Harris M. A. auteur aut IRD Chevrel Magdalena Oryaelle auteur aut IRD Parsons J. T. auteur aut IRD Latchimy T. auteur aut IRD Thordarson T. auteur aut IRD Hoeskuldsson A. auteur aut IRD Moreland W. M. auteur aut IRD Payet-Clerc M. auteur aut IRD Kolzenburg S. auteur aut IRD text journalArticle eng text/pdf born digital access Viscosity is a fundamental physical property that controls lava flow dynamics, runout distance, and velocity, which are critical factors in assessing and mitigating risks associated with effusive eruptions. Natural lava viscosity is driven by a dynamic interplay among melt, crystals, and bubbles in response to the emplacement conditions. These conditions are challenging to replicate in laboratory experiments, yet this remains the most common method for quantifying lava rheology. Few in situ viscosity measurements exist, but none of those constrains the spatial evolution of viscosity along an entire active lava flow field. Here, we present the first real-time, in situ viscosity map of active lava as measured in the field at Litli-Hrútur, Iceland. We precisely measured a lava viscosity increase of over two orders of magnitude, associated with a temperature decrease, crystallinity increase, and vesicularity decrease from near-vent to distal locations, crossing the p specialized ISLANDE 060 066 53 2 181-185 2024 0091-7613 https://www.documentation.ird.fr/hor/fdi:010093643 10.1130/g52558.1 0091-7613 [F B010093643] https://www.documentation.ird.fr/hor/fdi:010093643 https://www.documentation.ird.fr/intranet/publi/2025-04/010093643.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2025-04-02 2025-11-06 fdi:010093643 fre