NSF Award
2420723
Effective civil protection during effusive volcanic eruptions requires an understanding of the lava’s ability to flow (its rheology). This is because forecasting methods for lava flow paths and velocities use models of the lava’s flow properties (i.e. how viscous it is) to estimate what areas the lava flows may affect and how fast lava may reach certain areas. <br/> The current understanding of the flow properties of natural lavas is largely based on controlled laboratory experiments on small volumes of analogue materials or remelted rocks and is limited by the fact that bubbles (a fundamental component affecting flow properties of natural lavas) cannot be contained in laboratory experiments. This project is motivated by three main points: 1) An incomplete understanding of lava flow properties. 2) A lack of viscosity measurements of lavas in their natural state. 3) The need for shorter response times between eruption and lava flow-path forecasts. The project will tackle these challenges by: 1) Building two new and unique field tools to measure the viscosity of lava while it flows. 2) Using these devices on active lava flows to generate the most complete dataset of natural lava viscosity ever measured (i.e. containing bubbles, crystals and melt). 3) Performing two-phase (melt plus crystals) laboratory experiments at the conditions relevant to the natural environment (characterized during fieldwork). 4) Developing a pipeline for field viscosity measurements of active lava to be used in lava flow forecasting efforts at volcano observatories. This project will entail working with volcano observatories in the US, Iceland, France, and Italy to gain safe and effective access to active lava flows. Combined, the field and lab measurements help to characterize the effect of bubbles on three-phase lava flow behavior by comparing the field measurements (with bubbles) and lab measurements (bubble-free). This has been an open challenge in understanding how lava flows for decades. The team and facilities that are part of this project are in a unique position to do this for the very first time. The project results can be used during effusive eruptions in the future to help guide decision making in civil protection efforts. Project results will be incorporated into the University at Buffalo EarthEd program, providing content for K12 educators serving underrepresented communities, and promoting science literacy. It also aims to contribute to science education through the development of a museum showcase. This project supports two early-career researchers and one PhD student. It involves international collaborations (USA, Italy, France, Iceland) in academia and at volcano observatories.<br/><br/> <br/>Accurate forecasting of lava flow paths and advance rates is crucial to hazard mitigation, civil protection, and management of eruptive crises. This task has been hampered by an incomplete understanding of multiphase (melt+crystals+bubbles) lava rheology. Field viscosity measurements of lava are extremely rare, commonly done using uncalibrated devices and have never been tied to laboratory data. This highlights the dire need for more, and better in-situ measurements. While the understanding of the flow properties of lavas has advanced significantly over the past decades, two core limitations have always remained: 1) Accurate reproduction of natural emplacement conditions (scale, textures, fO2). 2) The inability to maintain three-phase suspensions in the lab (bubbles escape on experimental timescale, limiting measurements to two-phase crystals-melt suspensions). Measuring the viscosity of lava in the field removes both limitations. Importantly, when combined with bubble free lab measurements it has the potential to quantify the effect of bubbles on multiphase lava rheology. Further, in-situ field measurements have the potential to enable the optimization of near real time lava flow forecasting by providing accurate viscosity data from the field directly to the modelers. This project takes a holistic approach to lava rheology to advance our understanding of flow properties and the emplacement of natural lavas. It does so by deploying two field rheometers and pairing the data with laboratory experiments that mimic emplacement conditions. This enables the team to gather the first ever suite of rheological data that ties laboratory rheology to actual field data. Doing so achieves three fundamental goals: 1) Deploy two new and unique field rheometer prototypes to generate the most comprehensive dataset of natural lava rheology ever measured. 2) Perform two-phase (melt+crystals) laboratory experiments at the temperatures, shear rates, and fO2 of lava measured in the field. Combined, the field and lab measurements enable them to deduce the effect of bubbles on three-phase lava rheology by contrasting the field measurements (with bubbles) and lab measurements (bubble-free). This has been an open challenge in understanding lava rheology and the team and facilities that are part of this project are in a unique position to do this for the very first time. 3) Develop a pipeline for rapid lava viscosity measurements to inform lava flow forecasting efforts done at volcano observatories. The large impact that combined field and lab measurements can have on scientific understanding of lava flow properties paired with the transfer of this knowledge to eruption management teams and the availability of already trained experts set this project up for success and to address some of the major limiting factors to advancing the understanding of lava flow emplacement for decades. Transfer of knowledge to relevant staff at volcano observatories is done via demonstration and training campaigns at the USGS Hawaii Volcano Observatory (HVO), the observatory of Piton de la Fournaise (OVPF), The University of Iceland (HI) and INGV Catania. The project results can be used during effusive eruptions in the future to help guide decision making in civil protection efforts.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
