An ash plume from the first recorded explosive eruption at Hayli Gubbi was detected in satellite data at around 1130 on 23 November. According to a news report, residents described hearing a loud sound and feeling a shock wave; an explosion was heard 50 km from Semera (190 km S of Hayli Gubbi). Ash plumes quickly rose to 13.7 km (45,000 ft) a.s.l., later reaching as high as 15.2 km (50,000 ft) a.s.l. At around 1400 satellite data showed that the plume was spreading into the upper troposphere and contained approximately 220,000 tons of sulfur dioxide. A sequence of satellite images showed the higher ash plume drifting ENE. The images also showed a lower altitude cloud of pyroclastic material moving to the N about 130 km and spreading about 60 km laterally. That plume appeared to be on or low to the ground, and followed terrain, suggesting that it was the dilute part of a pyroclastic density current. Photos included in news reports showed ash plumes rising from the flat ground at some distance from the crater, consistent with material rising from a PDC, although the exact location of the photos was unknown. News reports noted that many surrounding villages, including Afdera (28 km W), were covered in ashfall; no deaths were reported. Several flights were cancelled or diverted across various countries in the region. Although the Toulouse VAAC reported that eruptive activity ceased by 2300, a large ash plume with a significant sulfur dioxide component persisted over Yemen, with lower-level ash continuing to drift over Ethiopia.

The Toulouse VAAC stated that by 0057 on 24 November a substantial ash and sulfur dioxide cloud was present over Yemen and Oman, and by 1058 the plume was situated between Oman and Pakistan, moving ENE at altitudes of 7.6-13.7 km (25,000-45,000 ft) a.s.l. By 1700 a broad ash cloud was spreading E across southern Pakistan and northeastern India, with a possible plume of resuspended ash rising to 4.6 km (15,000 ft) a.s.l. detected near the Gulf of Aden. By 2300 the ash cloud was detected over northern Indian (over Delhi, 4,130 km NE) and was moving quickly towards China. News media reported flight disruptions in India on 25 November.

According to the UK Centre for Observation and Modelling of Earthquakes Volcanoes and Tectonics (COMET) response reports, explosive activity at Erta Ale (12 km NW) on 15 July was accompanied by an intrusion of magma along a dike that propagated SE towards Hayli Gubbi. Sentinel satellite imagery on 16 July showed a line of fissure vents that produced lava flows outside the S caldera of Erta Ale (6 km S of the northern pit craters). Another group of four fissure vents opened further along the rift to the SE, with the most distant only 2 km from the Hayli Gubbi crater. No lava lakes were seen in the pit craters after 18 July, but satellite data indicated uplift in the region during 21 July-3 August, and an anomalous white cloud within Hayli Gubbi’s crater was observed on 25 July. Satellite data showed that the white plume covered the crater floor in most of the images (several per month) at least through 18 November.

Geological Summary. Hayli Gubbi is the southernmost volcano of the Erta Ale Range. Recent tectonism has created a NW-SE graben across the summit, with a 380-m-diameter scoria cone at the summit and a 260-m-diameter crater displaying fumarolic activity. A sequence of fissure vents and lava fields extends 6 km NW to the southern caldera of Erta Ale. Additional dark flows that originated from the summit area cover the W and NE flanks, and SE before turning E at the base on the shield. More fissure vents extend ~3.5 km SSE within the graben to another small shield. From there, the line of vents continues, along with a lava field that spreads across the Afrera Plain, to a distance of 25 km from the summit crater. Barberi and Varet (1970) reported that those basaltic flow fronts covered sediments in the plain which Roubet et al. (1969) described as lacustrine limestones and diatomites deposited around 8,200 years BP above hyaloclastite formations. This places the eruption of the SE-most flows sometime within the last 8,000 years, but no additional information about how recent they might be is known; in appearance they are similar to very recent flows from the Erta Ale shield. On 15 July 2025 a dike intrusion that originated at the Erta Ale N caldera pit craters produced active fissure vents and lava flows within and on the S flanks of the south caldera; another set of fissure vents were active 4 km SE from the caldera rim, within 2 km of the Hayli Gubbi crater. A large explosive eruption on 23 November 2025 excavated the previous summit cone and created a second large crater (~200 m in diameter) in the summit area, and a third smaller crater.

Sources: Toulouse Volcanic Ash Advisory Centre (VAAC), Copernicus, Associated Press, The UK Centre for Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET), Gulf News, Simon Carn, Afar Communication Bureau, The Week, Hindustan Times