The first documented volcanic eruption of Hayli Gubbi, Afar, Ethiopia

Abstract Hayli Gubbi volcano in the Afar Regional State of Ethiopia experienced its first historically documented volcanic eruption on 23 November 2025. The event produced a short-lived sustained eruption column, with ash dispersal and fallout primarily towards the north and east of the volcano, and the formation of two new craters at Hayli Gubbi’s summit. Ash from the northern lobe has a basaltic (trachy)andesitic composition. The eruption was preceded, in July 2025, by a dyke intrusion originating from neighbouring Erta Ale volcano, migrating over 30 km southward and intercepting Hayli Gubbi where inflation occurred. Renewed ground deformation started again in Erta Ale ~ one month before the Hayli Gubbi eruption during which a sudden reservoir contraction and a new collapse caldera was formed. Synchronous deformation signals suggest both volcanoes are structurally coupled. Intense degassing continues at Hayli Gubbi during the months after the eruption. We provide the first accounts of the eruption’s development, assembling on-the-ground observations, geophysical and geochemical data and satellite imagery to characterize the physical features of the eruption and its impact. Whilst impact remained limited, partly due to low exposure in the remote region, the eruption did cause disruption to international air traffic. This eruption is another stark reminder of the urgent need for increased capacity for volcano monitoring and data-supported volcanic hazard assessment in Ethiopia.