Abstract
Volcanic eruptions such as Kilauea (2018), Fagradalsfjall (2021), La Palma (2021), and the most recent Meradalir eruption in the Reykjanes peninsula are fed by dikes, sheet-like intrusions that transport magma through the crust to the surface, where they initially form elongated fissures extending typically several hundred up to thousands of meters. Although field, seismic, and geodetic data indicate that feeder dikes can extend laterally and vertically for several tens of kilometers in length and depth, eruption along a fissure becomes discontinuous and localizes to discrete vents only a few hours after the onset of the eruption. Understanding the processes that lead to localization is important for forecasting the evolution of, and flow localization during, future fissure eruptions in almost all volcanic settings. This is of great relevance in areas that could potentially be affected by such eruptions, including Auckland and Mexico City, among others. Here, we aim to understand the thermal processes that drive eruption localization using an artificial fissure (ArtFish), a novel experimental apparatus that replicates a dike-fissure segment with wax as a magma analogue fluid. This analogue model allows for changes in fissure width, fissure geometry, wall temperature, and volumetric flow rate. Our first experimental series intends to solve the relative influence of each of these parameters through systematic variation of the panel matrix. This series, currently being conducted, will allow us to test our hypothesis that localization is favored when the fissure is narrower than a critical width, high thermal contrast between wax and wall and/or with a slow flow rate. Future experiments after this initial series will explore more complex fissure geometries such as lateral and vertical narrowing, as well as variations in wall temperature within the fissure.