This Week
in Fire

This week's strongest change came from Kīlauea, where the expected Episode 55 fountaining did not simply arrive on schedule. Instead, a cluster of new vents opened on the floor of Halemaʻumaʻu. By 17 September the new vents had stagnated and no active lava flows remained. Etna again cycled through RED and ORANGE aviation codes, Sakurajima generated a burst of ash advisories, and IMO published a fresh assessment confirming continued uplift beneath Svartsengi.

🇺🇸 Kīlauea WATCH · ORANGE

Kīlauea remains at WATCH / ORANGE. HVO reported new vents opening at the summit eruption site beginning on the night of 14 September. By the evening of 16 September, vent 6 had opened on the floor of Halemaʻumaʻu just north of vent 5.

HVO's 17 September daily update says the new vents stagnated during the previous night and there was no active lava on the ground. The north, south and west vents continued to glow. Minor summit deflation had begun around 5 p.m. HST on 16 September, while deformation and seismicity remained confined to the summit region.

HVO's 15 September status report said the summit region was pressurised above the level required to begin a fountaining episode and that further changes in eruption style or location were possible. The current summit eruption has produced 54 lava-fountaining episodes since it began in December 2024.

🇮🇹 Etna ORANGE · Weak Ash

Etna again moved through rapid aviation-colour changes this week. INGV issued RED VONAs on 14 and 16 September. The latest VONA, issued at 05:16 UTC on 18 September, lowered the aviation colour code from RED to ORANGE.

INGV says explosive activity is decreasing, although weak ash emission is still ongoing. No ash cloud is being produced and volcanic ash is confined to the summit area. Satellite monitoring updated today describes summit thermal activity over the past week as moderate.

🇯🇵 Sakurajima Renewed Ash Activity

Sakurajima became noticeably busier in official aviation reporting this week. Tokyo VAAC issued a concentrated sequence of advisories from 13–16 September, including numerous advisories on 15 September. The latest listed Sakurajima advisory was issued at 19:31 UTC on 16 September.

This is a clear increase in ash-reporting activity compared with the quieter late-August spell. No plume height or eruption magnitude is added here unless supported by the current official material used for this roundup.

🇮🇸 Reykjanes — Svartsengi Uplift Continues

IMO published a fresh Reykjanes assessment on 15 September. There is no eruption underway. Slow uplift continues at Svartsengi, seismic activity remains low and the hazard assessment is unchanged.

Deformation measurements show the land has risen by approximately 5 cm over the past three months. IMO says the uplift indicates continuing pressure build-up several kilometres below the surface. A slight recent increase in small earthquakes has been observed, including within the magma intrusion.

The most likely scenario remains a future magma intrusion from Svartsengi toward the Sundhnúkur crater row, potentially followed by an eruption. IMO says the timing cannot be predicted and short warning time should still be expected. The hazard assessment remains valid until 30 September. The 15 September update does not publish a new magma-volume estimate, so an older figure is not presented as current.

🇵🇭 Mayon Level 2 · Ash Events This Week

Mayon remains at Alert Level 2 — Decreased Unrest. PHIVOLCS recorded short ash-emission events on 15 and 16 September: one lasting one minute and another lasting 46 seconds.

Today's 18 September bulletin records 19 volcanic earthquakes, fair crater glow, a moderate plume reaching 700 m above the crater, and sulfur dioxide flux of 887 tonnes/day measured on 17 September. Ground deformation continues to show inflation of the edifice with short-term deflation on the northeastern sector.

Tokyo VAAC issued a fresh Mayon volcanic-ash advisory at 01:47 UTC today. The 6 km Permanent Danger Zone remains off-limits.

🇵🇭 Kanlaon Level 2 · Gas Output Elevated

Kanlaon remains at Alert Level 2 — Increased Unrest. PHIVOLCS' 18 September bulletin records 10 volcanic earthquakes and sulfur dioxide flux of 3,042 tonnes/day, measured on 17 September.

Voluminous emissions produced a plume reaching 700 m above the crater and drifting north. Ground deformation continues to show inflation of the edifice with short-term deflation. The 4 km Permanent Danger Zone remains off-limits.

🇺🇸 Alaska Great Sitkin + Shishaldin

AVO's 17 September update keeps Great Sitkin at WATCH / ORANGE. Slow lava eruption continues within the summit crater, accompanied by weak seismicity. Minor earthquakes were detected and clear satellite views showed slightly elevated surface temperatures.

Shishaldin remains ADVISORY / YELLOW. AVO reports continuing low-level seismic unrest, with minor seismic and infrasound activity and steam emissions visible from the summit crater.

🇵🇭 Taal & Bulusan Level 1 Unrest

Taal remains at Alert Level 1. Today's bulletin records four volcanic earthquakes, sulfur dioxide flux of 183 tonnes/day measured on 17 September, a moderate 700 m plume and short-term inflation of Taal Volcano Island.

Bulusan also remains at Alert Level 1. PHIVOLCS recorded five volcanic earthquakes, sulfur dioxide flux of 12 tonnes/day, a moderate 50 m plume and short-term inflation of the edifice.

🌍 Also on the Global Board

USGS currently lists Ahyi Seamount at ADVISORY / YELLOW; its 18 September weekly update reports no plumes in satellite imagery and no significant geophysical signals. Persistent eruptors elsewhere continue to generate routine observatory and aviation products, but they are not presented here as new escalations unless the responsible agency reports a material change.