RAPID: Response to the November 2025 Hayli Gubbi Eruption

On 23 November 2025, Hayli Gubbi volcano in northern Ethiopia explosively erupted. The eruption sent ash and volcanic gases nearly 15 kilometers into the atmosphere and disrupting air traffic across large parts of the globe. Eruptions in this region are usually gentle and lava-producing. The explosive nature of this event was very unusual and poorly understood. Volcanic ash fell on nearby communities and contaminated water and grazing lands. Because ash, gases, and surface features degrade rapidly due to erosion and continued gas release, there is an urgent need for rapid scientific study. This team wants to understand how and why explosive eruptions occur in basaltic rift settings. By improving our knowledge of these rare but high-impact events, the project supports NSF’s mission to advance the progress of science and promote public safety. The results will contribute to improved volcanic risk assessment for aviation, infrastructure, and communities in Ethiopia and globally, including in the United States where similar volcanoes exist. This RAPID project will conduct time-sensitive field and laboratory investigations of perishable volcanic products from the 2025 Hayli Gubbi eruption. The team aims to determine eruption magnitude, eruptive style, degassing behavior, and links to regional magmatic processes. Fieldwork will include stratigraphic logging, ash thickness measurements, and systematic sampling of ash and lava deposits, complemented by near-vent volcanic gas measurements. Petrological and geochemical analyses of matrix glass, melt inclusions, and mineral phases using EMPA, LA-ICP-MS, and FTIR will constrain magma storage conditions, volatile contents, and ascent histories. These datasets will be integrated to estimate erupted volume, assess degassing efficiency, and test hypotheses regarding shallow magmatic connectivity between Hayli Gubbi and the Erta Ale volcanic system. The project will provide new constraints on the conditions under which basaltic magmas transition from effusive to explosive behavior, advancing fundamental understanding of volcanism in continental rifts and informing hazard models for similar volcanic systems worldwide. 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.