafjallajokull ice cap. This phase of eruption was on a non-ice covered area and activity ceased on April 12th. Only two days later (April 14th at 02:00 GMT) a large subglacial explosive eruption started beneath the 2.5 km-wide summit caldera of Eyjafjallajokull (to the west of the original fissure eruption). Within hours the eruption melted through 200 m of the ice cap and became fully phreatic, producing a major 8.5 km-high volcanic plume (with subsequent serious implications for pan-European air traffic). By 07:00 GMT on April 14th, rapid melting of the Eyjafjallajokull ice cap generated volcanogenic jokulhlaups that cascaded from Gigjokull and down Nupakotsdalur on the northern and southern flanks of Eyjafjallajokull respectively. The initial jokulhlaup from Gigjokull reached peak discharge in the Markarfljot river system several hours later, damaging Iceland's main ring road near the Markarfljot bridge. Subsequent increases in eruption intensity generated repeated jokulhlaups from Gigjokull that inundated the Markarfljot. On an overflight at 18:55 GMT on April 15th, Dr Matthew Roberts (Icelandic Met Office & project partner) witnessed an enormous jokulhlaup (peak discharge ~ 10^4 m^3s^-1) from Gigjokull which prompted the immediate evacuation of the population within the entire Markarfljot area. This jokulhlaup was 'sediment-laden', characterised by a viscous, smooth-surfaced, lobate flow front followed by a more turbulent fluid flow body. These initial observations suggest that the frontal wave of this jokulhlaup was hyperconcentrated. In this project, we aim to improve understanding of volcanogenic jokulhlaup impacts and processes due to a subglacial volcanic eruption. In order to do this, we will acquire post-jokulhlaup data for the Gigjokull proglacial area and the Markarfljót to compare against our directly pre-eruption (9th -16th March 2010), full 3D TLS topographic datasets. We therefore have an UNPRECEDENTED and UNIQUE OPPORTUNITY to (1) accurately quantify the geomorphological and sedimentary characteristics of a series of jokulhlaups and (2) to use these to inform and validate our reconstructions of the hydrodynamic characteristics of a series of volcanogenic jokulhlaups capable of valley-scale geomorphological and sedimentary impact. To do this, we need to re-survey areas for which we have important baseline data but where the evidence of volcanogenic jokulhlaup impacts and processes is transient (hence this Urgency application to NERC). A second and important phase of the project will use this data to model the impacts of the eruption on the outflow system.

Anthropogenic emissions that affect climate are not just confined to greenhouse gases. Sulfur dioxide (SO2) and other pollutants form atmospheric aerosols that scatter and absorb sunlight, and influence the properties of clouds, modulating the Earth-atmosphere energy balance. Anthropogenic emissions of aerosols exert a significant, but poorly quantified, cooling of climate that acts to counterbalance the global warming from anthropogenic emissions of greenhouse gases. Uncertainties in aerosol-climate impacts are dominated by uncertainties in aerosol-cloud interactions (ACI) which operates through aerosols acting as cloud-condensation nuclei (CCN) which increases the cloud droplet number concentration (CDNC) while reducing the size of cloud droplets and subsequently impact rain formation which may change the overall physical properties of clouds. This consequently impacts the uncertainty in climate sensitivity (the climate response per unit climate forcing) because climate models with a strong/weak aerosol cooling effect and a high/low climate sensitivity respectively are both able to represent the historic record of global mean temperatures. On a global mean basis, the most significant anthropogenic aerosol by mass and number is sulphate aerosol resulting from the ~100Tg per year emissions of sulphur dioxide from burning of fossil fuels, but these plumes are emitted quasi-continuously owing to the nature of industrial processes, meaning that there is no simple 'control' state of the climate where sulphur dioxide is not present. On/off perturbation/control observations have, to date, been limited to observations of ship tracks but the spatial scales of such features are far less than the resolution of the weather forecast models or of the climate models that are used in future climate projections. This situation changed dramatically in 2014 with the occurrence of the huge fissure eruption at Holuhraun in 2014-2015 in Iceland, which was the largest effusive degassing event from Iceland since the eruption of Laki in 1783-17849. The eruption at Holuhraun emitted sulphur dioxide at a peak rate of up to 1/3 of global emissions, creating a massive plume of sulphur dioxide and sulphate aerosols across the entire North Atlantic. In effect, Iceland became a significant global/regional pollution source in an otherwise unpolluted environment where clouds should be most susceptible to aerosol emissions. Thus, the eruption at Holuhraun created an excellent analogy for studying the impacts of anthropogenic emissions of sulphur dioxide and the resulting sulphate aerosol on ACI. Our research will comprehensively evaluate impacts of the Holuhraun aerosol plume on clouds, precipitation, the energy balance, and key weather and climate variables. Observational analysis will be extended beyond that of our pilot study to include high quality surface sites. Two different climate models will be used; HadGEM3, which is the most up to date version of the Met Office Unified model and ECHAM6-HAM, developed by MPI Hamburg. These models are chosen because they produce radically different responses in terms of ACI; ECHAM6-HAM produces far stronger ACI impacts overall than HadGEM3. Additionally, the UK Met Office Unified Model framework means that the underlying physics is essentially identical in low-resolution climate models and high-resolution numerical weather predication models, a feature that is unique in weather/climate research. In the high resolution numerical weather prediction version, parameterisations of convection can be turned off and sub-gridscale processes can be explicitly represented. Thus the impacts of choices of parameterisation schemes and discrete values of variables within the schemes may be evaluated. The research promises new insights into ACI and climate sensitivity promising us great strides improving weather and climate models and simulations of the future.

The volcanic plume from the Eyjafjallajökull eruption has caused significant disruption to air transport across Europe. The regulatory response, ensuring aviation safety, depends on dispersion models. The accuracy of the dispersion predictions depend on the intensity of the eruption, on the model representation of the plume dynamics and the physical properties of the ash and gases in the plume. Better characterisation of these processes and properties will require improved understanding of the near-source plume region. This project will bring to bear observations and modelling in order to achieve more accurate and validated dispersion predictions. The investigation will seek to integrate the volcanological and atmospheric science methods in order to initiate a complete system model of the near-field atmospheric processes. This study will integrate new modelling and insights into the dynamics of the volcanic plume and its gravitational equilibration in the stratified atmosphere, effects of meteorological conditions, physical and chemical behaviour of ash particles and gases, physical and chemical in situ measurements, ground-based remote sensing and satellite remote sensing of the plume with very high resolution numerical computational modelling. When integrated with characterisations of the emissions themselves, the research will lead to enhanced predictive capability. The Eyjafjallajökull eruption has now paused. However, all three previous historical eruptions of Eyjafjallajökull were followed by eruptions of the much larger Katla volcano. At least two other volcanic systems in Iceland are 'primed' ready to erupt. This project will ensure that the science and organisational lessons learned from the April/May 2010 response to Eyjafjallajökull are translated fully into preparedness for a further eruption of any other volcano over the coming years. Overall, the project will (a) complete the analysis of atmospheric data from the April/May eruption, (b) prepare for future observations and forecasting and (c) make additional observations if there is another eruption during within the forthcoming few years.

In this project, we will use a newly developed system to tackle the air pollution hazard in Nicaragua. Air pollution is the largest environmental root of ill-health and premature loss of life. Each year it causes over 4 million deaths, with 90% of these in developing countries. Air pollution stems both from anthropogenic activities as well as a variety of natural sources. In the developing countries air pollution is generally poorly understood due to lack of scientific research and routine monitoring. Furthermore, while public air quality (AQ) alerts and advisories are legally mandated in the UK and other high-income countries, they are almost non-existent in the poorest parts of the world. The World Health Organisation therefore recommends that monitoring of air pollution is improved in the developing countries to better understand the impact it has on health, and to assist local authorities in establishing plans for improving AQ. In a previous research project, our team looked at a poorly understood source of air pollution from persistently active volcanoes, using Masaya volcano in Nicaragua as a case study. Volcanic air pollution (VAP) is a chronic natural hazard potentially present in over 30 countries on the Official Development Assistance list but absent from their mitigation strategies. Almost nothing is known about the interaction of VAP with anthropogenic air pollution and the resulting impacts on health and the environment. Our previous project developed and trialled a system for monitoring VAP and assessed ways of making the system suitable for operational use. This new system can be used for monitoring AQ both from volcanoes and other sources, including anthropogenic activities such as traffic. We will install a network of permanent AQ stations that will stream data in real-time to the Nicaraguan natural hazards observatory. We will also introduce techniques and tools for visualising and interpret the data. Nicaragua already has a well-developed system for monitoring and mitigating a number of other natural hazards, such as earthquakes, hurricanes and tsunami. The AQ network will be integrated with the pre-existing system and used alongside monitoring of other hazards. We will be collaborating with the Nicaraguan natural hazards observatory, the civil protection, and multiple other local and international end-users. The AQ data will be used to make forecasts and issue public advisories for unhealthy air pollution levels. Public advisories allow the decision makers and the public to take measures to protect the most vulnerable persons, such as people with respiratory and heart conditions, children and the elderly. AQ monitoring also increases the awareness of decision makers and the public on air pollution issues, and is therefore an important initial step towards improving AQ in the country. We will be working closely with the local communities to ensure that the public advisories are applicable, easily understandable, and useful for their lifestyle. At the end of the project, the local end-users, such as the natural hazards observatory, will have the necessary capability and knowledge to run the AQ network and expand it as needed.