This Week
in Fire

This week ends with three volcanoes demanding attention simultaneously. Kīlauea is in the middle of — or hours away from — Episode 50, with a notable behavioural change: the south vent initiated precursory spattering before the north vent for the first time in the eruption series. Piton de la Fournaise has now been showing simultaneous inflation on both shallow and deep sources for nine consecutive days without erupting — an extended pre-eruptive signal with no clear precedent in its 2026 cycle. And Iceland's IMO hazard assessment for the Svartsengi system expires on 30 June.

🇺🇸 Kīlauea Watch · Orange

Episode 50 was forecast as most likely for today, 26 June, within a window of 25–27 June — and as this report is published, precursory activity is well advanced. The most recent HVO notice available at time of writing, from 25 June at 8:33 AM HST, reports that both inflation and seismic forecast models place Episode 50 onset between 25 and 27 June with 26 June most likely. Summit tilt has recovered 14.9 microradians since Episode 49 ended on 14 June — the episode itself produced 15.5 microradians of deflationary tilt, so the summit is within 0.6 microradians of being fully recharged.

The most significant development in the inter-episode period has been a change in which vent is leading precursory activity. At 7:22 PM HST on 24 June, the south vent produced its first spatter burst ahead of the expected episode — a pattern HVO described explicitly as notable because precursory spatter bursts have always previously initiated from the north vent during this eruption series. Through the overnight hours of 24–25 June, tremor became cyclic — dropping and spiking every ten minutes — with each spike associated with flaming and occasional spatter from the south vent. Both vents are producing continuous strong glow. No overflow events — the more definitive precursory signal — had been reported as of the 25 June HVO update. Check HVO's observatory messages and webcam feeds for the current status of Episode 50.

🇷🇪 Piton de la Fournaise Vigilance · Inflating

Piton de la Fournaise has now been showing sustained dual-source inflation for at least nine consecutive days — from 15 June through 23 June confirmed from OVPF daily bulletins, the longest sustained pre-eruptive GNSS signal of the entire 2026 eruptive cycle. Every OVPF bulletin during this period has reported both summit GNSS stations (shallow source pressurisation) and far-field GNSS stations (deep source pressurisation) recording inflation simultaneously. Elevated CO₂ flux at both the PCRN (Plaine des Cafres, west flank) and GITN (volcano lodge) stations has persisted throughout. This combination — both sources simultaneously charged, elevated ground CO₂ — is the most complete pre-eruptive suite of signals Piton has shown since before the February 2026 eruption began.

What is unusual is the duration. In previous 2026 eruption precursors, the dual-source signal developed and an eruption followed within days. Here it has persisted for over a week without eruption onset. OVPF will be examining whether this reflects a deeper or more diffuse recharge process, or whether the eruption is simply taking longer to nucleate. The alert level remains at Vigilance. OVPF are monitoring 24 hours a day. A fifth eruption of 2026 at Piton has been building for some time.

🇮🇸 Iceland — Svartsengi VALS 2 · Orange

The IMO has not published a new update since the 9 June briefing that reported 27.5 million m³ of magma beneath Svartsengi. The current hazard assessment, which identifies magmatic dike propagation toward the Sundhnúkur crater row as the most likely scenario for any future eruption, expires on 30 June 2026 — four days from now. The IMO typically publishes a new assessment before the previous one expires, which means a new document covering July is due imminently. Given the record magma accumulation and the fact that the current pause of 330+ days is the longest in the Sundhnúkur series, the updated assessment will be closely watched by the volcanology community. Seismicity along the Sundhnúkur crater row and near Grindavík remains low, and ground uplift continues at approximately 2 cm per month.

🇵🇭 Mayon Alert 3 · 170+ days

Mayon's eruption has now passed 170 consecutive days. The most recent PHIVOLCS bulletin available, from 22 June, confirms the eruption is continuing with lava effusion, Strombolian activity, rockfalls, PDCs, and gas-and-ash plumes. The seismic network recorded 8 volcanic earthquakes including 5 volcanic tremors lasting 11–36 minutes, 271 rockfall events, and 1 pyroclastic density current signal. Lava flow lengths remain unchanged at 3.8 km (Basud), 3.2 km (Bonga), and 1.8 km (Mi-isi). Alert Level 3 and the 6 km Permanent Danger Zone are in force. There is no indication of any imminent change in eruptive behaviour or alert level.