This Week
in Fire

Kīlauea returned to vigorous precursory overflow activity this week, but HVO still describes the activity as part of the summit eruption rather than a new numbered fountaining episode. Sakurajima was markedly active, Etna returned to RED aviation code on 24 September, and several other volcanoes produced genuinely new eruptive developments during the week.

🇺🇸 Kīlauea WATCH · ORANGE

Precursory overflows from Kīlauea's north vent resumed on the night of 22 September. HVO's latest daily update, issued on 24 September, reports strong glow from the north-south-west vent complex and intermittent spatter from the north and south vents.

There are currently no signs of activity at the newer vents 1–6. The summit inflated slightly during the previous 24 hours and continuous tremor remained the dominant summit seismic signal. HVO reported no anomalous activity outside the summit and no significant activity along the East or Southwest Rift Zones.

The alert level remains WATCH and the aviation colour code ORANGE. HVO continues to call the renewed flows precursory overflows; a new numbered lava-fountaining episode had not been declared in the latest daily update.

🇯🇵 Sakurajima Ash Activity Intensifies

Sakurajima has become substantially busier in Tokyo VAAC reporting during the latter part of September. The official Tokyo VAAC list shows advisories resuming on 20 September and continuing repeatedly through 21, 22, 23 and 24 September.

The activity continued into this morning. As of the Tokyo VAAC list update at 06:06 UTC on 25 September, the latest Sakurajima advisory was VAA 2026/247, issued at 06:01 UTC. Four further Sakurajima advisories had already been issued since 23:30 UTC on 24 September, at 01:16, 01:53, 05:12 and 06:01 UTC on 25 September.

This represents a clear increase in aviation ash reporting compared with the quieter early-September period. The previously quoted weekly event count has been removed; this section is based directly on the current JMA/Tokyo VAAC advisory record.

🇮🇹 Etna Aviation RED

Etna returned to RED aviation colour code this week. INGV's latest published VONA was issued at 05:19 UTC on 24 September and states that ash emission is ongoing.

The preceding weekly picture included gas emissions, periodic minor ash emissions from Northeast Crater and Bocca Nuova, and Strombolian activity at Bocca Nuova. INGV's satellite page, updated today, describes thermal activity over the past week as moderate, with the latest measured thermal anomaly on 24 September at a low level.

🇻🇺 Ambrym New Eruptive Activity

Vanuatu's VMGD reported that a new eruption at Ambrym likely began on 19 September. Satellite data detected an intense thermal anomaly and high sulfur dioxide emissions, while ground observers reported dark grey ash-and-gas plumes from Marum Crater and rumbling.

Minor ashfall was reported downwind. On 20 September ash-and-gas plumes remained visible and satellite observations detected lava effusion within the crater. The alert level remained 2, with established permanent danger zones around Benbow and Marum craters.

🇷🇺 Chikurachki Explosive Eruption

KVERT reported that an explosive eruption likely began on 20 September. Ash initially rose to around 3 km above sea level and drifted 140 km northeast and east. Tokyo VAAC subsequently reported ash reaching approximately 2.7–4.6 km above sea level during 20–21 September.

KVERT raised the aviation colour code to ORANGE on 21 September as intermittent explosions continued.

🇨🇱 Nevados de Chillán Renewed Eruptive Activity

SERNAGEOMIN reported a dense ash plume at Nevados de Chillán at around 14:10 on 18 September, rising 380 m above the summit and drifting south-southeast. By 22 September seismicity indicated eruptive activity, although weather prevented direct views of the summit.

A long-period earthquake associated with fluid movement was recorded on 23 September. The alert level remains Yellow, and Chilean authorities continue to warn that eruptive effects may occur within 1 km of the active crater.

🇵🇭 Mayon Level 2 · Ongoing Unrest

Mayon remains at Alert Level 2 — Decreased Unrest. Today's PHIVOLCS bulletin records 18 volcanic earthquakes and one rockfall signal. Sulfur dioxide flux measured on 24 September was 763 tonnes per day.

A moderate plume reached 750 m above the crater and drifted west-southwest and southwest. Ground deformation continues to show inflation of the edifice with short-term deflation on the northeastern sector. Earlier in the week PHIVOLCS reported several short ash emissions and minor Strombolian activity.

🇵🇭 Kanlaon Level 2 · 1.3 km Plume

Kanlaon remains at Alert Level 2 — Increased Unrest. PHIVOLCS' 25 September bulletin records nine volcanic earthquakes and sulfur dioxide flux of 1,157 tonnes per day measured on 24 September.

Voluminous emissions produced a plume reaching 1,300 m above the crater, drifting southwest and southeast. The edifice remains inflated with short-term deflation. During the week, PHIVOLCS also recorded an ash emission on 19 September that lasted just over two hours.

🇺🇸 Alaska Great Sitkin + Shishaldin

AVO's 24 September update keeps Great Sitkin at WATCH / ORANGE, with slow lava eruption continuing inside the summit crater. Wind and cloud obscured useful seismic, satellite and webcam observations during the previous day.

Shishaldin remains ADVISORY / YELLOW with low-level unrest continuing.

🇵🇭 Taal & Bulusan Level 1 Unrest

Taal remains at Alert Level 1. PHIVOLCS' 25 September bulletin reports a continuous volcanic tremor that began at 15:41 PST on 21 September, sulfur dioxide flux of 160 tonnes/day measured on 24 September, a moderate 1,200 m plume and short-term inflation of Taal Volcano Island.

Bulusan also remains at Alert Level 1. Today's bulletin records four volcanic earthquakes, a moderate 150 m plume and short-term inflation of the edifice.

🌍 Also on the Global Board

This week's official reporting also documented continued eruptive activity at Ibu, Karangetang, Lewotolok, Merapi, Popocatépetl, Puracé, Sabancaya, Sangay and Semeru. Of particular note, Sangay activity increased during 19–21 September, while Puracé continued to produce ash emissions under an Orange alert. These are retained as watch-list items rather than expanded into full sections unless there is a clearer material change for Volcoholics coverage.