This Week
in Fire

This week produced two very different headline events. Kīlauea's episodic summit eruption returned with Episode 54 on 25 August, while Ambae in Vanuatu generated an exceptionally high ash plume during an escalation later the same day. Etna moved the other way: after weeks of changing effusive and explosive activity, INGV issued an end-of-phenomenon notice on 26 August and returned the VONA colour code to GREEN. Puracé, Kanlaon and Villarrica also produced verified activity worth watching.

🇺🇸 Kīlauea Episode 54 Complete

Episode 54 of the ongoing Halemaʻumaʻu summit eruption began at approximately 10:30 a.m. HST on 25 August and ended at 7:33 p.m. HST, after nine hours of continuous lava fountaining from the north vent.

HVO measured maximum fountain heights of about 500 ft (150 m). The south vent and the newer west vent did not fountain during this episode. The eruptive plume reached approximately 17,000 ft (5,200 m) above sea level. Most tephra remained within the closed area of Hawaiʻi Volcanoes National Park, although HVO received one report of trace Pele's hair in the Kaʻū district.

HVO estimates that about 5.2 million yd³ (4.0 million m³) of lava erupted, covering around 30% of the Halemaʻumaʻu crater floor. The Uēkahuna tiltmeter recorded roughly 12.7 microradians of deflation during the episode.

As of HVO's 27 August update, Kīlauea is not erupting and remains at ADVISORY / YELLOW. Reinflation initially resumed after Episode 54, but then stopped and was replaced by variable deflation. HVO says another lava-fountaining episode remains likely in the coming weeks if normal tilt patterns return, but more data are needed before a forecast window can be modelled.

🇻🇺 Ambae 54,000 ft Ash Plume

Ambae produced the week's most significant ash-column event. VMGD reported continued eruptive activity during 21–26 August, with gas, steam and ash emissions visible through much of the period and seismicity indicating a high level of activity.

The eruption escalated at 20:40 local time on 25 August. Wellington VAAC satellite analysis placed the ash plume at approximately 16.5 km (54,000 ft) above sea level by 21:24. The plume then declined to around 15.2 km and 12.8 km before lower ash emissions continued during 26 August.

VMGD kept Ambae at Alert Level 3. The public was advised to remain outside Danger Zone B, defined as a 3 km radius around the active vents in Lake Voui, and to avoid drainages during heavy rain.

🇮🇹 Etna Phenomenon Ended · VONA Green

After dominating recent roundups, Etna's August sequence ended this week. INGV-OE issued Update No. 30 on 26 August at 11:21 UTC, stating that the previously reported phenomena had ended.

Earlier that morning, at 06:44 UTC, INGV issued a VONA returning Etna to GREEN. The notice states that the volcano had reverted to its pre-eruption state and reported no ash cloud. It was marked as the final aviation notice for the event sequence.

This is a substantial change from the repeated ORANGE and RED aviation notices seen earlier in August: by 26 August the official aviation status had returned to the lowest colour code.

🇨🇴 Puracé Orange Alert

Colombia's Servicio Geológico Colombiano reported intensifying eruptive activity at Puracé during 18–26 August. Seismicity was dominated by signals linked to fluid movement beneath the volcano, while sulfur dioxide flux remained above baseline and slow deformation continued within the Puracé–Piocollo–Curiquinga area.

Several ash emissions were recorded, with plumes reaching as high as 2.6 km above the summit. Ashfall was reported in multiple communities downwind during the week. The Alert Level remained ORANGE.

🇵🇭 Kanlaon Prolonged Ash Emissions

Kanlaon continued eruptive activity through 19–26 August. PHIVOLCS recorded 0–8 volcanic earthquakes per day, including three tremor periods during 24–25 August that lasted from 21 minutes to as long as five hours and 42 minutes.

Ash emissions occurred repeatedly. Five ash-emission episodes were recorded on 22 August, with some lasting for hours, followed by further episodes on 23 and 24 August. Plumes were generally low, reaching up to around 200 m above the crater rim. Sulfur dioxide emissions ranged from 1,244 to 2,092 tonnes per day.

Kanlaon remained at Alert Level 2, with the 4 km Permanent Danger Zone still in force.

🇨🇱 Villarrica Minor Explosive Activity

SERNAGEOMIN reported several episodes of minor explosive activity at Villarrica beginning on 21 August. A plume rose roughly 40 m above the crater rim during the first reported event, with incandescence from the lava lake visible overnight during 21–22 August.

Another small ash plume on 22 August rose approximately 60 m above the crater rim and drifted northeast. Despite the activity, the official volcanic alert level remained GREEN.

🇮🇸 Iceland Svartsengi Watch Continues

There was no new major Reykjanes escalation in the official English-language IMO material reviewed for this roundup. The latest Svartsengi assessment continues to describe slow but steady uplift and magma accumulation, with modelled accumulation at approximately 29.1 million m³ since the July 2025 eruption. IMO continues to describe a new dyke intrusion, potentially followed by an eruption, as the most likely eventual scenario.

At Múlakvísl, IMO reported on 21 August that the small glacial outburst flood that began on 18 August appeared to be subsiding; both conductivity and discharge had decreased and no gas pollution was being detected at that time.

🌍 Also on the Global Board

The Smithsonian/USGS Weekly Volcanic Activity Report for 20–26 August listed 26 volcanoes meeting its reporting criteria. Besides the volcanoes expanded above, the report included new activity at Karangetang, Klyuchevskoy, Krakatau and Nevados de Chillán, together with continuing eruptive activity at Aira, Dukono, Fuego, Great Sitkin, Ibu, Lewotobi, Lewotolok, Popocatépetl, Rincón de la Vieja, Sabancaya, Santa María, Semeru, Sheveluch, Stromboli, Telica and others. The weekly report is a curated activity summary, not a complete list of every active volcano worldwide.