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Advanced Volcanic Ash characteriSaTion

Periodic Reporting for period 1 - AVAST (Advanced Volcanic Ash characteriSaTion)

Reporting period: 2017-08-01 to 2019-07-31

The problem:
Airborne volcanic ash is particularly hazardous to aviation. When ash falls it also poses hazards to health, infrastructure, agriculture and the environment.
Following the closure of European airspace during the 2010 eruption of Eyjafjallajokull, causing an estimated €1.7 billion loss to the aviation industry, the impacts of volcanic ash rose to the top of the agenda for civil society. Ash dispersion models are crucial to risk assessments of air traffic routes, however their usefulness requires a better scientific basis for input parameters including ash particle characteristics (size distribution, shape, composition). In addition, volcanic ash particle characteristics modify sintering and abrasion intensity, and are essential for jet turbine engine manufacturers to test the resilience of their products to ash ingestion, as required by the European Aviation Safety Agency.

The sooner the size, shape and composition of volcanic ash can be estimated, the more effective the response.
I aim to show how rapid characterisation of volcanic ash particle properties using QEMSCAN® Particle Mineralogical Analysis (an automated mineralogy tool) can help to determine risks to aviation and interpret deformation during volcanic eruptions in order to help predict and respond to volcanic crises.

The goal of AVAST is to create a proven, open framework to predict volcanic ash properties produced during different eruptive activity.
I aim to characterise ash particles to deliver a ‘map’ linking ash particle characteristics and fragmentation mechanisms that can be used to better inform ash-plume dispersion models and turbine engine resilience tests and to predict ash particle properties during monitored volcanic activity.
Research in the AVAST project was directed at identifying the signatures of different types of volcanic activity in the ash particles produced during eruptions. To do this, the researchers fragmented volcanic rocks in the laboratory using specialised apparatus to replicate natural processes occurring during an eruption. Rocks were rapidly decompressed using a shock tube apparatus (think of a champagne bottle for volcanic rocks at up to 900 degrees C) to simulate volcanic explosions that produce ash plumes, and tumbled in a rotary drum to investigate gravity-driven pyroclastic flows, and slid against one another to investigate fine particles created during some volcanic earthquakes, called fault gouge.

Research has focused on two case study volcanoes, Mt. Etna, IT and Volcán de Colima, MX. Field trips to collect natural samples and coordinate with local monitoring and hazard management agencies took place in 2017.

A major innovation in the project has been the imaging of ash particles using QEMSCAN®, a state-of-the-art automated SEM-based particle mapping procedure that can rapidly identify glass and common minerals in fresh volcanic ash. This allows image analysis of ash samples in a fraction of the time it would normally take using manual mineral identification. 90 samples were analysed by QEMSCAN during the fellowship, and the researchers gained in-depth immersive training in the technology.

The AVAST project has shown that both the composition of volcanic magma or lava and the type of volcanic activity change the properties of volcanic ash particles. During fragmentation the physical properties of the components forming the volcanic material (the minerals present in the magma, the volcanic glass and bubbles or pores) help to determine the size, shape and composition of the volcanic ash. Additionally, the AVAST project has investigated the rate at which ash is produced in pyroclastic flows and the way the rocks become smaller and smoother during flow, using a set of pumice samples from Laacher See, DE, the Azores, PT and Valentano, IT. This helps to understand the mobility of pyroclastic flows, often the most deadly volcanic phenomenon, and the importance of flows in generating volcanic ash.

Understanding of these intrinsic and fragmentation-specific controls can better define hazards from volcanic ashfall, helping to prepare and mitigate the effects on vulnerable zones, as well as improving ash cloud detection, monitoring and forecasting efforts. Associated project results have been disseminated in research papers, seminars and workshops; final project results are being prepared and these will be shared with local monitoring and civil protection agencies in Italy and Mexico via workshops.
Volcanic ash particles created by natural eruptions and by simulated volcanic activity in the laboratory have been described in unprecedented detail, using QEMSCAN automated mineralogy. False colour phase maps that depict the composition, size and shape of hundreds to thousands of particles at high resolution have been collected and analysed.

Researchers are working to complete a product allowing particle properties to be constrained based upon observations of volcanic activity, and regulated by magma composition. These data can be used to understand how particle properties are affected by different magma evolution and fragmentation processes, and allow scientist to get better at predicting the characteristics of volcanic ash produced during eruptions. That can enable improvements to ash plume detection and hazard assessment without even needing to sample the ash.

Research into volcanic ash generation in pyroclastic flows has introduced some of the first systematic experimental constraints on ash production and clast evolution during flow transport and should advance our ability to understand flow mobility and associated hazards. This works helps to estimate flow parameters and ash production from flow deposits and can shed light on past activity and help to inform current hazard assessment and modelling.
QEMSCAN image of experimentally fragmented volcanic ash particles