RAPID: Deployment of a Field Rheometer Prototype

This project deploys a field rheometer prototype to the reawakened eruption at Geldingadalir Volcano, Iceland with the goal to test its field performance and to gather the first ever rheological data on active Icelandic Mid Ocean Ridge Basalts (MORB) in the field. Access to active lava flows is challenging due to the unpredictable nature of the timing and occurrence of effusive eruptions. This eruption, which started August 3, 2022, provides unparalleled ease of access to active lava flows whose nature is sufficiently “well behaved” to facilitate in-situ measurements of lava properties. This project strives to achieve two fundamental goals: 1) Travel to Iceland to deploy the field rheometer prototype to collect the first field measurements with this device and test its limits. 2) Performing a series of two-phase (melt+crystals) experiments at the temperatures, shear rates, and fO2 of lava measured at Geldingadalir Volcano. Combined, this enables this team to collect the first field measurements of the rheology of Icelandic MORB lavas and to deduce the effect of bubbles on three-phase rheology by contrasting the field measurements (with bubbles) and lab measurements (bubble-free). InSAR data published by the Icelandic Meteorological Office suggest higher magma influx rates for this eruption than for the 2021 eruption. This could mean either that the eruption lasts longer than that of 2021 or it could mean that much of the available lava is erupted through the pathway created during the previous eruptive event over a short period of time. Accurate forecasting of lava flow paths and advance rates is crucial to hazard mitigation ahead of and during effusive events, civil protection, and management of ongoing eruptive crises. This task has been hampered largely by an incomplete understanding of multiphase (melt+crystals+bubbles) lava rheology. Field viscosity measurements are extremely rare and largely limited to a narrow compositional range (dominated by Hawaiian Basalts). This highlights the dire need for more, and better in-situ measurements on a broader range of compositions. While our understanding of the flow properties of lavas has advanced significantly over the past two to three 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. This project therefore has the potential to address some of the major limiting factors to advancing our understanding of lava flow emplacement for decades. Results will be shared with stakeholders within and beyond the scientific community, and some samples and tools from this work will be incorportated into the Buffalo Museum of Science. Project insights will also be incorporated into hands on exercises in the UB EarthEd program, providing content for K12 educators. 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.